Battery Charge from Multiple Source

[MutinyGuy]

I have a 2010 Winnebago View with 2 solar panels installed by AM Solar. I have the stock Parallax single stage converter and a 180 Amp alternator. Lets say I have the engine idling, solar panels on and the converter on shore power. What source is really providing the charging current? Which one takes precedent or do they all somehow work together?
Would like to understand how these 3 different charging sources work together...hopefully in some kind of harmony!

Kind regards,

Jim

[RV Wizard]

Technically a good charging controller will reduce the charging voltage when it sees the battery voltage coming up to set point. Saying this, there is no way to know which source is actually charging at its full potential. It is true that all sources are giving at least a float charge and possibly the alternator will continue to charge a bit more in some scenarios.

[Alan Roberts]

Hello - to build on RVWizard's answer - each charger will source current based on the voltage that it sees. If only one charger is in place then it only sees the battery and throttles back as the battery voltage rises to the adsoption set point. When you add a second charger (set at a slightly higher set point), the first charger sees the artificial rise and scales back a bit.

In my case my alternator is set at 14.1 and can supply 160A; my solar system is set at 14.8 and can supply 20A. When I roll down the road I see the maximum capability of the panels and the alternator scales back by roughly 20A. If the set point of the solar panel was lower then the alternator, then the reverse would happen. I see similar results when I run the generator.

From a practical view, when you are early in the charge cycle (bulk), the larger charger will dominate (amp-hours) and in float, the higher set point will dominate.

The simple answer is: whichever charger is at the highest voltage; then the current from each souce will modulate according to its capability.


Alan
02 Windsor
Beeaverton, Or (Currently in Yuma)