BFL13 wrote:
ken white wrote:
This is a much debated topic, but for the minimal series/parallel battery systems typically found in an RV, cable lengths really don't have a very significant effect on charging if a quality multi-stage charger is used.
During heavy battery loading/charging, there will be a slight imbalance in current flow due to varying cable resistance which creates a corresponding voltage drop across the connections.
If the batteries are in good condition and of the same type/size, then as they approach full charge current is reduced and voltage drop issues are reduced too, so the charge starts to balance and is eventually very close as long as the varying cable lengths are not severe.
Having mixed age, size and type batteries will typically create an imbalance condition that has a much worse charging/discharging effect than cable lengths.
Ken you must be assuming the wiring is near enough for being right to say it doesn't matter that much.
It sure does have an effect on charging when your charger to battery cables can't handle the amps of the charger at that voltage---you don't get that many amps. That is why all the fuss about getting the charger close to the battery so you can use a reasonable gauge of wire.
I agree that if the cables are undersized, then the voltage drop may become excessive during heavy charge currents.
But the batteries will eventually charge as the current tapers when the battery voltage reaches a full-charge magnitude, though heavy discharge may still be an issue depending on which cables are undersized.
If the controller/converter cables are undersized, and the controller/converter has a voltage sense connection, then the wire gauge become much less of an issue since the output compensates for the lower terminal voltages.
