Dual Battery Systems and Winches

Can you give me an idea of the cost for the isolator?

Sparky

Connect to main battery, it re-charges the quickest.

I run a good constant duty silver contact 250a solonoid as well as battery isolator on my car, and the solonoid is powered from the winch motor, so when the winch is winching, the batteres are joined, so all the current isnt going through the dual battery system.

Will be at Pirahna day this Sat to find out why my Pirahna dual batt system has stopped working....again.

Alan,

If both batteries are the same there is no issue, except, that if you are winching with the engine running, the huge voltage drop may cause the isolator system to cut off (which is what is supposed to do at low voltages) so you end up draining the battery quicker.
I would connect it to the vehicle's battery as the alternator cicuit is made to quickly recover to that battery and run all accessories such as A/C etc.

In addition I also have a switch to completely cut off (isolate) the aux battery when winching to protect (in my case) the deep cycle battery and to also keep that circuit reserved...

I had a X9 superwinch on my Prado when I bought it with only the one main vehicle battery. I thought this was a bad practice, even though that battery was replaced with a heavier 600CC battery.

I installed a dual battery system using a second 600CC battery and a Sure Power isolator. They are connected together using 4G wire, via the isolator, so I could link them together in emergencies for starting or winching. (The 4G wire is rated at 110 amps) I re-routed the wiring for the winch to use the second battery only, unless I manually connect them via the isolator.

I just like to have the main battery for the vehicle elecrtrics only and all the asseccories running off the second battery. Particulary as I do most of my 4 wheel driving solo, so I don't want to get stuck with a flat starting battery. For winching you will need a CC battery, not a deep cycle as the current draw is massive at times.

I have only used my winch once since I bought the vehicle 3 weeks ago and that was to winch my friend up a wet and slippery 'cliff face' type track last weekend. Normally I leave the engine running as I winch so the battery can charge up a bit but on this occassion I was slipping, pulling myself down rather than pulling him up as I had no anchor point. I turned the engine off and left the vehicle in low range with foot brakes applied to prevent me slipping/rolling down. I winched for over 5 minutes without the battery showing signs of dying. I then started my own vehicle, knowing that I had a full main battery, and we continued on.

I think it would be a matter of choice. Normally your main battery charges first and generally the fastest. Common practice is also to have the engine running when you are winching so you don't have to worry so much about having a flat battery and not being able to start the vehicle at the end. You also have to look at how much winching you do. Once every 2-3 months for about 5-10 minutes?

Like I said, for me personally, I leave the main battery alone and run all accessories off the second battery. Maybe I'm a little paranoid, but I don't like a flat starting battery.

Hi Alan,

There are many different ways to connect as described above. None are wrong, but some ways will suit your needs better. With your system, I would connect to the aux battery as this will ensure the main battery stays charged (voltage drop while winching will cause redarc isolator to open, hence no charge to aux battery, but full charge to main). However, I would fit the voltage overide switch, this way you can select the main battery into circuit if the aux starts to run low and you need to keep winching.

Note that even with the alternator charging both batteries as you are winching, you will still flatten both batteries if you winch for too long. Many modern vehicles, petrol and diesels, will stall if battery voltage gets too low (cannot run the ECU electronics), hence why I prefer to winch off the aux battery and keep main charged.

If the aux battery is low while winching, you probably already have a hot winch motor so its better to stop winching and get some charge into the aux battery. This lets the winch cool down, aux battery recharge and main battery still 100% so can start vehicle if motor stalls.

Cheers

Captain

Correct me if I am wrong but you can put a switch in place with the Redarc isolator so you can "bridge" both batteries for winching etc. Wether your winch will stay cool during that time is unknown.

cheers Dave

As there is no definite one way or the other I believe I still need to think more about it. We are planning a 6 month solo vehicle extended trip next year so I am leaning towards connecting the winch to the second battery and leaving the main vehicle battery alone (just for piece of mind) but I am still undecided.

Thanks everyone for your replies, much appreciated.

Alan.

Alan
Truckster has the answer
(as stated in the redarc literature)

However if the second battery is used as the source for the winch, and the two are connected by the solenoid, and both are initially fully charged, remembering that you have driven to where you are (in a ditch) and need to use the winch to get out, and the engine is supplying power, via the alternator to both batteries, because they are both fully charged, I personally don't know why there would be a problem!

Remember that both batteries would be directly connected and equally supplying power to the winch, would the winch use the amount of power to get both batteries down to 10.6 ? (solenoid cutout) Volts under these conditions?
I don't have a winch!