Takigama
New Member
Howdy All
I have two disparate battery/solar systems (ones about 200ah of agm with its own solar, mppt, etc in a car completely diy) and the other is a roughly 240ah lifep04 setup (own solar, mppt, etc in a caravan) and the two are connected via a battery to battery charger (car -> caravan). Both systems have a 12v -> 48v step up converter attached to them to power some custom 48v stuff.
The short version:
On the road we broke the battery to battery charger. I had a spare mppt charger and as a stop gap I hooked the output of the cars 48v into the MPPT charger, connected it to the caravan's Lifep04's and we had to run like that for about 2 months. But it actually improved the capacity noticeably and it has me wondering why was it so much better?
Reason for all that is with the car we can just kick the engine over if we have to to regain some charge and the caravan's only option on cloudy days is to charge from the car. (Technically, it can charge the caravan's batteries from mains power and the car has an inverter which can provide it, but the van's charge controller will only operate from solar+car OR mains and cant do solar or car + mains)
The 12v->48v step ups are CHEAP, a bit electrically noisy, but surprisingly efficient and the other bonus is the mppt charger has alot more control than does the battery to battery charger so i'd like to leave it all in place and more or less wire it permanently but Im wondering what the downsides are if any?
I have two disparate battery/solar systems (ones about 200ah of agm with its own solar, mppt, etc in a car completely diy) and the other is a roughly 240ah lifep04 setup (own solar, mppt, etc in a caravan) and the two are connected via a battery to battery charger (car -> caravan). Both systems have a 12v -> 48v step up converter attached to them to power some custom 48v stuff.
The short version:
On the road we broke the battery to battery charger. I had a spare mppt charger and as a stop gap I hooked the output of the cars 48v into the MPPT charger, connected it to the caravan's Lifep04's and we had to run like that for about 2 months. But it actually improved the capacity noticeably and it has me wondering why was it so much better?
Reason for all that is with the car we can just kick the engine over if we have to to regain some charge and the caravan's only option on cloudy days is to charge from the car. (Technically, it can charge the caravan's batteries from mains power and the car has an inverter which can provide it, but the van's charge controller will only operate from solar+car OR mains and cant do solar or car + mains)
The 12v->48v step ups are CHEAP, a bit electrically noisy, but surprisingly efficient and the other bonus is the mppt charger has alot more control than does the battery to battery charger so i'd like to leave it all in place and more or less wire it permanently but Im wondering what the downsides are if any?