Bought a Prado with a dual battery setup - i have questions :)

[Psydesign Lurker Find all posts View Profile Close Psydesign]

Hey guys,

noob here so go easy. if this needs to be in a different section let me know.
So I just bought a 2010 Prado 150 GXL which has a dual battery setup and I have some questions.

First off current setup:
Primary battery seems to have the standard in car power accessories (12v 220v plug) , additional spotlights, and a Anderson plug at the rear
secondary battery is connected via a red arc SBI12 and only has the uhf connected to it


I deduced that the Anderson plug in the rear is connected to the primary battery by disconnecting the positive terminal on the primary battery and confirming that the Anderson plug has lost power.

I am trying to understand why anyone would have the Anderson plug connected directly to the main battery in this type of setup?
ideally in my mind I want the Anderson plug connected to the secondary battery so I can run any accessories when the car is off and know that he redarc will cut the connection to the primary battery once it gets to a certain voltage. that way I don't have to worry about getting stranded and being unable to start?


i have attached a photo of what i plan to run any accessories on when the car is off and connected to the Anderson plug.
also attached photos of the red arc.

i am currently at work but if you need more photos let me know and i will take some tonight.


for what i want to do should i just rewire the Anderson plug to connect to the secondary battery?


Cheers

[RPP Senior Member Find all posts View Profile Close RPP]

The purpose of the Anderson plug at the rear might have been as a convenience to power a compressor.
Its time consuming to lift the bonnet every time to clip it on to the main battery.

If you re-wire the connector to the Aux battery, don't run a compressor off it as they can be power hungry, Its best to have them driven off the main battery with the engine on.

[EddieF Member Find all posts View Profile Close EddieF]

Hi Psydesign,
I installed a similar setup in my old Patrol before I got the Prado. I had the second battery connected so it would provide power to the rear for the fridge when travelling. But I also used the second battery in the boat. The idea was that I could pull out the second battery fully charged an put it in the boat (which was stored near the water as got sick of batteries dying sitting in the boat). If I needed to pull the second battery but still wanted power to anderson plug I might connect to main battery. In your case might be more likely they just didnt think it through.
cheer Eddie f

[Psydesign Lurker Find all posts View Profile Close Psydesign]

The purpose of the Anderson plug at the rear might have been as a convenience to power a compressor.
Its time consuming to lift the bonnet every time to clip it on to the main battery.

If you re-wire the connector to the Aux battery, don't run a compressor off it as they can be power hungry, Its best to have them driven off the main battery with the engine on.

Hi RPP thanks for the response! my plan was through the Anderson plug connected to the aux battery connect my accessories box (pictured) to all sorts of things camp lights through the 12v cigarette lighter and was even thinking of installing a second Anderson plug on that box and run it all through the original Anderson plug.


my compressor has battery clips (like jump cables) so will run that off the battery directly. ran the compressor of the aux battery last night but in future will run it off the primary with car wunning as you suggested

i was under the impression i could run heaps off the one Anderson plug at the back (given they power caravans..

[RPP Senior Member Find all posts View Profile Close RPP]

Its probably a 50A Anderson connector. You should confirm.
But the battery is the limiting factor.
Check the Amp Hr rating and if it is a deep cycle battery, and do some calculations.

It should be good for a fridge and a few low power accessories overnight.
Anything that guzzles amps will drain the battery very quickly (ie compressor etc) and reduce its lifespan.

Put a fuse at the closest point to the Aux Battery and then individual fuses at the accessory outlets (if they don't already have their own).

[Psydesign Lurker Find all posts View Profile Close Psydesign]

Its probably a 50A Anderson connector. You should confirm.
But the battery is the limiting factor.
Check the Amp Hr rating and if it is a deep cycle battery, and do some calculations.

It should be good for a fridge and a few low power accessories overnight.
Anything that guzzles amps will drain the battery very quickly (ie compressor etc) and reduce its lifespan.

Put a fuse at the closest point to the Aux Battery and then individual fuses at the accessory outlets (if they don't already have their own).

thanks mate will check the rating of the anderson - pretty sure its 50amp i should be run a bit through that right?
understand limiting factor is battery just checked aux battery is this one not sure if its any good? https://www.deering.com.au/product/marshall-lcs27-97/

will have a look if i can find a calculator online for what i can and cant run off it



thanks heaps

[money_killer Member Find all posts View Profile Close money_killer]

the rear anderson plug is wired to the main battery for caravaning purposes. eg. to a dc to dc charger in the caravan. they are not wired to the aux battery

[Leethal Advanced Member Find all posts View Profile Close Leethal]

The anderson plug might also be for a electric winch on a boat trailer, there are many possible reasons for the power run to the rear.

Lee

[vf34 Member Find all posts View Profile Close vf34]

I just brought a ZR which also had a dual battery setup, which appears to be a similar setup to what you have on your Prado. Also running a Redarc SBi12 isolator and a cable from the main battery to the rear with an Anderson plug (I think previous owner use to tow...). In my setup it looks like everything runs off the main battery, should the main battery run flat there is a bridging moment switch inside the cabin where I can link the secondary battery to the main to start the car. So it's like the secondary battery is just a backup battery for the main for starting only!

I don't really want to run everything off the main battery so I'm about to pull off all accessories cabling on the main battery and transfer over to the secondary with a new fuse block and cabling to the rear internally to power my fridge.