different size batteries

[KEVINL]

Ben is right on

In a Parrallel battery circuit The voltage is still 12volts the Avaliable amps is the sum of both batteries

My Blazer on the other hand has a series wired system both 12volt batteries are wired in series which increases the voltage to 24volts however the amperage remains the same. So two 800CA batteries in series is still 800Ca but the higher voltage allows the starter to half the current of a 12volt starter

 

[THEFERMANATOR]

I don't think it matters so much as to having both batteries being teh same size so much as them both being teh same age or condition. At least Ford looks at it this way. If you ever look at a Ford diesel van, they have 2 completely different sized batteries in them, and you never hear of trouble out of them. The only problem I'm aware of is if you have a new battery and say an aging battery that is holding say a 1/2 volt under a full charge due to age. The lower battery will pull the new battery down every time it sits. Other than that I don't see it being a big deal.

 

[ArrBee]

yes I do.



I have been working on both duramax and gas GM pickups/SUV's for years, please trust me, there is no fancy wiring for the second battery on diesels. It is simply wired in parallel to the first battery. The truck doesnt even know there are two batteries hooked up. Like I said above..



All diesels have two batteries, so its cheaper to just wire them in parallel. Dual battery option on a gasser is rare, im guessing thats why they have the fancy relay system. I dont know why they didnt do the dual battery gassers just like the diesels, but thats just the way it is.

If you still dont believe me, go disconnect one of your batteries and try to start the truck. Ill put a billion dollars on the fact that it will still start and run just as normal. If you had some fancy battery relay or some other isolation device it wouldnt start. Ive run my truck on only one battery for the past 3 years. Even in -20* it still starts fine even without being plugged in. Cranks slowly when its that cold on only one battery, but it still starts fine.

ben

Page D52 doesn't distinguish between gas and diesel "aux" batteries.
I take it the red text in the diagrams is your own ?
On the '03 and beyond the aux battery relay 12052641 is in the distribution area right under the driver side floor, nowhere near the passenger side battery that you indicated.

OK, so maybe all that is wrong, or I can't read schematics (-:
So I went out and unhooked the "aux" (passenger side) battery anyway to prove/disprove one thing or the other.
Guess what ?

NO volts on it's positive cable when that cable is unhooked from the battery with the key out.
About 9, rising to 11.4 after preheat recovery on it when I turned the key to the ON position.

Now, it might be magic, it might be the phase of the moon, it might be that I am wearing long sleeves, but there are no extra aces in them so I am FAIRLY SURE that the 11.4 or so is coming from the driver side battery and it is only there when the key is ON, i.e. via the aux battery relay 12052641.

So maybe, just MAYBE they drew the schematics the way MY truck is wired ? - - Ooops, I mean; Maybe they wired my truck the way the schematics describe the design.

No matter, I got my answer - it came from a meter and maybe that is the best way.

Thanks anyway.

 

[chrisuns]

Thanks anyway.

You're not serious are you? Go pull your battery cables and tell us what you see(It's going to be a cable system wired in parallel with no type of AUX battery relay; I know this because the cables happen to be right next to me). I'll personally sent you a card with 200 bucks to you're store of choosing if you find that the duramax diesel batteries are wired to a fancy Aux relay system. I will guarantee that A. You don't know how to operate a volt meter, or B you're full of shit.

Ben, you SHOULDN'T run into problems doing this. Now, you probably won't experience the full life cycle of the batteries doing this(Which is vague at that). Voltage is electrical pressure of current, as long as the voltage charge differential matches with .2 iirc of each other you won't have problems there. If it's more, you'll start running into charge problems into the weaker battery. Now, the electrical current is another story, one battery will supply a bit more amps vs the other one at the same voltage. Will it hurt anything? Probably not. Will it shorten that batteries life span? Probably so.

Now, would I do it? No. Just because I know of the possibly damaging electrical pulses(Think voltage spikes "theory" of the GMT-900 heated washer system, in which GM blamed the supplier for the problem when they the supplier had no idea of the underlying issue) gm systems can contain. It's more than likely the field collapse of all the relays used the the vehicle without proper isolation. Add an unbalanced system(Different current ratings) in the mix, and you run further into the unknown. Just my 2 cents, I'd pry take it with a grain of salt though. I'm not a electrical engineer, just avid reader of my electronics books.

 

[duratothemax]

Page D52 doesn't distinguish between gas and diesel "aux" batteries.
I take it the red text in the diagrams is your own ?
On the '03 and beyond the aux battery relay 12052641 is in the distribution area right under the driver side floor, nowhere near the passenger side battery that you indicated.

OK, so maybe all that is wrong, or I can't read schematics (-:
So I went out and unhooked the "aux" (passenger side) battery anyway to prove/disprove one thing or the other.
Guess what ?

NO volts on it's positive cable when that cable is unhooked from the battery with the key out.
About 9, rising to 11.4 after preheat recovery on it when I turned the key to the ON position.

Now, it might be magic, it might be the phase of the moon, it might be that I am wearing long sleeves, but there are no extra aces in them so I am FAIRLY SURE that the 11.4 or so is coming from the driver side battery and it is only there when the key is ON, i.e. via the aux battery relay 12052641.

So maybe, just MAYBE they drew the schematics the way MY truck is wired ? - - Ooops, I mean; Maybe they wired my truck the way the schematics describe the design.

No matter, I got my answer - it came from a meter and maybe that is the best way.

Thanks anyway.

OK whatever you say. It appears you have a one in two million duramax that has some stupid ass unique battery wiring/setup.

Either that or you were so sure you were right, argued with me, went back and checked and realized you were wrong, and now you are feeding us a line of bullshit to backpedal your way out of this. Every single one of the (almost) two million duramax's out there will show battery + voltage if you disconnect the passenger side battery terminals and put a volt meter to them regardless of whether or not the key is ON or OFF.

Post up pictures of your underhood setup, Im dying to see this special 2003 dmax of yours.. I really am.

Ben

 

[McRat]

It's no news that a bigger battery takes longer to charge at a given amp.

So when you have different capacities, the smaller get charged first, then continues to receive current as the bigger one continues to charge.

But the voltage threshold will be reached before the big battery is fully charged, since it's the average (kinda) of the voltages of the two batteries.

Now how much does that hurt? Dunno. Ideally you'd want both batteries to come up to voltage together.

 

[ArrBee]

OK whatever you say. It appears you have a one in two million duramax that has some stupid ass unique battery wiring/setup.

Either that or you were so sure you were right, argued with me, went back and checked and realized you were wrong, and now you are feeding us a line of bullshit to backpedal your way out of this. Every single one of the (almost) two million duramax's out there will show battery + voltage if you disconnect the passenger side battery terminals and put a volt meter to them regardless of whether or not the key is ON or OFF.

Post up pictures of your underhood setup, Im dying to see this special 2003 dmax of yours.. I really am.

Ben

There Ya go (-:

You checked the page and part number I quoted, right ?
and of course in YOUR schematics that page doesn't exist and neither does the relay - or it is all marked "gas engines only" ?
I have quoted you page numbers from GM docs, you have quoted me
personal experience - which I acknowledge as exceeding my own.

OK, I think we're about done here.

Thanx for the grinz

EDIT:
I guess I should PS this in;
You probably HAVE seen the guts of many times more D'maxs than I have,
I yield on that, maybe 50 or even 100 times more.
I've only messed with mine and a few of friends and neighbors.

I doubt that you have seen enough of the 2 million or however many there
are for your sample to be statistical "proof" that they are "ALL" wired the way
you say they are. Not even enough to allege that mine MUST be unique.
Every one YOU have seen ? quite possible, even very likely if there are
two or three ways and your sample size is around 500.
i.e. you have dealt with a very small sample size, relative to the total population.

Many of us know that in the way long ago the 6.2 "naturally aspirated"
klattermotors had their batteries wired full time in parallel.
So preconceived notions about this DO exist.
Hint/clue; It might be time to let go of some "stuff"

END EDIT

 

[duratothemax]

There Ya go (-:

You checked the page and part number I quoted, right ?
and of course in YOUR schematics that page doesn't exist and neither does the relay - or it is all marked "gas engines only" ?
I have quoted you page numbers from GM docs, you have quoted me
personal experience - which I acknowledge as exceeding my own.

OK, I think we're about done here.

Thanx for the grinz

EDIT:
I guess I should PS this in;
You probably HAVE seen the guts of many times more D'maxs than I have,
I yield on that, maybe 50 or even 100 times more.
I've only messed with mine and a few of friends and neighbors.

I doubt that you have seen enough of the 2 million or however many there
are for your sample to be statistical "proof" that they are "ALL" wired the way
you say they are. Not even enough to allege that mine MUST be unique.
Every one YOU have seen ? quite possible, even very likely if there are
two or three ways and your sample size is around 500.
i.e. you have dealt with a very small sample size, relative to the total population.

Many of us know that in the way long ago the 6.2 "naturally aspirated"
klattermotors had their batteries wired full time in parallel.
So preconceived notions about this DO exist.
Hint/clue; It might be time to let go of some "stuff"

END EDIT

you're an idiot, you're full of shit, and finally, learn how to use the damn smileys correctly.

Post detailed pictures of your underhood wiring.

 

[03 D-max]

 

[03 D-max]

Straight from GM
This is from a 2006 duramax

 

[duratothemax]

Straight from GM
This is from a 2006 duramax

oh but thats a 2006, the 2003's must be different.

 

[ArrBee]

you're an idiot, you're full of shit, and finally, learn how to use the damn smileys correctly.

Post detailed pictures of your underhood wiring.

Ahh, resorting to senseless attacks ?
That is OK with me.

If you want to start in on me for the proper use of smileys.
It isn't formally defined and I have been using what I use since mid/late 70s.

A suggestion; you may want to get around to "proper" sentence structure and punctuation first.

Here's a reference you MAY want to follow up on (or not);
K33253a_005_03

I admit to not remembering where I got it from, but it is the schematic set that I am using.
My truck appears to have been built to it, the ones you have seen may or may not have been, I am not in a position to comment on that.

Can we keep this civil, or is it already too late for that ?

 

[03 D-max]

Ahh, resorting to senseless attacks ?
That is OK with me.

If you want to start in on me for the proper use of smileys.
It isn't formally defined and I have been using what I use since mid/late 70s.

A suggestion; you may want to get around to "proper" sentence structure and punctuation first.

Here's a reference you MAY want to follow up on (or not);
K33253a_005_03

I admit to not remembering where I got it from, but it is the schematic set that I am using.
My truck appears to have been built to it, the ones you have seen may or may not have been, I am not in a position to comment on that.

Can we keep this civil, or is it already too late for that ?

You have your vin # i can show you exactly what it came with from the factory:thumb:

 

[ArrBee]

You have your vin # i can show you exactly what it came with from the factory:thumb:

The VIN number is something (else) I don't carry around in my memory, or in computers.
Maybe when I get home to it, if the snow has cleared, but it is likely irrelevant anyway
a) I know what I have, whether others decide to believe differently or not.
b) The answer is in any case "not much, from the factory" since it was a Chassis/Cab, i.e. an "incomplete vehicle".

This HAS led to problems when looking up parts, e.g. the brakes are a size larger than the consumer level "regular pick-up" 1 ton brakes - just ONE example.

Come to think of it, I might have downloaded the schematics from GMs up-fitter site. Possible, even likely.

Golly Gee, I wonder if they wire incomplete vehicles differently ?
I know the PTO wiring is all there and I seem to remember that the PTO wasn't possible on the consumer level '03.
Although it was on the trans the consumer version of the floor pan somehow got in the way of using it.
The cab to axle distance is 60 inches vs 58 on the tin box bed "consumer" vehicles too, I remember that much (-:

Hahh, someone just sent me a message asking if this is an April Fool's Joke.
Well, its kinda long in the set-up if it is, don't Ya think ?
(-:

 

[Chevy1925]

The VIN number is something (else) I don't carry around in my memory, or in computers.
Maybe when I get home to it, if the snow has cleared, but it is likely irrelevant anyway
a) I know what I have, whether others decide to believe differently or not.
b) The answer is in any case "not much, from the factory" since it was a Chassis/Cab, i.e. an "incomplete vehicle".

This HAS led to problems when looking up parts, e.g. the brakes are a size larger than the consumer level "regular pick-up" 1 ton brakes - just ONE example.

Come to think of it, I might have downloaded the schematics from GMs up-fitter site. Possible, even likely.

Golly Gee, I wonder if they wire incomplete vehicles differently ?
I know the PTO wiring is all there and I seem to remember that the PTO wasn't possible on the consumer level '03.
Although it was on the trans the consumer version of the floor pan somehow got in the way of using it.
The cab to axle distance is 60 inches vs 58 on the tin box bed "consumer" vehicles too, I remember that much (-:

Hahh, someone just sent me a message asking if this is an April Fool's Joke.
Well, its kinda long in the set-up if it is, don't Ya think ?
(-:

so you post up all this "info", you try to make everyone believe what your sayin but yet you wont provide proof via vin, pic, a dmax shematic, and so on. then go on to only degrade 03 dmax after all he asked for was a vin? care to explain why anyone on this forum to put any repsect or trust into what you are saying? you cant believe everything on the net because one person says its right, thats why we ask for proof so we all know its a true fact. untill then, your blowin smoke

 

[chrisuns]

The VIN number is something (else) I don't carry around in my memory, or in computers.
Maybe when I get home to it, if the snow has cleared, but it is likely irrelevant anyway
a) I know what I have, whether others decide to believe differently or not.
b) The answer is in any case "not much, from the factory" since it was a Chassis/Cab, i.e. an "incomplete vehicle".

This HAS led to problems when looking up parts, e.g. the brakes are a size larger than the consumer level "regular pick-up" 1 ton brakes - just ONE example.

Come to think of it, I might have downloaded the schematics from GMs up-fitter site. Possible, even likely.

Golly Gee, I wonder if they wire incomplete vehicles differently ?
I know the PTO wiring is all there and I seem to remember that the PTO wasn't possible on the consumer level '03.
Although it was on the trans the consumer version of the floor pan somehow got in the way of using it.
The cab to axle distance is 60 inches vs 58 on the tin box bed "consumer" vehicles too, I remember that much (-:

Hahh, someone just sent me a message asking if this is an April Fool's Joke.
Well, its kinda long in the set-up if it is, don't Ya think ?
(-:

Wow... That's all I can say to this.

So now you're saying even your brakes are larger than the rest of our 1-tons? Am I catching that right?

I'm very interested is this "FrankinMax" that you claim to own. Until I see a vin, or pictures of this claimed bullshit. I can agree and go along with everyone else and don't have a problem calling you on it... BULLSHIT!

 

[ArrBee]

so you post up all this "info", you try to make everyone believe what your sayin but yet you wont provide proof via vin, pic, a dmax shematic, and so on. then go on to only degrade 03 dmax after all he asked for was a vin? care to explain why anyone on this forum to put any repsect or trust into what you are saying? you cant believe everything on the net because one person says its right, thats why we ask for proof so we all know its a true fact. untill then, your blowin smoke

I cannot provide the VIN number until I get to the vehicle.
Right now it is about 150 miles from where I am, I will be there late on Monday, Tuesday at the latest.

I am NOT just sitting around here with it outside, I am on a trip, that truck is NOT with me.
This is the same reason that I cannot supply any of the requested pictures.

The only thing I have WITH me for reference is the schematics that I have already given the number of, page # and part number of the aux battery relay.

This is NOT important.
Everyone is welcome to believe what they want to.
I have little/no interest in convincing anyone to believe anything, nor do I need to earn the respect of anyone here by bowing to their wishes for "proof".

I have an answer that agrees with the schematics that I have and with the test that I ran with a meter before I left on my trip.

DONE.

 

[ArrBee]

Wow... That's all I can say to this.

So now you're saying even your brakes are larger than the rest of our 1-tons? Am I catching that right?

I'm very interested is this "FrankinMax" that you claim to own. Until I see a vin, or pictures of this claimed bullshit. I can agree and go along with everyone else and don't have a problem calling you on it... BULLSHIT!

One more response before I get back to WORK.
As I recall the 1 ton chassis/cabs are NOT 3500s.
3601 maybe ?, though I don't have registration, title or anything much else with me.
The cab to rear axle is definitely 2 inches greater, I remember that distinctly from when I went to get a flat bed put on.

It is NOT a FrankenMax, it is regular production, though "incomplete"
That term is kinda fun - thanks.
Check out chassis/cab specs sometime, you MIGHT learn something.
I don't know how the current production models are different from commuter trucks either, I might look 'em up too when I get home.

 

[03 D-max]

and part number of the aux battery relay.

I think you got some bad info because part number 12052641 superseeds to 12102747 which is a connector for a coolant level sensor....

 

[MACKIN]

Oh I was afraid to post since the grammar police have 'done' shown up! :roflmao:

He did say it was a incomplete. So it has me wondering if he ordered it , someone else did and it went out for some custom work then canceled, etc etc etc. The only true way to know is having the history on the build and or pictures I guess.

But nonetheless who cares? I don't but please don't stop I'm enjoying the banter. Old phart verses new phart. :roflmao: