The ideal solution would be a Jimny Bits battery tray but it sounds like that's out of the question due to the aircon pipes, which is a pain.
Personally I would not want to use a battery so small it fits in the standard battery tray for starting and winching duties as you might well flatten it with the winch and it won't last too long with that sort of usage.
So you're left with the problem of where to put a bigger battery whether you use one big battery or a twin charging system for the standard battery and a bigger one.
I once mounted a big Numax Leisure battery in the boot. They're great batteries for starting and winching duties but I decided it was not a good idea to have a lead acid battery in the passenger compartment due to the gasses produced when charging from the alternator and the possibility of explosion and battery acid spraying on us. Unlikely but possible.
My big Numax is now under the bonnet in a Jimny Bits Battery tray!
I think that you could fit a big leisure battery in the boot and use a gel battery (AGM), like Odyssey, Optima or Excide. You want as many Cold Cranking Amps as you can get, so 800 cca if you can.
The cca's are needed for the massive draw of the winch under load.
Have a look here:
www.tayna.co.uk/leisure-batteries/
Use no less than 50mm squared cable to go from the battery to the front of the car (live and earth) and winch and perhaps use a buzz bar that's isolated electrically from the car body for the live to connect the car to this supply and the winch.
My lives are all bolted to the original battery live connector and wrapped in insulating tape but I really need to sort out a proper solution.
50 mm cable needs big crimp connectors and a big crimp tool to go with them.
None of this is cheap but to my mind it's the best solution.
There is another benefit to using one big battery for starting and winching duties. This is that the standard battery is only just adequate when the car is new. Suzuki have never used wiring that is any more than the minimum and it breaks down with age, gaining resistance. So the puny cca it provides is reduced by old wiring and the starter struggles. This causes carbon build up in the starter motor and shortens its life.
When I added a big battery it was like I'd fitted a new starter motor too! It flew over! I thought I could drive the car on the starter motor!
Kirkynut
