Dual battery kits?

I’m looking at chucking a dual battery system into my ute to make it better for camping/hunting trips.
I have a spare 150AH AGM battery up at the farm, I have a bunch of anderson plugs, solar regulators etc. I know my way around 12V & solar, but I haven’t had any experience with these dual battery car systems.
I really only need to run a fridge, a couple of light’s etc.
The dual battery kits you can buy consist of a relay and some wires basically, I know.
I’m looking for advice on brands and shit, I can grab an Adventure Kings one pretty cheap, but I’d love to know what people are using and any pro’s or con’s of them.
@JSS I know you do a bit of camping, what do you use mate?
Everyone else’s 10c is welcome too.


My Cruiser came with twin batteries so i just had them split using a Redarc bcdc40d which works well and also takes & converts the charge from my solar panel on the roof as well as the alternator, it also has an extra solar input that i can plug another portable solar panel into.
I’m only running a Full River 120ah deep cycle in mine because that’s all that could fit in the factory second battery spot, although when it dies i’ll replace it with a similar sized lithium, but generally go as big as you can, your 150 should be heaps for just a fridge & some camp lights & stuff.
My solar panels are both 120 watt, again because that’s what fits for me. I have two different shape ones (a std shape one and a long slimline) and i only use one at a time depending on whichever fits with what crap i shove up on the roof platform, but 120watt works fine for me and keeps everything topped up, i run a 65 litre fridge, lights & charging stuff, but again go as big as you can. One of my panels is Enerdrive and the other one is a Redarc which were chosen on their dimensions, but i’d recommend getting a good brand one as they are honest with their outputs and do actually seem to work better than some of the cheaper stuff.
With the 12v stuff you do generally get what you pay for, but in saying that a lot of the good stuff has come down to more reasonable prices when it comes to solar panels.
All the gear in my Cruiser is 6-7 years old now and i’ve never had an issue with any of it.

I’ve just ordered a new GMC 3500 which is about 12 months away for delivery but it’s going to get the full canopy for touring and a big 12v setup to run two fridges induction cooking and 12v hot water which will either be all Redarc or Enerdrive as i’ve been happy with their quality.

The only kings thing i’ve had was a solar blanket i got to try and it fell apart before it was 12 months old after being used a couple of times, but by the time i got around to actually calling them about it it was just out of warranty (buy a week or two from memory) and they didn’t want to know about it.

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Watching this one also…i have the solenoid switch that, i think keeps your crank battery safe…but i should have 2 batteries in the Prado, it has the space for 2nd battery…

There’s also a new Enerdrive charger ( i haven’t heard any reports from anyone i know but assume being Enerdrive it’ll be good) but it will take both solar input AND alternator input at the same time, whereas everything else to date will just pick the best source to use at a time.
It’s not so important with agm & deep cycle batteries as they’re limited to the rate of charge they can take, but if you might ever switch to lithium down the track they can take huge loads and charge quickly and makes it a winner.


Im in this boat too. Just installed drawers and have a 200AH lithium batt. Onlynthe best highest quality Kings SupaCentre and yes, upgraded my fire insurance. Going with MPPT charger and non-kings panels x2.

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LMAO! Im literally doing it for 24/7 cold beer. Kegs inbound.

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I use a Redarc bcdc, these dc to dc chargers seem to be the best way to set up dual batteries. You can plug solar in when you pull up or run it all the time. They also have no chance of accidentally draining your main batt.


…and they detect the “smart alternators” too. I have an “eco” VW amarok alternator which charges low, like 10.2v, so that bit of gear is essential for me.

Thankfully I’m working on a dinosaur 94 mod mazda B2600, so it should be simple enough.
I was looking at getting something newer, but I’m best off not gaining any new assets until I can get my divorce and settlement sorted.
Looks like redarc is the way to go then, thanks all!


I run the 25 amp version and charge a 105ah agm.


So what real benefits does the above offer that justifies it being almost 10 x the price of the one below?

I can think of plenty of other things to spend 800 bucks on…

Wonder what you get for the extra 300 bucks.

They now make an in cab one that’s isn’t dust or water proof that is a bit cheaper.

The solenoid ones are okay and it depends on where you’re putting the second battery. You’ll have to run a fair size cable to prevent voltage drop off its going on the rear of the vehicle, this isn’t a problem on the dc chargers.

They are better for your agm or lithium batteries as they also have charge modes to suit.

I was going to have a look into this as I have no personal experience with the products but am technicaly very qualified to give an opinion. when you use the term agm can you please explain.
Do either of the units also contain a 240 V inverter?

I’m hoping to fit the battery under the bench seat, but I’m not sure if it’ll fit yet. Its only a single cab with a tray on back. If it won’t fit under the seat I’ll tryto mount it under the tray somewhere.

This is the sort of battery I’m going to use. I have a bunch of these at the farm to run my off grid power there. Mine are all second hand ones from the back up systems on phone towers.

The difference is the Redarc is Redarc and the Kings is Kings lol.
But really the Redarc will separately fully charge your second battery instead of just thinking one battery is ok so stop charging both even when the second one is low. It will take your solar charge without needing an extrenal mppt, and it’s better quality.
The kings is just an isolator switch and that’s all it does. Even if you choose to just get an isolator, get a Redarc one or a different brand than Kings.
Here’s an apples for apples redarc version of the Kings isolator, and this way your car won’t burn to the ground lol.

Isn’t that battery like 4.5ah? It’ll run you fridge for about 30mins when it’s compressor is running.

Mines 150AH AGM

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Cool i just went from the photo and thought “oh fuck your beer wont be very cold lol”.

Also if you can’t find a good mounting spot it might be an option for you to go a portable dual battery system. That way when you don’t need it you can just remove it plus you can take it & the fridge out of the car to leave at the campsite or take it from car to car. There are tons of companies making them these days and it’s an all in one setup that you just need to run a cable to.

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Mate the biggest problem that you may have with those batteries is if they were designed for phone towers they are probably what they call Stationary batteries. As the name says they are made to a lighter duty of robustness. In a car the plates may fall apart. But if they were free give them a go.

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We had 2x100AH AGM batteries, with a 1000w redarc in the camper, they worked well enough, but i think there’s better options out there, at least in place of the AGMs. Redarc is good!