Batteries

[Montreat]

currently am running (2) 12 volt agm batteries which have 78 ah each. After running nothing but the refrigerator overnight they drop to 12.5 volts. I feel I need to increase my capacity and find 12 volt size 24 batteries at 100 ah. I also see 6 volt batteries have 220 ah, if I run (2) 6 volt would this give me 440 ah or do I reduce this in half because of it being 6 volt? Any suggestions would be appreciated.

 

[Jsoboti]

When running two 6V batteries you must connect them in series vice parallel. When two batteries are connected in series you do not add the ah, however you do add the voltage. Therefore 2x 6V 220ah batteries, wired in series, will yield you a 12v battery bank with 220ah. You may be able to take them down to a deeper depth of charge but I'm not 100% certain on that.

I'm surprised you are using so many watt hours running just the refrigerator, might be worth installing a battery monitor so you can see how much amperage you're actually drawing / able to design your new battery bank around your expected needs.

 

[Montreat]

Thanks for the response. I have a battery monitor on order so should get some further information on my usage

 

[JaSAn]

Two 6V batteries (6V, 220AH)
- run in series = 12V, 220AH
- run in parallel = 6V, 440AH

 

[Montreat]

Thanks

 

[Vic Harder]

currently am running (2) 12 volt agm batteries which have 78 ah each. After running nothing but the refrigerator overnight they drop to 12.5 volts. I feel I need to increase my capacity and find 12 volt size 24 batteries at 100 ah. I also see 6 volt batteries have 220 ah, if I run (2) 6 volt would this give me 440 ah or do I reduce this in half because of it being 6 volt? Any suggestions would be appreciated.

12.5V doesn't sound like a problem. 12.6 is fully charged, resting voltage. Before buying new batteries, get a Victron BMV 712 so you can determine the actual SOC (State of Charge)

 

[Montreat]

Have a monitor on order, thanks