Alternator Power Options

prius driver

New Member
Apr 30, 2022

I searched around this site and others and can't seem to find the answer to: Can an inverter/charge combo be used to charge house batteries off the alternator/starter batter while the engine is running? It seems a DC to DC charger is used to draw power from the alternator to the house batteries, but inverter/converter combo is used to draw power to house batteries from shorepower/general home wall power connections so can this also be used to draw power from an alterntor without buying and instaling a dedicated dc to dc charger? Looks like another option is to use a dc/dc charger with built in mppt can be used accept power from solar panels and an alternator to go to the house battery, then allagator clips hooked to a house battery and plugged into shore power for that option?

Applying this to my current situation. Renogy has a solar panel kit that includes an mppt controller, so buying that kit for the cost savings on the individual panels/wires/mounts, buying a inverter without converter and buying a dc/dc charger with mppt would added cost and I'd end up with the extra mppt unit from the panel kit (standard solar controller that comes with the kit would need to be sold on craiglist or something at a loss), or I buy the solar panel kit with standard mppt solar controller and buy an inverter/converter and hopefully don'y need to also buy a dc/dc charger if the inverter/converter can draw power from the alternator.

If you made it this far, you're my hero. Thank you for any input.

Edit*** may have found helpful info to my question here -

DC to DC charger with built in MPPT solar controler -
Solar Panel Kit -
Inverter/Charger -
Inverter Alone -
LiPo Battery -


Photon Sorcerer
Mar 20, 2021
That inverter charger will only create alternating current. Yes you could run a 120v extension cord back to a battery charger. But then when you want to make coffee the inverter will be drawing down the start battery. At lease there will be coffee while waiting for a jump start. Then when parked and plugged in, the inverter/charger will only be charging the start battery. Although 120v power would pass through to that on-board charger again so that would sorta work. Not going to work well.

Best to get the DC-DC charger. This will sense when the alternator is producing power and send some back to the house battery. That inverter/charger will serve better connected directly to the house battery. Can get a DC-DC without the MPPT to avoid duplication of equipment. Or save that extra MPPT for a solar expansion project.


Apr 24, 2020
Somewhere South of Denver
I would avoid the Renogy DC-DC/MPPT unit. It has too many restrictions.

You need a DC-DC charger to get power from the alternator into your LiFePO4 battery.

I have a Victron Multiplus that is an inverter/charger. It only charges when there is AC shore power available.


Photon Sorcerer
Jan 3, 2021
I'd stay away from the Renogy stuff. On my truck camper, I have a Growatt SPF3000LVM. To charge the 24V system off my 12V truck electrical system, I went a different route.

Works very well, I can run an easy 60A at 24V into my camper LFP bank thru the Growatt AC to DC charger. Sure, there are some efficiency losses converting DC to AC and back to DC, but to get anything upwards of 1500W off a 12V system and upping it to 24V would be very costly. An added bonus is I have a backup inverter.