What is the best set-up for dual batteries in a car . i am currently running a GEL battery in the boot for amp

Question

I am currently running a GEL battery in the boot with a solenoid of the master battery.... but it doesnt seem to be charging up the battery when the vehicle is running..the second ( GEL ) battery is used to power up a mono-block amp... is it possible to just run the second battery in parallel with the master battery... if not what other options do i have .... weblinks or evevn pictures would help... even datat about recharging from the main battery

Answer 1

PAC or Stinger make a good 200 amp isolator at about 30 to 40 bucks.

An Isolator is a simple switch that disconnects the two batteries, when the engine is turned off. When the relay reconnects the batteries, the drained battery gets Charged from the Main battery.  The transfer of current from one battery to another  can shorten their life,  But thats part of having a high output sound system.  

The Isolator has 4 connectors on top, 2 larger and 2 smaller.  Hook up to your Main Battery Positive a 4 or 1 guage wire to one of the larger connectors.  Then connect the other larger connector to the positive rear battery terminal.

Next Ground one of the smaller connectors.   Finally, the other smaller connector wired into an ACCY wire.  

This way, when you turn your Key and start your engine, the 2 battery Positives are connected and the rear battery begins to charge.  When you remove the key, the 2 batteries are separated.

With the rear battery positive disconected, you can check the isolator with a test light to make sure that the isolator is correct in connecting the batteries together when key on and separated when key off

Good luck, hope this helps

Answer 2

Do NOT run an isolator, they are a complete waste of money. The whole point of running dual batteries is to get the voltage gain and storage of 2.

Just run them + to + and - to - and you are fine. This is how most cars are setup and you won't have to worry about it. With my car I have 3 Kinetik HC2400's wired in parallel along with my under the hood battery.

Good Luck =)