01miller said:
what you found still does not tell me how much of the 600watts is available and not being used by the bike!!
You're not going to get a reliable answer to that question since it's not a static figure.
Take, for example, the lights. Yes, we know the headlamp takes 55w and the tail-lamp takes 5w etc and we can add all those up. But how much do you include for the horn and the brake light and the starter and the winkers, all of which you use
sometimes.
The starter may only be used for a few moments but gives the battery quite a load which is then recovered over a period according to the varying internal resistance of the battery, the available voltage from the alternator etc etc.
Other items like ignition and, perhaps, the brakes use varying amounts of current according to the circumstances of their use.
You have to consider how the bike is used. If you spend long periods with the engine at idle (like at traffic lights etc) the alternator may not be generating enough juice to keep the various systems running and the battery will have to supplement the available supply. This then has to be recharged with what is available when the engine is running faster.
It's all too dynamic to be able to say 200w or any other figure come to that.
But experience shows that the alternator and electrical systems of all the oil-head Beemers are robust enough to support nearly anything you are likely to want to add.
Finally, just to add confusion, the 600w figure will be at about 14.5v, whereas the loads quoted by bulbs etc will be a 12v.
Go figure (as you say!).
Greg
