Battery relocation and power distrabution....

Going to be moving my battery to the back. Plan is to run a 2 gauge welding wire to the front and attach it to a power distribution block. Then run a wire to the winch, 2 gauge, the starter, 2 gauge also?, then to the power distribution center, 4 gauge or 8 gauge? not sure there yet. Should the alternator be attached to this block too or run a wire back to the battery? Also any suggestions on power distribution blocks that will not break the bank? Thanks.

This is the power distribution block I used when I relocated my battery to the driver side.

Distribution Block

I really like the BlueSea bars https://www.bluesea.com/products/category/BusBars/PowerBar. The one with four 3/8 studs is rated for 600 amps of continuous duty, thats enough to drive a starter motor or a mid-level winch. I have plans to use one of those for front accessories, and another for rear accessories (in the cargo area), possibly one of the five-post smaller bars for the rear (inverters, pump, etc). They also have some covers and stuff for them too. Nice stuff. Not horribly expensive for marine-grade parts.

Here is what I used :

The main cable from the rear is 00. I used a wire clamp to secure it. That line is very important to insure proper routeing and securing, as it is connected directly to a batt. In some parts of the routing, I used rubber heat shield. It's important to note in this kind of install, that routine inspection of main lines is needed.

Once the main 00 Power line is in engine bay, I connect to a power distribution block.

The 4 large power lines :
1. To factory fuse block
2. Wench
3. custom fuse and relay distribution center (off-road lights, Primary electric fan power (I use a custom triple redundant, dual automatic thermal control circuit to power the cooling fans. 12V power is supplied va 2 sources of power on self resetting circuit breakers.), relays, and other after market equipment that needs power.
4. large cable to starter motor







I also extended the ground. It connects to rear, near Batt, connects to body (with a stud that coes through for AMP hook up), and then connects to front frame. At that same point, a very large flex ground to the engine (4 AWG)

When most people relocate a batt, they don't apply as much focus to the ground. When in fact, the ground is just as important as the hot, if not more so.

DaKing said:

Here is what I used :

The main cable from the rear is 00. I used a wire clamp to secure it. That line is very important to insure proper routeing and securing, as it is connected directly to a batt. In some parts of the routing, I used rubber heat shield. It's important to note in this kind of install, that routine inspection of main lines is needed.

Once the main 00 Power line is in engine bay, I connect to a power distribution block.

The 4 large power lines :
1. To factory fuse block
2. Wench
3. custom fuse and relay distribution center (off-road lights, Primary electric fan power (I use a custom triple redundant, dual automatic thermal control circuit to power the cooling fans. 12V power is supplied va 2 sources of power on self resetting circuit breakers.), relays, and other after market equipment that needs power.
4. large cable to starter motor







I also extended the ground. It connects to rear, near Batt, connects to body (with a stud that coes through for AMP hook up), and then connects to front frame. At that same point, a very large flex ground to the engine (4 AWG)

When most people relocate a batt, they don't apply as much focus to the ground. When in fact, the ground is just as important as the hot, if not more so.

Click to expand...

Nice set up. Ok so you ran a ground wire from the front to the back? Also what about the alternator wire? Can I attach it to the + post/power distribution up under the hood? Winch ground is currently on the battery. Does it need to be the same? Who makes that Power distribution block?

You should run alternator to the battery(ies) and then attach the battery to the distribution block. The battery provides float voltage between the spikes from the alternator's diodes. Battery provides smooth voltage, alternator maintains the battery.

ehall said:

You should run alternator to the battery(ies) and then attach the battery to the distribution block. The battery provides float voltage between the spikes from the alternator's diodes. Battery provides smooth voltage, alternator maintains the battery.

Click to expand...

The factory wire is a very high gauge. What Gauge should I use? 8?

The factory B+ from the Alt connects to the factory fuse / relay center under the hood. The Factory cable is thick enough for the stock alt, and a bit more. Its a short run from the alt to fuse center.

I'm not done with my Jeep yet, but the end design will be Alt to that power distribution block, with a heaver gauge cable. Also installing a bigger alt (bigger in amp's, not size.. well it may be bigger in size... don't know..

I would agree on connecting the alt to the batt to reduce noise and voltage fluctuations. If thats doable. The problem is having to run another cable to the rear, and that will have to be much bigger then the short cable going from Alt to factory fuse block. The longer the run, the thicker the cable should be. The risk of electrical damage or fire doubles for every line you run. weigh the risks.

I think connecting the Alt to the new main distribution point will be fine for most everyone.

On my Race HEMI RAM, I did have to run the Alt B+ all the way to the rear too. This was for the engine kill switch. The Alt would make enough power to keep the engine running, if the main batt kill switch was pulled. So, if some pulled the kill switch, the engine would not shut down. By putting the ALT B+ feed before the switch, this allow the switch to totally kill engine. (The other option was to use a solenoid based kill system, but it added more failure prone equipment to the equation. Always try to remove failure points in a build, and add redundancy where needed.)

On your questions of the Winch ground, I grounded mine on the frame. My grounding is a bit extreme. multi point grounding locations. Batt to Frame, short run near rear batt. Batt to Cab, Via a stud that penetrates the cab. That same stud is for grounding the audio amp and inverter. From that same stud (outside of cab, under) another ground cable runs forward to engine bay, near motor mount. Grounds to the frame neat motor mount. From that same point and very large flex ground line bolts to the factory ground point on engine.

I used heavy gauge wielding cable with a very high copper content. Even though the ground wire is not a important to secure and route as the HOT, you don't want it to rub through. Any exposed copper will corrode rapidly. Same with all the end points. make sure to properly terminate and protect each end point. Issues may show years later, and be difficult to diagnose.

You need to calculate the voltage drop for the amperage and distance and then pick a wire size that is not going to suffer too much loss.

http://www.rapidtables.com/calc/wire/voltage-drop-calculator.htm is one of many calculators

maximum load from alternator charge, say 14 volts DC pushing 120 amps, shows 10 feet of 4ga wire loses about .5 volt, pretty heavy drop, but you won't be running maximum output very often so not a big deal. Now you go back up to your distribution block and figure the same thing, what is your amperage draw from the starter and winch and lights and whatever else, what is the distance, what is acceptable loss

you guys aren't isolating your batteries? So if your winching or listening to system with key off, you always have starting battery isolated from current draw?

ehall said:

You need to calculate the voltage drop for the amperage and distance and then pick a wire size that is not going to suffer too much loss.

http://www.rapidtables.com/calc/wire/voltage-drop-calculator.htm is one of many calculators

maximum load from alternator charge, say 14 volts DC pushing 120 amps, shows 10 feet of 4ga wire loses about .5 volt, pretty heavy drop, but you won't be running maximum output very often so not a big deal. Now you go back up to your distribution block and figure the same thing, what is your amperage draw from the starter and winch and lights and whatever else, what is the distance, what is acceptable loss

Click to expand...

Ok so all that electrical talk makes my simple head hurt. So are you saying that 4ga isn't big enough to run from alt to battery in rear? Also are you saying I should have two wires from alt to distribution block and to battery?

denverd1 said:

you guys aren't isolating your batteries? So if your winching or listening to system with key off, you always have starting battery isolated from current draw?

Click to expand...

I was under the impression that isolators were used in a dual battery set up for charging and was going to leave it out for the simple task of relocating the battery to the rear.

what is the distance from the alternator output to the expected battery location (go measure)

do you have a stock alternator or something high amperage

are you running a winch or any high powered lights or other accessories

ehall said:

what is the distance from the alternator output to the expected battery location (go measure)

do you have a stock alternator or something high amperage

are you running a winch or any high powered lights or other accessories

Click to expand...

11' - 12' Didn't think it was quite that far....

Stock atm. I hear the ZJ one is better though.....

Warn M8K Winch, and KC day lighters for headlights on occasion....

Ahah! ! That makes sense!

Without showing math, you need 1ga wire from the battery to the distribution block and on to the battery. You will lose about 1.5 volts, with the engine running and providing 14v you will still have 12.5v (enough for maximum load). You can run less but your winch won't be able to max draw.

ehall said:

you need 1ga wire from the battery to the distribution block and on to the battery.

Click to expand...

Alt to distribution block to battery?

Ghost said:

Alt to distribution block to battery?

Click to expand...

Run 1ga from alt to battery, and another 1ga from battery to the distribution block.

With a 136 amp alternator providing 14v output, 1ga wire will lose .4 volts over 12 feet distance at maximum output, meaning the 14v alternator output drops to 13.6 volts by the time it reached the battery. I would not go lower on this link or you won't be able to keep a charge on the battery very effectively.

Connect your winch, starter, and lights to the distribution block, so that everything draws from the battery (and the alternator tries to keep the battery charged). I am guessing that the winch is probably another 3 feet past the distribution block, so about 15 feet total longest point to point and assuming 400amps at peak load (maximum draw) for an 8k winch.

You would be better off using 0 ga on these links but 1 ga should work, if the calculations are correct.

ehall said:

Run 1ga from alt to battery, and another 1ga from battery to the distribution block.

With a 136 amp alternator providing 14v output, 1ga wire will lose .4 volts over 12 feet distance at maximum output, meaning the 14v alternator output drops to 13.6 volts by the time it reached the battery. I would not go lower on this link or you won't be able to keep a charge on the battery very effectively.

Connect your winch, starter, and lights to the distribution block, so that everything draws from the battery (and the alternator tries to keep the battery charged). I am guessing that the winch is probably another 3 feet past the distribution block, so about 15 feet total longest point to point and assuming 400amps at peak load (maximum draw) for an 8k winch.

You would be better off using 0 ga on these links but 1 ga should work, if the calculations are correct.

Click to expand...

Thanks I really appreciate the play by play. I found some 1/0 gauge welding wire on ebay that was reasonable. I've got 25" coming next week so hopefully I can knock this out next weekend. Ended up with a Jegs distribution that looks just like the Painless one. Again, thanks! My next concern is the lugs for the alternator side of it all. My 94 one is in a recess. Do they make a stud I can screw on to get it off the body some? Or should I measure it and try and find a 1/0 gauge lug that fits?

ehall said:

You should run alternator to the battery(ies)

Click to expand...

So I was looking at a wiring diagram for an automatic isolating relay... in this case, do you connect the alternator directly to each battery?



Thanks,
Mike

Your alternator to "house" battery only. When the 2nd. battery is used the Alt. will provide a full 14v to the "house" batt., and then to a 2nd. as used.