Thread: Second car battery?

This is a must for me as I have a tiny 12v as stock and with the amps playing my fuel pump doesnt even get its full share and that is leading to a lean out condition in the motor......which is bad, I need advise how to do it and would it be better to ocnvert to one bigger battery maybe located in the boot, I htink that would be cost effective, as there is no way to fit a bigger battery in the engine compartment, I have heard of regulators and switch boxes that do the load balancing between two batteries, but have yet to find a good tutorial or step by step, I am also keen on info and the pros and cons of one BIG battery as opposed to two smaller ones ?

Help

and glad to know i am not the only one out there with this question


Cheers

Thanks for the info, any links, pictures, manufacturers urls etc, pretty please

Originally Posted by arkadiyp

It is possible that you have bigger problems with your car than just battery, since you say they run down often. Did you check if your alternator is working properly and your battery is charging fine?

My alternator is fine and the battery is fine. I have setup the CarPC in such a way that it can stay on while ignition is off along with the 2 amps powering the speakers and the subs. As you can imagine this can such much of the juice within an hour or two.

Nobias mentioned 2 batteries with an isolator. Im not too electrical savvy, but would it be possible to have a relay switch instead of an isolator where in the ignition OFF position the backup battery is seperate from the main battery (with the CARPC running off the backup battery), if the backup dies, so be it. When ignition is switched on the relay restores the connection between the backup battery and the main battery thus allowing the alternator to charge both?

My initial question still remains unanswered though, would I need to wire up the two batteries in parallel or serial? would the voltage double (to 24v) if I do it in serial? do i need any special regulators to do this?

you need a reply and a second sealed battery but these batteries cots £200 or $300, use nothing less, any descent car audio shop will show you have to go about it.

The way I understand the isolator is a relay...just a big one. My friend and I put two stinger dry cell batteries (800 front and 1000 back) in his 91 Z. We hooked the front one up regularly then ran 0 guage from the pos post of front to fuse to isolator (stinger brand and needs to be hooked into the on to know when to close the circuit) then ran that all the way to the back to fuse then pos side of back battery. Ground both and presto...no probs whatsoever. He can run for hours off that back battery with Phoenix Gold Titanium 600 watt amp and PG T 12" sub. All run at 13.6 volts even with car off (fuse block in back has lcd voltmeter built in)
This setup allows for the key to be in acc and amp only runs off back battery when it is in on - whether the car is started or not - it takes from both batteries

ok great, thanks guys
ill be heading down to one of Sydneys biggest car audio stores today (Strathfield Car Radios, for those who know) and get more info on this. Ill post what I learn.

what i have in my car is a Stinger isolater/relay.. redtop optima.. the stinger
only charges the 2nd battery when the first main battery is fully charged.. therfore,,, no stress on the alternator trying to charge both batteries at once.. this can kill an alternator if its too small or weak..