Only use 1 house battery?

[FW28z]

Both batteries may be bad, especially when wired in parallel.

Hate to say it, but you should not swap out just one battery but both whenever replacing them. They must be the same type and model and age, so the conventional wisdom is to change out both batteries when one goes bad.

Batteries lose charge capacity with age. If you put a new battery in parallel with a significantly used battery, you will have a capacity imbalance that means one battery will be fully charged before the other battery.

This can cause the fully charged battery to be overcharged and boiled as the older battery continues to be charged. This has a lot to do with the sophistication of the charger, but that is the risk. Therefore, mating a new battery with an older battery could damage your new battery.

While there is some validity about only changing one battery if the other battery is known good and fairly new, it sounds as you are having significant issues that may very well cause the "good" battery to be damaged.

The real problem is if you replace one battery, you can expect to pay $80~120 for it. But if it fails because you did not replace both batteries, then you are going to have a bill for 3 batteries. I guess it all depends on luck.

The idea to disconnect the batteries for a day and check them is not a bad one, however, I would go for less than a 0.1V difference. For lead-acid batteries, 0.1V is around 12.5% of charge. So I would want to see a smaller voltage difference.

To check, do this:
1. disconnect both batteries from the RV.
2. put them on a trickle charger for at least 24 hours. Charge them separately, so if you only have one charger, do each battery in sequentially.
3. disconnect the battery(s) from the charger(s) and wait 24 hours.
4. take your voltage measurement.

Unfortunately, RVs are made as cheaply as they can be. For example, boats typically have a multi-bank charger, with one bank for each battery - so they charge independently. The batteries are then connected together using a 1-both-2 switch, combiner, isolator, and so on. That would be the ideal setup as it alleviates most problems with parallel wired batteries.

However, buying a second battery will certainly be less expensive than rewiring your RV.

[Metalman]

Originally Posted by junior30

I am completely frustrated with my rv. After switching to one battery that battery started boiling over. I now cannot retract my levelers or start my generator due to low voltage.

I also bought a new battery and installed it in the house and still got the low voltage. I checked the breaker in the battery area and it's not tripped.

I had a tripped planned for Thursday and cannot go now. I am quickly coming to hate this rv. I have never bought something and had continuous issues. I will be bringing it in to my dealer but he's 2 hours away so that presents its own issues.

If the battery is boiling over, you either have a battery problem or a charging problem. Can you check the voltage when the battery is being charged? Some charger/maintainers will get as high as slightly over 15 volts, but only for a short period of time. Once charged, my batteries are between 12.9 and 13.1 volts while connected to the maintainer or RV charger. If you specify your RV age and brand in your profile, perhaps you can get specific information from someone on this forum.

[flogger]

Metalman - had a great conversation with Bill at Thor customer service - it seems when we are connected to the shore power, we needed to flip the use switch on - that will keep both the truck and house batteries charged. Regarding connecting to the house power, that's not going to keep everything charged as a 30 amp service. He suggested connecting the refrigerator directly to an extension cord to get it cold prior to taking off for the next trip. He was extremely helpful with a couple of other tweaks we need to make -

[Metalman]

Originally Posted by flogger

Metalman - had a great conversation with Bill at Thor customer service - it seems when we are connected to the shore power, we needed to flip the use switch on - that will keep both the truck and house batteries charged. Regarding connecting to the house power, that's not going to keep everything charged as a 30 amp service. He suggested connecting the refrigerator directly to an extension cord to get it cold prior to taking off for the next trip. He was extremely helpful with a couple of other tweaks we need to make -

Very interesting. From your above post, I assume you have some type of travel trailer and truck combination. I am surprised that you cannot run all 12 volt devices when plugged into 120 volt 12/20 amp shore power circuit and keep your batteries charged. We have never had a problem with any RV when plugged into 120 volt 15/20 amp shore power. Of course we can't run the AC unless we switch the water heater and refrigerator to gas.

When preparing for a trip and first using the refrigerator, I run it on gas, as it cools much faster than when using electricity.

[gmc]

Well.. you either have 2 bad batteries - or a problem with the charging circuit...

Originally Posted by junior30

I also bought a new battery and installed it in the house and still got the low voltage. I checked the breaker in the battery area and it's not tripped.

Where are you measuring the voltage? and what are you reading as 'low'?

I'd expect putting a new battery in would provide normal voltage - though I would disable the charger (circuit breaker) until you have the system checked. No need to boil a third battery.

[gosman]

I am looking at buying a used Four Winds Class C 31E 2014. His truck battery is dead. So we will have to look into. I have a question for this thread: Will I be able to run my CPAP machine in the bedroom plugged into the 110 outlet without the generator running while dry camping? Will the two house batteries carry me through the night? Or can they even invert to 110 in the back? Has anyone installed an invertor on their Class Cs?

[EA37TS]

Originally Posted by junior30

I am completely frustrated with my rv. After switching to one battery that battery started boiling over. I now cannot retract my levelers or start my generator due to low voltage.

I also bought a new battery and installed it in the house and still got the low voltage. I checked the breaker in the battery area and it's not tripped.

I had a tripped planned for Thursday and cannot go now. I am quickly coming to hate this rv. I have never bought something and had continuous issues. I will be bringing it in to my dealer but he's 2 hours away so that presents its own issues.

In my coach the engine must be running and the isolator closed before the jacks get enough power.

Usually I get the low voltage error when I try turning on the leveling system power too soon after starting the coach. When I get the error, if I turn the jack power off and wait about 30 seconds and turn it back on the error goes away and the jacks will function.

[Marine By Choice]

Originally Posted by gosman

I am looking at buying a used Four Winds Class C 31E 2014. His truck battery is dead. So we will have to look into. I have a question for this thread: Will I be able to run my CPAP machine in the bedroom plugged into the 110 outlet without the generator running while dry camping? Will the two house batteries carry me through the night? Or can they even invert to 110 in the back? Has anyone installed an invertor on their Class Cs?

Not sure how your rig is set up, so cannot answer your question. My wife uses a CPAP machine. I put in a 12V receptacle, bought a 300W inverter at Loves ($29.99 on sale!) and will be running it from that. Depending on how many other things will be drawing power (refer, furnace, lights) will determine how long it will run. Hopefully will get a full night from the 2 batteries.

Remember to moniter the battery water levels closely, as drawing down and charging often requires more water.

[gosman]

Thanks so much! I was wondering if a cheap invertor would work. I have heard that if you run the CPAP with out the water, it will consume less power. I'm not sure if this coach has a 12 volt outlet. But I thought most do?

[Marine By Choice]

My Vegas 24.1 has a dash 12V, but that runs from the single chassis battery. Didn't want to drain that single battery, so went with my mod.