F540HD

Look at the pulley on the large alternator to see if the ribs are worn down.

When it comes to dealing with the public you can make recommendations but the customer won't always go for it. Many don't mind paying thousands of dollars for amps and woofers but nickels and dimes for the charging system. It was hard to get this customer to even get this alternator and 1 decent battery. We suggested a dual setup and at least 2 batteries.

When I say excess load I don't mean an overcharge situation but a high amp load. If you don't use the stereo you can't get the problem to happen even with everything the truck came with at maximum draw. Start turning up the 15,000 watt system though and if the truck is cold you get about 20 minutes but if it's been using the system and already tripped a couple of times you may only get 3 minutes before it's no charge time. Before it goes to no charge the voltage drops to 12.8 for about 30 seconds then begins dropping toward 11 quickly. Killing the stereo and other loads brings voltage back to 12.3 or so but not higher and no amperage showing on power wire from alternator. Unplug the regulator and voltage comes up, might hit 13.8 at alternator but battery shows 13.5-13.6 volts. Alldata and Transpo say the regulator is controlled by the ECU. I was hoping somebody had found an easy way around this. I haven't added extra grounds but I can't say the stereo installer didn't. I'll call him tomorrow and ask. By the way, this alternator makes 324 amps @ 13.2 volts. The main power wire from alternator to starter / alternator block was upgraded but the factory wire from there to battery is intact.

A few details were off as mentioned. I had to snicker though when he called that a Nippon-Denso. The workings were very accurate. The regulator schematics on that part are fairly complex. A very good simple to make universal and adjustable voltage would be a ford design sold by Transpo. The part number is my screen name. Two things he mentioned though that was off and need to be corrected. A 12v alternator is NOT a good candidate for high voltage output. A few of them CAN make high voltage but starting with a 24 or 32 volt alternator will work much better. The wattage of an alternator can be changed by replacing the stator and rotor with parts designed for higher amperage. This was the output on a test bench of a CS144 that was rated at 120amps but now makes a little more. The stator and regulator in this particular alternator I used for my avatar.

I'm incorrect on year, it's an 06. It did this with the original regulator as well as two replacements. The regulator has a B+ and a stator signal internally. It will not self excite but will remain charging if unplugged. I was quite suprised to see it start charging upon unplugging. The belt has great coverage and is new. The pulley doesn't over heat so I'm sure it is not slipping plus the unplugging making it charge says slipping isn't the problem. Sorry about the year model mistake. I've been dealing with this truck for 4 months now.

Any suggestions to keep the ECU happy on a high amp alternator setup on an 04 Avalanche? Once the ECU sees excessive load it turns the alternator off and doesn't restart until the key is cycled. Unplugging the alternator while in this condition will yeild 13.5 volts and bring the amps up but turns on the battery light on data center. Mistake, it's a 2006.

Running the wires together can create noise. Short ground to frame is best. Make sure other battery has good frame and body grounds as well.

Dom, Are you serious? You really think no rebuilders are smart enough to test a high output alternator? I use a snap-on for testing on vehicles that displays over 400 charging amps and doesn't use aligator clamps. Please climb off your high-horse and enjoy a little reality. I see alternators pass over my bench that will make over 300 amps each. I'd love to test one of your units and be honest about what the performance level truly is. Bill