framallo avatar image
framallo asked

Victron SmartSolar To starter battery


I have an old jeep xj with parasitic loads and an agm starter battery (Optima red). I understand that the stock alternator only charge 80% of the agm battery. Plus I have other loads like lights a fridge and so on.

The car is parked outside days sometimes Weeks. So I instead of using an external battery charger like nocco to top off the battery when I want to use the truck I want to put solar to keep the battery charged.

I want to install 240w solar panels and a victron smart solar controller to the starting battery. So I can keep the fridge running and keep the agm battery 100% charged.

My intention is that while driving during the day both the alternator and solar would be charging the battery.

Can I do that?

Could the alternator affect the solar controller?

Do I need to install a diode to prevent electricity running in the wrong direction inside the solar controller?

All the documentation talks about connecting a service battery but nobody talks about the starter battery.

My use case doesn't justify a second battery because I have limited space and want to keep the weight low. The fridge has low voltage protection. And if the lights drain all the battery I carry a portable li-ion battery starter to start the truck.

I might eventually put a smart shunt to protect the battery.

smart solar set-up help
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1 Answer
kevgermany avatar image
kevgermany answered ·

Yes you can do this.

If you install a diode the voltage drop over it will lead to an undercharged battery.

Alternator voltage is only likely to be an issue if you have a smart alternator. If this is the case, check how high the voltage can be. But unlikely to be an issue as the MPPT is capable of handling 24V batteries as well.

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