High Amp alternators

[bkozlow]

I am not sure where this should go but here is the story. I run two large (16 inch puller and pusher) fans on my coupes, drawing a lot of amps. You could really see on the volt meter when they kicked in. Add air and lights and fuel pumps and the amp draw at low RPM's is a lot. I was running a Generation One 140 amp alternator. I felt this was not enough at 1000 RPM idle. So, I called one of the major performance automotive supply houses and asked the question what was the output of their Private Label 150 Amp Generation 3 unit compared to their 240 Amp Gen 3 at 1000 RPM idle. The sales person did not know but gave me the phone number of the manufacturer of their private label units. I called them and we had an extensive conversation.
I asked about the private label units and how they compared to the manufacturer's units. The representative, I spoke to was up in the sales administration end of the company. I was told they manufacture the P/L units TO THE CUSTOMER's specs. Asking how did they differ from their units and was told that the supply houses P/L units had 8 diodes as the manufacturer's unit had 12 diodes for the same output. He said, there were other differences that help reduce the cost of the P/L units without going into detail. So, I went ahead and ordered a 150 AMP unit from the manufacturer. It came in with a QC tag attached which said, 148 amps output a 800 rpm and 176 amps at 1800 rpm. The manufacturer's units are rated at a minimum of 150 amps and 240 amps. While some of the auto supply houses are a max of 150 amps output not a minimum. I am quite satisfied with this Generation 3 unit and know at low rpm, I have all the amps I need for my electrical requirements. The only change to the system was the addition of a 200 amp fuse out of the alternator to protect the system. One thing, these units are not stocked but built to order, check them out on the internet at mechman.com.

Bill K

[cycleguy55]

I don't have the charts in front of me, but I remember when I was looking at changing from a 100 amp 1G alternator to a 130 amp 3G alternator, the 3G produced more output at idle than the 1G did at 2,000 RPM. That was enough to seal the deal for me. I installed the 130 amp 3G and haven't looked back.

[Gaz64]

Originally Posted by bkozlow

I am not sure where this should go but here is the story. I run two large (16 inch puller and pusher) fans on my coupes, drawing a lot of amps. You could really see on the volt meter when they kicked in. Add air and lights and fuel pumps and the amp draw at low RPM's is a lot. I was running a Generation One 140 amp alternator. I felt this was not enough at 1000 RPM idle. So, I called one of the major performance automotive supply houses and asked the question what was the output of their Private Label 150 Amp Generation 3 unit compared to their 240 Amp Gen 3 at 1000 RPM idle. The sales person did not know but gave me the phone number of the manufacturer of their private label units. I called them and we had an extensive conversation.
I asked about the private label units and how they compared to the manufacturer's units. The representative, I spoke to was up in the sales administration end of the company. I was told they manufacture the P/L units TO THE CUSTOMER's specs. Asking how did they differ from their units and was told that the supply houses P/L units had 8 diodes as the manufacturer's unit had 12 diodes for the same output. He said, there were other differences that help reduce the cost of the P/L units without going into detail. So, I went ahead and ordered a 150 AMP unit from the manufacturer. It came in with a QC tag attached which said, 148 amps output a 800 rpm and 176 amps at 1800 rpm. The manufacturer's units are rated at a minimum of 150 amps and 240 amps. While some of the auto supply houses are a max of 150 amps output not a minimum. I am quite satisfied with this Generation 3 unit and know at low rpm, I have all the amps I need for my electrical requirements. The only change to the system was the addition of a 200 amp fuse out of the alternator to protect the system. One thing, these units are not stocked but built to order, check them out on the internet at mechman.com.

Bill K

Very good info there Bill.

Note to all, that the quoted rpms are alternator speed, not engine speed.