Tag Archives: RV Batteries

Getting The Correct Charging Profile For Your Battery Type

10 Wednesday Jul 2024

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For years, Flooded Lead Acid (FLA) batteries were the standard for deep-cycle RV batteries. The only decisions that needed to be made were 12-volt or 6-volt and how many Amp Hours (Ah) were needed. FLA batteries have lead plates suspended in electrolytes in individual cells and are the cheapest, but require more maintenance. They gas when recharging and require more distilled water to be added frequently.  6-volt batteries have three cells that produce 2.1-volts and require two batteries connected positive to negative, in series to create a 12-volt bank. This however does not double Amp Hours.

12-volt batteries have six cells, each producing 2.1-volts and can run a smaller rig with just one battery.

In the mid-80s Absorbed Glass Mat (AGM) batteries were being developed for the military as they were less prone to sulfation, required no maintenance especially distilled water being added, and lasted longer. They also have positive and negative plates and electrolytes however fiberglass mats are placed between the plates and absorb the liquid. AGM batteries started showing up in the RV world sometime in the late 1980s as the demand for 12-volt power grew. There were also challenges with placement and since the AGM battery is completely sealed there was no maintenance and no leakage. Plus the gases that are produced are kept internally rather than vented so they can be placed almost anywhere.

Lithium Iron Phosphate (LiFeP04) batteries have individual cells with no gassing and can be drained 100% of available amp hours. They do require a higher charging voltage and are much more expensive.

FLA and AGM batteries should only be drained to 50% Ah and discharging them lower than that will reduce the life expectancy. A fully charged FLA and AGM battery should read 12.6-volts and the misconception is a 50% drained battery is not 6.3-volts. Here is the discharge chart.

Voltage – FLA                                    State Of Charge                                Voltage – AGM

12.6-Volts                                         100%                                                  13.0-Volts

12.5-Volts                                         90%                                                    12.75-Volts

12.42-Volts                                       80%                                                    12.5-Volts

12.32-Volts                                       70%                                                    12.3-Volts

12.2-Volts                                         60%                                                    12.15-Volts

12.06-Volts                                       50%                                                    12.05-Volts

11.9-Volts                                         40%                                                    11.95-Volts

11.75-Volts                                       30%                                                    11.81-Volts

11.58-Volts                                       20%                                                    11.66-Volts

11.31-Volts                                       10%                                                    11.51-Volts

10.5-Volts                                         0%                                                      10.5-Volts

A FLA battery that is discharged to only 50% should last 300-500 cycles while an AGM battery can last 600-1000 cycles. Lithium Batteries can cycle anywhere from 2,000-10,000 and several of the high-line brands are guaranteed for 10 years and some even for a lifetime! If they are maintained and charged properly!

Proper Charging Profile

As an FLA battery is drained, sulfur coats the plates and needs to be conditioned or desulfated. A typical RV converter charges the battery at 13.6 volts until it reaches 12.6 volts and then drops to a maintenance charge of 13.2 volts. This does not break up the sulfation and the sulfation will thicken on the plates and the battery will not hold a charge or last as long as it is designed. FLA batteries require an initial bulk charge of 14 volts or higher and then an equalizing and float charge. Only a multi-stage charger will condition FLA batteries properly. This can be done with an inverter/charger or even a solar panel with a charge controller.

Winnebago Industries has worked with Progressive Dynamics to engineer their charger to put out 13.8 volts for 8 hours to condition FLA batteries. Other converters like the PD 9300 have programable charge profiles to customize the voltage for specific battery types.

The challenge with AGM batteries is every manufacturer seems to have a different charge profile and they can not agree on what is best. Recently I contacted my “Go To” guy at Progressive Dynamics and he stated that they have been working with battery companies and RV manufacturers for over 20 years trying to standardize charge profiles to best maintain batteries.

For example, the Go Power “Solar” AGM battery wants 14.4 V – 15.0 V for the initial charge then a float or maintenance charge of 13.5 V – 13.8 V. You can find the charge profile in the specification sheets.

Trojan Batteries require 14.4 V and a float of 13.5 V, and most don’t even give the parameters such as Interstate which is a popular replacement for RV owners.

What this means is that your typical deck-mounted converter/charger like this WFCO will not fully charge an AGM battery and could cause sulfation even though many brands advertise that AGM is not prone to sulfation!

Progressive Dynamics has introduced their 9300 Series which can be programmed for the different charge profiles.

Flooded Lead Acid (FLA) Mode

The patented Charge Wizard 4-stage system uses microprocessor technology to add intelligent charging capability. It constantly monitors the RV battery and automatically adjusts the converter output voltage based on the battery’s charge status – designed to eliminate battery over & under-charging problems associated with most other battery chargers and provide rapid yet safe battery recharging after dry camping. The Charge Wizard constantly monitors battery voltage and battery usage and then selects one of the following four operating modes to properly charge and maintain the battery. BOOST Mode 14.4 Volts – Rapidly brings the RV battery up to 90% of full charge. This mode is maintained for 4 hours. NORMAL Mode 13.6 Volts – Safely completes the charge. If light activity is detected after 33 hours in this mode, the Wizard switches to the storage mode. STORAGE Mode 13.2 Volts – Maintains charge with minimal gassing or water loss. EQUALIZATION Mode 14.4 Volts – Every 21 hours for a period of 15 minutes prevents battery stratification & sulfation – the leading cause of battery failure. This functions as part of the Storage mode

Absorbed Glass Mat (AGM) Profile

BULK Mode 14.0 Volts – Initial charge to 70% State of Charge. Occurring at startup, this procedure will last for 2 hours.

ABSORPTION Mode 14.7 Volts – Finish charge to 100% State of Charge. Running for a minimum of 1 hour, after which the converter switches to “FLOAT” mode when either the current drops below a preset limit or times out at 4 hours.

FLOAT Mode 13.6 Volts – Maintains charge. The converter will stay in this mode indefinitely as long as the converter has AC power. Once a week “DESULFATION” mode will activate for 1 hour then revert back to “FLOAT” mode.

DESULFATION Mode 14.7 Volts – Once a week for 1 hour to prevent sulfation and refresh the battery charge. This occurs as part of the “FLOAT” mode operation.

Lithium Iron Phosphate (LiFeP04)

Although the optimum charging voltage for the LFP battery is 14.6 VDC, many manufacturers are specifying a charge voltage of less than 14.6 volts and setting the high voltage cutoff at 14.6 volts through the Battery Management System (BMS). In general, this is not a user-adjustable function. Progressive Dynamics has run numerous tests at 14.4 volts showing that the battery can receive a full charge at the converter rating. Progressive Dynamics has developed a Lithium multi-stage charging profile with the ability to monitor the voltage and current. This allows the Charge Wizard to select the correct charging voltage as needed while providing DC power to the RV. These are automatic functions. The Charge Wizard will properly charge and maintain the battery while providing safe operating voltages within the RV.

CHARGE Mode 14.4 VDC – Initial charge to full. Automatically selected at start-up. After 1 hour and the current drops off, or 8 hours of charging has elapsed, the charger switches to

 IDLE MODE. IDLE Mode 13.6v VDC – This is a nominal voltage for an RV connected to shore power. This mode is continuous but will revert to CHARGE if the power demand is high or AC power is reapplied.

REFRESH Mode 14.4 VDC – Occurring during IDLE mode. Once every three weeks, a charge voltage is applied for 1 hour to refresh the battery.

So to get the ultimate life out of whatever type of deep cycle battery you have or looking to replace your existing battery with, it is important to do a little research regarding what voltage is required for initial charging and the charge profile. Some of the “big box” store batteries don’t show a charge profile or any other information as they don’t want your batteries lasting 5-7 years, rather see you come back in 2-3 years and buy more batteries. You really do get what you pay for!

About the author: Dave Solberg: Managing Editor, RV Repair Club

For the last 25 years, Dave has conducted RV maintenance and safety seminars, developed dealer and owner training programs, written RV safety and handyman articles, authored an RV handbook reference guide and logged over 100,000 miles on the road in an RV.

RV Repair Club

RV Repair Club is your go-to online resource for enthusiasts who want quality RV maintenance, repair, and upgrade information – a community where passionate RVers can come together to gather knowledge and share their experiences.

Learn more about RV Repair Club.

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Considering Lithium RV Batteries? | Part 2

04 Wednesday May 2022

Posted by in Tech Tips

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In part one we discussed the difference between lead-acid, AGM, and Lithium batteries. Since then I have talked with our technical department and asked “how do you know if the lithium battery you are considering is good quality? They indicated that “lithium” is the new hot button in the RV industry and they are flying off the shelves. Many “opportunistic” companies are doing a “lick & stick” (his words exactly) by purchasing cheap overseas lithium and putting their sticker name on it. Many of these have prismatic and palmer cells that can not withstand the vibration and bouncing the typical RV encounters as well as temperature changes. This creates connectivity issues and produces thermal events.

Quality lithium batteries use cylindrical cells for the internal pack and protect them with molded ribs instead of foam filler. Also, the connection between these cells is best with mechanical connection rather than solder which is cheaper but is not as stable.

So how do you know? First, look for the UL listing and the file number. Then ask for an exploded view and description of the interior of the battery! If they can’t provide it, chances are the components are sub-par!

Then I asked; “What else should we look for in Lithium Batteries for an RV?” The answer was a good Battery Management System or BMS built into the battery. A BMS monitors the cells within the battery and keeps them from operating in an unsafe condition due to overcharging or undercharging. It can detect any shorts in the connections and balance the charge in each individual cell. If it does find an issue, it will shut the battery down before any damage can occur. This is especially important if your charger has a bulk charge stage or if you’re trying to get that last bit of sunlight in your solar panel charging system.

Temperature Is Important

The BMS will also monitor the temperature to make sure the battery either shuts down during extreme high and low temperatures or controls fans or heaters that could be part of the system. Extreme high temperatures can cause thermal runaway and charging a Lithium Battery at below-freezing temperatures will ruin the battery. The BMS will shut down the battery if it is not equipped with a cooling fan or heater. A quality Lithium Battery will either have an internal heater or heat pad/blanket that the BMS will activate when needed.

Now that we know what to look for in a quality Lithium Battery, there is more information you need to consider before jumping into the Lithium world! In Part 1 we talked about the WFCO converter that was used in the RV and how it only provided a 13.6-volt charge however you need to research what converter/charger or inverter/charger you have and how it operates. Most Lithium Batteries want 14.6-volts for charging and can be charged much faster than the typical lead-acid batteries. If your converter only provides 13.6-volts it will take longer to charge and will not charge 100% so you lose about 35% of what you paid for. Even worse, if you have a multi-stage charger it will start the bulk charge at 16-volts to break up sulfation in the lead-acid battery and then go to a float and equalizing charge. 16-volts will ruin a Lithium Battery unless it has a BMS in which case it will shut down and won’t charge!

One option is to install an upgrade to your converter such as the Progressive Dynamics 4655CSV model. This runs approximately $250 but is well worth it to get 100% out of your Lithium Battery.

If your converter, inverter, or solar charger is not putting out 14.6-volts I would recommend you consider upgrading the charger, lead-acid, or AGM. I did speak to a representative at Magnatek which is owned by Parallel Power Supply and they are using a stand-alone converter that puts out 13.8-volts and recommending it for use with Lithium. If you have a larger diesel pusher model and/or a residential refrigerator chances are you have a larger inverter that is also a battery charger and need to verify what voltage it is providing. Most newer models have a setting for Lithium.

DC To DC Charger

If your rig has the capability to provide a charge from the engine battery whether it’s a tow vehicle pulling a trailer with the 7-pin connection or a motorhome through the Battery Isolation Management solenoid (BIM) your alternator could potentially provide over 225 amps such as the case with a Mercedes model. This would require a DC to DC Charger that will regulate the amps. Battery Born recommends the Victron and Mike Sokol of The No Shock Zone recommends the Redarc model.

The Advantage Of Lithium Batteries

The biggest advantage of Lithium Batteries in my opinion is they do not sulfate and do not require much maintenance. Yes, the cost can be 5 times as much, however, the average lead-acid battery lasts about 2-3 years unless it is maintained religiously then it could last up to 4-5 years. The average Lithium Battery will last 8-10 years, so if you plan to keep your rig for more than 5 years, it will most likely cost about the same, however, you get all the other advantages.

A Lithium Battery can be drawn down to almost 100% vs a lead-acid battery at only about 50% and it will charge up about 5 times as fast so you get longer battery usage when dry camping and faster recharging so you don’t have to run the generator all day or worry about only getting a few hours of sun with a solar charging system.

Lithium Batteries are about ½ the weight of lead-acid batteries and you get the same amp hours out of one 100-amp hour Lithium vs two lead-acid batteries. So the Lithium Battery is lighter and takes up ½ the room in a compartment or on the tongue of your trailer.

Once you review all the information and what type of charging system you have, you can now decide if Lithium is the right choice for you and worth the money.

About the author: Dave Solberg: Managing Editor, RV Repair Club

For the last 25 years, Dave has conducted RV maintenance and safety seminars, developed dealer and owner training programs, written RV safety and handyman articles authored an RV handbook reference guide, and logged over 100,000 miles on the road in an RV.

RV Repair Club

RV Repair Club is your go-to online resource for enthusiasts who want quality RV maintenance, repair, and upgrade information – a community where passionate RVers can come together to gather knowledge and share their experiences.

Learn more about RV Repair Club.

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Considering Lithium RV Batteries?

06 Wednesday Apr 2022

Posted by in RV Safety, Tech Tips, Tips & Tricks

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Over the past few years, I’ve written several articles about deep cycle batteries such as “RV Battery Types and The Power They Provide” in May of 2018, “Choosing The Right Battery For Your RV” in October 2020, and others along the way.

For the past 6 months, RV shows have started back up and I have been conducting seminars again and it seems that Lithium batteries are the rage! I would guess mostly due to the fact that the lead-acid batteries used in most of the new rigs for the past 20 years have been failing miserably in just a couple years. I ask attendees at the seminars about who has changed batteries every 3 years and once in a great while I’ll find an owner that has had the same batteries for over 3 years! Mostly because he has a multi-stage charger in his rig and they have not sulfated.

Is Lithium Worth The Money?

This is the most important question to ask yourself when it comes to upgrading to Lithium batteries and it really depends on how much dry camping you are planning to do and how long. A good friend of mine just bought a motorhome that has two Interstate batteries that will not hold a charge and had not been maintained very well if at all.

As you can see, the batteries are bloated, there is corrosion at the terminals, and a rat’s nest of wiring. These batteries are also 6-volt batteries as they only have 3 cells and so they are connected in series which means the positive cable of one battery is connected to the negative battery of the second battery which gives a 12-volt “bank”. This is not original equipment, rather someone that obviously did not maintain his batteries very well and when the original set went bad, they ran to an interstate distributor who set them up with these. I did a little research and this rig has a WFCO converter which is the charger and it provides a 13.6-volt charge when the battery is drained to 50% capacity and drops to a 13.2-volt maintenance charge when the batteries get to 12.6-volts. This will do nothing to break up the sulfur that will coat the plates during normal operation so it will get thicker and thicker with every cycle and eventually look like this. I also find it ironic that the fill caps have the quick-flick bar as I call it so you can just pinch the two bars together and take all three caps off at once. The problem is…the batteries have little or no water/acid so it was a waste of product!

The first question I asked was; “How often do you plan to boondock or dry camp?” Then I had to explain what that meant as he is really new! “How often are you going to camp where you will not have shoreline power to plug into so you can recharge your batteries?” “Never” was his answer, so buying a $1000 Lithium battery would be a waste of money! In his situation, a good set of Absorbed Glass Mat (AGM) batteries would be the best as they require little maintenance and are not as affected by sulfation. He could get by with just one 12-volt deep cycle that would give him 100 amp hours but then since the Flooded Lead Acid batteries can only be drawn down about 50% he might want to go with two 12-volt FLA batteries just in case he wants to tailgate at a football game. The two 6-volt batteries that are currently in there only increase the voltage when connected in series, not the amp hours so he would need to go with four 6-volts instead. There are several advantages of 6-volt batteries that were covered in the previous articles, mostly longevity in cycles and years of use.

The History Of Lithium Batteries

Lithium batteries have been available for over 40 years and there is still some concern from owners about their safety. You hear stories about them catching on fire and even have to take them out of suitcases in checked luggage when flying. The Lithium batteries that are available for the RV market are not the same type, rather Lithium Iron Phosphate or LiFEPO4, and are very safe. Initially, these batteries were too expensive for the RV market but new technology and completion have brought the price down to a more manageable level if you consider $1000 manageable? However, the value of this type of battery price compared to FLA or AGM is a Lithium battery can last 3-5,000 cycles at which time it has a 75% capacity and can outperform the others for 10 or more years.

You Get What You Pay For!

This is so true in so many products and especially Lithium Batteries. I talked with several different manufacturers such as Go Power, Renogy, and a new one called Expion 360. For the past 7-8 years I have been working with Zamp Solar out of Bend OR with my seminars at shows and videos on RV Repair Club. I believe they make some of the best quality solar panels on the market and are rugged enough to withstand the brutal wear and tear of RV use. John Yozamp is the original founder of Zamp Solar and was an avid camper frustrated with poor-quality solar panels. I won’t bore you with all the quality details, however, he sold Zamp and has started another company to supply a superior Lithium battery to the market…Expion 360. I talked with John and their technical department and there are so many cut-rate batteries flooding the market that will not stand up to RV use. Many are made for the solar explosion in the residential and industrial market and the batteries are housed in a climate-controlled room and never move. These are made of thinner plastic, cells are divided by paper board or foam, and connections are soldered, all of which will not last in an RV.

And there is so much more. In part 2 we will discuss the importance of a smart Battery Management System incorporated into the actual battery, cold weather charging issues, and if your converter will properly charge a Lithium battery or ruin it!

About the author: Dave Solberg: Managing Editor, RV Repair Club

For the last 25 years, Dave has conducted RV maintenance and safety seminars, developed dealer and owner training programs, written RV safety and handyman articles authored an RV handbook reference guide, and logged over 100,000 miles on the road in an RV.

RV Repair Club

RV Repair Club is your go-to online resource for enthusiasts who want quality RV maintenance, repair, and upgrade information – a community where passionate RVers can come together to gather knowledge and share their experiences.

Learn more about RV Repair Club.

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The “Gremlin” In Your House Battery System

02 Wednesday Feb 2022

Posted by in RV Information, Tech Tips, Tips & Tricks

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Remember the 1984 original release of the movie “Gremlins”? If not, according to Wikipedia:

“The term “gremlin”, denoting a mischievous creature that sabotages aircraft, originates in Royal Air Force (RAF) slang among the British pilots stationed in Malta, the Middle East, and India in the 1920s.”

I like to use the term “gremlin” to describe an intermittent incident, failure, or event that is difficult to explain.

There are several areas gremlins hide in an RV, the 12-volt electrical system, appliances, 120-volt electrical system, and even in roofs. And how about those annoying refrigerators that won’t cool efficiently only to hit 34 degrees sitting in the service bay! We’ve all experienced some type of gremlin in our RVs and it can be not only frustrating, but expensive. For this blog, we are going to focus on the gremlins that can plague our 12-volt electrical systems.

12-volt DC Deep Cycle Lead Acid Batteries

Lead acid batteries have been a frustration for years for RV owners and typically last about 2 years, however they should last 5-6 years. The deep cycle batteries in your house system are designed to be drained down to approximately 50% of their amp hour or power storage capacity and recharged either by a converter, inverter, or solar panels many times, or “cycles”. They are measured in amp hours which means the approximate amount of time they can provide power to 12-volt systems such as the lights, roof vents, water pump, and any appliance running on LP. Lead acid batteries can only be drawn down about 50% of their capacity so a Group 27 battery with 100 amp hours can only provide about 50 amp hours.

Lead acid batteries are simply storage devices for power and as that power is drawn out of the battery, sulfur attacks the lead plates and coats them. If this coating is not removed during the recharging process, it gets thicker and eventually limits the storage capacity.

Traditional converters that are part of the distribution center simply start the charging state at 13.6 volts and then reduce to 13.2 volts when the battery reaches 12.6 volts. This is the voltage that the battery will no longer accept a charge so it is a maintain state. 

This is a typical distribution center with the circuit breakers for 120-volt applications and the converter behind the grill at the right. This type of charge will not break up the sulfation and will limit the batteries chemical to electrical conversion. Sulfation can also occur when a battery is stored without a full charge during the winter as all batteries will experience a slight drain if not connected to a charging or maintenance system.

To properly charge a lead acid battery, your system needs a multistage charger that starts with a bulk or de-sulfation stage which is a high voltage charge that literally boils the acid and breaks up the sulfur. This also causes excess gassing and acid depletion. This means more maintenance is required on each cell. Chargers like the Progressive Dynamics models with Charge Wizard, inverters with chargers, and solar panels with charge controllers all have the multi-stage chargers that will properly charge and maintain a lead acid battery.

You can get more information on the Progressive Dynamics products here: www.progressivedyn.com/rv/charge-wizard

The gremlin in this case is in the actual condition of the lead acid battery. If the battery is sulfated, it can be charged to 12.6 volts which is a fully charged lead acid battery, however it will drop fast and not provide the amp hours it was originally designed for. And it can not be accurately tested by local auto shop and service center equipment. According to my sources at Lifeline Battery, Trojan, and US Battery, the only way to truly test a batteries condition is to properly charge the battery and place it on a 25 amp load machine and verify how many hours it provides power which almost never happens! And I get this all the time, “I had the batteries checked by a technician and they are fine”, “The batteries are 12.6 volts so I know it’s not the battery”, “The batteries are only 6 months old and register 12.6 Volts so I know they are good”.

If an appliance such as the refrigerator or air conditioner has intermittent performance, the first gremlin I look for is 12-volt power. Yes, even though both of these run on 120-volt AC power, they require 12-volt DC power to run the control module, thermostat, and other components. If your batteries are sulfated, they can draw down fast and limit the DC supply to those components before the converter kicks in and starts to charge. The first thing I recommend when there is intermittent functions is to connect a portable charger to the house batteries to see if that eliminates the situation. Then you know it’s not the batteries and can dig deeper into the system.

I get many questions from readers that the system did not work while out camping only to bring it to a dealership and it works fine! What typically happens in this situation is while you are camping, there are several variables that affect the operation such as higher ambient temperatures that would make the roof air conditioner and refrigerator run more often drawing more power and sometimes at the same time. Other components will be used such as the interior lights, water pump, water heater, all of which come on at times you are not aware of and draw power. Then you take it to the dealer and they plug it into a good 30 amp service with nothing else on and the appliance works great. Next time you take it out, it doesn’t work again! One reader indicated they had an issue with a furnace and the service center actually pulled the unit out and bench tested it three times and it worked every time! This tells me that the unit is working fine and there is an issue with air flow restriction, temperature, or the house battery since the furnace was isolated on the bench?

That is why it is important to test in real world situations and always document everything being used.

About the author: Dave Solberg: Managing Editor, RV Repair Club

For the last 25 years, Dave has conducted RV maintenance and safety seminars, developed dealer and owner training programs, written RV safety and handyman articles, authored an RV handbook reference guide and logged over 100,000 miles on the road in an RV.

RV Repair Club

RV Repair Club is your go-to online resource for enthusiasts who want quality RV maintenance, repair and upgrade information – a community where passionate RVers can come together to gather knowledge and share their experiences.

Learn more about RV Repair Club.

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House Batteries-Storage, Maintenance, and New Technology

06 Wednesday Oct 2021

Posted by in Tech Tips

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We have written several articles about deep cycle batteries commonly called house batteries and produced numerous videos over the years so you might be saying, “Ok, we get it already!” However, in the last couple of years, there have been several new battery companies that came into the market, new technology with not only the standard lead-acid and AGM but also Lithium-Ion models as well.

Buying a Good Battery

When I first started in the industry in 1983 at Winnebago we used Goodyear Die Hard batteries and the warranty was through Sears stores across the nation. Back then there were thousands of stores, today I think the last one finally closed somewhere in the Midwest. The battery was good, the issue was for a warranty on the battery you had to take it out of your rig and bring it into a store! A lot has changed since then and there have been dozens of battery manufacturers that have come and gone and the old saying; “You get what you pay for” is still true today.

Batteries simply store energy that is used by the RV and replaced by a refilling or charging system. An acid solution reacts with the lead plates They all have lead plates in cells with acid covering them. The difference comes in the materials used inside the cells. Materials such as thicker positive plates, superior paste, better and fewer welds, and superior plate holders. Less expensive batteries that are offered by discount stores just do not last.

Typically Marine batteries are a hybrid with thinner cells and if they are rated with Cold Cranking Amp (CCA) or Marine Cranking Amps (MCA) they are designed for starting and may not be a true deep cycle design.

Lead Acid Gets A Bad Wrap

Even the good lead acid batteries can go bad prematurely if they are not properly maintained. As the energy is drained and recharged, sulfur coats the plates and needs to be removed during the first stage of recharging. A typical RV converter simply comes on at 13.6 volts until the battery is charged to 12.6 volts and then stays at 13.2 volts at which rate a fully charged battery will not accept a charge. To break up sulphation in a lead-acid battery, the initial charge commonly referred to as “bulk” charge needs to be approximately 14.6 volts. This would require a multi-stage charger such as the Progressive Dynamics “Charge Wizard” technology, a solar panel system with a charge controller, or an aftermarket product such as Battery Minder. Improper charging causes the sulfur level to get thicker and reduces storage capacity. Batteries look like they are fully charged at 12.6 volts but deplete fast due to sulphation.

Another issue with lead-acid is gassing and liquid depletion. As the battery is being recharged it create gassing which is hydrogen and oxygen and the liquid depletes. Therefore it is important to inspect the fluid level periodically and add distilled or deionized water to cover the plates. Low fluid levels expose the plates and cause them to deteriorate prematurely.

Absorbed Glass Mat-AGM

At my seminars, I’ve talked with many RVers that got fed up with their lead-acid batteries and went to AGM batteries because they provide more power and are less maintenance. This is half right, there is less maintenance as they are sealed and do not have gas, and are less prone to sulfation. They do not provide more power initially however, as they are less prone to sulfation, they provide the rated power over the years as the sulfated lead acids will start to underperform as discussed earlier.

Storage

All batteries will lose a charge during long periods of inactivity such as storage. Batteries should be recharged when they show under 70% capacity. And they need to be kept from freezing. If you do not have access to 120-volt power to charge or a solar panel, it is recommended to remove the batteries and maintain them store them properly.

Another option is using a solar panel with charge controller or Battery Minder which not only keeps the battery from freezing and properly maintained. This is good for lead acid, gel, and AGM. Not for use with Lithium Ion. Lithium-Ion batteries should be stored at 50 degree temperature and at 40-50% capacity.

Lithium Ion

In the past, Lithium Ion batteries were very expensive and did not perform well in cold weather. Technology has changed and more companies have developed Lithium Ion batteries that are getting closer to AGM batteries. Granted they are still about twice as much initially, however they can be drained down to almost 0% capacity vs 50% of other batteries so you can get by with fewer overall batteries. Also, they last longer so if you plan to keep your rig for a long time and do a lot of dry camping, the pay for themselves. Plus with proper charging,  they are not affected by cold weather as older versions.

About the author: Dave Solberg: Managing Editor, RV Repair Club

For the last 25 years, Dave has conducted RV maintenance and safety seminars, developed dealer and owner training programs, written RV safety and handyman articles, authored an RV handbook reference guide and logged over 100,000 miles on the road in an RV.

RV Repair Club

RV Repair Club is your go-to online resource for enthusiasts who want quality RV maintenance, repair and upgrade information – a community where passionate RVers can come together to gather knowledge and share their experiences.

Learn more about RV Repair Club.

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Choosing The Right Battery For Your RV

08 Thursday Oct 2020

Posted by in Tech Tips

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Choosing The Right Battery For Your RV.

“What is the best battery for my rig?” The best or correct battery for your rig depends on a variety of factors such as:

  • How often will you be boondocking/dry camping?
  • How many 12-volt components will you be running and for how long?
  • How long do you plan on staying out before needing to recharge your batteries?
  • What type of budget do you have?

Most battery manufacturers make a variety of batteries for different applications. To start with, let’s look at the different types of batteries starting with cold cranking amp and deep cycle types.

Start/Engine Batteries

Start Your Engine Cold Cranking Amps (CCA) is a term used to identify the batteries’ ability to start an engine in cold weather.  Since it’s harder to start an engine in cold weather, the higher CCA means more amp power available to turn the engine over and start in a 30-second time frame.  This type of battery should not be used in your house battery application.

Deep Cycle/House Batteries

A deep cycle battery simply stores energy to provide steady power to 12-volt components in your RV such as lights, water pump, roof vents, and any appliance that runs on LP such as the stovetop, water heater, furnace, and others.  It is designed to be discharged and recharged repeatedly which is known as a cycle.  This type of battery is the best for an RV application.

RV Batteries

Most RVers are concerned about the “best” house battery for their rig rather than the start battery so let’s look at the different types of deep-cycle or house batteries available.

Flooded Lead Acid (FLA)

The flooded lead-acid battery has been around for years, in fact, it was invented in 1859 by a French physicist well before any RV hit the road and there have been quite a few improvements over the years.

Flooded Lead-Acid Battery

Lead plates are surrounded or submerged by an electrolyte solution of sulfuric acid and water and require more maintenance as water is lost during recharging and distilled water should be added periodically.  They are also more prone to sulfation if not recharged properly with a multi-stage charger.   They also need to be stored upright otherwise electrolytes will spill out the vent caps.  These batteries tend to be the most cost-effective.

Absorbed Glass Mat (AGM)

AGM batteries also have lead plates with an electrolyte solution, however glass sheets or “mats” are used to absorb the solution and due to the design, there is no gassing or solution loss and less maintenance.  They are also sealed and can be stored in an out of the way location without the need to check fluid levels or worry about leaking.  These batteries are typically twice the price of FLA batteries.

Absorb Glass Mat

6-Volt vs 12-volt

Whether you have FLA or AGM batteries, there are two different schools of thought in what RV manufacturers decide to use: 6-volt batteries connected in series, or 12-volt connected parallel. In either case, the end result is a 12-volt DC system!  6-volt batteries require two batteries that are connected positive to negative which is called in-series and creates a 12-volt battery bank.

Connecting two 6-volt batteries in series does not double the amp hours, to do that you need to add two more 6-volt batteries in series and connect them parallel to the system. The advantage of the 6-volt battery is they typically can by “cycled” or discharge and recharged more often so they will last longer but do not provide more power or amp-hours.

12 volt connected parallel

A single 12-volt battery can be used as a cost-effective method to provide power. Additional amp hours can be added with one more 12-volt battery connect parallel which is positive to positive.  This will double your available amp-hours.

Battery Size-Amp Hours

Deep cycle batteries are rated in groups, or available amp hours which is how long a battery can provide power before being discharged.  Here are some of the common amp-hours per group:

Group 24 – 70-80 amp hours

Group 27 – 80-100 amp hours

Group 31 – 100-130 amp hours

This means that the 100 amp hour battery will provide 1 amp of power for 100 hours.  However, we will use much more than 1 amp per hour so we need to determine what is being used and keep in mind that most batteries can only be discharged 50% before shortening the lifespan of the battery.

To calculate the best battery for your needs, start by determining how much time you will be boondocking or dry camping. Then identify what components you will be running and for how long.  Any appliance that uses LP such as the refrigerator, stovetop, oven, and water heater will use 12-volt power, however, they will not be running full time.  Items like interior lights, roof vent fans, and water pump will also need to be factored in.

If you are going to be camping with access to an electrical source, you can get by with a small group or amp hour battery and save some money as your converter will recharge your batteries.

Here are some typical 12-volt components and the amp draw from them

  • Incandescent Lights = 1.5 amps
  • Halogen Lights = 1 amp
  • LED Lights = .12 amp
  • Smoke Alarm = 1 amp
  • CO Detector = 1 amp
  • LP Leak Detector = 1 amp
  • Furnace = 10-12 amps
  • Water Pump = 5 amps
  • Refrigerator on LP Mode = 2-3 amps
  • Stove Top = 1 amp
  • Roof Vent = 3 amps

As you can see, there are several factors in what usage you might have in your rig, especially if you are camping in cold weather.  It’s not uncommon for a smaller rig to have a 10-15 amp draw which means you will only get about 4 hours with a group 24 battery! Here is the math:

80 amp hour battery x 50% = 40 amp hours

40 amp-hours / 10 amps drawn every hour = 4 hours of battery life

The more you use and the longer you need to stay out before recharging with either a generator or solar panels, the more amp hours you will need.

One other important item to consider when looking for the best battery for your application is the quality of the battery.  Several discount franchises offer a cheap “Marine/RV” deep cycle battery and the only feature of those batteries is the cheap price.  They are made with thinner plates, insufficient lead oxide paste and acid ratios, and inferior welds on intercell connections.  In short, they sulfate faster and go bad with dead cells and less storage quicker.  I would recommend getting a battery endorsed by the RV industry such as Trojan, Lifeline, and even NAPA batteries are being used with much success. Take some time researching the information on the website about thicker positive plates used and superior workmanship and you’ll find you get what you pay for.

In summary, the best battery for your application is not a simple answer, rather a calculation in the way you are planning to RV.

About the author: Dave Solberg: Managing Editor, RV Repair Club

For the last 25 years, Dave has conducted RV maintenance and safety seminars, developed dealer and owner training programs, written RV safety and handyman articles, authored an RV handbook reference guide and logged over 100,000 miles on the road in an RV.

RV Repair ClubRV Repair Club is your go-to online resource for enthusiasts who want quality RV maintenance, repair and upgrade information – a community where passionate RVers can come together to gather knowledge and share their experiences.

Learn more about RV Repair Club.

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Three Boondocking Tips for Newbies

25 Thursday Apr 2019

Posted by in Tips & Tricks

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Boondocking

Are you unsure about experiencing RV life without hookups? If you haven’t made the leap but want to give it a try, these three boondocking tips for newbies can prepare you for your first big off-grid adventure.

Boondocking is Total Freedom

One of the biggest joys of RV ownership is the ability to camp anywhere your rig can go, without being hooked up to water, sewer and electric utilities. This kind of “boondocking” is a camping style that makes the most of your self-contained home on wheels. With full freshwater holding tanks, robust RV batteries and conscientious camping habits you have the ability to enjoy some of the most stunning locations in places where less ambitious campers are willing to go. Of course this kind of freedom comes with a price. For RVers, that means keeping in-tune with how you use up RV resources like battery power, water and holding tank space.

RV Boondocking Tip #1: Conserve Energy

Your RV batteries are a lifeline to comfort during off-grid adventures. The most important thing you can do to make your boondocking adventures a success is to get to know your RV generator and understand RV battery basics. This will keep your batteries in prime condition and ensure a comfortable experience.

Make an effort to drop those power consumption habits you learned at home. Your goal when boondocking is to reduce reliance on your RV generator. Start by switching your RV appliances like the water heater and refrigerator over to propane power. And don’t forget to unplug mobile devices once they’re done charging. When the sun sets, make a conscientious effort to turn off lights you aren’t using. Every small power consumption reduction helps when your life is powered by your RV batteries.

RV Boondocking Tip #2: Conserve Water

Daily water consumption in a normal home isn’t a huge concern. But when you rely on storage capacity of your RV’s freshwater holding tanks, everything changes. Whether your rig has a 50 or 100 gallon fresh water tank, your supply is still limited. If you want to camp longer in the backcountry, break those water-wasting habits, starting in the kitchen and bathroom. For instance, don’t use fresh water to clean your plates or sinks. You’re better off grabbing a paper towel to wipe down surfaces. Swipe food scraps off dirty plates and utensils before doing a final wet wash. And over in the bathroom, have a stockpile of water-saving bath products, like dry shampoo and disposable body wipes. Finally, if your chosen off-grid campground has a public toilet, use that instead of your own. RV toilets are one of the biggest water guzzlers in the roaming home.

RV Boondocking Tip #3: Conserve Noise

For many RVers, camping without hookups seems positively prehistoric. But for many others, off-grid boondocking is a way of life. This group of RVers is in search of a scenic, quiet place to park, camp and get closer to nature. And once they arrive, it’s safe to say that most don’t appreciate other campers’ late night parties and audible generator buzz. Should you find yourself boondocking with strangers in the outback, please keep your noise level in check to keep the peace. Don’t run your generator too early or too late in the day, try to minimize your dog’s barking and if you party with friends, follow good neighbor quiet hours (10 pm to 8 am usually).

Some of your best RV adventures can happen when you unplug from water, sewer and electric utilities. Just follow these tips for better RV boondocking and eventually you’ll get the hang of it. Once you give off-grid life in the backcountry a try, you’ll open the door to unforgettable experiences and enjoy all the comforts of home wherever you go.

About the author: Rene Agredano 

Rene Agredano, a Coach-Net member since 2015, is a self-employed full-time RVer who enjoys writing, jewelry design and animal advocacy. Her adventures with a three-legged dog and husband Jim are chronicled at LiveWorkDream.com

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Your Battery Disconnect Switch

19 Monday Nov 2018

Posted by in RV Information

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Battery Disconnect Switch

Many RVs have battery disconnect switches installed in them. However, these switches sometimes go unused or unnoticed by owners. Battery disconnect switches are a great way to conserve your batteries while your RV is in storage, even if just for a short time.

When I park my RV at the storage lot, I usually disconnect my batteries at the switch even if I’m going to be back at the RV in a week or so. In addition to preventing parasitic loads from slowly draining your battery, it also prevents battery drain from loads that might inadvertently be left on, such as lights or fans. Even though my RV has solar panels that keep the batteries fresh (as long as there is some solar energy), I regularly make use of my battery disconnect switch, which is conveniently located with my other RV controls.

Battery disconnects come in many different styles, from blade switches located at the battery terminal to relay-controlled remote switches. A very common style for trailers is the marine-style rotary contact switch. Whatever form you have, it is a good idea to make use of the battery disconnect switch whenever you are going to be away from your RV, unless of course your coach is plugged in while it is in storage.

RV Stored Away

If your RV doesn’t have a disconnect switch, you may want to consider having one installed. Simple switches are quite inexpensive and don’t take long to install. It is actually quite a simple DIY project if you are relatively handy and have the tools required. As with any project, be sure to plan it out first. Know where you would like your switch and the tools needed for installation. The basic tools required are:

  • a wire cutter
  • a crimper large enough to handle the gauge wire you are working with
  • an extra battery wire
  • hardware necessary to mount your switch

How to Install:

Simply splice the switch into the positive lead from the battery at a convenient mounting location (as close to the battery as possible is ideal). If you are not handy with basic electrical work, have someone else do the job for you.

If you live in a fairly mild climate where the coldest it gets is around freezing, you can leave your batteries in your RV over the winter (if you are not using your coach) and simply disconnect your batteries at the switch. You don’t have to remove your batteries for winter storage, as long as they remain dry in the RV. Just make sure they are fully charged and topped up with electrolyte (unless they are maintenance-free). With the batteries disconnected, you don’t have to worry about loads draining the battery, and in the spring, you can just flip the switch and you’re ready to go. Note that the battery may self-discharge over the winter to some extent, but if it does so to a large extent, it’s about time to have the batteries tested, as they may be worn out.

RV Stored Away

So, make good use of your battery disconnect switch. It is there for a good reason, and it provides peace of mind while your RV is in short- or long-term storage. If you visit your stored RV frequently, like I do, you can be sure your lights will work when you need to grab that item you left in your RV. Also,no more lying awake at night wondering if you left the fridge on in your RV.

 

About the author: Steve Froese 

Steve Froese, an avid RV owner, traveler, and Coach-Net member since 2013, is the principal of “A Word to the Wise Technical Communications”, a published RV author, certified RV technician, and licensed Professional Engineer. He frequently collaborates with the “RV Doctor”, Gary Bunzer, and has worked with the RVIA/RVDA as a technical and training writer and consultant. Professionally, he works as a quality engineer and musician. Watch for more of Steve’s work in upcoming Coach-Net publications.

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RV Battery Types and The Power They Provide

23 Wednesday May 2018

Posted by in Tech Tips

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RV Battery Types12-volt Deep Cycle batteries are the lifeline for RV enjoyment.  Not only do they power the common 12-volt functions like lights, roof vents, and such, but are also essential for powering any appliance running on the LP mode and even the absorption refrigerator on the 120-volt mode as the temperature sensor and monitor panel are powered by the 12-volt batteries!12-Volt battery

For the past 50+ years, RVs have mainly been powered by deep cycle, lead acid batteries which have lead plates placed vertically and are covered with a solution of water and sulfuric acid commonly called electrolyte.  In the RV application there is either a 12-volt battery that consists of 6 cells with plates, each producing 2.1 volts per cell.

The other type is a 6-volt batteries connected in series (positive to negative) which creates 12-volts, however two batteries are needed in this application.  There are only 3 cells per battery and each produces 2.1 volts per cell, so each battery produces 6.3 volts or 12.6 volts total just like the single 12-volt battery.  Each cell consists of a positive lead plate covered with lead dioxide and a negative plate made of a specific type of lead with an insulating material placed between the two plates.

These batteries require a specific multistage charging procedure each month and are subject to sulfation if not stored and charged properly.  They “gas” during the bulk stage charge and lose acid which requires periodic inspection.  Most owners do not properly charge and store their lead acid batteries and therefore they have become a hot topic for replacement options.

Gel batteries where introduced in the Mid 70’s and still maintained the lead plates, but had a gel acid instead of the liquid which was designed to be a superior battery with less maintenance.

AGM batteryThen came the AGM or absorbed glass mat battery which was maintenance free and literally had fiberglass mats inside the battery to absorb the acid and could be stored sideways!  Many RVers believe that replacing the lead acid batteries with AGMs will double the power available.  This is not true, rather the AGM batteries require less maintenance and are less prone to sulfation.  This makes them a more powerful battery only after the lead acid batteries develop sulphur between the plates and lose storage capacity!

In 1980 Lithium Ion batteries were introduced, but were not used much until the early 2000’s as the price was out of this world!

12-volt deep cycle batteries are simply storage devices for power, they can not produce or create voltage without receiving a charge from an outside source known as a charger from either a converter, solar panel, or other source.  The size of the plates and amount of electrolyte determine the storage capacity or amp hours (AH) the battery can provide.  These are classified in terms of “Group” ratings such as Group 24, Group 27 etc.  The higher the group rating, the higher the amp hours and therefore the longer the battery can provide power before needing a recharge.  A typical battery rated for 125 AH can provide 10 amps of power for 12.5 hours, or 20 amps of power for 6.25 hours.

Lead Acid Discharge and Sulfation

When a 12-volt source is activated, such as an interior light or roof vent, a chemical reaction between the lead plates and the electrolyte occurs which produces the energy for the light.  This chemical reaction also begins to coat the positive and negative plates with a yellow build up known as lead sulfate which is normal during the discharge process. Lead sulfate continues to coat the plates as the battery discharges to the 10.5 volt stage at which time they are completely covered.

Lead sulfate can be reconditioned back to lead and electrolyte if conditioned or recharged properly and immediately.  If left in a discharged stage the lead sulfate will form hard crystals that can not be converted back to lead and electrolyte and will diminish the storage capacity.

When not in use, all lead acid batteries will discharge, the rate depends on the condition of the battery, temperature, and what parasitic draw is on the battery.  Typically a battery with no sulfation and with no additional draw, will discharge at approximately 4% per week.

A 125 AH battery left in storage without a charger will lose 5 AH per week which means it will lose 80 AH capacity in four months or well over 50% of it’s capacity in just one year!

Proper Recharging

Lead acid batteries require a multistage charge every month which starts with a bulk charge or high voltage (16V) charge which breaks up the Lead Sulfate on the plates and then goes into an equalizing and float charge.  Typical converters and battery chargers are simply a fixed voltage charger that recognizes a low charge (10.5v) and applied a fixed charge of 13.6 volts, which can not reconvert the lead sulfate on the plates.  Plus, the recharge time is very long compared to a multistage charger.

Some larger inverter/chargers do have a multistage charger which will condition the batteries.  Check your system to see if the charger of your inverter has a multistage and conditioning feature.  During the recharge stage, the water is being converted back to hydrogen and oxygen “gases” and can be flammable.  That is why they are contained in a vented compartment.  This is also why lead acid batteries need to have water added periodically as well.  Sealed batteries such as the AGM type contain the gases and keep them with the electrolyte.Vent well

There are some alternatives to getting a very expensive inverter/charger such as the Battery Minder from Northern Tool.  This device has had much success in the aviation and golf cart industry and is starting to turn some heads in the RV market.  The Battery Minder uses high impact waves rather than high voltage to condition the batteries which means less gassing and less water loss.

Progressive Dynamics has introduced converters/chargers with a smart charging system called the Charge Wizard which recognized the condition of the battery and adjusts the charge accordingly to provide proper conditioning.  For more on their system visit https://www.progressivedyn.com/rv/power-converters/

Here are some quick tips for better battery maintenance:

  1. Use a multistage charger or conditioner
  2. Check your fluid level before every trip and add as needed
  3. Match the correct size battery with your 12-volt needs.  Don’t expect to dry camp for days on a group 24 battery!
  4. Find ways to reduce your need for battery power during dry camping such as
  5. Using the campfire to cook and make coffee
  6. Replace halogen and incandescent bulbs with LED
  7. Use a portable Catalytic Heater vs the RV furnace

About the author:

Dave Solberg: Managing Editor, RV Repair Club

For the last 25 years, Dave has conducted RV maintenance and safety seminars, developed dealer and owner training programs, written RV safety and handyman articles, authored an RV handbook reference guide and logged over 100,000 miles on the road in an RV.

RV Repair ClubRV Repair Club is your go-to online resource for enthusiasts who want quality RV maintenance, repair, and upgrade information – a community where passionate RVers can come together to gather knowledge and share their experiences.

Learn more about RV Repair Club.

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The RV Electrical System – Part 1

26 Tuesday Apr 2016

Posted by in Tech Tips

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DC Electrical SystemBy far the largest volume of technical support I provide to RV owners is related to the electrical system. This is not surprising however, considering the electrical and propane systems basically comprise the entire house system. Many owners struggle with both these areas, but the electrical system remains the most elusive. Over the next few weeks, I will be discussing the RV electrical system.

Although the propane system is currently central to a recreational vehicle, manufacturers are moving towards electric appliances, which is resulting in less reliance on propane and more on electricity, making the electrical system truly the “heart and soul” of the RV.

The electrical system is complicated by the fact that there are really two sub-systems involved; the 12V DC and 120V AC components. Although this confuses some consumers, it’s relatively straightforward. In this multi-part column, I will attempt to simplify the topic and provide information that will enable any RV owner with basic technical skills to identify and troubleshoot RV electrical problems.

batteriesA logical place to start is with the 12V DC system. The 12V system provides power to all the interior lights (although there may be some 120V lighting in some coaches), range hood, water pump, vent fans, and some entertainment systems. It also controls many of the LP, and even 120V AC, appliances. This causes many owners to scratch their heads when troubleshooting AC or propane problems with their coaches, not realizing that the root of the problem lies with the 12V system.

The DC system begins with the batteries. Hopefully your coach has at least two deep cycle batteries powering the house system. Some dealerships provide only single batteries when they sell smaller trailers. They do this to save money, but a single battery is not sufficient, especially if the unit has a slide-out. If your RV has only a single battery, add another one.

The next question is whether to use 6V or 12V batteries. 12V batteries must be connected in parallel, which maintains the 12V, but doubles the current capacity. 6V batteries are connected in series, which doubles the voltage, but keeps the current the same. The current capacity is basically a measure of how long the batteries will last. Since 6V deep-cycle batteries contain much larger di-electric plates, the current capacity of a single 6V battery is more than twice that of a comparable 12V battery. The result is that using 6V batteries provides more current capacity than two 12V batteries, making it a better option. If you use primarily shore power for your RV, the battery question isnot as critical, and you can certainly save money by using 12V batteries, but the extra power capacity really comes in handy when you find yourself unexpectedly without shore power. Although it is true that the more batteries the better, this is not usually practical. Generally speaking, the ideal solution is to have four 6V batteries installed in the coach, any more than that takes up too much space and may create weight issues. If you have room in your battery bay, or you can create the space, I highly recommend the four battery setup. This requires a series-parallel wiring scheme. The details of this are outside the scope of this article, but wiring information for series, parallel, and series-parallel can be found on the internet.

Next week I will move on to the 120V AC electrical system.

About the Author: 

Steve Froese, an avid RV owner, traveler, and Coach-Net member since 2013, is the principal of “A Word to the Wise Technical Communications”, a published RV author, certified RV technician, and licensed Professional Engineer. He frequently collaborates with the “RV Doctor”, Gary Bunzer, and has worked with the RVIA/RVDA as a technical and training writer and consultant. Professionally, he works as a quality engineer and musician. Watch for more of Steve’s work in upcoming Coach-Net publications.

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