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Expand RV capacity with physically split banks?

Swamplizard

Ready to unplug and wander the USA
Joined
Oct 21, 2020
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I currently have a 24 V volt 280 amp hour battery pack in my RV. I would like to double the capacity however space is at a premium. Is it possible to have the second battery bank be comprised of two 12 volt packs located about 6 feet apart and combined into a 24v pack?

There is a small amount of room in front of each wheel well inside the RV which could accommodate a 12 V pack. I am not sure what gauge wire would be needed to connect them and make a 24 V secondary battery pack. Has anyone done that successfully?

As always …. Thanks
Swampy
 
Quick answer is yes but they may charge and discharge differently since you will have different cable lengths.
 
I have not done it but if I were to try I would...
Use intermediate balance leads to a terminal block so that you could use a single bms.
Use 12 awg wire allows yellow ring terminals which crimp nicely without having to double the wire.
Use 12 awg to the terminal blocks and fuse each positive link as close to the battery terminal as possible.

You could use this ^ table to make the resistance somewhat equitable between the cell interconnects and the groups of cells.
 
hadnt thought of doing the balance leads - good stuff - thanks
 
I have a spot in my RV that had been my original choice for where to place my batteries (2 x 280Ah 12v 4s). I found a better spot that I could get the batteries and all the other components into (MPPT, inverter, etc) that required a shorter run of cable to the batteries.

In the back of my head the idea of adding more battery capacity has me considering that original location. The cable length would be four times longer than what the current batteries are using. Changing the existing batteries to have the same length of cable as the new batteries seems like a huge cost and effort. I would likely have to jump from 2/0 to 4/0 on all the cables, but I might be able to get away with keeping the 2/0 on the existing batteries and use 4/0 on the new ones. I would have to run the numbers on voltage drop and figure out resistance too.

The effort involved and the much higher cost of cells has this addition on indefinite hold.
 
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