How do a Dual Battery system for Dummies?

I have a 12v fridge that I want to run. I am totally confused! Some say run a dual battery system others say just run a good AMG battery. Other say just buy a battery for the fridge. HELP

 

We need some more details . I can see why you could be confused so many options depending on your use .

you want to run this like 24/7 ? How long you plan to run your fridge at one time helps decide your best choice

Another option again depending on run time is a second battery you charge when your at home with the battery charger

Do you have any idea of the draw ?? some come with a draw time in the instruction book

The best answer is a dual battery set up with a isolater that way your cranking battery is fresh no matter how low the fridge draws the second one down yet it allows it to charge when the engine runs

If you have more loads such as lights you can also run them off the second battery

 

I’m not sure about load, though I do know it will stop drawing from the battery when it is low. I have done some reading on this, would a DCDC charging system be better than the isolator.

As far as running the fridge, there will be a few times that the truck will be parked, not running for 2 to 4 days.

So a dual battery with the second battery as a deep cycle battery would be best?

 

Which way will work best for your use is the real question.

For me two batteries with a isolater is the best I have been running that type of set up on different vehicles since the mid seventies

It might not be what works best for you .

Is expense going to be factored in??

Maybe two deep cycle batteries if one will not handle running things long enough. charge them at home

Nothing like being alone off the beaten path try to crank and the battery is dead

 

look up 4xoverlands discussion on batteries for some good details about 2nd battery choice. Something I've just figured out, having bought a truck with dual batteries installed, is the power consumption aspect when choosing a battery.

short version is that many deep cycle battery suck to recharge, so while they will last for many discharges, getting the juice back in them isn't a matter of idling the truck for an hour.

My set up has two group 35 Optima yellow tops controlled through a National Luna intelligent solenoid. The batteries are isolated to one as a starting battery and the aux for all other power demands through a SPOD power station. The two batteries are 48 amp hours each, which isn't much really, and using a deep cycle for a starting battery doesn't really make sense, unless I run my winch from it. Keeping it as starting only, there's no need for deep cycle since they don't have high cold cranking amps. IMO, I'd be better off with a red top and a yellow/blue top for the aux.

My fridge is an edgestar which isn't all that efficient through the cig plug in, but a bit better hard wired. I'm going to relegate it to freezer duty and buy an ARB which has very low AH demands for frequent use.


That said, I like the National Luna system, and while there are stories of troubles with them failing, there are untold users that have never mentioned how well they work. The key value for me is the automatic battery isolation and dual battery controller display that shows charge and allows for connecting the batteries for self jumping via an in cab button.