Suspected Converter Problem

BFL13 wrote:

What I don't get is now your pos and neg are not equal from their junctions to the converter. The two pos are equal and the two negs are equal but they are not equal to each other. I am unclear (to say the least) if they are supposed to be.

Generally, the pos and negs do not have to be the same since it is a circuit and it is the total R of pos and neg that counts. So it ought to be ok if the pos links are equal and the neg links are equal but the paths from pos and neg junctions to the converter are not the same. Or maybe it does matter. I have no clue.

....

So perhaps somebody who does have a clue about all this like PT does, can step in here and explain it all. :)

For balanced connections to the battery, the wiring impedance seen by each battery needs to be the same. It matters not one whit whether the impedance is on the positive or the negative side, nor whether the impedance on one side is equal to the other.

If you think about it, the standard way of paralleling two batteries (with diagonally opposite connections for positive and negative) does not lead to equal positive and negative impedances for the batteries, and in fact the extra impedance from the paralleling wires is on the positive side of one of the batteries and on the negative side of the other one. It works because the total impedance, and hence voltage drop, is identical for each battery.

When there are more than two batteries, it can get a bit more tricky as sometimes some wires around the batteries carry more current than others, and so the voltage drop is greater in them when their physical characteristics are otherwise the same...but that's of no importance in this particular case.

I'm a fan of keeping things simple and of not having too many connections on one stud/bolt. Bus bars do often accomplish this nicely. A short length of copper water pipe, squished flat in a vice, makes the guts of a very effective and inexpensive bus bar.