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Dual Battery System

Mark Chapman

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Joined
Mar 17, 2017
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united_states
Many members have added dual battery systems to deal with the increase electrical needs of a winch, fridge, solar, multiple charging ports and/or other.

I am considering doing the same and there are a number of kits available making my choice confusing.

In your opinion what is the best dual battery kit on the market and why? Or is their some hybrid system of various suppliers that is better and what is it composed of?

Thanks in advance for your help.
 
Hi Mark,

I've got the National Luna split charge system on mine. It was super easy to install (electrics are not my strong point) and has worked flawlessly. HOWEVER, the monitor is useless. If you wiggle the data cable that connects the solenoid to the monitor then it changes the supposed state of charge of both battery. In the end I took it out and replaced it with a £5 voltmeter which is much better.

So if you go with the National Luna save yourself some money and don't buy the monitor.

Hope that helps

N
 
I have used the T-Max kit on two different vehicles and both installations have worked flawlessly from day one.

Some people don't like the solenoid that comes with it and replace it with relay.
 
Does the 80 not have a 24v starter? So i guys we are talking about a third battery not a second one. Or is that a 'snow' / EU spec only thing?
 
Redarc BC-DC 1225 is what I use.
And personally I think it's the tits!!
It's a smart 3 stage charger and isolater all in one. I also hav my solar panel on an Anderson plug so when I'm parked up, plug it in and she's away charging. No need for a MPPT controller with the panel either, as the redarc unit takes care of the fluctuating voltages and currents.

I've seen/read about a guy who had his redarc system come loose from its mounts and get dragged behind the car for 100 or so kms and it was still working...
any who, enough of the sales pitch... the only thing is these are an Australian product, and I'm not sure if/how much it is to ship overseas...
 
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Redarc BCDC charges are great, I've got one fitted to my work truck and never had an issue.
 
So not to start another topic, I have a question related to the topic but regarding a Landcruiser 120 LC5 3.0D.
My LC 5 has a factory dual battery system, and I was thinking of replacing one of the batteries with a deep cycle charged via a DC to DC system to power mainly a Snomaster 35 l fridge.
My question is, will the LC 5 run properly on only 1 battery ? I know it also has to power the compressor for the air suspension as well, so maybe it is not recommended to modify the factory settings.
It will really save me a lot of space if I can repurpose one of the factory batteries. .
What size would you recommend for the leisure battery ? I don't think I will stay more than 2 nights in the same spot, so I should be able to recharge it every couple of days.
Thank you.
 
I used a Blue Sea ML-ACR (magnetic latch, automatic charge relay) which is an easy install and has a dash switch for manual override if required. Kinda cool to be able to jump start myself from the cabin too.
 
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The Intervolt DCC Pro are a very neat under bonnet charger. Look them up when the time comes. I have one left. That’s not your question really though. If the batteries are permanently connected in parallel then I dare say if you increased the vehicle battery CCA to the biggest physical size that will fit in the space then I would imagine all would be fine. You could try it with your existing batteries by disconnecting one of them and seeing how well it copes. You’ll need tobtrace the heavy wiring though and work out if they are in parallel which I think I’m right in saying they are.

A solenoid can be fitted across the two as suggested above. I have this ready to go on my 80. There’s even a switch I have my eye on. :)

The DCC Pro will take solar too by the way should you wish to add at a later date.
 
My Ctek has been running for over 8 year without issue it's a 250 and smartpass, when or if it packs up I will replace with another one like it
 
The batteries seems to be connected in parallel. As far as I know only the LC 5 with air suspension has a factory dual battery setup, and it is probably for the needs of this particular system. Same engine 3.0d 120 landcruisers have by default only 1 crank battery.
For example, after I stop with the ingnition off, even after a few minutes, I can sometime hear the compressor starting to work to level the car, depending if the terrain is level or if I unload a significant weight from the trunk.

It is a very good idea to try and remove 1 battery to see how it works, to test it for a few weeks.
I would prefer to do it like this if it works, less strain to charge 2 batteries instead of 3 for the alternator as well. And less GVM as well.
I will contact you regarding the intervolt thing on private.
Thank you.
 
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