Alt To Back Bank

[rmzsuzuki89]

I saw a discussion about this a long while ago on some audio site and can't find it again.

I just wanted to know if there are any substancial advantages to running power wire directly from the alt to the back battery bank.

For example: I have 4 runs of 1/0 running from front to back, 2+ and 2-. Right now, both + are running back from the + on my front battery. Would it be advantagous to run one run back from the + on the front battery, and the other from the + on the alt to the back battery bank? Advantages, disadvantages, not matter?

My electrical will consist of 2+ and 2- runs of 1/0 from front to back, big 3 in 1/0, one 290 amd DC alt (2 in the future), g34 YellowTop up front (soon to be a Deka 9a31), and 4 Deka 9a31's in back (soon to be 6-. All in an 03 Expedition XLT.

Will be powering either 4 SAZ-3000d's (each at 1 ohm and gained down) or one Soundigital 12kd or 16kd (at 1 ohm gained down quite a bit).

[sully]

I would run direct to the front and back with charging wires, I haven't ever noticed a difference in running to the front battery and then to the back if you are using a bus bar or similar connection at the front battery. Electricity will find the route of least resistance so as long as there is wire to support that kind of current draw you should be fine.

[Soulman07]

I don't think it's noticeable enough really tbh, in most situations I'd just double up on the run of the alts to front battery before anything. They length of the run will really determine the most as far as efficiency goes and how many runs you have will make up for the difference.

Example...

94 deville 300 amp unit 15.4 idle voltage at alternator big 3 and 15 foot runs to the rear bank. single alt to battery up front was around 0.1 loss to front battery, two runs to 2+ 2- to rear = .2 loss on top of that.

Two runs front alt to bat = no loss two runs with bridges in between both rear batts made up for around 0.07 worth of loss total.

My power wire run was quite long though.. nearly 6 foot in length from the alternator to battery and it had to be ran along side the block because of the way the engine was mounted. So I'm quite sure heat had something to do with the amperage/voltage loss.

All in all, two runs from alt to front battery should suffice. If you have buss bars up front make up for the difference in the power runs to the rear... If you really do have 4 3k's I'd recommend 6+ or 6- with some good wire... but that's just me.

[rmzsuzuki89]

I don't think it's noticeable enough really tbh, in most situations I'd just double up on the run of the alts to front battery before anything. They length of the run will really determine the most as far as efficiency goes and how many runs you have will make up for the difference.

Example...

94 deville 300 amp unit 15.4 idle voltage at alternator big 3 and 15 foot runs to the rear bank. single alt to battery up front was around 0.1 loss to front battery, two runs to 2+ 2- to rear = .2 loss on top of that.

Two runs front alt to bat = no loss two runs with bridges in between both rear batts made up for around 0.07 worth of loss total.

My power wire run was quite long though.. nearly 6 foot in length from the alternator to battery and it had to be ran along side the block because of the way the engine was mounted. So I'm quite sure heat had something to do with the amperage/voltage loss.

All in all, two runs from alt to front battery should suffice. If you have buss bars up front make up for the difference in the power runs to the rear... If you really do have 4 3k's I'd recommend 6+ or 6- with some good wire... but that's just me.

I'm planning on running more, this is just where I'm at right now. My car is actually gutted right now getting ready for my build. Just trying to get my electrical squred away.

Either amp setup I go with will only be putting out about 8k wrms total for now. The only reason I'm looking into the 16kd is to have headroom for when I change up te subs.

[mlstrass]

I'm planning on running more, this is just where I'm at right now. My car is actually gutted right now getting ready for my build. Just trying to get my electrical squred away.

Either amp setup I go with will only be putting out about 8k wrms total for now. The only reason I'm looking into the 16kd is to have headroom for when I change up te subs.

I go alt to front batt and 4 runs + from front batt to rear batts. Lose .01v front to back...

[newls1]

I have my setup like this: (I have dual alts) A run of + from behind both alts to front batt. 2 runs of + from front batt to rear buss bars. Also have a run of + from behind each alt to rear buss bars. Total runs of + = 4 (all fused of course) and 4 runs of - (2 directly from rear buss bars to chassis, and 2 from front batt)

[rmzsuzuki89]

I have my setup like this: (I have dual alts) A run of + from behind both alts to front batt. 2 runs of + from front batt to rear buss bars. Also have a run of + from behind each alt to rear buss bars. Total runs of + = 4 (all fused of course) and 4 runs of - (2 directly from rear buss bars to chassis, and 2 from front batt)

This is kind of what I was thinking.

[mikey634]

Just remember your car electrical runs off your front battery, so if you skip it with an alternator, going straight to the back, your audio will still cause voltage drop as far as your headlights, power windows, dash lights, etc. are concerned, even if your back batteries voltage is stable as anything. Recommend just hitting the front battery, then having runs going to the back from the terminal.