Handy solar info for lead acid batteries
Handy Bob
Forum Discussion
A criticism of pwm performance is that temperature can drop PV voltage below battery voltage. This criticism is make when a 36 cell panel charges a 12V battery, or a 72 cell panel charges a 24V battery.
BLF has a 24V panel that has only 60 cells, not 72 cells. That means his panel voltage is 1 - 60/72 = 17% lower than a 72 cell panel. That panel will more likely run out of voltage headroom in hot weather than the 72 cell panel.
Victron white paper
BLF has a 24V panel that has only 60 cells, not 72 cells. That means his panel voltage is 1 - 60/72 = 17% lower than a 72 cell panel. That panel will more likely run out of voltage headroom in hot weather than the 72 cell panel.
Victron white paper
BFL13 wrote:Salvo wrote:
Your 24V panels are not "true" 24V panels. A true 24V panel has 2 * 36 cells. You have less. That means the cliff where current drops is more to the left, at a lower voltage. Add the effect of temperature and your 24V pwm controller will have problems at higher temperature.
I was able to get the 24v battery bank to 30 volts before it ran out of steam due to the overhead, so it is not true that a 60 cell panel can't fully charge a 24v battery.
