Thread: Dual Battery System - can of worms

In my opinion, you do not need a DC/DC charger, just a battery isolator.
I have one of these, SC80 | TRAXIDE TRONICS | Traxide

Originally Posted by babooon

I've bought my disco 2 back in November and it's been back to the garage a couple of times to get some small issues sorted under warranty. Now that the warranty has expired and I've got the car back I have started tidying up an sorting a few other jobs out.

Not the most important, but what I hoped was going to be a relatively simple job was to get the dual battery system all working. Previous owner looks to have fitted something themselves but removed the 2nd battery and just taped up all the connections.

After removing 2 broken Anderson plugs I've found the live and ground to connect to a battery in the rear passenger side storage bin, but the cables look a little thin so I am debating upgrading them to 6 B&S along with fitting a couple of fuses (there are non at the moment!)

I've googled, you tubed and browsed through forums to try and get definitive answers but just want to do a final sanity check...

I am going to replace the cable with 6 B&S, with a fuse (80A) between it and the solenoid in the engine bay and a 60A circuit breaker fuse in the rear storage bin where my AGM battery will go. I will also be fitting a fuse board in the storage bin to run a couple of cig sockets, usb ports and Anderson plugs from.

I have tried to research the solenoid but other than having 12V on it I cant work out what it is or where it is from, should I replace it with a newer VSR (cant justify a DC/DC charger just yet)?

DualBattery_Solenoid.jpg


Also, I spotted that this solenoid is wired to another 'thing' in the engine bay, not sure what it is?

PXL_20220220_232734859~2.jpg


Sorry for the long winded post, I was hoping that this would be a simple job of connecting a new battery, open to any (low cost) ideas to make this a safe and usable system.

Cheers.

Oh and to top it off, I now cant open the bonnet, cable seems tight so I don't think it has snapped but it isn't releasing the catch. Another job for the list to keep me occupied .

That’s an old school dual battery setup - done a few myself and they’re still going. The solenoid is a similar looking to an old-time starter motor solenoid but it would be for higher load continuous duty. It looks very much like it is switched by an auxiliary oil pressure switch so the batteries are connected ONLY when the engine is running. It’s a simple and reliable setup and if money is tight atm I’d have no qualms continuing on with the solenoid after doing the necessary upgrades to the wiring.

The thing wired to the old relay is a pressure switch, it looks like they are using a building up of pressure in the engine, probably oil to energize the relay.
Newer style dual battery relays do it automatically by the voltage it detects.
I would be removing it all the replacing it with a newer style. Dont go the DC-DC, no need for the D2, its just going to cost you more and charge the second battery slower than a standard relay.

Originally Posted by babooon

I've bought my disco 2 back in November and it's been back to the garage a couple of times to get some small issues sorted under warranty. Now that the warranty has expired and I've got the car back I have started tidying up an sorting a few other jobs out.

Not the most important, but what I hoped was going to be a relatively simple job was to get the dual battery system all working. Previous owner looks to have fitted something themselves but removed the 2nd battery and just taped up all the connections.

After removing 2 broken Anderson plugs I've found the live and ground to connect to a battery in the rear passenger side storage bin, but the cables look a little thin so I am debating upgrading them to 6 B&S along with fitting a couple of fuses (there are non at the moment!)

I've googled, you tubed and browsed through forums to try and get definitive answers but just want to do a final sanity check...

I am going to replace the cable with 6 B&S, with a fuse (80A) between it and the solenoid in the engine bay and a 60A circuit breaker fuse in the rear storage bin where my AGM battery will go. I will also be fitting a fuse board in the storage bin to run a couple of cig sockets, usb ports and Anderson plugs from.

I have tried to research the solenoid but other than having 12V on it I cant work out what it is or where it is from, should I replace it with a newer VSR (cant justify a DC/DC charger just yet)?

DualBattery_Solenoid.jpg


Also, I spotted that this solenoid is wired to another 'thing' in the engine bay, not sure what it is?

PXL_20220220_232734859~2.jpg


Sorry for the long winded post, I was hoping that this would be a simple job of connecting a new battery, open to any (low cost) ideas to make this a safe and usable system.

Cheers.

Oh and to top it off, I now cant open the bonnet, cable seems tight so I don't think it has snapped but it isn't releasing the catch. Another job for the list to keep me occupied .

If the current solenoid works use it.
it will do the job fine.
I have one just triggered by ignition on and it is simple and foolproof.
I would go 4 b&svas one day you may want to add van electrics.
regards PhilipA

If the current solenoid works use it.
it will do the job fine.
I have one just triggered by ignition on and it is simple and foolproof.
I would go 4 b&svas one day you may want to add van electrics.
regards PhilipA

And my opinion 80 amp is to high a fuse 40 maxi fuse is all ya need so it blows if something isn’t right.

Originally Posted by RobMichelle

And my opinion 80 amp is to high a fuse 40 maxi fuse is all ya need so it blows if something isn’t right.

Hi Rob and as Babooon is using 6B&S ( 13.5mm2 ) cabling, which has a derated continuous load rating of 105 amps, his 80 amp fuse is fine.

Hi Baboon,

I have just gone through this exercise, I have also used the traxide SC80 and you definitely want both black & red in 6 B&S running straight to the battery (this is what is advised in the literature from Tim @ Traxide) and can confirm that after three days up the high country it works precisely as advertiseed, I have a 105 AH AGM mounted in the back connected to a KINGS 12V Distribution panel (cheap but not particularly nasty!) with the SC80 mounted to the face of it, running a National Luna 60L Fridge Freezer.
Disco2 Rear Cargo Area.jpgKings 12V Dist Panel.jpg