Thread: D1 Duel battery setups

Hi offrdn, you didn’t post what you were actually going to use the auxiliary battery for.

If it’s anything other than winching then the SC40 will give you a lot more stored capacity than any other set up and at a fraction of the cost of DC to DC step ups.

While DC to DC step ups can actually charge a battery to a higher State of Charge ( SoC ) there is a little inconvenient requirement with any form of battery charging while driving and that is that you have to drive long enough for them to work and the lower the battery the longer you have to drive.

The same is the case with just fitting one of my SC40s BUT with and solenoid/relay type of isolator, is that they take advantage of the way an alternator works and the lower a battery is, cranking and/or auxiliary, the more current the alternator turns out.

So if your just planning on topping off your battery then some form DC to DC step up will work better then a cable only set up BUT if you are planning on using a lot of power, your alternator will not only do a better job of replacing the bulk of your charge in a shorter time but the lower the battery, the higher the current supplied by an alternator.

Now, because of the way the SC40 works, you not only increase your auxiliary battery’s stored usable capacity by at least 50%, turning say an 80 Ampere/Hour ( A/H ) battery into a 120 A/H battery, but because it does this by using the surplus capacity of the cranking battery, you get a number of advantages over any other Dual Battery System, where if you have an 80 A/H battery, thats all you have, an 80 A/H battery.

The obvious one is the automatic increase in stored capacity at no extra cost.

Because you are spreading the load over two batteries, you will help extend the operating life span of your auxiliary battery, another cost saving.

Again, because you are spreading the load over two batteries, so you will not need to take either battery down as low as you would have to do with any other set up, including a DC to DC step up type set up and this means because the batteries weren’t as low when you start your drive, you will actually charge them in a much shorter drive time.

So at the end of a days drive, you will have higher charged batteries and this means you won’t be taking your auxiliary battery as low to meet your needs so again, this just helps to extend the battery's operating life.

It’s always a case of horses for courses but you need to know about the course and the horses running on it.