Why Is RV 12 Volt System Not Working?

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Published Date: September 27, 2020

Last Updated on October 24, 2022 by camper front

Why is RV 12 volt system not working? This is a question I got from an RV user recently and I’ve decided to discuss it here today.

A 12-volt system powers most of the necessary devices in an RV. This includes overhead lights, the water pump, vent fans, furnace fan, range hood fan, LP gas leak detectors, stereos, 12-volt TVs, and even the refrigerator when it’s operating in the LP gas mode.

So when it stops working, its a major problem; and this is probably because your RV’s 12-volt system runs off of the batteries. If they are dead or not fully charged, the 12-volt system will not function properly, or it could be your inverter/converter, there are a couple of reasons why an RV 12-volt system might not work.

Let’s talk about them!

Why Is RV 12 Volt System Not Working?

Why RV 12 Volt System is Not Working

To find out the reason why your RV 12-volt system isn’t working, you need to carry out some investigation and troubleshooting, and when you find the culprit, we can then move on to the solution.

However, if you have no prior knowledge about electricity or you do not feel comfortable handling it, please do well to call on a certified electrician, as dealing with electricity is very dangerous and could cause you serious harm, or let’s get to the reason we are here;

1. Batteries

As you already know, a 12-volt system has to be powered by a battery, and most RVs are equipped with a couple of batteries to be able to power the 12-volt system for quite a while. But each of these batteries all come together to make up the 12 volts.

Undercharged batteries

So without proper charging and maintenance, your batteries can die, just like the battery of your smartphone.

To prevent this, it is highly recommended that you always keep an eye on your batteries level and make sure to recharge them once they are halfway down their charge because if they are completely drained before you try to charge them,

it will be harder and take a longer time, and sometimes they won’t be able to hold a full charge effectively anymore.

When charging your batteries, also, you should strive to ensure that your batteries reach a full charge before using them, because your 12-volt system works best when the battery is as close to fully charged as possible.

If your batteries charge is low and not adequately recharged, it is going to affect the performance of your 12-volt system. And sometimes, it might not even work at all, so a proper charge is highly needed, and its importance cannot be overemphasized.

Dead Batteries

So you have been charging your batteries for hours on end, and they don’t get a full charge. You need to check your batteries for any loosed connections, as that might prevent the battery from getting a full charge; you also want to check on the battery fluid and see if they are at the right level.

If both of these issues are okay, then you should get another set of batteries to charge to find out if the problem is with the 12-volt system; if the batteries do just fine, then your batteries are completely dead, and you should definitely think of replacing them.

Low level of Battery Fluid

If you can charge your battery pretty well and they are able to get to a full charge, yet you are still not getting any power from your 12-volt system, and your appliances don’t work, it is highly likely that the fluid level in your batteries is low.

You might be wondering, fluids? Well, your RV batteries have electrolytes in them that are composed of roughly 60 percent water and 40 percent sulfuric acid.

The negative and positive plates of your batteries create lead sulfate as you make use of the battery, and this causes the level of the sulfuric acid to reduce, but you can restore it by charging.

But the water evaporates when the battery is overworked and overheated. This could also cause your battery to stop working even with a full charge; it is easy to undo this as all you need to do is to refill your battery with some distilled water and you are good to go.

Loose DC Battery Connection

If you have more than one battery, then this is highly possible as the batteries are connected with wires and are then housed into a parallel circuit. So sometimes, this tends to get loose, causing the batteries to become disconnected even when they are fully charged.

Tighten the wires to get this fixed. However, it is not advised to get into your circuit board yourself because you run a high risk of electrocuting yourself unless you are a certified electrician yourself.

You should hire the services of one to come to help you tighten up the wires, and if it doesn’t help, the electrician will be able to further diagnose the problem and get you a fast and safe solution.

2. Loosened or Burnt Inverter/Converter Fuses

An RV usually comes with three electrical systems, one of which is the 120-volt system that powers other appliances like the TV. But with a converter/inverter, you can turn 12-volt power into 120 volts of alternate current or AC power and vis versa.

And that is only a possibility if your inverter/converter is functioning as it should; if the fuses are loosened or burnt from overuse, this conversion won’t happen.

You might have a single or double fuse depending on the type of converter you happen to have; all you have to do is take a look at fuses if they are burnt.

Although you may not be able to tell if it is disconnected, then get an electrician to help you figure out if it’s burnt or loose and the person will also help you in the process.

The electrician will also be able to tell if your converter/inverter is bad and needs to be replaced.

3. Tripped Circuit Breaker

This can easily occur if you try to run too many appliances at once, and you can easily fix this by just resetting your breaker.

But you have to ensure you don’t do this often as constant tripping can cause damage to your breaker; try to do your wattage requirements calculations and only run a couple of appliances the 12-volt system can power at a time.

Your 12-Volt System STILL Isn’t Working

12-Volt System STILL Isn’t Working

You have done all the above regiments, and there is still no power from your 12-volt system; it is frustrating, but not the end of the road.

Before you dump your batteries or even your whole RV in the trash, check if your RV is plugged into a source of power because, without that, your 12-volt system or 110-volt system won’t work.

Also, none of your appliances or heating or AC will work, your RV will basically be powerless. So please do check that out.


If all of the tips mentioned above and methods do not restore power to your RV, you might have to take it down to a technician/electrician to get it checked out.

Remember, always observe safety precautions when handling electricity as one mistake can lead to severe electrocution. But hopefully, this article will help you find answers and solutions to why RV 12-volt system is not working.

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