Dual Batterys

samjr · October 8, 2008

ok guys i know this is on here alot but i got to ask i got a 04 sierra can i just run (+) of the 2nd battery to the (+) of the oem battery and the (-) to the engine block.Or well it fry my truck wood that make it 24 and not 12 now ?

just want it for my plow and all my lights

Superman TNT · October 8, 2008

+ to + and - to - hooks them up in parallel . . . it will stil be 12v.

If you connect them + of 1 to - of the other they are in series . . . 24v.

Kodiak450 · October 8, 2008

ok guys i know this is on here alot but i got to ask i got a 04 sierra can i just run (+) of the 2nd battery to the (+) of the oem battery and the (-) to the engine block.Or well it fry my truck wood that make it 24 and not 12 now ?

just want it for my plow and all my lights

Why do you need dual batteries? My 03 2500 works fine with my plow and sound system, I had to run dual batteries on my 96 F250 cause the plow along with sound system would drain power, but the GM trucks have plenty of power to go around. I also run 3 amber strobes on roof, and 4 corner hidden strobes all on stock battery. If you are concerned of power drain when operating plow and dash lights dimming, that'll also happen with no matter if you have two batteries or one.

Also where the hell would you mount the second battery? On the PS upper right corner is where my Western module is mounted, and seeing you have a Fisher along with same plow lights, you're module most likely is the same size. Actually it might be the same module seeing how Western owns Fisher now and Fisher uses Westerns plow lights, but calls them a different name.

Majorleaguebass · October 8, 2008

If you are worrried about the lights dimming out, get a stronger alternator, it would be alot better than running 2 batteries. I woulkd get a 210 alternator

merlin5577 · October 8, 2008

If you are worrried about the lights dimming out, get a stronger alternator, it would be alot better than running 2 batteries. I woulkd get a 210 alternator

+1. Once the engine is running a higher output alternator will help you a lot more then another battery.

Kodiak450 · October 8, 2008

They make 210's? Damn!

My 2500 came with a 105 alt, and seriously questioned why so small, as compared to my 96 F250 which came with a 125 alt, which later replaced with a 135. I found out that GM Alt's are under rated, so that 105 i have is actually more like a 140 plus on a Ford. I transferred the sound system from the F250 to the 2500 after I bought it, and never had any issues like the voltage meter moving and the dash lights diming when the sound system is cranked in my 2500. Now before adding dual batteries in my F250, I had those problems.

Majorleaguebass · October 8, 2008

man when i had my sound comp. Colorado, i had a 1000$ stinger alt. that put out 310!!!! That was a bad ass mammer jammer

merlin5577 · October 8, 2008

They make 210's? Damn!

My 2500 came with a 105 alt, and seriously questioned why so small, as compared to my 96 F250 which came with a 125 alt, which later replaced with a 135. I found out that GM Alt's are under rated, so that 105 i have is actually more like a 140 plus on a Ford. I transferred the sound system from the F250 to the 2500 after I bought it, and never had any issues like the voltage meter moving and the dash lights diming when the sound system is cranked in my 2500. Now before adding dual batteries in my F250, I had those problems.

They make as high as you want to go. I saw a guy at a car show with a custom made (huge) one putting out 800amps....at idle. It was used to run a ton of stereo equipment and hydraulics (lowrider) in his S-10.

Are you sure your 2500 is only 105? My Silverado came with a 140. The one in my Suburban is a 105. So maybe thats the standard with the gas engines?

merlin5577 · October 8, 2008

ok guys i know this is on here alot but i got to ask i got a 04 sierra can i just run (+) of the 2nd battery to the (+) of the oem battery and the (-) to the engine block.Or well it fry my truck wood that make it 24 and not 12 now ?

just want it for my plow and all my lights

To add to what was said earlier, Jegs and Summitracing both sell complete kits to add a second battery if your so inclined. Good luck.

Majorleaguebass · October 8, 2008

yea the diesels have a little bigger alt. my old alt idled at 250....

merlin5577 · October 8, 2008

yea the diesels have a little bigger alt. my old alt idled at 250....

Huh?

Kodiak450 · October 8, 2008

Yes. that is what my build sheet said (105 alt).

Have to make a correction. The guy with the fisher has the older style plow lights (Halogens). Just saw your close up pics in another thread. I hated those halogen plow lights, they hardly lite up anything. The newer plow lights are much better, but still not as bright as my stock head lights. Don't know why, they use similar bulbs, same watts too. I always drive with the high beams on when the plow is on, when driving at night, it also doesn't seem to bother incoming traffic too.

5Alive · October 8, 2008

Careful... some of those aftermarket alternators out there rob Peter to pay Paul... they sacrifice voltage to gain more current.

Also, note what the aftermarket alternator's output is at idle, and low rpms... ie snow plowing parking lot speeds.

I just added dual batteries to my 2005 GMC 6.0L gas. It came with a 145 amp alternator, DR44G, which I was tempted to "upgrade", but after doing some research on a lot of the so called high output alternators, and learning about the caveat emptors, I decided to keep the factory alternator in place.

The second battery is really just like having an emergency battery to start the truck in case the first one stops working. The truck is wired such that either battery can back up the other, only one battery can be drained by the vehicle with engine off, both batteries contribute to starting the truck, and both batteries are charged by the alternator when the engine is running.

I used all GM factory parts for the dual battery option found in gas engine applications, such as Police Tahoes, including wiring harnesses, solenoid, tray, bolts, nuts, clips, and retainers. There are some posts in this forum that detail the different dual battery RPO codes available (there are seven or eight different versions over the last 8 years).

pm26 · October 9, 2008

About connecting dual batteries:

As mentioned, parallel connection (+ to + and - to -) will give you twice the single battery reserve capacity and still retain the 12 Volt system.

Connecting two 12 Volt batteries in series is done to produce a 24 volt system. The total reserve capacity is the same as that of one battery, but the voltage is doubled. series connection is + to-, and - to +). If batteries are in close proximity for series connection, you would need a short jumper to connect +and - terminals of two batteries. Connecting two batteries in series by mistake in a 12 Volt system would fry your electronics and damage your electrical system in a heartbeat.

12Volt automotive batteries connected in series are often used in emergency lighting system units.

If you connect ten of them in series, you have one battery reserve capacity at 120 Volts , which makes this system extremely dangerous, as it can electrocute a human instantly. Anything over about 35 Volts in potential can be dangerous to humans. Your skin resistance is one big reason why touching terminals of a 12Volt or 24 Volt system will not hurt you, regardless of the current reserve available.