There have been several inquiries from owners, old and new, about converters and inverters, and it’s clear that there is some confusion about their capabilities and functions. This is completely understandable, as there are various types of converters and an even greater number of inverters! So, let’s dive in!
Converter
A converter is basically a battery charger that receives 120-volt AC power from either a campground source or a generator and turns it into 12-volt DC power to charge the house battery or batteries. The most basic converter is located in a distribution center alongside the 120-volt circuit breakers and is called an all-in-one unit similar to this style.
The converter/charger is located behind the vents or grills on the right side and has a dedicated circuit breaker which is usually the one closest to the converter.
These are a less expensive model, however, they can be noisy and produce heat so some manufacturers are moving to a standalone model and putting it under the bed or inside cabinetry. There is still a distribution center with circuit breakers and 12-volt automotive-style fuses, but the converter/charger is hidden.
Above is a photo of a WFCO installed under the bed behind a false wall. They can be difficult to find and even more difficult to remove and install the new converter when looking to install lithium batteries!
A typical converter is connected to the house batteries and senses the charge. When the batteries are low, (approximately 50% drained) the converter will provide a charge of approximately 13.6-volts until the batteries reach 12.6-volts which is fully charged. Then the converter will drop to a float charge of 13.2-volts in order to avoid overcharging the battery/batteries.
The disadvantage is that it does not provide proper charging and maintenance. Sulfur will coat the lead plates in lead acid and AGM battery as it drains and only a high voltage charge known as the bulk charge or desulfation charge will break up the coating. Otherwise, it just gets thicker with each draw and eventually greatly reduces the battery’s ability to store power. It can also take 8 hours or longer to charge.
Progressive Dynamics offers a charger that provides 13.8-volts for 8 hours, which creates some desulfation, and the PD9200 with Charge Wizard also does a nice job.
A multi-stage charger will provide a bulk charge at 14.6-16-volts that will break up the sulfation and then moves to an equalizing charge to equalize each cell, followed by a float charge.
NOTE: You do not want to use this type of charger with Lithium Batteries as they require only a 14.6-volt charge and the bulk stage could ruin them!
There is very little maintenance required with either the all-in-one version or the standalone other than to monitor the condition of your lead acid battery/batteries. It is also recommended to periodically check all wiring connections for corrosion and tight fitting. If a converter goes bad it will either lose its ability to charge or not come out of the initial higher charge of 13.6-13.8 volts overcharging the batteries. Be sure to check the fluid level of the battery and in my opinion, it is a good idea to get a good battery monitor other than the three-light versions on the monitor panel.
The monitor shown below is a Go Power! product and is the version we installed in our Thor.
Inverter/Charger
An inverter is designed to take 12-volt DC power from the house battery bank and change or invert it to 120-volt AC power for appliances and outlets. Smaller inverters were first used with the entertainment centers to power just the TV and VCR and were about 100 watts. This was designed to power the TV while boondocking or dry camping temporarily and did not power anything else in the rig.
As more power was needed for other outlets and appliances such as residential refrigerators, larger inverters came along such as the Freedom 2000 which also had a battery charger incorporated.
This type of inverter would not only take 12-volt power from a larger battery bank and provide pure sine wave 120-volt power to several outlets and the residential refrigerator but would also provide a multi-stage charge to the house batteries.
Several companies have made their way into the market with inverters/chargers as low as 1000-watt models. The key in deciding which is right for you is to look at what wattage requirements you need for your rig, the battery bank you have, and the amp rating of the charger.
Companies with a reliable track record according to the RV manufacturers and service centers that I have worked with are Go Power, Xantrex, Victron which Keystone uses, and Renogy.
As with a converter, there is very little maintenance required for inverters other than battery maintenance and periodic checking of connections for corrosion.
Which Do I Need, A Converter Or An Inverter/Charger?
Usually, you don’t have a choice as the rig comes from the factory with a distribution center that has a converter/charger incorporated. This is either in the distribution center, standalone, or an inverter with a charging option.
The time to decide is when the converter fails or you want to upgrade your battery capacity. The determining factor is the amount of time you will be boondocking or dry camping. An inverter is only needed if you are not going to be plugged into a campground source and need to run some 120-volt appliances which would need an inverter or generator power.
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 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.
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12-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!
Then 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!
This article is the second part of my electrical system primer. This week I will cover the 120V AC system.
When the coach is plugged in, the shore power is shared between the 120V AC appliances and the converter or inverter. Most coaches, except after-market installs and high-end diesels, utilize converters.
but not on generator, the first thing to check is the circuit breakers on the generator. Many users may not be aware that the generator has its own circuit breakers. Locate these breakers, which usually consist of a 20A and 30A breaker, and make sure they are not tripped.