So I know how to wire up a battery isolator. I have the isolator. Run a power wire from each post of the isolator to each + battery post. Then a true igniton source and a ground. My question is, how does the second battery get charged from the alternator? Is it when the true ignition turns on, the charge going to the main battery then goes to the second battery as well?

 

you can save yourself alot of trouble by just wiring the 2 batteries together in parallel...

both batteries get charged and you dont need an isolator

 

yes but wiring in parallel causes them to drain each other so they are both equal. So a 14 volt and a 10 volt will equal out to 12 volts each which isn't what I want.

 

not really sure what you mean since most car batteries are 12v...you can get higher voltage ones but ive never head of a 10v?

 

I meant if one 12 volt battery is dying and at 10 volts

 

You need an isolator for two batteries or it will kill both batteries they drain and equal out which just kills it. When you receive power from the true ignition source it allows the batteries to basically be in parallel to charge both batteries off of your alternator and allow your vehicle to pull from both batteries during starting, when the power shuts off the batteries disconnect from each other and keep it from draining.

 

exactly!

 

Did you find a line to use for the true ignition source? Im waiting to hook my dual battery setup this thursday with a Dual 7" HU.

 

I planned on using the fuel pump line since I am already tapped into that for the IC pump.

 

Did you just tap into the fuse then or the actual wire?

 

the fuse, otherwise you could try the ignition wire

 

Alright thanks for the help that was my two thoughts igniting or fuel pump.

 

On the instructions it says the alternator which I might since I'm replacing that too

 

See thats whats weird my instructions says nothing about alternator just a true ignition source. I think I will just go with the fuel pump fuse will make it a little easier I think. I had read on some tutorials to use the alternator so idk.. Either way I will make it work.

 

The alternator can also be used for a true ignition source.

 

i gotcha, but ive had 2 batteries ran in parallel for at least a year or so and the only time my batteries died was when i left my headlights on all night..