I want to add a second battery bank(2 GC2's). I don't have the room to add anymore batteries to the main bank(4 GC2's). I want to use the second bank mainly to run a 300 watt inverter for the bedroom TV/Sat System. I do not plan on running the inverter at max loads. If I put a relay with #10 wires in that will connect the two banks together will all the battery slowly equalize, when not being drawn on. I was thinking I could put a separate charger for the second bank, or should I just keep them totally separated? Any useful input will be great full. Thanks Gary

Hi,The 2nd bank will not totally equalize with the main bank. The longer the wire distance between the two banks and the thinner the wire the poorer the results will be.Eventually the 2nd bank may become a parasitic load on the first bank.I'm sure someone will "chime in" and tell you that what I said is baloney. Refer them to this site: correctly interconnecting multiple twelve volt batteriesYou could add a "buck/boost" device with a battery voltage sensor on the 2nd bank and "dial in" the correct amount to overcome the resistance in the wiring.You could "rotate" the battery positions once a week to keep them all equally compromised.A separate charger would work, too.The reason for wanting to interconnect all six jars is to take advantage of the Peukert effect. Think of all the bank as three large 12 volt batteries. Two in parallel will provide power longer than using one and then switching to the next. Similarly three in parallel will run longer than each being used "one at a time". This is useful when boondocking or in a non powered campsite.

I know that puzzle! :)The separate pair of 6s will be fine except for charging them at the same time as the main bank. "Depends" on your set-up.You can have longer links between one pair of batts than the other pair has between them. But now how do you attach the loads with three 12s? There is a proper way but not very convenient.Bottom line is, wire them up however works best in your own set-up. "Perfect is the enemy of Good Enough"BTW when linking a low set of batts (12.1v) to a fully charged set 12.7V) the "spread" is 0.6v, so you don't get many amps! Takes hours and days to equalize their voltages. Forget all that. You can jumper the two batts onto the four batts whenever you happen to be charging the four. That will get something done. "Depends" if that is enough.Story is you can do anything you like --it all works. Just takes time and a bit of effort.

My thought process was to have two separate banks, and charge them each with there own charger. Than, I thought if I installed a relay to connect the 2nd bank to the first it would help it out a little with the Peukert effect? When I go to watch TV I would separate the two system and charge them before linking them together again. Am I wasting my time with this? Will I gain anything or just keep it with two totally separate systems. I am not looking for the perfect system or I would be using a lot heavier wires

There are so many ways to do it and I am unclear just what your wiring diagram would be. They all work. Peukert is good for discharging the whole batch of batteries at once. You get more than twice the AH from doubling! :) But it doesn't matter how you recharge them except at home when going to 100%. Then separate them by type and age and do their 90-100s and Equalizes separately

Adding 2nd Battery bank | Good Sam Community

pianotuna
Nomad III
Aug 07, 2013
Hi,

The 2nd bank will not totally equalize with the main bank. The longer the wire distance between the two banks and the thinner the wire the poorer the results will be.

Eventually the 2nd bank may become a parasitic load on the first bank.

I'm sure someone will "chime in" and tell you that what I said is baloney. Refer them to this site:

correctly interconnecting multiple twelve volt batteries

You could add a "buck/boost" device with a battery voltage sensor on the 2nd bank and "dial in" the correct amount to overcome the resistance in the wiring.

You could "rotate" the battery positions once a week to keep them all equally compromised.

A separate charger would work, too.

The reason for wanting to interconnect all six jars is to take advantage of the Peukert effect. Think of all the bank as three large 12 volt batteries. Two in parallel will provide power longer than using one and then switching to the next. Similarly three in parallel will run longer than each being used "one at a time". This is useful when boondocking or in a non powered campsite.

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