Battery Issue

[rhunter]

I was hoping to confirm the correct way to connect my coach battery bank. I think I've got it wired incorrectly since performing some battery maintenance. The batteries appear to be charging (I've got a heart interface charger/inverter), however, once I disconnect shore/generator power the batteries discharge very quickly.

I've inserted a picture below and marked with red lines the 4 connections from the battery bank to the coach. I think my problem lies with one of those connections.


I'd appreciate any assistance you can provide.

Thanks

[CA_Traveler]

Normally the only heavy draw appliance on the inverter is the MW. The refer and HW should not be on the inverter. Perhaps someone rewired your MH? Does the HW work on propane?

Good time to check the charging. With discharged batteries you should see 14.4V+ bulk charge tapering to 13.4V+ float.

[rhunter]

Thanks for the replies. The electric water heater was in fact turned on. I didn't even think about that being an issue as I assumed that it wasn't wired to the inverter. That might just be the problem as I was seeing a big load on the inverter when it was inverting. I'll check tomorrow.

Also the inverter is a Xantrex Freedom 458 combo/charger.

Thanks again for the advice. Much appreciated.

[CA_Traveler]

Or you could disconnect the inverter positive cable and see if that is the source of the drain. Note: For safety disconnect both negative cables first.

[MrWizard]

those batteries fully charged should read over 13v No load
and not drop very much when you turn on the inverter

is this an inverter-charge combo unit, or a stand alone inverter

if this is a stand alone, rember to turn off the converter
also remember to make sure the fridge is LP not 'Auto or A.C.'
same for the water heater, turn off electric mode

all of those things are big 'power suckers'

[DrewE]

I think your battery connections are basically okay but your inverter is powering something you don't realize it's powering, like maybe the converter (if you have a separate one) or the fridge element or even the water heater element.

The battery connections should ideally be taken from diagonally opposite corners for the same thing--so 2 and 4 to the inverter, 1 and 3 to everything else, or vice-versa, or both on 1 & 3 or both on 2 & 4. It's not entirely clear to me that you've figured out if that's currently the case or not. Failing to do so would leave the batteries slightly imbalanced and eventually tend to lead to uneven wear and various difficulties associated with that, but would not cause a big loss of capacity right off.

[rhunter]

Sorry - the cables don't go to the starter. I have chassis batteries for that. I believe they go to the inverter - a Xantrex 458 Freedom.

Here's a picture of the batteries cleaned up. I did check the back 2 batteries with a hydrometer and they are good to go.



When I say that the batteries are discharging rapidly, I say this based on the reading on the remote panel connected to my inverter. When I initally got the RV I could get quite a bit of use of the RV with the inverter turned on before the batteries discharged. The kids could watch TV for example. I currently get very little - if I disconnect from ac with batteries fully charged I get very little battery life. The batteries go from 12.5 volts down to 10.5-11 volts per the remote panel on my inverter quickly.

[CA_Traveler]

Find out where the two starter? cables go. It doesn't seem right that those 6V deep cycle batteries start the engine. How about confirming that they are GC2 batteries. Don't you have chassis batteries?

[MrWizard]

the wiring 'as stated' should be ok

but something wrong with the math or the neasuring

5.4v each

5.4 plus 5.4 =10.8 NOT 13+

to get 13+ each battery has to be over 6.5v

IF they are really that low 5.4v each they are almost dead
they are NOT charged
which explains why they do down real fast

now why are they not charging
what is the voltage per battery, after 6hrs of shore power or generator
and the 120v disconnected

[CA_Traveler]

Post a clear picture showing +- terminals. But they may be OK.

Check the back 2 batteries with a hydrometer.

Next load test the batteries to see if they are good. Were they new at 5/18 as the blue label implies? Kinda wonder how 3 month old batteries look that way. I'd certainly suspect a bad battery or 2.

Clearly there is terminal corrosion. It doesn't appear that any battery pads or spray was used. Clean all terminals and all cables.

[rhunter]

Correction to my last post. I double checked the battery voltages and they are at 6.5 volts so they should be good to go. I also checked the acid with a hydrometer on the front 2 batteries and all cells registered as good.

[chuckftboy]

You have them wired correctly but a fully charged 6 volt battery should read 6.3 volts. At 5.4 volts, those batteries aren't charging.

[gsf35099]

It looks like you should be pulling from 1 & 4 or 2 & 3 for your leads out to whatever 12v they supply. Use a meter and make sure those read 12v.

From what I can see, you have the batteries connected as what others have shared to make 2 - 6 volts in series = 12v and then 2 sets in parrellel to = 12v with more amp/hr

Your voltages are really low and each battery should be ~6.8v. It's very possible as mentioned one of them is cooked and that left front would be suspicious to me.
A hydrometer is great to use and test each cell in the batteries for how good they are.

Something I would try is removing the leads to the coach & splitting the sets to try charging with a battery 12v charger & then seeing if the voltage still drops. If yes, then there is a battery issue, if no, then the coach is draining them.

[rhunter]

I cleaned up the batteries and traced the leads and here's what I found:

-The wet battery in my original pic had loose caps which allowed some acid to leak out. The lead plates are still covered in acid.
-All batteries measure 5.4 volts and if I measure the two series I get just over 13 for both "sets" of 6 volt batteries.
-The leads trace out as follows with numbers below corresponding to the numbers on the picture below.
1. positive lead to inverter
2. positive lead to starter I think. It goes up and over the engine.
3. negative lead to frame
4. negative lead to starter I think. Also goes up and over engine.

Note that the positive leads pull from different terminals as do the negative leads. Is this correct?

Recall that my symptom is that the batteries discharge very rapidly once i disconnect from shore power or generator even though the batteries show a full charge.

Additional thoughts?

[rhunter]

Thanks for the replies. Yes - I didn't take a picture before disassembling originally. My mistake... I'm going to do some troubleshooting this afternoon and see if I can fix it. Appreciate the assistance.