Boondocking --- Average AH consumption/day?
I'm going to be adding solar to my 2015 Class C Majestic 28a. I currently have 2 lead acid batteries that state they have 122AH capacity each (from Walmart). I'm trying to figure out if I should add...
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If from 50-70% SOC at 14.4v(say) the batts will accept at least 30 amps, AND both solar and charger (powered by the gen) are at the same voltage set at 14.4, then yes, they will add their amps so you get 30.
If the solar is at say 14.2 and the charger is at 14.6, then as the battery voltage rises closer to 14.2, the solar amps will taper, but the charger's will stay at 20, so you get less than 30 total, tapering till the battery reaches 14.2 and no more amps from solar. Now the 20 from the charger keeps raising the battery voltage until it gets close to 14.6 and amps start to taper from 20.
Once battery acceptance is down to what one charger can do, you can yank the other charger. Say you have two equal voltage chargers doing 20 amps each for 40 amps and they get down to 10 each. You can keep them going as each does 9,8,7 etc, or yank one and it will jump back to 20 and taper doing 18, 16, 14, etc by itself.
For best success you need to have adjustable voltage chargers, so you can make them all the same set voltage to keep adding their amps all the way so one does not drop out part way along. Most converters are not adjustable (PowerMax ones are though) but many solar controllers are, so most likely you will adjust your controller to match the converter's voltage.
I think you might like my old ugly graph everyone must be getting tired of :)
If the solar is at say 14.2 and the charger is at 14.6, then as the battery voltage rises closer to 14.2, the solar amps will taper, but the charger's will stay at 20, so you get less than 30 total, tapering till the battery reaches 14.2 and no more amps from solar. Now the 20 from the charger keeps raising the battery voltage until it gets close to 14.6 and amps start to taper from 20.
Once battery acceptance is down to what one charger can do, you can yank the other charger. Say you have two equal voltage chargers doing 20 amps each for 40 amps and they get down to 10 each. You can keep them going as each does 9,8,7 etc, or yank one and it will jump back to 20 and taper doing 18, 16, 14, etc by itself.
For best success you need to have adjustable voltage chargers, so you can make them all the same set voltage to keep adding their amps all the way so one does not drop out part way along. Most converters are not adjustable (PowerMax ones are though) but many solar controllers are, so most likely you will adjust your controller to match the converter's voltage.
I think you might like my old ugly graph everyone must be getting tired of :)
