PD or Iota for my upgrade?

BFL13 wrote:
I was thinking if you wanted 14.8 battery, your PD9280 should be at 15? I find you need 0.2 spread at least as you see in those graphs I posted.

Perhaps I missed something in your graphs. Do you mind spelling it out - why you think it needs 15?

My graphs show that even at 84 amps, I'm only losing about 0.1 to 0.13 volts in the cables. I monitor both the voltage at the battery and at the charger and I've never seen a 0.2 volt difference. During that part of the charging cycle, the converter is current limited, not voltage limited, and the charger is simply holding the voltage about 0.1 to 0.13 volts above the battery voltage - enough to maintain the preset current limit.

During charging, as the voltage at the battery climbs to about 14.65 - 14.7, (with the charger at 14.8 and the current about 75 amps), the charger is prevented from increasing the voltage to hold the high current level by the voltage limit setting at 14.8. Thus, the current begins to drop. This is the transition point in those graphs from near constant current mode to near constant voltage mode.

The current reduction reduces the voltage loss in cables. By the time the batteries have become nearly fully charged, the current is down 10x to below 8-9 amps and the voltage drop in the cables has dropped to below 0.01 volts. The battery reaches 14.79+ volts, which is exactly what I want/need.