Thread: Decisions, decisions, which dual battery system??

I would just link them directly if its about winching power and not touring & camping power drains.

2 Optima's and a big solenoid between them, that is all

my only concern is if I double them up, if one dies, I wont know, and if I go camping and leave something on (drinking too much may have something to do with it) I will run out of juice,


has anyone used those USI 160 jobs? any good?

Originally Posted by nat p

my only concern is if I double them up, if one dies, I wont know, and if I go camping and leave something on (drinking too much may have something to do with it) I will run out of juice,


has anyone used those USI 160 jobs? any good?

Hence the solenoid! Its the best and cheapest way, it's just hard on battery's that's why to use optimas.

Far from an expert on this topic, but had something happen recently that may be of interest.

Installed a Redarc isolator 10 years ago. Main battery was a Willow calcium (still going), aux was a brand new Exide lead acid.

Aux was never really good for jump starting and slowly died, seemed to be dragging the Willow with it. Disconnected the aux and the Willow has come good.

Read the Redarc tech sheet and it recommends that both batteries should be of the same type.

Comments on this would be appreciated!

cheers, DL

Originally Posted by nat p

has anyone used those USI 160 jobs? any good?

Hi Nat, the USI-160 was specifically designed for exactly what you want to do.

Unlike any other isolator, the USI-160 is a fully automated heavy duty isolator designed for both emergency jump starting and for linking batteries together for winching.

When used in it’s normal operation, in SHEARED mode, you get to use half of the capacity of your cranking battery to assist in powering your 12v accessories, giving use a 50% increase in available auxiliary battery capacity.

The USI-160 isolates the cranking battery when the common voltage of all the batteries gets down to 12.0v.

Then the cranking battery is isolated and left with heaps of capacity to be able to start your motor numerous times if you need to.

When you select WINCH mode, the USI-160, automatically resets it’s cut-out voltage level from 12.0v to 10.0v, to allow you to discharge your auxiliary battery to a much lower level during the high current draws that occur during winching.

When you have finished winch operations, simply select SHEARED mode again.

BUT!!!!!!

If you forget to change from winch mode when you finished winching, the USI-160 does not forget, and 5 minutes after you turn the motor off, the USI-160 automatically goes back into normal isolation operations, and resets the cut-out voltage level to 12.5v, so even if you forget, you will not risk flattening your cranking battery.

There is no other isolator with this sort of built in SMARTS, and there are plenty of D3 and D4 owners, all over the world, using my USI-160.

Where did the 160amps come from?

Yeah but that's for one battery, both batteries are linked in winch mode, so that's 320amps, or 480amps short peak load, plus whatever the alternator is making!?
I think I got it right?

Anyway, it starts my Isuzu with a big mother truck starter, and runs my 6hp high mount, works for me