I have your basic two brush 12V generator on my Ironhead and I can find neither a wattage rating for it nor any current rating from which I might compute it.

Anybody know what it is, or in the alternative, anybody tried running about 100W worth of electric jacket & gloves in addition to the bike's stock headlight and tail light?

Much appreciation in advance . . .

Harold in 32F but sunny Fla.

 

The current rating of a working generator's output is a minimum of 10 amperes. That converts to a minimum output of 120 watts. That output is then adjusted and regulated by the voltage regulator........... pg

 

As PG says, 10 amps. However if you have an original 1982 to E84 generator it is a whopping 13 amps!

I have not done any measuring, but approximately the headlite takes 4 amps, the ignition and the rest of the lights take 4 amps, leaving 2 amps to charge the battery and nothing for running extra electrical equipment.

What i suggest is, using an ammeter, measure the current at each circuit breaker with the engine running at 2500 RPM. Total it up, subtract from 10 and see what is left over.

Check the amp requirement of the equipment you wish to use and then decide.

I would like to see the results of the measuring.

I am terrible at understanding electrical stuff, so best to run this by someone else before proceeding.

 

Thanks to you and PG.

Although PG said 10 amps was the minimum, I think he meant the maximum, but in any case, it's ~120 watts. The head and tail lights draw about 60 watts, I figure the ignition about ten, so at least in theory, that doesn't leave much for the accessories.

Practically, I lit out yesterday for a fairly short ride -- 20 miles in some traffic -- during which time I was rarely turning more than 2000 rpm. I ran a 70 watt electric jacket and electric gloves that I believe draw about 20watts. I was fairly careful to turn the headlight off when away from traffic. The bike started normally after a lunch stop.

When I got home, I broke out a digital volt meter and noted the following at 2500rpm: 13.1VDC unloaded (just ignition); 12.8VDC with headlight/tail light on; 12.3VDC adding jacket; and 11.7VDC adding the gloves.

With lights, jacket and gloves, the system voltage would reach but never exceed 12VDC, even well beyond 3,000 rpm.

A system loss of .3VDC isn't a big deal over time, but the generator running full blast all the time might be, so at least for now, I'm gonna use only an old 40W vest.

Gonna talk to my ole gray-templed, dittohead generator/alternator man and see about the possibility of souping up the generator and regulator.

If he moves beyond lecturing me on the conspiracy/antichrist theory de jour I'll pass along what he says.

 

Although PG said 10 amps was the minimum, I think he meant the maximum, but in any case, it's ~120 watts. The head and tail lights draw about 60 watts, I figure the ignition about ten, so at least in theory, that doesn't leave much for the accessories.

Nope, I meant minimum. If the generator does not have an output of at least 10 amps, then there is a problem with it and it will not keep the battery charged. It sounds like your generator is working properly.

A standard headlight draws 45 watts on high beam or 35 watts on low beam.
The tail light draws 4 candle power, which is the exact same draw as the generator signal light.
You have a lot of reserve with the generator as it is now.
My opinion is that you do not need to do anything to the generator.
pg

 

Max what you can get from that generator is 17 amps, but with that current it doesn't last long... Best way to handle cold weather is wear correct clothing...
On top Gore-tex ( or what ever name that fabric brand is) under that fleece + normal clothing.
http://www.rukka.com/lfashion/rukka/...B?OpenDocument

Motocross helmet with motocross goggles with double layer lenses
http://www.smithoptics.com/technolog...ategory=3&id=8

It doesn't look nice but you can ride... right now here is only -10ºF... not very cold:-) when it goes to -20ºF that is cold...

 

The FM says 10 amps?

Also, regarding the thread title, i think that watts is the incorrect concept. The gen puts out 10 amps. Add up the amps pasing thru each circuit breaker and see what is left over for the other gear.

 

Watts, voltage, and current have a fixed mathematical relationship. Watts are computed by multiplying voltage X current: P=IE Watts is a measurement of energy. (watt hours, BTW, is a measurement of energy production or consumption over time)

Since I'm interested in whether the generator can support electrical gear that is rated in watts, it's easier, tho' not necessary, to think of the generator as a source of electrical energy in watts. I could almost as easily compute the current requirements of each accessory (at 12VDC) and do essentially the same arithmetic, but why bother.

The reason I asked for the wattage rating of the generator is that the generator will easily provide more wattage than its rating but, as Sepixlh points out, not for long. When it is working too hard, it will begin to melt the solder in the commutator and render the armature virtually irretrievably broken. That's why the answer I got regarding minimum current is worthless -- I already knew my generator was working "correctly" -- and my concern is not for the minimum, but the maximum. (Sepixlh, thanks for the note that it will produce 17 amps, with the implicit note that it ain't a good idea)

Dressing properly is a good suggestion. I dress so that my clothing doesn't interfere with my control of the motorcycle, both from the aspect of actual, physical control and from the aspect of isolating myself too much from the sensory feedback that's necessary to its control. Bundling up so that I look like the Michelin tire man doesn't serve either of those goals very well. That's why I prefer electronic gear to a laundry basket full of clothes. And because I have a good store of electrical gear that my other bikes support very well, it's easier to pull 'em down off a hook and haul ***. That said, if I lived 500 miles from the Arctic circle, I'd go with the laundry basket and the electrics!

With respect to modifying my generator, it may not make a whole bunch of sense given that the current cold snap here in Fla is (at least, before climate change) a once in a hundred year event, so I might not do it. (and might pass on the windshield too) But in my view it's desireable, if not necessary, that my generator not only provide enough energy to power the electrical accessories, to provide enough energy to power the native load (lights, ignition) but to replentish the battery as well, since my XLS lacks a kick starter.

So I either gonna modify the generator for higher output or confine my ironhead riding to warmer weather which, in Fla -- even North Fla -- ain't usually that hard to find.

 

OK, so now i am interested. How do you modify the gen for higher output?

 

You ask your generator guy well after the Rush Limbaugh show is over, when he's calmed down. You tell him you suspect that one would follow the same scheme one would follow to increase or decrease the power of an electric motor. If he tells you it can't be done, you carefully consider whether he's just never broken outside his tiny little comfort zone, or whether he's right.

It's a tough call. One that in my case might be entirely obviated by a warming trend in the weather. Kinda makes me causally wonder if the gears that were mercifully saved from the Dremel tool are enjoying their home in the land fill.

'scuse me, I gotta go ride.