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post #1 of 3 (permalink) Old 12-03-2012, 03:14 PM Thread Starter
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Bonneville Alternator Output

I'm trying to figure out just how much juice can be gotten out of the charging system to run accessories on a mag wheel bonneville.

Here's what's on the draw side...

Running Gear
ECU/Ignition 100
Headlight 55
Tail/Brake light 21
Turn signals 10

Vest 45
Grip warmers 25

Total draw = 256W

According to the manual, the output is 23A @ 2000 RPM, which means about 275W (@ 12V), so it looks like I could run the accessories I want. However, I've read that the rectifier is weak, so the actual output at idle is probably just barely enough to keep the stock running gear from killing the small (10 AH) battery.

I'm not well-versed in electrics, so I'm wondering what options are available to boost the charging system so that the battery can remain charged at idle. Bigger battery? Better rectifier?

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post #2 of 3 (permalink) Old 12-04-2012, 03:39 AM
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Originally Posted by psychodeathbot View Post
ECU/Ignition 100
Nowhere near = 1/2 that at most
(predominantly Fuel Pump - after that, is minimal - if Carb a LOT less)

... Tail/Brake light 21
Turn signals 10...
You can get rid of most of this by converting to LEDs
Also - remove front parking light bulb - ever use that feature?

Adding 70W is not a problem - even if you are discharging slightly momentarily at lights etc, for most part when riding normally you will not and will recharge any lost at this time
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post #3 of 3 (permalink) Old 12-04-2012, 05:06 AM
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with any generating system the output is dependant on a few things
1: the number of turns in the armature
2: the strength of the magnetic flux in the field windings or pole magnets
3: motion, rpm , turning etc.
at idle the output is minimal until revs are increased to a point where
max output is achieved. There is nothing to increase output at idle apart from a bigger generator or rpm. The circuit diagram I have the generator looks like a 3 phase ac output, put through a 6 diode network to give 12dc. Life expectancy of the rectifier is only compromised if it output rating is exceeded for extended periods and heat! + over voltage spikes if any!
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