Thread: CJT's D2 Battery Install - Opinions Please

The sc80 will not save your cranking battery from low voltage wired that way

Hi northiam, I think Chris’s intention is to have a 160Ah cranking battery.

Chris, and the only thing missing from the diagram is 50 amp Circuit Breakers, at the front and rear positive battery terminals.

Hello drivesafe
Im looking into a second battery for camping etc.
CJ still risks killing the cranking battery? Wouldnt using just one battery for cranking only then your sc80 would disconnect if the voltage gets to low.
Thanks

Originally Posted by drivesafe

Hi northiam, I think Chris’s intention is to have a 160Ah cranking battery.

Chris, and the only thing missing from the diagram is 50 amp Circuit Breakers, at the front and rear positive battery terminals.

Yep, the setup uses the 2 x 80ah batteries in parallel to create a single 160ah cranking battery for use with all the high draw accessories.

• Each winch when in use draw up to 338 amps
• The compressors draw up to 70 amp each

The second set of batteries are setup the same way in the cargo area for fridge and camp light usage only and will have a solar charge connected to them as well.

In regards to the 50A curcuit breakers, do you mean inline between the battery positive terminals and the SC80 unit?

Originally Posted by northiam

Hello drivesafe
Im looking into a second battery for camping etc.
CJ still risks killing the cranking battery? Wouldnt using just one battery for cranking only then your sc80 would disconnect if the voltage gets to low.
Thanks

Northiam,

The way I have proposed uses the 2 x 80ah batteries as a single cranking battery.

From what I have researched it is best to connect your positive feed from the auxilary to one of the batteries and your negative earth to the second battery in the bank.

You then link the positive terminals and the negative terminals on the two batteries creating one big one.

Just make sure you dont go positive to negative etc or you will be creating 24v by connecting the batteries in series.

So, even though I have two sets of batteries proposed you should really think of them as only two batteries and the SC80 will work as intended.

Originally Posted by CJT

Northiam,

The way I have proposed uses the 2 x 80ah batteries as a single cranking battery.

From what I have researched it is best to connect your positive feed from the auxilary to one of the batteries and your negative earth to the second battery in the bank.

You then link the positive terminals and the negative terminals on the two batteries creating one big one.

Just make sure you dont go positive to negative etc or you will be creating 24v by connecting the batteries in series.

So, even though I have two sets of batteries proposed you should really think of them as only two batteries and the SC80 will work as intended.

Chris, I'm likely to go a similar way but am considering one equivalent large battery in the engine bay instead of your two. It was pointed out to me that one problem of my approach is that if for some reason I lose power to my cranking battery I'm then at more risk than if I had 2 separate cranking batteries one of which could be voltage protected (and therefore I become reliant on getting power from my rear batteries). Unlikely scenario, but??? Carrying a generator might be one overkill option.

Originally Posted by gavinwibrow

Chris, I'm likely to go a similar way but am considering one equivalent large battery in the engine bay instead of your two. It was pointed out to me that one problem of my approach is that if for some reason I lose power to my cranking battery I'm then at more risk than if I had 2 separate cranking batteries one of which could be voltage protected (and therefore I become reliant on getting power from my rear batteries). Unlikely scenario, but??? Carrying a generator might be one overkill option.

edit: Sorry missed comment about an additional isolator between the two starter batteries.

Wiring the batteries in series doesn't give any more protection from discharge than a single large battery of the same AH rating. Because the batteries are in a bank charge is drawn from both batteries equally, so if one battery in the bank is flat that other will have the same state.

I believe the Traxide USI-160 has a jump start mode which will allow you to start off the rear batteries if they have sufficient charge left in them.

cheers
Paul

Originally Posted by OffTrack

edit: Sorry missed comment about an additional isolator between the two starter batteries.

Wiring the batteries in series doesn't give any more protection from discharge than a single large battery of the same AH rating. Because the batteries are in a bank charge is drawn from both batteries equally, so if one battery in the bank is flat that other will have the same state.

I believe the Traxide USI-160 has a jump start mode which will allow you to start off the rear batteries if they have sufficient charge left in them.

cheers
Paul

I agree. However I was thinking that it should be possible to set up a system whereby the connections between the two should be able to include a voltage protector of some kind for one of them