Winch, Battery and Power Configuration

Winch Power

As part of our decision process we had to firstly choose what type of winch set up we wanted. We explored all the main brands including Superwinch Warn etc and also hydraulic versus electric. In the end we chose to go for a Warn 24 volt 8274-50 high mount winch. Why the 24 volt version? Simple! They have a faster line speed of 7.9 feet per minute [assuming a full 8000 pound pull] compared to 6.1 feet for the 12 volt version and the current drain at this level was only 273 amps compared to 450 amps.  


Ok we had decided on a winch but since the Discovery operates on 12 volt and not 24 volt how the hell would we power it?

There were many options to consider. In the end we found an article written by the Roscommon Equipment center from 1971 which talked about using 24 volt military vehicles for civilian use. The link is . This offered the solution using a 12 / 24 volt series parallel switch set up. We just run it in reverse to the solution presented in the article. Ok not perfect but good enough for our purposes. To affect this set up we purchased a remanufactured Cummins Diesel Solenoid. We went for a remanufactured one at a cost of $206 compared to a new one of almost $650.

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The first picture above shows the series parallel [solenoid] switch in place. The second with all my scribbles is the wiring diagram. The last picture is the switching inside the Discovery. The white crap all over the terminals is silicon sealant. the only tube I had was solid and had to be cut open with the contents removed by hand. Not the neatest way to do it but since the Disco was shipping out later that day I had the choice of being messy or not doing it. Guess which I chose.

Using a switch mounted inside the cabin we can now switch the series parallel switch to allow for 24 volts feeding form both batteries and hence powering the winch. When not winching the switch is set to 12 volts and both batteries charge normally and all accessories work off the main battery.

Battery Disconnect or Kill switch.

One of the rules for the OBC is to have a battery disconnect or kills switch connected. To achieve this we purchased a Painless Brand Performance Remote Master Disconnect Kit from Summit Racing [part PRF-30205]. It was an easy install following the instructions and interrupting the positive feed to the engine and accessories from the positive of the main battery. Unfortunately the first one that turned up was defective however Summit replaced it by overnight courier at their cost and all now works well with a large RED switch inside for easy access.

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The White crap is as per above.


We are using dual Optima Yellow top batteries.