I have been working on putting together a complete map of the 650 Electrical system with wattages, etc so folks understand a bit better exactly how much you can add and what you can expect to be the outcome of adding extras.

The following items on the bike use the power constantly:

Headlight - 55W
Taillight - 8W
Front Running lights - 16W
Speedo light - 2W
Ignition Coils - 72W
Ignition Module - 20W

This means that under normal running conditions the bike will use at least 173W of power.

According to the test data from Electro sport in their comparison of their stator to the stock one, the stock system puts out 169W at idle(1200RPM) and 221W at 5000RPM. Yamaha states that the stock system puts out 280W Max so most bikes will fall between the 221W and 280W marks.

Here are some additional power usages:

Signalling - 28W
Braking - 27W
Carb Heaters - 60W
Passing lamps - 60W (smaller units) - 110W(larger lamps)
The carb heaters kick in when the temps are lower than 12 degrees Celsius.

What this means is that the bike will consume 173W + 60W = 233W of power when the carb heaters are on. My 2000 Classic puts out something like 235W-240W at 5000 RPM which is barely enough to keep the system running without using the battery while highway riding only. At idle, the charging system cannot keep up and an additional 64W are drawn from the battery.

I have a battery monitor on my bike and was able to verify the above.

I'm sure the "My battery died" posts are going to start now that the weather is getting cooler and a lot of folks falsely blame the battery when it is actually the weak charging system and too many electrical accessories that are to blame.

Bottom line is that if you ride in temps lower than 12 degrees Celsius, you had better not run your passing lamps or any other extra lights or you will drain the battery and have difficulty starting.