Battery charging with alternator and solar simultaneously

[Nelse13]

Hi all, sorry if this has been raised before, but I couldn’t find it

I’ve got a 40lt Engel in the car with a 105ah deep cycle aux battery set up through a red arc isolator charging system. This allows the fridge to run for about 4 days. If I do a 3hr drive, this is enough to re-charge the aux for another 4 days of use.

However, I don’t alway get the opportunity to get that 3hr drive in and the battery obviously drains

My thinking is,
- I hook a 110w solar panel through a regulator then straight to the aux battery via an in-line fuse.
- this will be charging the battery while it’s parked at work
- However, this will also be charging the battery at the same time the alternator charges while I’m driving

My question is
- Can this cause a problem if both charge at the same time

Your thoughts would be greatly appreciated

Cheers

[the evil twin]

You usually won't get both to charge all the time while driving.

Depending on the the Solar reg settings it will 'see' the Alternator voltage of 13.8 or more and think the battery is fully charged so should spend most of the time in float not bulk charge.
The Aux will usually accept most of its charge from the Alternator source, cable voltage drops etc aside.

If all components are OK it won't cause any problems

[Mc4by]

I have a 160w solar panel which I connect to the aux battery via an Anderson plug when I am camped. Keeps the fridge going forever.
I have not run the solar while charging the aux from the alternator. I do one or the other.

[Yeti's Beast]

As Evil said, the solar will stop working once the car starts


Proud BTrol Owner
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[Nelse13]

Thanks for the advice guys

Just what I’d hoped for

Cheers 🍻🍻

[DX grunt]

You usually won't get both to charge all the time while driving.

Depending on the the Solar reg settings it will 'see' the Alternator voltage of 13.8 or more and think the battery is fully charged so should spend most of the time in float not bulk charge.
The Aux will usually accept most of its charge from the Alternator source, cable voltage drops etc aside.

If all components are OK it won't cause any problems
the evil twin

You learn something every day.

I leave my solar plugged in 24/7...… sort of set and forget system. PML.