It was all time2roll's fault anyway! about 14 years back, he said I should try my new Vector 35 amper along with my then Vector 20 amper and i should get 55 amps. I did! So, if some is good more is better.
Here is a sequence of photos I posted about 10 years ago showing how it all works. Note that the 20 and 35s are 14.6 volts and the 40 is 14.8 volts, so it stayed on longest.
Amps tapered on the lower voltage chargers until they dropped out while the higher was still at full amps (40.4) then it started to taper as the bank continued to charge up.
I confirmed the total of the amps on each charger was showing on the Trimetric.
It works the same with solar controllers or whatever. You can't get exact same voltages by setting them due to wiring differences, but close enough to get the job done.
You can have alternator charging ( or 7-pin version) , solar charging, and even generator/converter charging all at the same time and it will work the same way. The alternator's voltage drops once you get going, so it could end up as the lowest voltage charger, not doing anything once the house batts reach its voltage while the other chargers do the work.
