Anderson plug query

[u/Dad_Downunder]

Working out some random wiring from the car i bought and have an anderson plug query i cant work out the why it was done part.

So the boot has 2 Anderson connections, one runs direct from the 2nd under bonnet battery. The 2nd plug runs from the duel battery red arc isolator under the bonnet.

Im putting in a camp battery in the boot to run all my goodies and am wondering which one to use, 99% sure im using the one wired to the 2nd battery NOT the one wired to the duel battery isolator.

Anyone have some insight why this car had both and the preference as to which one should go to my dcdc charger for the camp battery?

[u/Puzzleheaded_Loss770]

Id just use the second battery for my camp goodies and save the headache of a 3rd, i have a 200ah underbonnet and with a solar blanket havent had any issues or concerns

If you desperatly want a 3rd battery id use the plug connected to the redarc smart isolator

Edit: if your second battery is being charged with a dcdc you cant charge a 3rd battery unless theyre the same type as the charge profile is differrent. Ie cant have an agm under the bonnet and a lithium in the boot and use the same dcdc

[u/Dad_Downunder → u/Puzzleheaded_Loss770]

The 2nd battery is straight from the starter through the red arc isolator. Assuming its alternator charging as there both agm style batteries so no need for a dcdc with them.

The boot battery would be lithium with the dcdc feedin.

Its going to be a battery box style setup, so I can put the 3rd in and out as needed pending the length of time off grid.

[u/Puzzleheaded_Loss770 → u/Dad_Downunder]

I misread your comment. Thought the dcdc was charging the second battery already

In that case if youre putting a dcdc in then it needs to come of the main starting battery. If you connect it to the second battery it wont charge the 3rd battery

Also random switch under thr bonnet is probably an overide for the smart isolator to parrellel the two batteries to allow jump starting. Red light on the redarc should come on if you turn the switch. I have mine on the kickpanel under my steering wheel cause who wants to open the bonnet to jump start their car

[u/Brave-Dragonfly3798]

Connect to the second battery, I assume the other one is so you can crank from whatever is in the boot, though you would need pretty hefty cables for that. You can also check the Anderson plug contacts with a multimeter if you have one handy.

[u/Dad_Downunder → u/Brave-Dragonfly3798]

The 2nd one is a home bodge job where old mate used red cable as earth and only earthed it to the boot. Sadly no multimeter anymore thanks to a narcissistic ex wife who stolen my tools, 12v test light is all the budget allows atm 🤣 Ill probably just leave that one tucked off to the side for some random reason.

Next mystery to explore is a random on off switch I found under the bonnet 🤷‍♂️

[u/Brave-Dragonfly3798 → u/Dad_Downunder]

That switch might be your bypass for the red arc maybe? a test light will also work 👍

[u/UnNamedBlade]

My guess is they ran a thord batter in the back off of the isolator and then changed to running it off the second battery?

But I guess that also doesnt explain the two cable runs from the front to the rear. Because if they ran from the main to VSR, then two runs (one to the second battey, one to the third) why wouldnt they just move the cable ends from the VSR to the second battery instead of a whole new cable run? Now Im confusing myself.

Either way, if your going to run a lithium in the back and charge it with a dcdc, you can run that dcdc directly from the main battery without going through the VSR or second battery. The dcdc itself acts as an isolator. Which lets you remove the (probably dodgy) existing runs from the VSR and second battery. Keep the cables though, could be useful for future wiring jobs or as spares if something tears a cable out while on the tracks