Rear Mounted Batteries

[SamLogan]

Hey guys,

I am almost finished putting an LS1 into my surf with patrol axles and have hit a bit of a stumbling block. I can't fit a battery in the engine bay anymore due to a serious lack of space. So i am going to have to mount it in the back with my other one. The question is what size cable should i run. I have an insulated post in the engine bay for all of my hookups so will only need one cable to run to the back. Usually i would just use a 50mm2 welding cable but i also have a 12500lbs superwinch in the front. Would the 50mm2 cable be adequate? Or do i step it up to 70mm2. I don't mind if i have to even go to a 90mm2 cable but if i don't have to go that big i don't really want to.

Regards
Sam

[L-andy]

Hi Sam,
Good to hear your making progress. It's unlikely that your gonna want to winch and start your engine at the same time so that reduces the size a bit. My rover has batts under passenger seat (factory location) and I have a 70mm to a common stud in engine bay which powers everything including EP9 winch.

Andy

[SamLogan]

Hi Andy,

Thanks for that. Yeah i am thinking that the 70mm might be the goer.

Sam

[philux]

Have a ganda at this site, might give you an idea on what size you might need http://www.weldwell.co.nz/shop/Arc+Accessories/Welding+Cable++Fittings.html

[SamLogan]

hmm. that site is saying 95mm. thats huge. has anyone rear mounted batteries with a front winch?

Sam

[mudlva]

I did and ran 70mm welding cable to an engine bay central box buzz bar ran starter and winch off the buzz bar with no problems.
Just be aware welding cable doesnt like heat funny enough. The temps off the exhaust turned the sheaf into soft rubbery rubbish. Second time round i used the high temp covers over the starter cable and all good

[philux]

hmm. that site is saying 95mm. thats huge. has anyone rear mounted batteries with a front winch?

Sam

Perfect time to rear mount the winch underneath

[L-andy]

Hi Sam,
I had a quick look at Superwinch specs, 12.5 Talon is 530amps full load (compared to my EP9 at 350amps full load). Add another 20amps or so for other running loads and you would be starting to get near the limits of 70mm cable. The site below shows a good range of specs and duty cycles which are based on % of any 5 min period.

http://www.firstflex.co.nz/cables/single-core-cables/wc

Not sure how fussy the LS1 ECU is about supply voltage but I would go 95mm and have about half a volt less voltdrop when winching.

Andy

[wjw]

If you're looking for wire:

http://www.ebay.com/itm/Voodoo-Power-wi ... 3f320c948c

I found buying it from the US, even with trade discount here, was way cheaper.

[ChurchurDan]

I would be going 95mm cable. The winch will be a constant high current draw and any voltage drop will increase the amps required. Also any VD will make the winch work harder and increase the chance of burning it out.
remember kids you do not want VD

[TJ]

Wouldn't it make safer to run two separate cables. One just for the winch, the other for everything else.

[SamLogan]

Not really. The other stuff draws bugger all in the scheme of things. The winch is what I am trying to cater for. Being in the industry I am in I have access to a variety of sizes of cable. I have gone and run a 120mm2 cable front to back. Its a huge bloody thing to deal with but is rated to 500amps so will work a treat. Crimping the ends on even with crimp tools that can do that size is a mission.

Sam

[timmay556]

not here for your question, i want pics!!!

[darinz]

The cable on 24v Safaris betweeb the two batteries is longer enough to fit the batteries behind the seats in a LWB and connect them to the starter. (literally as I've done it) That cable is smaller than 95mm but bigger than 70mm. You use a 95mm crimp and start at 95mm then can almost close a 70mm at the end. I'd say it is about 80 to 85mm.
This is a factory cable when all factory cables are generally on the light side so clearly 70mm is too small.
I have setup my truck to run front mounted twin motor winch with rear batteries. I've run 2 Safari battery cables (as I had them). One to the starter and then forward to one motor and the other direct to the motor. This is a 12v system.
I have twin batteries running to a 1, 2 or both battery switch and then to an on off switch. Both are huge marine rated ones. 800amp contiuous (I think).

The thinng to consider is that although a 6 hp motor can draw about 550amps and you get power drop the longer the cable, intermitent loads are far higher than continuous load capabilities. And it is virtually impossible for your winch motor to pull 550 amps for any more than a few seconds or you'll either run out of power kill the motor. Remember that is a stall rating and even under heavy load it is using quite a lot less.

So if you're buying from scratch, go to BOC and get double insulated 95mm cable and use one of those per winch motor. Crimp, solder and seal each terminal to give the best possible connection and whatever you use for the power supply you should use for the earth as well.