Re: Batteries series parallel vs series for longevity
Probably several pros and cons here (speaking as an engineer--not as somebody with a lot of experience with these batteries)...
Series Parallel of 12 volt batteries:
- Fewer battery interconnects for you to maintain. Easier wiring.
- If one battery/cell fails, you still have 1/2 a bank to run on until replacement arrives
- If one cell dies, have to replace 1/4 of your battery bank.
Batteries need balanced current flow for proper charging and discharging--Series Parallel could favor (or deny) a weak cell in part of string--leading to over/under charging of just a portion of a bank.
- ~161lbs per battery--bit more difficult to service.
Series of 2 volt cells:
- Many more battery interconnects to make and maintain.
- If one cell dies, may have trouble running bank until replacement arrives.
- If one cell dies, only have to replace 1/12 of battery string.
- All cells get identical charging and discharging currents. Never out of balance with weak cell or other wiring/balance issues.
- ~65lbs per cell. Easier to move around.
IMHO, I would probably tend towards the single string of series 2 volt cells if price of 12 volt bank is not much different. Also look at which type(s) are available locally from stock to determine how quickly you can bring a replacement on-line.
If the company has good records of replacements based on series/parallel installations and finds series last 2x longer--would be a difficult data point to ignore.
And others have already posted similar comments as I was typing...
20x BP 4175B panels (replacement) + Xantrex GT 3.3 inverter for 3kW Grid Tied system + Honda eu2000i Inverter/Generator for emergency backup.