battery crazy

[OKpete]

2013 3170DS, still having problems trying to keep coach batteries charged for winter. Posted problem on this forum and got some great advice. Last winter I left rig plugged into 30amp in garage and batteries got cooked. Forum folks advised the rig had a converter that could not be left plugged in. I have atempted to connect a trickle charger/maintainer. For first day it seemed to work as charger indicated it was connected correct and was charging( I checked and both batteries showed 12.47 amps) but the next day charger, instead of indicating "float" mode, it indicatdd a red light meaning something was wrong. The batteries ars in the coach and connected the charger to the pos and neg term on just one battery, figuring since they are in parrellel the flow would go from one to the other and maintain both. Can anyone tell me what I am doing wrong. These are brand new batteries and would not want to ruin them.
P.S........I left the battery cutoff switch in the OFF position and did not disconnect cables from coach. Long story but maybe gjves enough to figure wgat is up. Thanks

[TURBS]

What charger are you using now?

[btritschler1437]

Since the batteries are in parallel you need to connect the charger to a positive on one battery and the negative on the other battery. The way it is now set up, you are only charging one battery. See the YouTube video - Charging Two 12V Batteries in Parallel.

[OKpete]

Using a green "Battery Tender " I WILL WATCH THE VIDEO. THANKS Y'ALL WILL LET YOU KNOW

[MNtraveler]

Originally Posted by btritschler1437

Since the batteries are in parallel you need to connect the charger to a positive on one battery and the negative on the other battery. The way it is now set up, you are only charging one battery. See the YouTube video - Charging Two 12V Batteries in Parallel.

That's enlightening since you would think the two batteries are directly linked up. Thanks for the tip and the video reference.


Land of 10,000 Lakes
2016 Forester MBS 2401R

[RamblerGuy]

How you connect a battery maintainer doesn't matter. The cables between them are so large and the charging current is so small the difference of current going to each battery is insignificant. High current during usage or charging can cause enough voltage drop across the cables to result in the batteries winding up with different levels of charge if the cable lengths are significantly different.

[trdutch]

I too keep the unit plugged in (to keep an electric heater on above freezing) and it was suggested to me on another thread that I just flip the circuit breaker for the converter to prevent 3 phase charging (that will cook the Batteries)
Then every month close the breaker for a day to keep the battery up.
I'm going to try that this winter

[funfinder5]

If you are turning the battery disconnect switch to "Off" then there shouldn't really be anything that is draining them. A good batteries selfdischage rate should easily get you 2-3 months before it needs a top off charge. If your batteries are discharging faster than that something is wrong with one of them and it's draining/killing both. This would be a good time of year to fully disconnect batteries you have in pairs and change them seperatly and let them sit (disconnect) to see if each has the same self discharge rate.

[drakethib]

Question.

Why the need for 2 12 volts, why not just one? If I don't do any boon docking, and the bulk of my camping is with shore power or via generator, do I really need 2, could I just go with one?

[Ford Idaho]

Originally Posted by drakethib

Question.

Why the need for 2 12 volts, why not just one? If I don't do any boon docking, and the bulk of my camping is with shore power or via generator, do I really need 2, could I just go with one?

I do the same type of camping as you, one battery has been quiet enough.

[drakethib]

Originally Posted by Ford Idaho

I do the same type of camping as you, one battery has been quiet enough.

I think this is the route I am going to take. I can always add one more later if needed.