Two 12v batteries - 11.7amp - Not good.

[Oregon_Camper]

My new Bighorn 3160 came with two 12v batteries wired in parallel (see image). After having the trailer charging at home for 48 hours on a 15ams circuit and then for another 48 hours while camping on a 30amp circuit, my system showed only 11.17 amps coming from the batteries.



I had an inverter installed to power the theater seating (they only operate on 110v...no manual open/close) and it was attached to the POS and NEG of just one battery. I would expect this should have been installed on the POS of battery 1 and Neg of battery 2. The inverter was OFF the entire time, so it shouldn't have been pulling any power.

I thought I had a bad battery, but once I got them home and on chargers, they both come back to 13.4 /13.6 volts.

Any idea what could be wrong?

 

[danemayer]

When you got home and "on chargers" I assume you mean battery chargers, not just getting a charge from the Power Converter in the RV.

If that's the case, you may not have been getting a charge from the Power Converter while at your campsite. One possibility is that the 12V mini-circuit breaker in between Power Converter and battery tripped.

If your rig came from the factory with 2 batteries, it probably also came with a residential refrigerator (and another inverter).

I've attached a wiring layout that's probably close to what you have if you do have the residential frig. There's also a picture of the buss bar and a closeup of the mini-circuit breaker. The reset button is teeny-tiny - sometimes easier to feel than see.

 

[Oregon_Camper]

Sorry...the trailer came with one battery...dealer installed the second. I do not have the residential refrigerator...just the standard RV type.

Yes..I meant went I got home, I removed the batteries and have them on 2 separate charging devices. They both charged for a while...now they are both in "float" mode on the charger.

BTW...they are cheap "Deka" batteries. Nothing I would ever purchase, but I want to resolve my issue, before dropping in some Trojan batteries.

 

[danemayer]

When you reinstall the batteries, do so with the battery cutoff switch OFF. Take a voltage reading. Then turn the cutoff switch ON. With shore power applied, you should see the battery voltage go up to 13.6V. If it doesn't go up, look for the breaker with the reset button and reset it. Then check voltage again.

 

[wdk450]

Are the battery cables big enough? Are all main 12 volt connections clean and tight, including the ground bonding??? High resistance in a circuit will limit the amps delivered. How did you measure the battery amps output?

A standard Group 24 type automotive lead acid battery (even deep cycle) should have enough amps to start a car - 100 to 150 amps or more - enough to weld with. Jeep owners on trips to the boonies will parallel 2 batteries to make welding repairs. That's another reason large lead-acid batteries are dangerous - don't cause a short with a screwdriver or wrench!!!

 

[JanAndBill]

Checking the voltage doesn't mean the battery is good. They need to be load tested. They could still have a bad cell. Take them to a battery dealer and have them tested.

 

[Roller4tan]

If the dealer installed the second battery and momentarilly hooked them up wrong, they may have blown the fuses on the converter that protects it from being cross wired. These are usually 2 large amp fuses on the converter next to where the battery cables hook to it.