Gary Lewis Posted July 15, 2023 Share Posted July 15, 2023 My entire drivetrain is from a 95 F150 4x4 donor vehicle. That alternator is what I believe was the original alternator on that truck. All 95 amps of it. Well, probably 65 amps, at this point - it's tired. Ok, makes sense. I have a stock 130A 3G on Big Blue, but it doesn't really keep up at idle with inverter when the air compressor is on. So I have considered a 200A upgrade, assuming that it'll give proportionately more at idle than the 130 unit does. Given that I'm interested to see what you find out. Link to comment Share on other sites More sharing options...
Pete Whitstone Posted July 15, 2023 Author Share Posted July 15, 2023 Ok, makes sense. I have a stock 130A 3G on Big Blue, but it doesn't really keep up at idle with inverter when the air compressor is on. So I have considered a 200A upgrade, assuming that it'll give proportionately more at idle than the 130 unit does. Given that I'm interested to see what you find out. The info on the alternator I ordered said full output (200 amps) at about 1400rpm, and 100 amps at 650rpm. Unclear whether that was expressed in engine RPM or alternator RPM. They did refer to the 650rpm figure as "idle" so I am assuming engine RPM. It gets here in a week, so it will be a little while before I have more info. Link to comment Share on other sites More sharing options...
Gary Lewis Posted July 15, 2023 Share Posted July 15, 2023 The info on the alternator I ordered said full output (200 amps) at about 1400rpm, and 100 amps at 650rpm. Unclear whether that was expressed in engine RPM or alternator RPM. They did refer to the 650rpm figure as "idle" so I am assuming engine RPM. It gets here in a week, so it will be a little while before I have more info. Do you have a link to that alternator? I'd like to see what they say. Our page at Documentation/Electrical/Alternators has the output results from Jim/Ardwrkntrk's stock 130A 3G alternator from DB. They show output of 106A @ 1600 alternator RPM's, 134A @ 2500, and 160A @ 6000. Not sure what pulley sizes you have, but the specs I see say they may give 3:1 RPM, so that would be 533, 833, & 2000. So that 100A @ 650 RPM does sound like they mean engine RPM. But I think you have a smaller alternator, which may be the difference, and that's why I'm curious to look at their page. Link to comment Share on other sites More sharing options...
81-F150-Explorer Posted July 15, 2023 Share Posted July 15, 2023 Do you have a link to that alternator? I'd like to see what they say. Our page at Documentation/Electrical/Alternators has the output results from Jim/Ardwrkntrk's stock 130A 3G alternator from DB. They show output of 106A @ 1600 alternator RPM's, 134A @ 2500, and 160A @ 6000. Not sure what pulley sizes you have, but the specs I see say they may give 3:1 RPM, so that would be 533, 833, & 2000. So that 100A @ 650 RPM does sound like they mean engine RPM. But I think you have a smaller alternator, which may be the difference, and that's why I'm curious to look at their page. I'd be interested in it too. My 60 amp alternator cannot keep up with my 12-watt sideband radio without flickering. I want to exchange it with a 50-watt GMRS, but if the alternator cannot keep up with the CB etc... Link to comment Share on other sites More sharing options...
Gary Lewis Posted July 15, 2023 Share Posted July 15, 2023 I'd be interested in it too. My 60 amp alternator cannot keep up with my 12-watt sideband radio without flickering. I want to exchange it with a 50-watt GMRS, but if the alternator cannot keep up with the CB etc... Is that at idle or full-tilt, Ralph? The 130A 3G puts out far more at idle than your 1G can ever hope to do. So you wouldn't have to go for the 200A unit. Even the 90A 3G would be a serious upgrade. Link to comment Share on other sites More sharing options...
Pete Whitstone Posted July 15, 2023 Author Share Posted July 15, 2023 Do you have a link to that alternator? I'd like to see what they say. I bought it from Amazon, not directly from DB. But here is the link to it. https://www.amazon.com/dp/B008R2ULUW?psc=1&ref=ppx_yo2ov_dt_b_product_details Rereading it, I misspoke earlier. The RPMs are stated as 1200 and 600. Link to comment Share on other sites More sharing options...
81-F150-Explorer Posted July 15, 2023 Share Posted July 15, 2023 Is that at idle or full-tilt, Ralph? The 130A 3G puts out far more at idle than your 1G can ever hope to do. So you wouldn't have to go for the 200A unit. Even the 90A 3G would be a serious upgrade. That's about 1200-1800 rpm engine speed. So cruising speed. Link to comment Share on other sites More sharing options...
Pete Whitstone Posted July 15, 2023 Author Share Posted July 15, 2023 Is that at idle or full-tilt, Ralph? The 130A 3G puts out far more at idle than your 1G can ever hope to do. So you wouldn't have to go for the 200A unit. Even the 90A 3G would be a serious upgrade. I also saw a lot of 95amp and 130amp units for a lot cheaper. I decided to go with the 200amp because I have the electric fans and a stereo amp. Mine is also an AC truck. So between what the compressor clutch pulls, and the fans and radio... and it's night so the high beams are on... and it's raining so the wipers are on... and the defrost has both the compressor and the fans on... it adds up and I wasn't sure 130amp was going to cover the worst case scenario. Link to comment Share on other sites More sharing options...
Gary Lewis Posted July 15, 2023 Share Posted July 15, 2023 Is that at idle or full-tilt, Ralph? The 130A 3G puts out far more at idle than your 1G can ever hope to do. So you wouldn't have to go for the 200A unit. Even the 90A 3G would be a serious upgrade. I also saw a lot of 95amp and 130amp units for a lot cheaper. I decided to go with the 200amp because I have the electric fans and a stereo amp. Mine is also an AC truck. So between what the compressor clutch pulls, and the fans and radio... and it's night so the high beams are on... and it's raining so the wipers are on... and the defrost has both the compressor and the fans on... it adds up and I wasn't sure 130amp was going to cover the worst case scenario. Amazon says "Under full load conditions, amperage output at 1200 engine rpm will peak at 200 Amps, amperage output at 600 engine rpm (idle) will peak at 100 Amps". And, as you can see below, that is the small-framed "95A" unit. So extrapolating to the 130A unit, which may not be fair, I'm seeing something like 275 for the max and 138A at idle. Think I'll look at what they offer... Link to comment Share on other sites More sharing options...
Pete Whitstone Posted August 3, 2023 Author Share Posted August 3, 2023 Amazon says "Under full load conditions, amperage output at 1200 engine rpm will peak at 200 Amps, amperage output at 600 engine rpm (idle) will peak at 100 Amps". And, as you can see below, that is the small-framed "95A" unit. So extrapolating to the 130A unit, which may not be fair, I'm seeing something like 275 for the max and 138A at idle. Think I'll look at what they offer... Well, so far so good. It seems to put out a little less volts than my old alternator, the voltmeter hovers around 13 with the new one. With the old one, it was a little over 13. I imagine that is a function of the regulator. I haven't driven the truck a whole lot, but with the fans on and headlights and wipers, and AC, it won't drag it down much on the voltmeter. The old alternator would drop to about 11v. Part of the new alternators output capabilities come from this, no doubt: When I saw that, I had to wonder if the belt was going to be short enough. It is, but there's a lot less room on the tensioner than there previously was. I will have to watch for belt slip as the belt ages and stretches. Link to comment Share on other sites More sharing options...
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