Uprated alternator, 400Watts
Hi all,
I've just replaced the original 280Watt on my '82 R100RS for an uprated 400Watt one from Motor Works. I had two 50Watt spots and heated grips and to prevent the battery running down I had to maintain a minimum of 4000rpm, i.e. 75mph in top gear at night, hardly ideal. The conversion has so far been a huge success, I've just got a heated waistcoat and it is sheer BLISS, should have done this ages ago.
I did the conversion about a month back and have done about 800miles since, about half of which was with all the electrics switched on. The max. voltage is still the same at about 13.8volts according to the voltmeter on the dash, and the electrolyte in the battery hasn't gone down as far as I can tell, so, so far, there's no sign of overcharging. With everything switched on (including the new heated waistcoat, 40Watts?) I can now maintain battery voltage at around 3,200rpm, making life a lot easier and warmer.
The kit consisted of new rotor and stator plus a new diode board and some new wiring, but NO INSTRUCTIONS. To be fair, Motor Works did tell me so before I bought it, and, actually, installation wasn't too difficult but then again I do have a certain amount of experience and qualifications with electrics. Beware, though, if you are replacing the rubber mounts for the new board with solid ones, there may be a problem with the live side of the mount: solid mounts will just short the output to earth, so it might be wiser to stick to using rubber mounts at ths particular point. I've had a thread on the HUBB (Horizons Unlimited Bulletin Board) under BMW Technical, see below,
http://www.horizonsunlimited.com/ubb/Forum11/HTML/000493.html
there's an awful lot mor information there. I also took photos as the job progressed if anybody's interested.
Cheers,
John