Very Low OCV on Full Batts???
I've been seeing lower than usual resting ocv this winter, compared to last. Figured it was either wear and tear, too high a charging voltage, or a parasitic draw. So I tried throwing a lower vol...
Forum Discussion
Niner,
I just EQ'd them a few months back, and have not had them in full service since. At that time, while top charging and EQ'ing, I noticed they didn't respond well to the higher voltages; ocv wise. A follow up charge at about 14.8 volts always resulted in better resting ocv.
Until just recently, I have been cold weather charging them with the Peak 40 amper, but its voltage was getting out of control. One rather cold day I saw it go as high as 16.2v, so I switched it to a lower amp setting (it has 4, 10, 20, and 40a) in order to drop the voltage a bit. The resulting ocv's have been lower than usual, so I figured maybe it was the high voltages?
I switched to the modded pm4b, last Tuesday, for better control of the charging voltage. I did a top charge to 2.3a @ 14.86v and then dropped it to 14.6v and continued that 'til ~ 1a. After 4 days, surface charge still had them at 12.84v.
Everything seemed normal until after I rewired everything. But if the batts were indeed down in soc, the pm4b-45 would not have behaved the way it did today. It usually stays at 45a 'til about 83% on half the bank (a single 215Ah series string). So at 75% soc on the 430Ah series/paralleled bank, it should have stayed at 45a for quite a while. It did not. Both it's voltage rose and amps tapered immediately, so the bank was not depleted... nor should it have been. There are no measurable draws, and the cold weather should help sustain a high ocv.
While charging today, voltages across all 4 batts were well within reason... varying, around 0.01- 0.02v, changing occasionally. (I took readings several times throughout the charge).
I just EQ'd them a few months back, and have not had them in full service since. At that time, while top charging and EQ'ing, I noticed they didn't respond well to the higher voltages; ocv wise. A follow up charge at about 14.8 volts always resulted in better resting ocv.
Until just recently, I have been cold weather charging them with the Peak 40 amper, but its voltage was getting out of control. One rather cold day I saw it go as high as 16.2v, so I switched it to a lower amp setting (it has 4, 10, 20, and 40a) in order to drop the voltage a bit. The resulting ocv's have been lower than usual, so I figured maybe it was the high voltages?
I switched to the modded pm4b, last Tuesday, for better control of the charging voltage. I did a top charge to 2.3a @ 14.86v and then dropped it to 14.6v and continued that 'til ~ 1a. After 4 days, surface charge still had them at 12.84v.
Everything seemed normal until after I rewired everything. But if the batts were indeed down in soc, the pm4b-45 would not have behaved the way it did today. It usually stays at 45a 'til about 83% on half the bank (a single 215Ah series string). So at 75% soc on the 430Ah series/paralleled bank, it should have stayed at 45a for quite a while. It did not. Both it's voltage rose and amps tapered immediately, so the bank was not depleted... nor should it have been. There are no measurable draws, and the cold weather should help sustain a high ocv.
While charging today, voltages across all 4 batts were well within reason... varying, around 0.01- 0.02v, changing occasionally. (I took readings several times throughout the charge).
