Upgrade alternator?????

[willard]

Dear fellow beemers, 60/7 1978, stock, only addition is a pair of hella lamps - total draw 110 watts for lamps. Stock alternator is, I think, 240 watt 0r maybe 280 watts. Installed digital voltmeter. At 3500 RPM reads 13.0-13.4 and up around 4000 RPM getting reading about 13.0-13.6 volts. This is with hella's on (and, ofcourse, headlight).

I figure this: total draw is about 260 watts (110 for hella, 100 for headlight and other lights, 50 for ignition). I am either darn close to total output of alternator or surpassing output.

Never had problem with starting.

Question: should I upgrade to 400 watt alternator - Omega????? Or, let it ride the way it is?

thanks, bill (vermont)

[The_Veg]

How long have you had this setup? How long have you had your current battery with this setup and how does it like it? Do you use any type of battery charger when not riding? The answers to those questions might help fill in the picture as it is now. It does sound awfully close though, and it's a good idea to leave the charging system some 'overhead.' You could install one of the LED tail lamp units from Motorrad Elektrik and reduce the total draw by a few watts, but you may still have very little overhead left. If you don't plan to add any more electrical accessories, you might want to combine the LED tail lamp with lower-wattage bulbs in the Hellas (go to 35W bulbs and save 40W).
If you do plan more electrical accessories, I'd go for a bigger alternator.

[willard]

Dear Veg,

Have had this setup for 2-3 months. Battery came with bike - have owned bike for almost 2 years. Do not use charger. Never a start problem. Also, no noticeable dimming of lights when voltmeter reads below 12 volts.

Was told that I am at max output of alternator and that, eventually, will overheat and fail. Sounds right. What do you think?

[Boxerkuh]

I would suggest adding a 400 watt Omega. I love mine. I think that you are forgetting about each start. I was told that one other difference is that the Omega system starts charging the battery back anytime over 1500 rpm's by the comparison to the stock system not charging the start back until 3500 rpm's. Other questions worth thinking about how much riding do you do after dark? Adding a battery tender would be a good idea.