# dual alternator, dual battery, anyone done this?



## jrs 94 (Jan 8, 2015)

Truck is a 2002 Tahoe with a snodogg MD75. Currently I am wired up with the factory alternator and single battery. Things are working fine but I am considering adding a second battery and also adding a second alternator to make a totally separate electrical system for the plow. With this setup the truck is totally unaffected by the plow, and obviously the plow electrical is stand alone. Has anyone done this? any reason not too? 
The last truck was the typical 2 batteries in parallel, this dual alternator / dual battery option just looks good to me. 

Thanks in advance.


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## Sawboy (Dec 18, 2005)

It's working fine. Leave it alone. I always try to live by the KISS method. 

Keep
It
Simple 
Stupid


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## Sprag-O (Dec 31, 2013)

We ran multiple batts and alt on our car audio rigs...

GM 1-wire alternator. No reason not to run the entire vehicle off it, more of a pain isolating things.


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## dieselss (Jan 3, 2008)

There's a thread in the dodge section. Guy did it


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## Plowtoy (Dec 15, 2001)

Its really not necessary... I have been plowing my bone stock 03 Tahoe for 3 seasons now and haven't experianced any charging system problems. Its fully loaded except sun roof and 3rd row. I have no problems running the heaters and heated seats radio/cd ect...ect...ect... The key is keeping the RPM's up while plowing (a lower gear). I try to pay attention and make my blade movements while under throttle, but don't always catch myself doing that. 
All I have noticed is that when I lift my blade, my voltage gauge drops just below the half point, then recovers within seconds...
Don't do it. Its a waste of money.


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## jrs 94 (Jan 8, 2015)

dieselss;1922542 said:


> There's a thread in the dodge section. Guy did it


found it, thanks.


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## chevyzrule810 (Oct 5, 2010)

I have a stock 2006 Chevy 2500HD with a single battery fisher minute mount 2 and a whelen 6 head strobe system I run when I plow.I've never had a problem.If i were to do anything I would install a second battery.


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## chevyzrule810 (Oct 5, 2010)

To answer your question unless your truck is losing so much power the truck almost shuts off when you operate the plow I would leave it alone.Do a second battery before a second alternator.


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## chevyzrule810 (Oct 5, 2010)

There is a sticky at the top of the forum that tells you how to install a second battery


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## snowymassbowtie (Sep 22, 2013)

unnecessary !


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## boss75 (Nov 6, 2012)

Had an 04 and a 13. Both ran fine with stock equipment, (plow package). leave it alone as long as it runs fine, save your money.


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## fastjohnny (Nov 14, 2002)

I'm running dual alts in my 99suburban with a 6.5. It had an anemic stock alternator, had provision for a second alternator, so that's what I did. Overkill, but works great.


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## Philbilly2 (Aug 25, 2007)

Concept... great, but I think the process of completing will not be worth it... unless you really need a project.

You would be better off going with more batteries that more alternators. You have to think of your charging system like a water tower. The bigger water tower that you have, no matter how small the pump is that is filling the water tower, if you have a big enough tank to supply the demand, the pump does not matter.


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## loyjms (Jan 18, 2015)

A second battery is worth more then adding a second alternator. Just good to have a little extra power stored up to run the plow, especially if your running extra lights.


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## IHI (Nov 22, 2003)

Honestly excuse my ignorance since I have no idea on the new/er GM trucks and their alternators, I just used aftermarket alt. on my race car, so don't know if the chevy trucks have a dedicated wire running to the battery for charging purposes...if so/if there's a way to upgrade the charge wire to a larger wire/smaller guage # it'd be a cheaper and easier upgrade before going a dual battery setup.

The typical 10ga charge wires of ole are just large enough to provide a charge, I seen a 3V increase on my battery throwing out my factory 10ga and wiring in a true 4ga wire. Went from everything running (everything electric like newer trucks) 12.8-13.3V to 14.8-15.2 with only a charge wire upgrade, lights went from typical dim/just lit up to bright for the very first time. Then at the race track instead of having to use a battery charger between rounds to keep things topped off, the charger grew dust bunnies from never being used again simply because I gave the alternator a larger "pipe" through which to flow it's output.....as mentioned with the example above of comparing batteries to water towers, so the more capacity the more reserve from which to draw, now try to fill those water towers with a 1/2" line vs a 2" line...which is going to fill faster? 

Quick, cheap and works wonders..I'd go that route first before the expense of adding a second battery and especially a second alternator LOL. There are plenty of people upgrading factory alternators with components to raise output/amps, used to just upgrade factory alt. to 200amp units when I was big into stereo stuff...but again, you still need a large charge wire to take full advantage of it all.


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## Nasty-Z (Nov 7, 2009)

FWIW ,

It has been done on many Chevys and works rather well , This is the engine pic for my '93 K3500 , but I also run the same setup on most of my trucks and many of my plowing customers.










Picture is on a BBC but a SBC would be the same concept , as long as you can find a place to mount the Alternator the wiring is the easy part .

This is the absolute best way to go if you are serious about add on accessories , especially on the newer rigs that have the low voltage shutdown. Start adding plow , spreader , strobes , stereo , etc.... , It adds up fast.

HTH

TOM


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## chuckraduenz (Jan 4, 2009)

I added a second battery on a 2013 chevy 2500. the battery I added is a optima battery. I however CANT get my self to cut the OEM gm battery lug off and add a different battery end to work on another optima battery. been like this for 2yrs now. haven't had an issue. I added a second battery as I do short driveways and lifing it many times drains the battery and dims the lights. I also have LED headlights so if the voltage drops to low it will turn the headlights off. but that only happens ever so often. tho this winter we only got 13 total inches of snow. so haven't had no problems this yr....


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## fastjohnny (Nov 14, 2002)

chuckraduenz;1973022 said:


> I added a second battery on a 2013 chevy 2500. the battery I added is a optima battery. I however CANT get my self to cut the OEM gm battery lug off and add a different battery end to work on another optima battery. been like this for 2yrs now. haven't had an issue. I added a second battery as I do short driveways and lifing it many times drains the battery and dims the lights. I also have LED headlights so if the voltage drops to low it will turn the headlights off. but that only happens ever so often. tho this winter we only got 13 total inches of snow. so haven't had no problems this yr....


Get the optima yellow top with top and side posts, no cutting needed.


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## WSBart (Mar 4, 2015)

Alternatively, you could run dual batteries and a larger alternator. XSPower batteries seem to be the best along with a larger alternator from Powermaster or even better DC power. This would cure any voltage drops you may incur, which is hard on electronics. 

Id lean towards do it as opposed to not.


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## kg26 (Feb 5, 2013)

WSBart said:


> Alternatively, you could run dual batteries and a larger alternator. XSPower batteries seem to be the best along with a larger alternator from Powermaster or even better DC power. This would cure any voltage drops you may incur, which is hard on electronics.
> 
> Id lean towards do it as opposed to not.


How do you supply a "charge" to the secondary battery?


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## Hydromaster (Jun 11, 2018)

Just like you hooked up yours 
you hook it up in parallel

2nd batt, run Neg to engine block, run poss to poss on 1st batt.

both batts get charged at the same time.


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## kg26 (Feb 5, 2013)

Hydromaster said:


> Just like you hooked up yours
> you hook it up in parallel
> 
> 2nd batt, run Neg to engine block, run poss to poss on 1st batt.
> ...


Got cha, I ve got mine neg to neg. Going to swap the alternator today. Trying to figure out which one to go with.


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## Hydromaster (Jun 11, 2018)

I’d replace that little wire coming off the alternator with the larger one and give that a try first .


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## dieselss (Jan 3, 2008)

Hydromaster said:


> I'd replace that little wire coming off the alternator with the larger one and give that a try first .


Didn't we/he have a thread on this already....and was already suggested to do this?


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## Hydromaster (Jun 11, 2018)

Yes,


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## Hydromaster (Jun 11, 2018)

kg26 said:


> Got cha, I ve got mine neg to neg. Going to swap the alternator today. Trying to figure out which one to go with.


Even if you get a higher output alternator you are going to need to replace that small lead coming off of the alternator with a bigger one.

Pay attention to the RPMs at which the alternator puts out its highest amps, 
Usually high output alternators have a higher RPMat wich they put out the max at.


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## kg26 (Feb 5, 2013)

Hydromaster said:


> Even if you get a higher output alternator you are going to need to replace that small lead coming off of the alternator with a bigger one.
> 
> Pay attention to the RPMs at which the alternator puts out its highest amps,
> Usually high output alternators have a higher RPMat wich they put out the max at.


Is that why some guys plow in 1st or in tow/haul mode, to keep the rpms up for charging?


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## Hydromaster (Jun 11, 2018)

I plow in first also and if you’re plowing in first why do you need tow haul mode .
why do you need to hold the gear longer or sift into it quicker if you’re not shifting into second?

( On long runs with a light snow load I’ll shift in 2 second)


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## Philbilly2 (Aug 25, 2007)

Hydromaster said:


> I plow in first also and if you're plowing in first why do you need tow haul mode .
> why do you need to hold the gear longer or sift into it quicker if you're not shifting into second?
> 
> ( On long runs with a light snow load I'll shift in 2 second)


tow/haul gives you more horsepower... everyone knows that... it is similar HP increase to installing one of them footprint gas pedals


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## kg26 (Feb 5, 2013)

Hydromaster said:


> I plow in first also and if you're plowing in first why do you need tow haul mode .
> why do you need to hold the gear longer or sift into it quicker if you're not shifting into second?
> 
> ( On long runs with a light snow load I'll shift in 2 second)


That was supposed to say or tow haul mode.


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## Hydromaster (Jun 11, 2018)

What does that do?


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## kg26 (Feb 5, 2013)

Hydromaster said:


> What does that do?


From what im reading on here it holds the gear longer before shifting, which is good for charging, also allowing more head room for Rpms to climb will delay shifting which keeps trans temps down. I can attest it does hold the gear longer. When I first bought my 2000 Z71 I saw the botton and wondered what it did so I pushed it and yes the time inbetween lower gears to shift is longer.


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## Hydromaster (Jun 11, 2018)

You said,


kg26 said:


> Is that why some guys plow in 1st or in tow/haul mode, to keep the rpms up for charging?


I ask, What difference does tow haul make? What difference is there with it on or off if it's only in first gear?


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## kg26 (Feb 5, 2013)

Hydromaster said:


> You said,
> 
> I ask, What difference does tow haul make? What difference is there with it on or off if it's only in first gear?


If I'm hearing you correctly. Most guys don't want the tranny to shift when plowing due to heat. so if they can hold the gear on passes that is what they are looking for in addition to the mentioned benefits. what is the difference with it on vs off, when its off my truck changes gears at 1.5 2k RPM with it on I can go to maybe 2.5-3k guessing its been a little while since i've used it.


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## Hydromaster (Jun 11, 2018)

Correct, we’re not letting the truck shift. we’ve selected first, it cannot shift into second.
As in your post we’re using 1st. 
what difference would it make if tow/Haul is on or off?


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## kg26 (Feb 5, 2013)

Hydromaster said:


> Correct, we're not letting the truck shift. we've selected first, it cannot shift into second.
> As in your post we're using 1st.
> what difference would it make if tow/Haul is on or off?


I really think its an either, or kind of thing, I'm not sure if your supposed to use both at the same time. Maybe if it goes out you can use first or if the truck doesn't have that feature, first gear can be used. My original post was supposed to say "or"


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## Philbilly2 (Aug 25, 2007)

Hydromaster said:


> Correct, we're not letting the truck shift. we've selected first, it cannot shift into second.
> As in your post we're using 1st.
> what difference would it make if tow/Haul is on or off?


Engine braking... :hammerhead:  :laugh:


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## Hydromaster (Jun 11, 2018)

Tow/ haul does nothing if you're only in 1st.
and it won't hurt anything if it's on.


Philbilly2 said:


> Engine braking... :hammerhead:  :laugh:


no difference


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## Philbilly2 (Aug 25, 2007)

Hydromaster said:


> Tow/ haul does nothing if you're only in 1st.
> and it won't hurt anything if it's on.
> 
> no difference


then longer turn signals!


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## Hydromaster (Jun 11, 2018)

kg26 said:


> I really think its an either, or kind of thing, I'm not sure if your supposed to use both at the same time. Maybe if it goes out you can use first or if the truck doesn't have that feature, first gear can be used. My original post was supposed to say "or"


It doesn't make any difference if it's on or off as it controls the shift points.
If you're only using 1st it hasn't shifted.
But , it will not hurt anything if it's on.


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## Hydromaster (Jun 11, 2018)

Philbilly2 said:


> then longer turn signals!


Big difference.


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## jonniesmooth (Dec 5, 2008)

Seems to be a lot of threads about variations of the same thing.
One thing I have not seen mentioned is this: all wire is not created equal.
There is fine strand and course strand.
Fine strand flows currant more effectively.


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## jonniesmooth (Dec 5, 2008)

Tow/haul mode only functions in Drive/ OD.
it keeps the transmission from shifting to a higher gear to lower rpm. To increase fuel efficiency. 
Working the transmission in o/d without tow/haul will take out the transmission prematurely.


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## kg26 (Feb 5, 2013)

jonniesmooth said:


> Seems to be a lot of threads about variations of the same thing.
> One thing I have not seen mentioned is this: all wire is not created equal.
> There is fine strand and course strand.
> Fine strand flows currant more effectively.


Zero gauge for the win lol


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## Philbilly2 (Aug 25, 2007)

jonniesmooth said:


> Tow/haul mode only functions in Drive/ OD.
> it keeps the transmission from shifting to a higher gear to lower rpm. To increase fuel efficiency.
> Working the transmission in o/d without tow/haul will take out the transmission prematurely.


No... You are wrong on much of this.

I will repeat myself again... It does change anything with overdrive. You still have overdrive in tow haul.

It will change the shift points. Has nothing to do with fuel economy.


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## RichardBongIII (Dec 8, 2021)

My anti-automatic transmission ban if implemented would clear this issue up fast-- no tow/haul mode on a manual gearbox. Problem and Mystery of the Tow/Haul Button solved all at once.


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## Fourteen Contracting Inc. (Jul 5, 2019)

RichardBongIII said:


> My anti-automatic transmission ban if implemented would clear this issue up fast-- no tow/haul mode on a manual gearbox. Problem and Mystery of the Tow/Haul Button solved all at once.


You running at the federal level? Or state?


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## RichardBongIII (Dec 8, 2021)

Fourteen Contracting Inc. said:


> You running at the federal level? Or state?


Federal of course


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