Serious 12 Volt Power for Your Chevy C/K Series Truck

Low Buck - High Power

Feb. 13, 2006 By Jarred Meyer

I bought my dads '93 Chevy K1500 from him about 4 years ago and started to add, one by one all the neat 4x4 accessories you can get. I had created a binder full of everything that I was planning to put on while I was in high school.    

First on the grocery list was a WARN Transformer Series Bull Bar for the front. I would later add the brush guards after I saved up more money. I then got a new engine from Jasper and had that put in since my old one was getting ready to throw a rod. I wanted to get the bull bar in the front to help protect the new engine I was getting.

Over time I eventually made it around to putting on a WARN XD9000I Winch in the front and a Harbor Freight Tools brand Winch rated at 8000 lbs in the back. At full load the Warn winch could draw 400+ amps. I just assume the Harbor Freight winch could draw about the same. I knew I would need a little more beef in the electrical system so I got another battery and a dual battery isolator from a local 4x4 shop. I thought for sure that would be sufficient for powering the winches.

I was definitely wrong. The very first time I get out and use my WARN winch I cook my stock alternator. Go figure. So I make some phone calls and ask around a little at some of the local truck shops and discover I should've purchased a high amp alternator. I get on the phone to Summit Racing and they tell me with much confidence that a bigger alternator will supply any of my electrical demands. 350 dollars and a 210 amp Powermaster alternator later I'm confident I have fixed the problem.

My ignorance of alternators got me into trouble again with this one. You see, although the alternator was rated at 210 amps they neglected to tell me at Summit that was the highway RPM reading. T his alternator actually only puts out like 115 amps at idle. Be sure you check this very carefully when purchasing a new alternator since you more than likely won't be winching while driving down the highway.

So during my next winching situation my friend Tim calls me and he has got his truck down a muddy embankment while trying to turn around at the end of a trail. So I got down there and boy was he in a pickle. This ravine was really steep and he was nose first at the bottom of the hill. The only way I was going to get him out was if I used my winch in the back of the truck to strap it to a tree at the top of the hill. Otherwise I was going to end up down the hill with him. We eventually managed to get him out but the whole ordeal took about 3 hours and it got dark so I began to use my light bar on the top.

Between the 7 lights on top and the two winches, I managed to yet again burn up another alternator. I called up Summit Racing to inquire about my warranty but it just so happened that I was 2 weeks past the 1 year allowance. 350 dollars down the drain.

So I was back on the phone once again trying to figure out what else there was I could do to support the load I was putting on my 12 volt power system. No one had any ideas around my local area so I got online and looked up alternator setups. I eventually stumbled onto the whole dual alternator setup that a lot of car stereo enthusiasts were using. I also learned that it was not too uncommon to find this setup in some off road rigs.

So, my main questions were; where do I get the bracket to support two alternators and where do I get the alterna tors from? I didn't want to spend 700 dollars on two Powermaster alternators so I went up to my local Advance Auto Parts and they were able to get me two AC Delco Alternators that put out 140 amps at idle and 195 amps at Highway RPMs. Two of these would be perfect and they would only cost me 80 bucks a piece. That would give me about 280 amps at idle, that would cost under 200 hundred dollars! Getting the two alternators for cheap turned out to be the easy part.

The newly fabricated bracket ready to bolt in
After searching and searching I couldn't find anyone who sold a dual alternator bracket for my truck.

So I made my own out of some 1/4" X 1 1/2" steel bars using my 110 volt Hobart mig welder. It took just about all day to finish the bracket because it had to line up perfectly with the belt.

Installing the new dual alternator bracket
After it was done I hooked up everything and realized I wasn't quite sure how to wire this. I talked to a few different people at the 4x4 shops and tried to hook it up the way they thought it should be done. Let's just say it's best to go to an expert about alternators if you ever have a question when hooking them up. I ended up going through three alternators (which Advance replaced for free...Lifetime Warranty baby!!) before I finally decided to look online for help.

I came across a company, Ohio Generators (, who specializes in dual alternator setups and alternators.

The second AC Delco Alternator is a perfect fit on the new bracket

They walked me through the whole process without me even making a purchase from them. They were a great help. I finally had my 12v system complete and it WORKED!! I could power just about anything from my truck without any problems.

I am currently running two winches, 11- 100 watt Baja off-road lights(four in the front, seven on top), a 3500 watt power inverter which I ran 120v receptacles to the front, cab, and back of my truck; which is like the best thing I have ever put on my truck, a 12v air compressor (Fills a 2 gallon tank in the engine compartment), and 6- 55watt work lights that are mounted around the top of the cab of the truck.(These things work great at night). The batteries I am using are 2 Diehard Rangehandlers (875 cold cranking amps) and have been using since just after I burned up my stock alternator.

So here are my recommendations. Yes, you will definitely need to upgrade your stock alternator. I believe those are designed to power only the factory setup in a vehicle and adding in accessories of any kind will begin to stress it. The battery or batteries you choose don't neces sarily have to be expensive. From what I've seen, just about any battery will work just as long as they have an ample amount of cold cranking amps. If you have room in your engine compartment to run another alternator you may want to look into that for future use. If you're not going to be pulling too much through your electrical system, then a high output alternator would most likely be a good choice. Just remember though, I spent less on a two alternator setup than I did on one high output alternator alone. Check out all your possibilities and you can use my situation as a reference for what you may or may not need. Newsletter
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