Not Balancing Three 12v Right
This post is just for info in case anybody else has a similar situation
I have learned the truth about wiring up three 12s as though they were two 12s.
With the load and charging pos and negs on the outer batteries, I have no measurements for discharging, but confirm that when recharging, the middle battery does not reach as high an SOC. It is the same voltage as the others of course, but has a lower SG for measuring SOC after the recharge is done.
Eventually, someday, the electrons might all even out and so the SGs might even out, can't say. Doesn't matter , can't/don't want to leave them undercharged that long.
This doesn't matter when doing fours days camping in a row, then going home and getting each set of batteries up to full baseline SG separately before putting them all on a Float.
(It is worth banking them all for those four days to get the Peukert advantage. Eg, I was able to go two days with them all banked before needing a recharge, where before with them in separate banks, I needed a recharge every day. Confirmed Peukert advantage!)
But, now heading into solar charging time for five months off-grid, I now see a peril in leaving the three 12s all hooked up as though two 12s, where the middle one will never get up to speed for months.
I can't wire them up "properly" for three 12s (various reasons) so I am going back to having two banks and properly balancing each bank for recharging.
I know that method works well from last summer, and with it being warmer and longer days, there is no daily AH need for the Peukert advantage doing 50-90s like in winter, no solar. I will be doing more like 85-97s on solar daily. I can't leave the middle battery undercharged for months!
Different situation, different set-up.
I have learned the truth about wiring up three 12s as though they were two 12s.
With the load and charging pos and negs on the outer batteries, I have no measurements for discharging, but confirm that when recharging, the middle battery does not reach as high an SOC. It is the same voltage as the others of course, but has a lower SG for measuring SOC after the recharge is done.
Eventually, someday, the electrons might all even out and so the SGs might even out, can't say. Doesn't matter , can't/don't want to leave them undercharged that long.
This doesn't matter when doing fours days camping in a row, then going home and getting each set of batteries up to full baseline SG separately before putting them all on a Float.
(It is worth banking them all for those four days to get the Peukert advantage. Eg, I was able to go two days with them all banked before needing a recharge, where before with them in separate banks, I needed a recharge every day. Confirmed Peukert advantage!)
But, now heading into solar charging time for five months off-grid, I now see a peril in leaving the three 12s all hooked up as though two 12s, where the middle one will never get up to speed for months.
I can't wire them up "properly" for three 12s (various reasons) so I am going back to having two banks and properly balancing each bank for recharging.
I know that method works well from last summer, and with it being warmer and longer days, there is no daily AH need for the Peukert advantage doing 50-90s like in winter, no solar. I will be doing more like 85-97s on solar daily. I can't leave the middle battery undercharged for months!
Different situation, different set-up.
