Dual Battery System Setup

[Doug1]

Originally Posted by ilikeike

So the agm battery in my car doesn’t charge ?

That is your statement not mine. The point being is that you cannot hook them up exactly as you did in your boat because they only get an 80% charge that way. Look it up.

The bottom line is you need better equipment to keep your AGM battery fully charged and to maximize it's life. The voltage regulation needs to be more precise than a wet battery.

I also imagine your cars starts fine with a semi fully charged AGM battery. It will just not live nearly as long as it should.

This stuff is not as simple as your are making it. Using the same old style charger a Lead acid wet batteries and also an AGM is like trying to run the same fuel pump for both carb to fuel injection. Can you get it to work? Yes. Will it last? No

Here's some info to help show that 12v isn't just 12v.

https://deepcyclebatterystore.com/ho...ain-batteries/