2013 DMax, so called "Smart Alternator"

Service manager at Isuzu dealership says otherwise, he also said that to replace one is $1800.00, that sounds like a lot for an ordinary alternator.
Dave

Hey Dave, do you want to buy some pills to improve your consumption.

What about a few Hiclones??

Wow, $1800 for an alternator. That's almost 5% of the value of a brand new vehicle (assuming the $40k drive away price is still available)

Price an OEM alternator, I'll think you'll find their all around that price!

The smart charge function is done by the engine management function and not the alternator, the alternator will be more or less standard except it will have an extra control wire, the Toyota Prado's for instance already have the control wire, it just is not being used as yet.

Leigh

Dave
You might be surprised? No one else has found one on their Dmax's.

Leigh
That being the case, do i or dont i need to use a dc-dc charger ?
Cheers
Dave

Dave,

As far as I'm aware the current DMAX does not have an ECU controlled alternator and doesn't need a DCDC charger or booster diode etc, a simple VSR setup should work well. If you would like to confirm for yourself I would suggest you do as follows:

After car has been garaged overnight, start car wait a minute or so and note the voltage across the cranking battery terminals with engine at 1500RPM, drive car for 30 minutes or so and do same, monitor for a few minutes.

If first reading is around 14.4V and second reading is similar then you have a normal constant voltage alternator setup. If you see the voltage dropping to under 13V you most likely have an ECU controlled alternator.

The following was lifted from the TJM site and lists the post 2012 DMax as having a variable voltage alternator
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Some vehicles released in late 2010 onwards with common rail diesel and petrol engines have variable voltage alternators that are on the vehicle CANBUS. These alternators vary output based on driving conditions at the time. The range of voltage can be between 12.3V and 15V For this reason, the alternator may not charge a dual or multi auxilary battery bank at all times, and may apply too high a voltage for the auxliary battery chemistry type at other times.

Known vehicles with this style of alternator - Nissan Navara D40, R51 Pathfinder 2011 onwards V6 Diesel only. Hyundai Santa Fe 2010 +, Range Rover 4 2011 +, Ford Ranger 2011 +, Pajero 2012 +, Mazda BT-50 2011 + and Land Rover Disco 4, Isuzu D-Max 2012.
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Just read Evaredy's post below, and it looks like TJM might have it wrong.

14.2 sounds a little low for a DCDC charger, I would have expected 14.4V to 14.5V.

Maybe volt meter is on the alternator and either the alternator is not ECU controlled or the function has been turned off, if so one would have to wonder why the autoelect installed a DCDC charger when a simple VSR would have performed better?

Leigh

i was told I need to use a DC-DC charger because of the so called "Smart Alternator", the voltage is off the alternator, The dc-Dc charger is not a real good one I think, its more of a "battery management control sytem" its an Invertec DC-SW-140.
Its not like the proper Ctek dc-dc charger I have on the camper.
Dave

Dave.
When you say, I was told, who is doing the telling?
It all revolves around who knows and says what and understands the variables of the intended usage.

Where is your dual battery?
If close to the main then probably no DCDC required.

I use a dual battery in the tub of a Dmax and with HEAVY wiring it runs at the same voltage as the battery.
I don't even have a VSR, just a simple heavy continuous solenoid.
However, here are situations where a DC/DC unit is a good thing to use, like in a camper where runs are long.

If the batteries get flat a 20amp DC/DC unit running flat out will take a few hours to charge it all.

Dave,

The DC-SW-140 is a VSR not a DCDC charger!

Cheers
Leigh

Ok, getting a little confused now.
I was told by the service manager at The Isuzu dealership and also an auto electrician.
Battery is in the tub.
Heavy cables used.
The output of the dc-sw-140 with the engine running is the same as the voltage at the main battery (14.2 volts)
If the Dc-sw-140 is a vsr and im getting a 14.2 volt output then it should work ok, right ?, on not.
Dave

I have never looked but logic would indicate that
DC is a DC supplied thing, and SW is a switch, and the 140 means that DC SWITCH can handle 140 amps.

Yes Dave,

The setup should work ok as is, no need to change anything.

Cheers
Leigh

Nothing scientific about it, its based purely on what my fuel economy gauge is telling me, which I know is not 100% accurate, but it did change right after adding the dual battery system !
Dave

To take notice of the dash abacus is probably not a goo d method to check things.

I do love the comment from Andrew L " BUM DYNAMOMETER.

If you wear thick nappylike undies that error may vary so it isn't a good method either.

I like the bum dyno as well.
Nothing scientific or, indeed, accurate about the method used. Trips vary, humidity and temps change, driver moods dictate right foot enthusiasm, traffic lights, wind speed and direction etc.

And yes, the DMax does not yet have a smart (or dumb) alternator.
So the whole concept is moot.

LOL A fitting finale to Act 1 of a most interesting discussion.
I await more with baited breath.

Not getting involved as to the test environment, just looking at the simple physics, if you add a dual battery system and use it you have to replace the energy you have used, in this case the energy is supplied by the motor. If you use a 100Ah at 14.4V that's around 1.4Kw you've drawn from the motor and that's not allowing for conversion loses etc.

So yes you will use more fuel. Same as turning off the smart charge function, if you raise the base voltage all the electrical equipment will consume more power and more fuel, you can't have it both ways though, if you need the power you have to burn the fuel.

It is interesting to look into the engine management ECU to see what lengths the car manufacture have gone to improve idle fuel consumption and hence minimise the pollution emissions to meet the standards.

Take the Toyota Prado diesel for example, they use a high compensation alternator to lower the charge voltage to reduce engine load, they have firmware in the engine management system to minimise fuel consumption at idle, the ECU looks at every cylinder as it fires and times the acceleration of the piston stroke and and continually adjusts the fuel flow to each cylinder at idle to balance the power output from each cylinder. Of course once you put the foot down it disregards all that and reverts to look up tables to get the horses going.

Cheers
Leigh

r

I meant to say Variable Voltage Alternator not regulator.