Alternators big enough for dual battery?

[isiman]

I remember a while back that someone mentioned that the navara alternators are not good (strong?) enough to run a proper dual battery setup. Can someone shed some more light on this please?
I am interested mainly in the d22 2.5cr but it may help others if the other variants are mentioned as well.

I relies that there are already 2batteries in my setup, but I am assuming they are not overly well rated.

I plan on removing one of the current cr2.5 batteries, putting in both a physical and automatic isolator (I don't trust pretty push button overrides) with a higher rated start battery and a century marine pro 700 for aux/failover. I will be running 35mm2 wiring so no issues with melting.
Oh, and if anyone knows, what size are the batteries in the 2.5s? I know it's going to be a tight squeeze to fit an n70 in there.

 

[KraftyPg]

What is a proper dual battery set up?

I don't remember reading too many dual battery installs here where owners have upgraded the alternator.

 

[FatBoy89]

What is a proper dual battery set up?

I don't remember reading too many dual battery installs here where owners have upgraded the alternator.

Maybe in the us...

 

[isiman]

Sorry, by 'proper'i meant putting in higher rated cranking battery, maybe around 700cca and a 720cca aux with deep cycle as the aux.
As I mentioned, it was just something I remember hearing about a fair while ago, that the nav alternators were not up to charging that kind of setup -I could be, and am very often incorrect, hence the question

 

[KraftyPg]

The problem with dual battery information on the net is that there is many different theories and many different methods, most of them work but many of them make waste of a number of components you just don't need.

Despite the D22 having a smaller Alternator than the D40 to make a dual battery system all you really need is 6-8mm2 cable, 1 isolator (redarc, projecta etc) 1 fuse, a second battery and some plugs (anderson are common but I often use low voltage clipsal plugs) anything else is entirely up to you but it's not required.

You can install the second battery anywhere but D22's do have room under the bonnet depending on the battery size, however the standard cranking battery and alternator has suited most if not all d22 owners on here so I don't see any reason to change them just because you are adding a second battery.

There is a terrible rumour around that no car alternator is up to charging a car's battery or aux battery properly but that is cocky sh@t however if you do subscribe to that theory then it's not the size of the alternator that is the issue it's the system and therefore a bigger alternator wont help you.

 

[isiman]

Great, that is exactly the info I was after. Thanks heaps!
For me, I have the cable so I might as well put it to good use, and saves me going to get more.

 

[Krankin]

Nothing wrong with the late model D22 alternator.

 

[Krankin]

and most dual batt isolators do just that...isolate one from the other....charge one at a time...
but your vehicle has the two factory batts,and charged at the same time,
has your alt grenaded yet???

 

[d22dave]

The problem with dual battery information is many different theories and many different methods,

There is a terrible rumour around that no car alternator is up to charging a car's battery or aux battery properly but that is cocky sh@t however if you do subscribe to that theory then it's not the size of the alternator that is the issue it's the system and therefore a bigger alternator wont help you.

The guru,s at Piranha in Melbourne talked a bloke with 120 series prado, Who already had a dual battery setup including anderson plug for camper trailer into putting another $1400.00 on the counter because they told him there wasn,t enough charge to fully charge his camper battery, Company,s like this are preying on peoples ignorance

 

[KraftyPg]

But the bigger problem is all the fantasy websites out there which back up the bullsh@t stories so that if someone does query what they are told and go looking on the net it doesn't take them long to find a website that agrees with the garbage the salesman told them and the salesman gets the deal. It makes you wonder just how many of these websites are frequented by the suppliers who stand to make dollars out of the stupid deals, you'd never prove anything though.

 

[d22dave]

At the starter battery i get a reading of 14.16 volts over at the second battery after the redarc i get 14.1 volts and down the back of the ute at the anderson plug i get a 14.1 volt reading, So i wont be rushing out and upgrading anything on the electric,s on my ute, I can live with that small amount of voltage drop,

 

[d22dave]

But the bigger problem is all the fantasy websites out there which back up the bullsh@t stories so that if someone does query what they are told and go looking on the net it doesn't take them long to find a website that agrees with the garbage the salesman told them and the salesman gets the deal. It makes you wonder just how many of these websites are frequented by the suppliers who stand to make dollars out of the stupid deals, you'd never prove anything though.

I was going to alter a couple of wires and add a plug for him but it was a matter of timing, He needed it for xmas but these pr#$ks talked him into it, This guy is not dumb but its not his "thing" and they spun the bull about not enough to fully charge and be left with a flat battery

 

[KraftyPg]

Trouble is you don't have to be dumb to fall for sales hype, we all fall for it to some degree otherwise we wouldn't own anything but some salesmen definitely know how to spin it. Years ago we used to call it selling ice to Eskimos then selling them the freezer to keep it in, but some of them take it a lot further than that these days.

 

[tatty]

There is a terrible rumour around that no car alternator is up to charging a car's battery or aux battery properly but that is cocky sh@t however if you do subscribe to that theory then it's not the size of the alternator that is the issue it's the system and therefore a bigger alternator wont help you.

This man (or woman?) speaks truth.

Car batteries (stock) take 15-20 minutes in a car to charge whilst driving from about half to 75% dead. So in under an hour, both batteries could be fully charged if the isolation switch did it's job.

Of course, always check your alternator charges properly with a healthy reading. My alt only reads 10-11v when idle but about 14v when revving over 1g. But I haven't had charging issues at all.

 

[d22dave]

Trouble is you don't have to be dumb to fall for sales hype, we all fall for it to some degree otherwise we wouldn't own anything but some salesmen definitely know how to spin it. Years ago we used to call it selling ice to Eskimos then selling them the freezer to keep it in, but some of them take it a lot further than that these days.

I dont how some people do it,

 

[KraftyPg]

The rumour is alternators wont charge batteries properly but then you admit that in under an hour both batteries could be fully charged?

So the rumour is true but the batteries charge anyway, seems contradiction is king on the internet.

 

[joe2006]

I had a spare wet cell of 550cca I think. That now resides in the tub & runs my fridge. When it is shagged I will buy another. Maybe a deep cycle although most probably not.

No intention of running the fridge for days without using the car so it always has enough charge for my needs.

Have I done something wrong?

 

[d22dave]

My system suits my use at the moment, Never had a issue with flat battery in camper touch wood, We go away for 4 or 5 days at a time battery,s are fine maybe if we where to travel for 12 months, The supposed lack of full charge may come into it , But as i think Rex Hunt said the kiss principle Keep It Simple Stupid, The redarc in my ute is simple cheap and effective and i,ve had it in 2 ute,s now in 3 years so i would say its reliable

 

[KraftyPg]

Joe: A deep cycle for something like the fridge would be a good idea but i wouldn't bother until the other one dies if it dies.

I thought I flattened a battery about 6 weeks ago by running the fridge for too long in the stinking hot canopy but it turned out after 2 years my Century developed an internal fault. Took it back to the guy I brought it off, it was 3 months out of warranty and he replaced it at no cost. The guy's still a dick when it comes to ripping people off for battery installs but atleast he did alright by me this time around.

Even managed to flatten the new battery over the new year period when I didn't realise I'd left the fridge plugged in and the internal thermostat spent 4 days in 35+ degree ambient temp (with the windows shut) telling the fridge it needed the thermo fan we installed in the fridge running constantly for the 12 hours it was sitting outside. We need to revise our thermo fan mod, wasn't actually made with the idea the fridge would be in a car 24/7.

 

[Krankin]

the alt in the 2008 and on is 90a.