Nissan Navara d22 Factory Dual Battery conversion help

[Oosti]

Hi,
I have a 2010 Nissan navara d22 STR 2.5L, and it came with a factory dual battery setup for cranking.
Both batteries need replacing and I thought Id look into converting it into a standard single cranking battery and then I have the option of adding a true second auxillary battery.

I have little automotive experience, and was wondering how I would go about converting the current 2 cranking battery setup into 1.
What will I need to do this? what type of battery do I need? Is this feasible for a DIY job.

Thanks

 

[Almostunseen]

For a simple cheap setup, all you need is a simple dual battery isolater/Volatage sensitive relay/solenoid. The more "advanced" types have ease of linking etc if you need to jump start.
Redarc, Projecta, NARVA, god forbid KINGS make them. Then combine with a yasau/century deep cycle(or your brand of choice) flooded lead acid battery.

There is the option of going for an AGM battery for better discharge characteristics etc, but I'm skeptical at their life under the bonnet with heat (there are heat tolerant AGM batteries but are more exey), plus you'd want to look into a DC DC charger to ensure the AGM is charger properly = more $$$.

In my D22 I isolated the 2nd battery with the projecta electronic dual battery isolator, then also ran a sealed AGM behind my back seat with a DCDC charger. I ended up swapping out my now main "cranking" battery for a larger size with increased CCA, as I live in the snow and the car actually needs the extra punch in the winter!

Honestly if there is Battery World or the like near you, check them out, the owner of mine was an absolute genius and no b/s kinda bloke.

 

[Oosti]

I went to ask for a quote at iron man and apparently they don’t recommend changing it to a single cranking battery as this will put more stress on the starter motor?

 

[Bru9]

All comes down to how much space you got under there. If you can fit 65-80AH century deep cycle flooded batts in each space you might just run with those and run your deep cycle gear off them, stay above 12v underload and carry a sizable solar panel, replace each a bit early before a big trip. common sense planning etc. my small 680CCA 80AH century can still start a 3.5L petrol V6 cold garaged when below half full, so twin 65AH deep cycle should be OK. the best batts under bonnet are flooded, with open cells to top up water and do an EQ charge.
only other option is just go the aux in the cabin/ute, but good 100AH AGM is like 500bucks to your door. pay half, buy twice...

The guy above is out of place about DC-DC getting the AGM properley charged, AGM is just a word, like car. cheap AGMs are not worth quality gear, a DC-DC only comes into play with good batteries & constant cycling like living on the road etc. weekend warrior has 0.002% benifit.

the stress on starter motor sounds made up, i have started mine soo many times when the batt is really low. i think starter motors die from simple surburb driving.

 

[Batts88]

Just done some research on the factory dual battery didn't come up with a reason why some vehicles have them but they have a 2.2kw starter motor my GQ has an aftermarket 2.5kw and starts easily with a 760cca single battery so your will start easy with a single 720cca battery. I was wondering if the dual battery was just an upmarket extra as a sales drawcard for some models as lots of Navara's with the same engine only have a single battery and have no issues.

So if you decide to change the set up to what you desire fit a single starter battery around the recommended cold cranking amps and the wiring for the starter and alternator only goes to the starter battery like most other vehicles have. Then fit your 2nd battery with a battery isolator like mentioned by Almostunseen and a voltmeter to monitor the battery level. If you are not keen on trusting an agm under the bonnet there are several brands of dual purpose batteries available. I have been using Supercharge Allrounder batteries for over 10yrs with 105ah or storage the more you have the better.

Another way is to leave the system how it is and replace your current batteries with 2 x dual purpose batteries and a voltmeter so you can monitor the power if your using a fridge or lights for camping.

 

[GDPhotos]

I went to ask for a quote at iron man and apparently they don’t recommend changing it to a single cranking battery as this will put more stress on the starter motor?

I think the fella at Ironman should stick to selling bull bars and fridges maybe ....that's rubbish.
The starter motor will only draw as much power as it needs, not more....so whether you have a battery with a capacity of 500CCA ( cold cranking amps ) or a battery with 5000 CCA, the starter will still only draw the same current. All a larger battery will do is give you far more cranks in cold weather ( hence the industry standard of CCA rating ) and means it won't go flat as quickly if your car won't fire up immediately. Same as how if you ran a much smaller battery, it would drain faster should your vehicle not fire up straight away.
Your starter has a current draw rating and that has nothing to do with what size battery you're drawing from it.

Think of current like water - the cabling is the hose and the current is the water.
If you turn the tap on flat out and have 5 sprinklers running of it, the same flow of water is still pushed along the hose from the tap - no extra. It just means the output pressure is divided between the 5 sprinklers instead of one. Hope that makes sense.

 

[Bigfish1]

I think the fella at Ironman should stick to selling bull bars and fridges maybe ....that's rubbish.
The starter motor will only draw as much power as it needs, not more....so whether you have a battery with a capacity of 500CCA ( cold cranking amps ) or a battery with 5000 CCA, the starter will still only draw the same current. All a larger battery will do is give you far more cranks in cold weather ( hence the industry standard of CCA rating ) and means it won't go flat as quickly if your car won't fire up immediately. Same as how if you ran a much smaller battery, it would drain faster should your vehicle not fire up straight away.
Your starter has a current draw rating and that has nothing to do with what size battery you're drawing from it.

Think of current like water - the cabling is the hose and the current is the water.
If you turn the tap on flat out and have 5 sprinklers running of it, the same flow of water is still pushed along the hose from the tap - no extra. It just means the output pressure is divided between the 5 sprinklers instead of one. Hope that makes sense.

haha...I thought the same thing.. There are some complete dills out there who run a business and don't know their products or technicalities at all. No wonder people get confused...