upgrading power converter

BFL13 wrote:

tenbear wrote:

BFL13 wrote:
No, I want the current to stay at 80 from start up till battery voltage reaches 14.4 (in PD case), not drop right off like Fisherguy's does.

With the converter voltage at 14.4v and the charging current at 80A, the battery voltage will never get to 14.4v with any resistance between the converter and the battery.:h

Right, converter voltage is a tad higher than battery voltage. That graph above shows more of a spread with my PM3-100 but most of that is voltage drop on the charger to battery wires (even though they are short and fat, it is at 100 amps)

Iota's IQ4 blurb used to explain how the Iota went to 14.8v and this got the battery to 14.6v, which was the "trigger" and 15 minutes after battery hit 14.6, converter would drop to 14.2 for its Absorption Stage.

So the PD if it goes to 14.4 will get the battery to almost 14.4.

BTW in that graph above, you see I had the PM3-100 mod set to 14.6 but it was still slower than the Vectors. I have since cranked the PM3-100 to 14.8 and now it gets it done as fast as the Vectors shown there.

So you raise the converter voltage to force the battery to accept more charging current to allow the battery voltage to reach 14.4v while charging at 80A. As you observed, it takes a large battery bank and low resistance wiring.

Edit: I think I would want to rewire my RV to draw the 12v off the battery instead of off the converter. Then you could raise the charging voltage to anything as long as the battery voltage didn't get too high.