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Battery Not Charging: Troubleshooting Tips
Dave SolbergDescription
To help you get your RV battery back up to full capacity, Dave Solberg teaches you how to troubleshoot a faulty battery by first diagnosing your specific problem and then making the correct fix. As Dave mentions, there could be a few different causes if you discover a battery not charging properly on your RV. Most often, though, battery capacity depends on the type of charging cycle you conduct prior to operation.
With this idea in mind, Dave talks about the difference between a static fill (which can lead to sulfation, deteriorated terminals, etc.) and a multi-stage charge. He also gives you tips for testing battery capacity and describes what you should do with one/both of your battery’s solenoid(s) when a 25-amp draw reveals the battery has zero charge. Heed Dave’s advice, and you will show your RV batteries the TLC they deserve!
One of the most common questions we get on our social media sites is low batteries. People having problems with them holding a charge, lasting very long. Now we got a very interesting question that just came in on batteries that says, I have a battery problem, had the engine and coach batteries on trickle charger. Usually a two amp battery minder, excuse me, battery tender and checked them before an upcoming trip. Both batteries were down to two volts.
Now that's pretty concerning right there. There was an event at our property that caused an electrical problem. After charging and installing the batteries, I noticed I was getting no juice at the coach battery. The converter shows 13 volts. Traced the converter to battery line, to box, to capacitor looking devices.
Can you help diagnosis? I have 13 volts at the box, zero volts at the battery. So, first thing is we got a typical battery set up here on a Monaco, this happens to be a 1996. It's got the start batteries and the house batteries. What a lot of people don't realize is when you are hooked up and just letting them charge on a normal charger, you're not conditioning the batteries properly.
They need to do a multi-stage charge. So you do like a 16 volt charge, it boils these batteries up and breaks up the sulfur. Then it goes into a float and an equalizing charge. And unless you've got one of the very large 2000 watt inverters with that multi-stage, by leaving it plugged in you're just simply letting the batteries drain down to 10.5 and then go get a hard charge and that'll bring them up to 12.5 and that's not gonna condition them. By just putting a two amp battery tender on it, same thing.
You're gonna get sulfation. So, a couple of things to look at, first of all this setup here kinda concerns me a little bit because we have our engine battery right here, the chassis battery. I've noticed on our terminals here that on this side of the terminal, it started to deteriorate and we only got about 1/8 of an inch of metal touching that. And this rig has had a lot of problems with batteries. They've replaced probably about five different times and mostly because they leave it in a storage facility just plugged in.
Now, the second thing that's a little interesting about this is, this is the tray for the house batteries and when this was brand new, it would've come with four Trojan six volt batteries hooked in series and then to parallel. Meaning positive to negative on the first two banks that would give me 12 volts of power then positive to negative on the second battery bank and then positive to positive so that the two 12 banks would create a 12 volt system but with a lot of amp hours. Now the concerning part about this one is I see that here are the traditional cables that came in with the spade, because most of your deep cycle batteries are going to have the wing nut or some type of fastener like that not the posts. This battery right here was just put in within the last probably two, three months. It has 1000 cold cranking amps.
Now a house battery, a deep cycle battery does not rate by cold cranking amps. You don't want that hard charge to start an engine, you want a deep cycle to be able to last longer. You're gonna look for amp hours. A group 24 is gonna have about 110, a group 27, so forth and, and the different groups and the more amp hours. And I think what happened with this one is they had problems with it, they went to an interstate battery which, not really familiar with motor homes and travel trailers.
And, and it looks like they got two cold cranking amp batteries in this down for house batteries. And then they just put an adapter over the years and, and popped it in. Cold cranking amp or start batteries are not designed to be drained and cycled back. House batteries, deep cycle are designed for that. So if you do this, you drain it down and just keep letting that happen, eventually they're gonna go bad.
Probably why they were having some problems with this one. Now in the question that we had here, again the two amp battery the first thing I would check, is take the battery somewhere, do a multi-stage charge. The only way you can tell the capacity of your batteries is to connect them to a 25 amp draw and see how long they last. I would bet they're sulfated. I would bet that they have very little capacity but now if it's showing zero in there, you also have what's called a momentary start.
It's a solenoid and he mentioned that in the question that there was two solenoids inside of it. When you're driving down the road in a typical motor home like this and a travel trailer won't have this, but motor homes will have a momentary switch. So when I'm driving down the road that engine alternator goes through that solenoid and charges my house batteries. If I'm at a campground and for some reason I leave my engine battery on, radio playing, whatever, that engine battery drains down. I can push that momentary switch and jumpstart my house batteries to my engine battery.
It's through that solenoid though. So if you had an electrical problem at the facility you have 13 volts coming out of your charger which he claimed to have with his meter coming out of your distribution center or your converter but you have zero at the batteries. Then I would say that you probably have those solenoids have shorted out. And usually they're located right in the same compartment. Now these, we've got a couple of disconnects under here, the solenoid is inside hidden but a lot of your, a lot of your motor homes will have it right in the step.
Well, right next to that. So, with that you're gonna have to get that solenoid checked. If it's not coming the other side, you probably need to replace it.
I have a 1996 Monaco similar to the one in the video. I recently replaced replaced all batteries but my alternator doesn’t seem to be charging my engine battery. I have had the alternator looked at and it worked fine when the repair shop pulled it out and tested it at their facility, but as soon as they hook it back up to the Monaco it won’t charge the battery. Have you ever run into this before?
I have a 1990 jayco mini i just replaced the battery. This is my first used rv i am clueless as to why it wont start.
My battery on my aliner is not charging after I drive with it all connected to my destination. The battery itself was tested and is chargeable. How can I troubleshoot this?
I had to replace my Class C engine battery. I was told to disconnect the positive terminal to preserve its life when in storage. My 2 6v house batteries are still connected in series. should I disconnect the positive on those also? And is it the positive that should be disconnected or the negative? thx
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