Factory positive battery terminal

Howdy,

I'm currently in the process of planning the cabling for a new winch and dual battery system. I'm intending on installing a bus bar in the engine bay to efficiently distribute the power, however I've run into a bit of a problem.

The factory D40 positive battery terminal doesn't seem to offer much in the way of options when looking to add an additional new cables (especially two large ones such as 2/0 AWG). I'm just wondering if anyone has any suggestions or photo's on how they've overcome this when cabling for winches/dual batteries. There is a single (seemingly unfused) 6mm bolt, however I'm not sure its suitable for the job. Considering I'm looking to install cabling and solenoids good for 450A (winch will be isolated via a solenoid), an 8mm bolt doesn't seem sufficient for the job.

Any thoughts?

Many ta's

you can get different batery terminals that have extra bolts on them so you can run more things off them, but even still iv managed to have the winch and dual battery cables on mine aswell as the spot lights and a few other extras without an issue, what size cable are you looking at running, i ran 35mm from both winch and dual batt and just got lugs for them with a 8mm hole i think it was and although there isnt much thread left on the bolts to tighten it still does the job

Not the best photo (hey, its dark outside)


Silver cable running up to the right is 4ga to Stereo and Canopy power
Red cable (black heatshrink) running right to winch

I would have thought you would run the winch and other accessories from a second battery?

The factory positive terminal has non replaceable fusible links built in and in my opinion is not suitable to hang high current devices off.

The best way to manage a second battery is to use either a DC to DC charger or an inverter and conventional charger, in that case you only need to connect a much lower current cable to the existing battery.

Hope this helps..

Running a winch off a second battery is a good idea, especially for long winchings, but you'd want to use an AGM battery as your second so that it can charge REALLY fast.

I winch directly off my starter battery, but keep the engine running. Hauling 350A to drive the winch is way more than my alternator can deliver anyway, but having the engine running already helps. My connection is direct to the pole of the battery itself, bypassing the fuse.

If your battery is rated at 100 RC (say) it means that for 20 hours it can deliver 5A before the voltage drops to a level where the battery should be considered "in need of charge". If you're winching @ 400A for 2 minutes, you're really only using 400*2/60 = 13.3Ah of battery. 2 minutes of winching should get most people out of trouble!

I'd never thought to use a second battery to winch with. Given the short winch times, it's certainly feasible - only problem with mine is I can't get an AGM under the bonnet - actually, being a D40, it's difficult to get a 'D' sized battery under there!

That's certainly something for the D22 owners though. Use an isolator between starter and aux, and winch from the aux.

Old.Tony said:

Running a winch off a second battery is a good idea, especially for long winchings, but you'd want to use an AGM battery as your second so that it can charge REALLY fast.

I winch directly off my starter battery, but keep the engine running. Hauling 350A to drive the winch is way more than my alternator can deliver anyway, but having the engine running already helps. My connection is direct to the pole of the battery itself, bypassing the fuse.

If your battery is rated at 100 RC (say) it means that for 20 hours it can deliver 5A before the voltage drops to a level where the battery should be considered "in need of charge". If you're winching @ 400A for 2 minutes, you're really only using 400*2/60 = 13.3Ah of battery. 2 minutes of winching should get most people out of trouble!

I'd never thought to use a second battery to winch with. Given the short winch times, it's certainly feasible - only problem with mine is I can't get an AGM under the bonnet - actually, being a D40, it's difficult to get a 'D' sized battery under there!

That's certainly something for the D22 owners though. Use an isolator between starter and aux, and winch from the aux.

Click to expand...

I too winch off my starting battery and with the engine running. My aux batteries (2 x 105AH supercharger all rounders) are mounted in the tub and for the amount of winching I do I just couldn't see any sense in running welding cables from the tub to the winch. In nearly 3 years I've not used my winch in anger once so am yet to identify any downfalls from taking this approach.

i run my winch off my started battery and have used it in anger and for periods over 2 minutes skull dragging my car up hills it shouldnt have been on and havent had an issue, just keep the engine running and revs up abit and its fine, i can also start my car off my second battery which helps if i do flatten my starting battery

I have a 120amp deep cycle in the tub. I have run welding cables between the two through a BIG pot type relay.

I have the winch cables directly off the crank battery terminals.

I also only winch with the motor running.

Like ONLOCK, i have winched out of trouble for far longer than 2 minutes - I have the engine running, and TWO batteries to help get me out of trouble. AND i dont turn off the motor just after winching either, I keep the engine running so that the alternator can start charging the heavy draw just taken out of the batteries.

Those are fantastic replies; thanks heaps guys.

Interesting to see folks making that stupid terminal work. I desperately want to replace it, but with those fuses, I don't see it happening any time in the near future.

BravoBrad; are you able to tell me what size cable is running to the winch?

ONLOCK, what size cable are you running to the tray to facilitate starting?
I've been going off the listed capacities on 12volt.com.au and I'm wondering if I'm spec'ing the cable sizes accurately.

I spoke to the guys at my local ARB store last week about running the winch off the second battery and they recommended against it due deep cycle batteries apparently not appreciating high current draw. That said, I'm intending on using an Optima D34/78 yellow top which is dual purpose, so I don't see that being a problem. My bigger concern was the additional issues caused by such a long run of cable from the try to the winch. However, given folks are successfully doing it, I think I'll revisit it.

The dual battery setup I'm installing consists of the aforementioned Yellow Top, Redarc BCDC1220 and a 250A relay. The folks at Redarc have pointed me to an arrangement which allows self starting from the second battery (something I want if I'm going to all this effort/expense). This arrangement was going to use 1 AWG (aka 40mm) cable, which is good for up to ~280A. However, if I'm going to run the winch off it, it'll need to deal with up to ~400A meaning I'll need to move to.....3/0 AWG (aka 85mm) cable from the winch to the tray. Actually, that about answers it for me. I want to run a breaker on the cable going to the tray, and 400A is bigger than any breaker I've seen. Due to the dual battery arrangement I'm going to run, I can bridge both batteries if necessary anyway (though thinking about it I'll ditch the momentary switch in place of a toggle switch). This also means can stick with the isolation solenoid for the winch in the engine bay as planned, keep all the wiring runs short and continue with a 250A breaker for the second battery and starting system in the tray.

Out of interest, what size cable are folks running for the winch? I've been told battery cable, but that seems pretty light on when compared to the sort of current draw the winch is rated to.

Hmm....final question for the electrical guru's. My next thought is to weld up a bus bar of my own out of mild steel in order to extend power from that unfused bolt on the battery terminal to a more convenient place. I'm thinking of some 3mm plate welded to some 8mm round bar with a thread on it. However, I'm not sure how well it'll conduct (or, at the moment, how I'll insulate it). But has anyone got thoughts on the idea?

Thanks heaps again for the help gents.

The winch really wants a cranking battery. Deep Cycle Batteries don’t appreciate it at all.

I have always had them connected to my starter battery, and just keep the motor ticking for a good 20 mins after you finish winching. I have only flattened my battery whilst winching once, but it was a long pull up a steep hill. I just stoped winching for 15, and then finished the pull. I actually disconnect my 2nd battery when winching, so if I stall, I have a way to start again.

As Brad (and ARB) says, Deep Cycle (DC) batteries don't like dumping lots of current. Optima spiral wound batteries are different - they CAN be used as starters, but in a diesel that draws 500+ amps to kick over I'd be hesitant. Krankin tested a couple of vehicles for us and discovered that a petrol V8 only draws something over 300A to turn the engine over, so our diesels are really, really power hungry. As Brad - and ARB - said, it's best not to do that with a DC battery. It comes down to internal resistance and the damage you'll do to the structure of the battery.

In reality, I would not even consider winching from the front drawing power from the rear. It's just way, way too long a distance. Sure, some people might have done it, but in all practicality, your starter will provide more than enough power to get you out of most situations. Keep the DC isolated (the Redarc will do that) in case you need it to help later (just like Brad does). You won't need a massively heavy cable or fuse/breaker for that - just as much as the Redarc unit can safely handle, and install a fuse/breaker that will protect the Redarc on BOTH ends of the cable.

As for that bus bar, I'd not consider using mild steel. It'll rust before you can blink. The structure of mild steel (I am talking at a molecular level) is better than aluminium so it'll handle more current, but nowhere near as good as copper - I'd try for a piece of copper instead. It's easier to work with, but I'd not solder anything to it. If you are drawing 500A through a piece of anything, it'll heat up and may heat to the point of melting solder. Which reminds me - any joins you make for the winch cabling must be mechanical, not soldered - for the exact same reason.

I used the cables supplied with my winch to join to the battery and did not extend them at all. I fitted a 500A switch between so that people couldn't randomly attach my hook to my towbar and try to winch the front of my car into its own tailgate while I'm asleep.

Thanks Brad. That has solidified my view that I'll run the winch off the cranking battery in the front. You're point about not flattening the aux battery is well received.

Tony,

Thanks for the heads up on the current draw during starting. Redarc suggested a 200A continuous duty solenoid, thus I figured a 250A circuit would be sufficient. However, if the Nav is drawing 500A, that changes the ballgame somewhat. The solenoid I've been looking at will still be fine (250A continuous, 500A for 10 seconds) and I had intended on using 1/0 AWG (40mm^2 or 12mm OD) cable from the bus bar to the tray. However, I was looking at using a 250A circuit breaker, which will obviously be no good for the application. I've had trouble finding a 500A breaker (there are marine fuses up to 700A, but they get expensive to replace), however I'll have to redouble my efforts.

I'm not actually using a Redarc SBI; the BCDC1220 charger looks after the isolation of the two batteries. However to deal with self-jumping, the BCDC needs to be circumvented (due to the current draw) and the batteries bridged through a solenoid (circuit reference here). If the electrical system is pulling 500A, surely the cable will need to be capable of dealing with that. Going by the figures off 12volt.com.au, 1 AWG has a (continuous??) amp rating of 280A. So I'm somewhat confused. Am I going too big if I use 1 AWG (which it sounds to be going by the sizes other folks are running) or too small (given it's only rated to 280A); any suggestions?
This wire gauge malarkey is getting frustrating.

Thanks for the feedback on the bus bar idea. I think I'll head back to the drawing board this weekend and see what I can come up with. I might look to see if I can swap the bolt in the factory terminal for something longer, or try and track down some copper.

Yup, I'm doing the same thing with my winch install - fitting a remote battery switch (Blue Sea Systems 7700) to isolate the winch when its not in use. Also useful if you're in an accident and you end up with a bent bull bar.....no nasty shorts....

Really appreciate the help.

Just remember, you don't need to pull 500 amp from your aux battery. If you flaten your primary battery, you just turn off all the load, turn the aux battery back on, and let it sit for 20 mins. That will partially recharge your primary battery, and then you can start, with both batterys connected, and the aux will simply assist the primary battery.

Another issue about running your winch off of your second battery is will your aux controller (e.g. redarc) be able to support large amounts of charge coming through it to replentish the power draw of the winch.
There have been occassions where this practice has fryed aux battery systems.

point taken re running the winch from the crank battery, regarding the second battery isolated with the dc- dc charger, what I have done is anderson connected input after the solenoid and all the outputs to my second battery, so in the event of a flattened crank battery I would simply swap the input to one of the output connectors and turn on the ignition and allow the back feed to recharge the crank battery.

Using conventional isolation methods and relying on the alternator to charge 2 battery's is old school and a poor option..

i use my second cranking battery for all my accesories including winch
i will eventually put a 3rd in tub for fridge ect

sparra04 said:

i use my second cranking battery for all my accesories including winch
i will eventually put a 3rd in tub for fridge ect

Click to expand...

You've got space under your bonnet for a second battery in your D22, our D40s don't, that's why we have to go through these elaborate and often expensive contortions of electrical ingenuity to achieve the same thing.

I'd have to dump my air filter to fit an extra battery in. I doubt there's room where the ABS unit is (and rather like the ABS anyway). For now, I'm happy to leave mine as it is - aux battery in the tub NOT running any heavy loads, starter used for winching ONLY with the engine running.