What’s the one thing that’s more frustrating than a charger that won’t charge your smartphone? Not being able to get any juice to your camper batteries. Since these are far more essential – not to mention necessary if you want to charge your smartphone while camping – it’s a problem that takes priority.

Since your camper batteries are integral to your electrical system, that means a whole host of problems could be causing the lack of charge, such as faulty wiring, bad fuses, corrosion on the circuit board, corroded battery terminals, the battery is at the end of its cycle, or your RV converter is wrong.

Preventative maintenance is the key to everything, especially when it comes to batteries. Also, there is more than one type of battery for RV use and the lack of charge may have something to do with that.

For the most part, however, the most common problem with a trailer battery not charging is corrosion or a blown fuse. It can get more complicated than that and we will cover it down below.

How batteries work in a camper/RV

There are generally three types of batteries that are used in campers, not including the starter batteries on RVs. But since we’re talking more about campers here, we’re only focusing on the house batteries.

  • Flooded Electrolyte Batteries
  • Gel Batteries
  • Absorbent Glass Mat Batteries

Flooded electrolyte batteries are extremely common in campers and RVs. They’re also the cheapest in terms of upfront costs but they have a high charge capacity and will last a relatively long time. Unfortunately, they’re the most high-maintenance batteries of the three.

Gel batteries are just what they sound like because they are full of gel when the silica, electrolytes, and sulphuric acid inside combine. They’re low maintenance, high-capacity, longer-lasting,  and far more expensive.

Lastly, there are absorbent glass mat batteries (AGM). These batteries don’t suffer from corrosion, so if you are using them in your camper and they aren’t charging, you can mark that potential problem off of the list. It’s an excellent deep cycle battery with a lot of positive features.

To buy one, you may feel like you’re selling your kidney on the black market but it’s worth the price.

When you park the camper at a campground or at home, it’s hooked up to what is called “shore power,” which powers the RV and, by plugging your converter into one of the RV’s power outlets, the batteries as well.

This is also the best way to tell that the batteries are the problem and not your RV, because if shore power is properly supplying power to your RV and all of the lights are on, then the batteries should charge. If they don’t,  you know it’s a battery issue and now you have yourself a problem to solve.

Troubleshooting camper batteries that won’t charge

As you can see from our answer segment when your batteries won’t charge, there can be a pretty broad range of things going on that would make these batteries refuse to cooperate. We’ll cover them starting from the most common and work our way up.

Battery corrosion

If you are using AGM batteries, they are known for never corroding so you can keep scrolling farther down the list. When it comes to the other batteries, this could simply be the case and if it is, your DIY solution just became a lot easier.

You’ve probably seen it in your car a time or two over the years. Corrosion is that green/yellow/white foamy-looking build-up around the terminals. It’s caused by charging cycles and is a natural progression that you can head off through preventative maintenance.

  • Make sure you disconnect your battery and place it on top of a garbage bag so it will collect the corrosion as you clean it
  • Use baking soda with a splash of water on the terminals or a little bit of Coca Cola (because it really does work)
  • Use a soft-bristle wire brush to scrub the terminals from top to bottom, all around
  • Give the clamps the same treatment
  • Dry everything off thoroughly
  • Use a sealant spray on the terminals

That will pretty much cover you with the battery terminals and you can hook everything back up and give it a go when you’re ready. If they charge, that’s fantastic and if they don’t, move right along.

Check your converter

Is your converter the right one for your batteries? No one is accusing or pointing any fingers at anyone here. We all make our fair share of mistakes from time to time and not every person who purchases a camper is a Journeyman or Master Electrician.

However, the question has to be asked because it’s an important one, especially if shore power is delivering the goods for your camper but not your batteries.

The fact is, almost every single camper and RV on the planet (there are a few, weird ones out there) accepts either 30A/115V or 50A/240V. The difference is a three-prong plug for 30A and a four-prong plug for 50A.

All a converter does is serve as the red light in the middle of a busy avenue, sending power at the right levels where it needs to go. It also changes Alternating Current (AC) to Direct Current (DC), the latter of which is where your batteries come in.

When we say check your converter we mean that you need to look at several things:

  • Is the cooling fan working
  • Do you smell a “burnt rubber” smell
  • What type of battery did you install
  • How old is the converter

If you are using lithium-phosphate batteries, three-stage converters won’t charge them. Most converters in RVs today won’t charge LiFePO4 batteries either. So, this might be a case where you simply have the wrong battery for your converter or vice versa, however, you want to look at it.

If you smell burnt rubber coming from your converter, but the fan is running, you have a problem with the thermal sensor. If the fan isn’t running but there is power to the converter (you can confirm with a multimeter), your fan needs to be replaced.

Lastly, older converters from last millennium RVs aren’t going to charge today’s batteries and an upgrade is well in order.

Moving on to fuses and circuit boards

If you blow a fuse in your RV, it’s most likely due to a power surge, as that is the most common culprit when this happens. You’ll have to pull every related fuse and visually inspect them to confirm that they’re good to go.

It’s a slow and boring process of elimination, but you’ll be happy if you locate the burned-out fuse. However, if you come across scorch marks, which you will be able to see directly on the circuit board, it’s going to require a professional, unless you happen to be an electrician.

Those scorch marks are failed diodes or resistors and because they have failed, you essentially have yourself an open circuit and your batteries will never charge, not to mention whatever else the damage will affect.

  • Check the circuit board thoroughly
  • Pull all of the relevant fuses, visually check them, and run their associated appliances
  • Remove the RV from shore power if none of the above-located anything
  • Unscrew and remove the circuit board panel once you are sure that the power is cut off
  • Check around the circuit board for signs of corrosion

If you don’t see anything, replace everything in reverse order and move on. If you spot corrosion, you’ll need a professional once again and some components may have to be replaced. Fun stuff.

Batteries are at the end of their cycles

Every battery has a finite number of cycles, which is the singular vernacular for defining the process of draining and charging again. Some batteries are designed to tolerate deep cycles and some can be damaged if completely drained and left that way.

Whatever the case, your battery may simply be on its last legs. Fortunately, there’s a method for figuring out if your battery is gasping its last breaths or if there is still some life remaining in it.

You need to isolate the battery (disconnect switch if applicable) and attempt to charge it to full capacity in whatever manner you can find, even if you need to hook it up through a generator. Give it some juice for a couple of hours.

As soon as you take it off the juice, use a multimeter to check the level of charge. Now, sit back and wait for two hours. use the multimeter again. If there has been a noticeable drop-off, your battery is kicking the bucket and it’s time to replace it.

Final thoughts

Corrosion is your worst enemy because it is the most common problem when it comes to charging your house batteries. It’s also a problem with the circuit board. Preventative maintenance will help to avoid all of that.

Also, it’s a good idea to brush up on converter functionality. You don’t have to get a Master’s Degree and write a thesis on it or anything, but it’s good information and it will probably save you a headache or two down the road.