# Aux battery and plow electric



## SteveVB (Oct 7, 2003)

Im finishing up the install of my plow tomorrow. Hopefully 

I have an electrical question:
My 1991 K2500 has an Aux Battery package. Build code TP1.
It is an aux battery with a relay to prevent a drain on the aux battery from stealing from the starting battery.

Is there any reason NOT to use the aux battery as the feed for my E-60 pump solenoid. 

This is the second plow Ive had on the truck, I removed and sold the last one- it was connected directly to the starting (main) battery. Im thinking the installers had a reason to do so? Or maybe just habit they installed to the main battery and didnt know about the aux battery?

Anyone run off the aux (camper) battery terminals?

Thanks


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## Crash935 (Sep 3, 2003)

go off the aux battery, if you run down the aux battery the truck will at least still start


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## The Grassman (Oct 22, 2003)

I was thinking of putting in a second battery into my 96 k2500 i have asked a few people on how to do it and they say just run pause and neg cables from the main battery to the aux battery and away you go. The problem i see with this is or have read about over or under charging one of the 2 battery's. There is something called a battery isolator and if i am not mistaken it prevents the over under thing from happening. If it was just a matter of running 2 cables to a spare battery hey i could do that no problems, but i want to be sure i am doing the right thing here and don't want to mess up my electrical system on my truck. 

any suggestions on how to do this properly ?


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## The Boss (Oct 22, 2003)

Hi grassman:waving: 
I put another battery on my old truck the same way you are describing (pos. and neg. cables from the existing battery to the new aux. one) After that I put in a 140 amp alternator and never had a problem. It worked great!
Good luck


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## HerkFE (May 13, 2002)

*Battery Isolator*

If you are running dual batteries for items such as plows and winches, etc you should run a battery isolator in between them. It prevents the heavy accessory draw from depleting your main battery as well as ensuring both batteries are being charged correctly. Here's the url to a site with some good explainations and great tech help. www.hellroaring.com/

Upgrading your alternator is also a great idea. It has been discussed on the boards here before.

Good luck!

Pete


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## The Grassman (Oct 22, 2003)

*Thanks Boss*

Hey Boss :waving:

I was trying to make it look clean by going hunting for a old diesel GM truck where i can get a Battery Tray and the cable's if possible.

GM put's in a storage box in the engine compartment if it isn't a diesel or don't come with 2 battery's. l want to get rid of it because i don't put anything in it and a extra battery would serve me better since i have 2 150watt spot lights on the front of my truck and prolly will add a plow soon and a salter and some reveres lights and strobes. Lean mean plowin machine 

Did you get 2 new battery's or did you keep the old one and add a new one in ? I have been told to get 2 new ones. How many cranking amps are your battery's ? The alternator in my truck is 105 amps. Does your volt meter move when you raise the plow or does it stay at the 14 volt line ? I never payed attention to that when i got in a plow truck last year, i know the lights dim a little when you move the blade.

Thanks Boss man...

Dave.


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## The Boss (Oct 22, 2003)

HI grassman:waving: 
I no longer have the truck but here's what I did:
I left the factory battery in the truck and went and bought a 750 cranking amp battery. I didn't have to put in a tray because there was room for it in top of the wheel well. I secured it with a battery hold down kit. I then took black gm tubing and wrapped the pos. and neg. cable with it so it looked real nice in the engine compartment.


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## The Boss (Oct 22, 2003)

Sorry, I forgot,
After I did all that, I gauge never moved when I raised or moved the plow. Keep in mind though I had to install a bigger alternator.
Keep me posted!:waving:


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## campi (Sep 23, 2003)

*aux battery*

I agree with boss, always had trouble with power, I installed 2 new batts, dont just replace 1new and 1 old!! also put a 140 amp alt. in 2 yrs ago i have 1980 i ton run all my stuff no problem now!!! Campi !!!!


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## The Grassman (Oct 22, 2003)

I have been told i should add a isolator so in case one battery gets drained i can use the other to boost it ?


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## campi (Sep 23, 2003)

*aux battery*

grassman, i dont know about this islator your talking, like i said before, my mechanic hooked up the 2 new batteries same size, put in 140 amp alt. had no problems since! i also said my truck is 1980 1 ton, it does not have the electronics, that a newer truck has!! had the charging system checked last week, both batts were charging at the same rate, alt was putting out what it should!!! whin i redid my truck, put 84 front clip on it , ibought 2 batt boxes from dealer that are for a diesel truck bolted righted in hope you make out ok , you dont want to fry elec, system!! Campi !!!!


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## Mac (Jan 24, 2001)

An isolator is a very good idea for two reason. 1. It will not let current flow between your secondary battery and main battery unless the alternator is producing current, its like a big switch between the primary and secondary batteries. So in return you will always have a healthy battery. 2. If you leave an older run down battery in the truck, and add a new one you can cause the new battery to fail quicker then it would normally. This is were a isolator can protect you new battery because the batteries are only connected when the alternator is producing current. So in return you would only have to buy one battery. 

I personally do not have a isolator I just brought two new batteries the same type, size, and manufacture.


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## SteveVB (Oct 7, 2003)

Thanks for the responses- hooked the plow motor solenoid to the Aux battery.

Everything works well.

I checked my batteries - starting batt has 12.7 volts in it. The aux battery has 11.5 volts in it both sitting with engine off. With the engine running the voltage at the terminals of both batteries is 14 +. Tells me the isolator is doing its job- keeping the main battery from discharging into the other battery to equalize the voltage. 

The stock chevy "camper package" with the aux battery uses the isolator- I bet you could find one in a yard someplace- and the wire harness for the control voltage. Though I doubt the part is much more than 30 bucks new. I have the FSM with a schematic if someone wants to see the set up-


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## tileman (Mar 2, 2003)

*Aux batt*

Steve I WOULD NOT hook up to the aux batt. The primary batt (start batt) is in the charging system first. You will run down the aux batt with the plow on it, It can not be charged up fast enough.

I have a 2000 gmc with factory dual batts. The truck has snow plow prep on it. The plow was installed by the upfitter the plow is on the primary batt.

The aux batt is just a back up not the main.

Tileman


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## SteveVB (Oct 7, 2003)

*Re: Aux batt*



> _Originally posted by tileman _
> *Steve I WOULD NOT hook up to the aux batt. The primary batt (start batt) is in the charging system first. You will run down the aux batt with the plow on it, It can not be charged up fast enough.
> 
> I have a 2000 gmc with factory dual batts. The truck has snow plow prep on it. The plow was installed by the upfitter the plow is on the primary batt.
> ...


Tileman,

Why do you say one charges up first? Im weak when it comes to electrical systems. I thought that the charge would go to both- the voltage readings Ive taken lead me to believe they will both charge. The isolater allows the batteries to charge, but not discharge- like a one way valve. The isolater on mine prevents one from charging, or discharging the other, but the alt can charge both. Maybe Im mistaken. This system is different than the dual starting batteries such as the diesels have.

Anyone else have a view on the aux batt hook up?


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## porkhead1 (Jan 28, 2003)

"SteveVB".......

Now's the time to see if your set-up works (hooking up your plow to the Aux. battery).......with your plow hooked up, raise/lower/turn your plow a number of times just like you were actually plowing....if possible, actually drive the truck up/down your driveway. My theory is that after a while your plow will slow down because your aux. battery is not being re-charged fast enough to keep up with the demands of a plow. The factory "camper special" aux battery was intended to supply electricity a slide-in camper. Even if you were to only plow one driveway a couple of times a week, your aux. battery would probably slowly go dead.

Try this site for some information.....

http://www.snowplowing-contractors.com/

Try this site for a High Output Alternator....

http://motorcityreman.com/stal.html

Good luck.........


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## SteveVB (Oct 7, 2003)

It seems to work fine, Ive been driving around lifting, lowering, left right for the last couple of days. I checked the batt yesterday and I will again today. I have no reduction in volts available at the battery- either main, or aux.

Everyone keeps saying the battery will wear down faster since its second in line to be charged, but I don't think thats the case- the alternator output doesn't know its going into one battery or another - it just puts out. With the engine running, if I check voltage at the main battery and the aux battery it is the same. The batteries will accept the charge if they need it up to the volt limit on the alt. 

Any electrical gurus out there back up either view expressed here? 

Porkhead- if the alternator cant keep up with the demands of the plow then it wont matter which battery I hook to- either one will go dead. As I understand it the battery acts as a reserve. If the alt cant keep up then the plow takes what it needs from the aux battery (doesn't effect the main in my set up) if the alt cant keep the battery refilled then the battery dies , but in my case the aux battery is dead, but I can start the truck and drive to the shop since the plow has only taken the capacity from the Aux batt not the starting batt. 

Ill see how it goes if we get some snow this season. I just need to coat the connections and Ill be finished.


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## Mac (Jan 24, 2001)

SteveVB 


It does not matter which battery you hook it up too. They will both charge at the same rate as long as the internal resistance of the two batteries are comparable. Another factor would be the gauge of the wire between the two batteries. An inadequate gauged wire will cause a resistive load, which will herder the alternators ability to charge that battery.


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## SteveVB (Oct 7, 2003)

> _Originally posted by Mac _
> *SteveVB
> 
> . Another factor would be the gauge of the wire between the two batteries. An inadequate gauged wire will cause a resistive load, which will herder the alternators ability to charge that battery. *


Good point, Ill look into upgrading the alt to aux battery connections. Currently they look to be 8 gauge, so Ill look into upping them to 4 or 6 gauge.


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## porkhead1 (Jan 28, 2003)

"SteveVB"..........

That's why I gave you the link for a High-Output Alternators. Most plowing is done at low speeds, which means your std. alt. is not putting out max amps. Continous low speeds along with alot of plow maneuvering ( aka. plowing driveways) + lights/heater/wipers/radio all on & a lot of snow will takes its toll on the batteries. You may want to ask what some of the other people on this site think of installing a High Output Alt.


Good luck....:waving:


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## Mac (Jan 24, 2001)

I blew by large amp. alternator in a storm last year. Only thing I could get was a 75 amp. I finshed last year off with it, no problems. This running a western uni-mount, and ether a V-Box Sander or a tailgate salter.


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## SteveVB (Oct 7, 2003)

Ive plowed for 10 years with no problems (commercial sub) with the original stock alt... but since it is 10yrs old I went ahead and ordered a new one with more amps at low speeds. Ill keep the current alt as a back-up.
Im checking all of the grounds and going to upsize the battery to isolator to alt connections.

Thanks for all of the input.


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## KentuckyPlow (Nov 26, 2002)

I may be wrong, but here is my thoughts on how the isolator works.
When the engine is running the isolator switch closes allowing both batteries to be charged, which actually means that both batteries are hooked in parallel. When the engine is off, the isolator opens up, seperating the two batteries. So the only time the secondary battery will discharge is when the engine is off and something is being operated by the secondary battery. So it doesn't matter which one you hook it to, as long as the engine is running while you are plowing.
At least that's how I think it works. Otherwise, I would not see any advantage to having two batteries. The reason for having two batteries is to double your capacity. If one was just going to sit there and not do anything, why not just carry one of those jumper boxes in case you get stuck.

If I'm wrong, I'm sure someone will let me know and I appreciate it, as I will be adding another battery to my truck soon.
Thanks


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## Mac (Jan 24, 2001)

KentuckyPlow 
Your rigth about the isolator that how it works.


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## SteveVB (Oct 7, 2003)

*post storm(s) update*

Thought Id post my results.
Here in DC we had back to back storms this past weekend- Friday about 7 inches (really wet & heavy) 
Sat had another 3-4 inches not so heavy.

I was out 13 hours on Thur/Fri and 9 hours Sat + 2 hours today

Only one problem- The new high amp alt I installed disintegrated -the pulley started making all sorts of noise, on the drive back to my garage the pulley flew off throwing the belt- Down for 45min as I replaced the alt and searched the snow for the bolts I kept dropping. Replaced the alt with my old one - no problems.

The run off of the aux battery seems to be fine. I am wondering what the rating of the isolator is though. Im wondering if the capacity of the isolator is large enough for the current drawn by the pump motor. Im trying to find the rating info. My headlights dim quite a bit running the motor - more than I remember with my old E-47 set up. (I have the E-60 now)


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## Rick Loncosky (Dec 14, 2002)

Does anyone know what alternator to use for high amp output. I went to the local parts house and asked. They list a 64 amp as the highest. This will be on my 77 K20. Do you adapt a special alt. or one from another vehicle. Thanks, Rick.


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## porkhead1 (Jan 28, 2003)

Rick........

Try this site........

http://motorcityreman.com/gmford1wire.html :waving:


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## shadowmaker1969 (Dec 5, 2003)

I had 2 batteries connected with pos and neg cables, no isolator. I used the stock 105 amp alt and had zero problems at all. Alternator lasted 12 yrs and 150 k miles. Batteries were Diehard Gold with 900 cca and lasted 6-7 yrs. Dont know much about the isolator but the setup we used worked great.

Brad


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## Dave_Dean (Dec 14, 2002)

The type of battery may help . A normal battery does fine with the small drain which is placed on it such as during starting. If you take a regular battery and and keep placing significant drains that require constant recharging the battery wont last long. In the off-road world we use what is called a deep-cycle battery. These batteries are designed to be able to sustain large discharges and multiple recharges such as when using an electrical winch. From my perspective I'm thinking that would be perfect for a plow although I'm not familiar with how much demand the plow places on a battery.


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## QuadRacer041 (Sep 1, 2003)

i had been having amp problems when i use the plow and the truck stalled while doing a lot of saturday, i had to wait for the pick to come over and give me a jump.
i think with all the added amperage(sp?) the plow needs the alternator was doing the job.i had the alt. tested and it wasnt putting out its full amp rating, which is only 100amp. so i replaced it and it seems to be ok now.
i wanted to upgrade to a bigger alt but i was told by my parts supplier they didnt make one that fits.the truck is a 97 chevy 3500 dump the truck has a snow prep package but i figured the alt would be a higher amp rating but ever since i put the plow on (which is about 2-3 years ago) it always drops the volt gauge real low when i work the plow.
i was told that they make a 140 amp but it really does fit in the mounting bracket because the housing size is much bigger, i would also have to charge part of the alt wire hareness.
like i said i put the new 100amp on and it seems to be ok, ill have to find out for sure in the next storm,if it not good i guess ill have to install a dual battery set up.

any other chevy guys have the same problem????


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## sonjaab (Jul 29, 2001)

TTT


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## Bolts Indus. (Dec 22, 2003)

I just priced a 140 amp. alt. for my 97 3500 /454 at NAPA. so one is available.


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## sonjaab (Jul 29, 2001)

GUYS...I messed up and brought up that thread with the
pics taken by Wyldman. But its posted in the Snowplowing
discussions. I asked the mods to move it here !

Wildmans pics show installation of the big boy units and
the mods he used to install them !
Thanks Wyldman!.....................geo

BTW: The post is called "Alternator pulley for more idle juice"


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## Robhollar (Dec 27, 2003)

i put a 2nd battery in my 88. I went to the dealer and asked for the battery tray for a diesel truck. It was pricey but i didnt really mind.

Now an Isolator for the best of my knowledge isnt going to help you from running down your main battery while the truck is running. They are mainly for a RV while parked out some where. If your motor is running then your pulling from both batteries even with an isolator. Save your money wire your batteries in parallel. Ive dont it for years with out any problems. The whole thing i was trying to do while out plowing i wanted to make sure i was getting as much power to my truck while at idle or just above. The drive to the next job will be enough to recharge my batteries. This is just been my experiences


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