Second battery in car

[mela]

Does anybosy know how to hook up a spare battery in the trunk of the protge 5? I would like to put one back there as a spare for the stereo.

[CrazyCaker]

I have thought about this as well. As it turns out, having a second battery will not help your system. After reading MANY articles about this, I found out that a second battery will actually cause more drain on your electrical system. The main purpose of adding batteries is to play your system longer when your car is off. The only answer to fixing inadequate power, is to have your altenator custom built to handle the power demands.

With that being said, can someone recommend a place to me? http://ib2.toprotege.com/iB_html/non-cgi/emoticons/wink.gif

[CrazyCaker]

Oh.. and to answer your question though.  First you need an isolator, or a relay.  Take the switch from some accessory in your car that turns on when you turn the ignition key of your car, that would be the switch of the relay or isolator.  Then connect a cable from the + terminal of the first battery to the 2nd battery, much better if they are the same kind of batteries, dont forget to ground the - terminal of the 2nd battery too.  Use at least 4 gauge cable.

Just remember though, if your alternator is not handling the power demand as it is already, adding a second battery is only making things worst.

[tiwing]

Most RVs have this setup to run the lights etc. when parked. You can absolutely KILL the second battery without risk of touching the battery used to start the car. If you're considering adding the second battery for this, use a deep cycle RV or Boat battery that can handle being nearly discharged and charged repeatedly. I can see how after starting your car, IF the second battery was a bit discharged, it would be harder on your alternator to try and be recharging TWO batteries and running your system, but this would be an excellent reason to have an ammeter installed so you can see alternator output and when it's "OK" to crank the tunes again.

Edit: as crazycaker said, if your problem is that your current alternator can't handle your system you have to get a better output alternator.

Edit again: I think that there is a place by Lockdown that does high-perf rebuilds.

[Gen1GT]

rekanize....http://ib2.toprotege.com/iB_html/uploads/post-18-33508-2003_0304car0004.JPG