Another…charging…issue

[Rob Frankham]

The critical things, as far as I'm concerned, is (1) whether any additional charge current, over and above that supplied by the stock alternator is needed, (2) whether the existing charge circuit is working efficiently, (3) if the stock charge circuit isn't working efficienlty, whether it is more cost effective to repair if or replace the whole thing and (4) How keen are you to keep the bike standard.

1) The stock charge circuit is more than adequate to supply the requirements of the bike unless and cope with a reasonable amount of additional current drain. If you are using Hi power additional lamps or heated clothing or other high consumption accessories, or if you do a lot of stop start riding, then a higher output soultion is worth investigation. If you're not, then it is a waste of money. Any modern alternator/charge circuit will only supply the amount of current required so all that extra power output won't be used.

2 & 3) If your stock set up isn't meeting your needs, then is that because it isn't working right. Checking the individual components and repalcing the faulty ones may well be far more cost effective than buying a complete setup.

4) This is largely a matter of your own preferences... the only thing I would say is that the stock setup may well be far easier to repair in the case of future failure than an atermarket solution.

One final point... the so called 'High Output' or Police regulator will not cause the bike to charge at low revs (despite what some vendors claim), nor will it increase the maximum output of the alternator. Both of these attributes are limited by the alternator itself and not affected at all by the regulator. What the replacement regulator does is simply raise the limiting voltage at the output of the charge circuit. This means that the battery will recover a little more quickly when the vehicle has been used for stop start running. The 'Police' regulator was specifically designed for patrol vehicles where they might be sitting idling for some time or be used for a lot of short journeys, Circumstances where rapid recovery of the battery is important. The downside is that the rapid charging and continuouns high charge voltage can reduce battery life in the long run. If it is substantially over 14 volts, the additional voltage will also shorten bulb life.

Rob

[Gibson]

Check the Rectifier board also, grounds etc. That was the problem on my bike.

[DP55]

About the "police version" regulator: in the 70ties, when those BMW's were developped, the alternator was sufficient for starting and riding. And in case of....... there was also kickstarter. The lights were only on during night.
In the 80ties, from 1984 on, we (in Europe) were obliged to ride with the lights on.
Later, the driving schools and police departments start to complain that sometimes battery problems occur. That's why BMW Motorrad came with this "special" voltage regulator.
However with 2 remarques: for bikes from 1981 on and with regular check of the battery acid level.
Nowadays I use an AGM Odyssey PC680 battery which may charge at 14,7 V and is maintenance-free.
For a gel battery this regulator is not appropiate.
On my 1987 R 100 RS with a Bosch G1 14V 20A 21/280 W AC alternator I mesure (with the lights on) 12,05V@ 1000 rpm, 12,20V@ 1200 rpm, 12,70 V@ 2000 rpm and 14,00V@ 4000 rpm.
When I have to change an old defective bulb I choose always the "longlife" or "ultralife" bulbs from Phillips or Osram.

Regards,

Dirk.