2 battery system

[TDot]

Is anyone running two batteries or know anyone running two batteries in the M only? If so, was it possible to fit it in the hood?

For the people with the real big audio systems, did you upgrade your battery? If so, how long can you run your system without the engine before you worry about being able to start your car?

[06M4.5]

I have done this to a few of my cars in the past and would have to say to use a Dual Battery Isolator.

I would use the isolator which seperates the car battery from the stereo battery. This allows you to kill the stereo battery and still be able to turn on the car and drive away.

IMO the battery should be place in the trunk.

[TDot]

Yeah, I know about the isolator. My issue with the trunk is I simply don't want to run a second wire for the ground back to the front battery. I know it may seem counterintuitive because it may be easier to run a second wire, but that's what I'm looking at for now.

The only reason I was asking about simply upgrading the main battery is I know the discharge between the two batteries on start after the second one was used up can shorten their lives. So I figure one of the good deep discharge batteries be good enough to upgrade to and run for 40 min without issues.

[PlatinumM35]

TDot,what all are you running?

[PlatinumM35]

TDot,what all are you running?

[TDot]

My amp maxes out at 80 amps and 1600 watts (only 900 watts RMS, but will never pass 550 watts RMS according to all my speakers, so I suspect I shouldn't hit more than 30amps very crude calculations and assumptions), the carputer maxes at 10 amps and generally doesn't see more than 4 amps if I remember correctly. So I'm looking at a max of 90 amps which I'll never reach, and I believe an average use of 20-40 amps.

[PlatinumM35]

Ok. I would just run one really good battery and call it a day. Have you looked at either the red or yellow optima? That's what they were designed for. I'm running a red top now. I have my amp putting out about 800 RMS at 2 ohms pushing my RE Audio 15, along with headrest tv's. No problems at all.

[06M4.5]

Yeah, I know about the isolator. My issue with the trunk is I simply don't want to run a second wire for the ground back to the front battery. I know it may seem counterintuitive because it may be easier to run a second wire, but that's what I'm looking at for now.

The only reason I was asking about simply upgrading the main battery is I know the discharge between the two batteries on start after the second one was used up can shorten their lives. So I figure one of the good deep discharge batteries be good enough to upgrade to and run for 40 min without issues.

you only need to run one + wire to the trunk, you don't need to run a 2nd negative wire.

[TDot]

Yeah, I was looking at those.
1/ Which color is better?
2/ What size spec should I be getting?
3/ How long can you run your system without the engine with no issues?
4/ How is the cold start crank?
5/ How many winters have you been through with it?

[TDot]

you only need to run one + wire to the trunk, you don't need to run a negative wire.

That's the way I feel, you should be able to ground the second battery in the back. But everyone..."the experts"....i've checked with say the positive and negatives of the batteries should be connected.

[06M4.5]

you only need to run one + wire to the trunk, you don't need to run a negative wire.

That's the way I feel, you should be able to ground the second battery in the back. But everyone..."the experts"....i've checked with say the positive and negatives of the batteries should be connected.

I have ran 3 red-tops in the past together in 1 car with negatives in the trunk with no problems at all

but I will tell you the red-tops from the past are not the same as the new ones

[PlatinumM35]

They don't have a yellow top for our cars otherwise I would be running one. I knew it was a reason I went with the red top. I just couldn't remember. Here's the link http://www.optimabatteries.com/us/en/sh ... g-battery/. I ordered mine from advance auto parts months ago and got 25% off during a sale and got it for like $160. Look around online if you're not in a rush.

[06M4.5]

Amazon $145 shipped

[TDot]

Cool, thanks.

[06M4.5]

always here to help