My MH alternator charging is around 20 amps after things settle down from about 35 amps from starting the engine and wait a bit.
However, with my big solar set, and it set to 14.x, it soon overwhelms the alternator voltage which ends up below the solar voltage by a bit, so the alternator contribution to the total amps is more like 10 amps--- not the 20 amps it would be without the solar.
In any case, the alternator charging isn't hurting anything and at best, does add some amps. If it is not sunny, there is no solar, so then the alternator charging is what you have going down the road.
