GOT AN OLDER RIG? THEN HERE’S A NICE LITTLE TRICK COURTESY OF REDARC’S SBI12
We’ve all read enough now to know that the older solenoid type SBI12 chargers don’t suit the newer 4WDs.
But with all of this education in the marketplace geared towards the newer 4WDs, what about the folks who are still running the older type 4WDs with the standard alternator setups.
Sure the BCDC range of chargers will do a much better job of charging and maintaining the auxiliary batteries even on these old systems, but most people have one question with these SBI12 setups …
WHAT DOES THE BLUE WIRE DO?
Because the voltages of the new 4WD charging systems fluctuate more, this can cause these solenoid types to cut in and out and be a bit unpredictable.
But if you’ve got an older vehicle, wiring up these SBI12 voltage sensing solenoids is quite simple. You run a wire cable between the positive terminals of the two batteries and put the SBI12 Solenoid in between.
The cable from the main battery goes to the terminal on the solenoid with the sensor attached to it and the other side of the solenoid gets attached to the positive terminal of the auxiliary battery.
The small black wire gets connected to earth and you’re pretty much done.
Back to the blue wire on the SBI12, though. This seems to be the only wire left over after a fitment of the SBI12 and some people don’t know what it is used for. This is a clever little wire and could actually help you without even getting out of the cab of your 4WD.
WHEN DOES IT COME INTO PLAY?
Let’s say you’re out camping for a few days and you find the main battery is flat. Sure, you could grab your jumper cables and connect up the red cable from positive to positive… Or, this clever little blue wire could help you do exactly that from inside your cab.
When wiring up your system you can run that blue wire to a switch inside your cab and back to the positive of the auxiliary battery, fused of course.
Then, at the push of a button, you will be able to switch on the solenoid connecting the two batteries and jump-start the main battery from the auxiliary battery.
HOW IS IT SET UP?
If you do want to wire it this way, there are a couple of things to be aware of.
The cable size you use between the batteries needs to be large enough to take the load of jump-starting and may need to be upgraded, and the inline fuses need to be 100Amp at least.
It’s a great system and something that I have unfortunately had to use a few times myself. You see, my kids do not listen, they touch things and leave lights on inside that 4WD.