Adding a second battery?

[19Cutlass94]

Ive thought about adding another battey ( mainly for my stereo ) but Ive had a couple questions about going this way

1) One battery will be in the stock location, under the hood, and the other will be in the trunk. If I wired the two batteries in parallel, using 4g wire, do I need an isolator between the alternator and the two batteries? Or will the stock 100amp alt be enough to charge both?

2) With the new battery being in the trunk, Ill be able to have MUCH shorter power wires, but then the power wires will be shorter than the grounds. Does this matter?

Does anyone have experience with this? Just looking for a couple answers/results from people who have done this before I do

Thanks

[Audiochef]

heres what i have always done.

make sure you make a new ground to your chassi for the rear battery, and just run the power in parrelle, unless your drawing over 2000 watts at 1ohm, you should be ok with your alternator.

[JiM P 2001]

Originally Posted by 19Cutlass94

Ive thought about adding another battey ( mainly for my stereo ) but Ive had a couple questions about going this way

1) One battery will be in the stock location, under the hood, and the other will be in the trunk. If I wired the two batteries in parallel, using 4g wire, do I need an isolator between the alternator and the two batteries? Or will the stock 100amp alt be enough to charge both?

2) With the new battery being in the trunk, Ill be able to have MUCH shorter power wires, but then the power wires will be shorter than the grounds. Does this matter?

Does anyone have experience with this? Just looking for a couple answers/results from people who have done this before I do

Thanks

You must use a relay or isolator. The alternator will charge both fine. On a long run for a battery I'd reccomend 1/0 gauge wire. You can put both batteries in your trunk of you want to clean up the engine compartment a little. Just make sure your power wire is fused under the hood and in the trunk. If you have any questions or need any isolators or high current relays, let me know.

[JiM P 2001]

Originally Posted by Audiochef

heres what i have always done.

make sure you make a new ground to your chassi for the rear battery, and just run the power in parrelle, unless your drawing over 2000 watts at 1ohm, you should be ok with your alternator.

2000w at 1 ohm has nothing to do with anything. You can't draw 2000w at 1 ohm. You draw amps.

Look at the on-board fuses of your amps and add them all up. The total is the MAXIMUM your system will ever draw. If you experience severe draw, look into having your alternator re-wound or replaced.

[mikecentola]

You need to come out to rochester and put my batter in my trunk jim We'll have an electricalfest

[19Cutlass94]

The thing about the isolators is, Ive been told to use them, also not to use them... I have an idea of what they do, however, Im not sure I completely understand them. As far as the fused power wire, what amp fuse should I be running? My total current draw is 210 amps between the two amps, however if I were to enter an SPL test, only the one amp would be getting used and I believe thats a 140amp draw max. Ive already get all the fuses and holders for the individual amps, but like a 200amp for the main power wire going to the trunk?

[blackparis]

Originally Posted by 19Cutlass94

The thing about the isolators is, Ive been told to use them, also not to use them... I have an idea of what they do, however, Im not sure I completely understand them. As far as the fused power wire, what amp fuse should I be running? My total current draw is 210 amps between the two amps, however if I were to enter an SPL test, only the one amp would be getting used and I believe thats a 140amp draw max. Ive already get all the fuses and holders for the individual amps, but like a 200amp for the main power wire going to the trunk?

Dont forget that 20 ft of wire adds resistance... I was powering 2 Directed 2400d w/ a 200 amp AFL and blew it when I did actually crank my stuff (they are only supposed to draw 100 amps a piece).... ended up getting a 250amp fuse...

[mustangraven]

I had also had power issues with my system I also pondered the second battery idea but in my case I upgraded my alt and upgraded to a optima yellow top battery and I have had no problems at all. they are pricey but the optima batteries are the best. I can go to the drive in with my stereo running the whole time and not have an issue starting the car and I run 4 amps! with 3 subs. hope it helps

[19Cutlass94]

yeah Ive tried the upgraded alt. I had a 170amp, but it shit the bed in 3 days. I got a second one, and Im still fighting to get my money back for it after 6 months now. So needless to say Im not very happy about that deal. If anyone knows where I can get one built/buy one local here let me know! Its a CS-130D alt. I know Im going to have to get an upgraded alt, theres just no way around it.

I listen to the stereo alot with the car off, so I think thats where the dual batteries will help out the most. Ive killed the battery too many times and have had to put it on the charger just so I can start the car again. Ill deff be going with optima batteries, probably the red top.

[Audiochef]

try running a 250 amp circut breaker that way you can turn off the power when you want to anyhow. and instead of replacing 5 doller fuses if you blow them you can just get out and reflip the switch.