Thread: USI-160 DBS question...

So I have a question about the USI 160 sold by Tim. I have had this unit for about a year but I'm only just getting around to fitting it now.

I have searched through so many threads on many sites and only got a partial answer to how it should be correctly set up with use of a winch in mind.

I always thought that you need to fuse all wires as close to the battery as possible. However I have seen a few set ups that just run the cable direct to the unit, and read that a high load device like a winch would trip the circuit breakers or fuses set in place when the unit is set to Winch mode or Jump Start mode.

Basically I'm trying to set up a DBS in my D1, all under the bonnet, nothing fancy. With the intention of running a winch and routing power to the back via 6B&S to power m fridge and a few low draw bits (LED's etc).

I am really confused as to what size wiring to use to actually hook the batteries together. I have read 2B&S with a 150amp CB in between both batteries and the USI 160 and again 2B&S to the winch.

Do I need the 150amp CB's? or do they need to be bigger? I didn't want to barrage Drivesafe with PM's so I thought I would ask the masses first.

Cheers,

KC

Originally Posted by KCJones

I didn't want to barrage Drivesafe with PM's

Hi KC and do not hesitate to PM, E-mail, Phone or contact me by any other means if you need to know something about gear you bought from me and if you think you have a problem, don’t wait, contact me immediately.

Now to your question, with an SC80 set up, I have most SC80s supplied with a 50 amp circuit breaker fitted to the SC80.

This 50 amp circuit breaker is not only there to give protection in the event of a short circuit but it also acts as a quasi over current limiter.

With your set up, because of the high currents that will need to be switched, the USI-160 does not require current limiting and as long as the two batteries and all the cabling between the two batteries is under the bonnet, no circuit protection is needed.

As for the cable you are planning to run to the rear, this must be protected, no bigger than a 50 amp circuit breaker for 6B&S ( 13.5mm2 ), 40 amp for 10mm2 and 30 amp for 8B&S ( 7.9mm2 ), and the protection must be in the cable somewhere between the battery and before the cable leaves the engine bay.

If you fit a battery in the rear of the vehicle, you will need a similar sized circuit breaker in the positive cable as close as practical to the rear battery.

Same for any batteries in a camper trailer or caravan.