24V starting system, 12V vehicle system + add aux battery

jfarsang

Adventurer
I have Nissan Patrol which operates on a typical 12V electrical system with the exception of a 24V starter.

Two batteries in the engine bay

What I would like to ask the wealth of knowledge in this section is what would be the ideal auxiliary battery setup for me.

Typical engel fridge, laptop, etc.. running off an aux battery, charged up by the alternator.

In the past I've used the National Luna smart solenoid and it served me well.

The kink in the tread is the 2nd battery in the engine compartment that is there to supply 24V's to the starter.

Correct me if I'm wrong but some cummins diesels are hooked up this way as well?

Cheers
 

jfarsang

Adventurer
no one?

stock:
12V system
2 batteries hooked up parallel
24V starter

I would like to add a 3rd battery as an aux deep cycle for the fridge and accessories.

The National Luna, IBS, etc.. systems. Will they work with a 3rd battery in place?
 

offero

Desert rat
Disclaimer: I'm no electrical guru and just recently added an auxiliary battery to my vehicle. I'll take a stab though, or at least get a conversation going.

What voltage is the alternator? I'm assuming it's either a 24V alternator that steps down the voltage for the other 12V stuff; or it's a 12V alternator that steps up the voltage to 24V to charge your parallel batteries.

If you have a 12V alternator, I think you'd connect that to the alternator side of the isolator/combiner and then connect a 12V battery to the other side just like normal. Not sure what you would do if your alternator is 24V... maybe get whatever type of component steps down the voltage and connect that on the alternator-side of your isolator-combiner and proceed as you would in most vehicles.

I don't see why you couldn't use the common systems like National Luna, IBS, Hellroaring (what I ended up with), etc., to add a third battery. Assuming of course, you're connecting 12V on the alternator side of that component.
 

jfarsang

Adventurer
Alternator/Charging system is 12V just like on the cummins diesels
When you turn the engine over, there is a set of solenoid/relays that connect the batteries in series providing 24V power to the 24V starter.

Everything else is operating on 12V's.

My question.

Which battery would I connect the National Luna/IBS system to or would it matter?
 

offero

Desert rat
I didn't connect my main battery to mine... I ran straight from the alternator. So it goes alternator>isolator-combiner>aux battery.
 

lowenbrau

Explorer
I meant which stock battery would I connect the solenoid to or does it matter?

You need to parallel the aux battery, though the isolator to the starting battery that has the negative post connected to ground when starting. Normally the manufacturer covers the high side battery with a cover so you can't make a mistake while boosting/jump starting. You'll have to look for the battery with the ground wire running directly from the neg post to the block or frame without passing through the series/parallel switch.
 

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