After receiving no responses about higher power alternators, except that I probably did not need one, I did some further research on alternators. Contrary to what others stated, alternator output can, and usually does, vary depending on rated output. There are also alternators with higher low rpm output.
Look at the two numbers on a Bosch alternator. They will usually be something like 31/80 or 31/100. The lower rating is the amperage put out at low rpm, about 1500-2000 rpm. The higher amperage is the high rpm output, usually 6000 rpm. These are minimums; actual output may be higher.
Most alternators are driven at 2:1 engine speed, and have a max rpm cabability. Many are rated for 15,000 rpm max (or 7,500 engine rpm), but some are rated for 18,000 rpm (or 9,000 engine rpm). The rated output, however is usually for two fixed rpm points, so 31/100 might be for 1800 rpm and 6000 rpm, respectively.
I have 31/100 amp Bosch alternators in my 88 and my 89 745Ts. This is insufficient for a really high power electric fan plus other accessories, at low rpm. Bosch makes a 55/100 amp alternator that I may look for, as well as a 60/120 and a ??/140.
Does anyone know whether any Volvo 7/9 series with B230 came with 55/100 amp alternators?
Thanks,
Philip Bradley
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