Running two batteries and 12 volts...

[JohnR225]

What is the best way to run two small 12-volt batteries together so they function as one? I want only 12 volts and have a terminal block I can hook them to.

Thanks.

[Techno]

Run a battery cable from postive to positive. And another one from negative to negative. A cable about as big as whats going to come off them to your load.

In parallal.

This makes it a battery of 12 volts and twice the amps.

Charge them together if they are always used together.
Treat them as a single battery.

You can also get a battery switch that is made for 2 batteries.
1,2, both, off. With this the negatives are tied together and each positive goes to the switch, with one wire coming off the switch for your load. The switch selects how the batteries are being used.

[JohnR225]

That’s similar to what I was thinking of doing… here is what I have in mind.

Run the positives from both the batteries to one post on the terminal block and the negatives to the other post on the terminal block.

Then hook up everything (accessories and engine) to the terminal block like it is the battery for charging and all… Whatcha think?

Thanks for the quick reply.