How to measure electrical output of bike?
 

Hi,

Did a few searches and couldn’t find the answer I was looking for and I hope you guys can help.
How do I go about measuring the electrical output of my Brozz 250?
Looking to add some lights and a usb plug, I know the watts they will use and I know the watts the bike is using. I am just missing the specific output of the bikes system. Manual doesn’t say. I thought I would post this here before I just start poking around with the multi meter, or say screw it and attach the lights and see what blows or gives out.

Thanks everybody.

P.S. What tf is a “betraying” light? Is it the running light in headlight, the license plate light or is it something completely different?

That small side mounted bulb in the headlight is a running light. In the US we have to ride with the headlights ON. In other parts of the world the small marker light is enough in daylight riding.

That small marker light makes a good point for 12v usb power and it’s switch controlled so you won’t drain your battery. Just plug the hole in the light.

As to the rest of your power question, some one smarter will chime in. FYI don’t let the magic smoke out or it stops working.

An ammeter or an amp clamp will allow you to test your output

this may not be the correct way or maybe it is ......

i just put my red + from my multi meter on the positive post of my battery and unsurprisingly the black negative - to my negative post of my battery and if i recall correctly was getting about 14 volts which is right on target i believe.....


you can buy a mutitester at harbor freight for under 6 beans... sometimes they are like 3 bucks on supe special sidewalk sales and the like....
https://www.harborfreight.com/7-Func...ter-63759.html

Yeah, if the charging system can't keep up, you've exceeded the wattage capacity of the stator. You're not likely to exceed the capacity of the stator with a cigarette lighter charger and LEDs, unless you've got a crazy powerful LED.

Using a standard multimeter like that is just telling you the voltage output ,the o.p. was wondering how many watts of power his electrical system is creating in order to add more accessories to his bike .An ammeter goes in-line between the alternator-generator-stator ,and the battery or voltage regulator ,the newer style is a big clamp that clips around the outside of the wire and is much easier to use as you don’t need to do anything but clamp it on .

Thanks everyone!!

Looks like I will be sourcing an ammeter in the future.

Side theory- If the stator is working at 100% all the time, accounting for the revs correlation to watt output, could I measure what the shunt is bleeding off as extra and see what watts I have to play with? Is there a way to measure that? I don’t really understand how the shunt bleeds the excess power. Does it convert all the excess into heat?

Not sure if the tbr7 uses the same stator as the Hawk (typical 8 coil found in most CG engines) but if it does, then it has around 120W output. If you are measuring amps, then the total output should be around 16V/3.5A at 1500rpm and about 36V/8.5A at 8000.

As for your theory on the Reg/Rec. Yes, the regulator's basic job is to convert unused DC power into heat to prevent overcharging. Some heat is also created in the rectifier when turning the AC input to DC output with the old Thyristor style rectifiers creating more heat than the more efficient MOSFET units of newer bikes.

to check the voltage dan is talking about you would unhook the stator and put the neg and pos probes into the socket and run the bike. idle will be one voltage and will increase with rpm's. ac voltage is what you want your meter set to.

sorry... i surely dont know everything about bikes but i have learned alot.....tbh i really never needed to fix any of my japanese bikes and they all were japanese bikes...

they all simply worked always.....

And meanwhile in China it is against the law to have your headlight on low beam! Weird place!

I stumbled into my answer. After putting 400+ miles on it, we finally had a few days of rain. Got a dry one and went for a ride. Started real weak, heavy lag. Ran kinda rough/weird. Brain kept telling me something wasn’t right. After 15 mins and 8 miles pulled into a gas station and shut it off. Wouldn’t restart. Clicked when pushed start button. Coughed at end of kicking but never caught. Got about a mile of push start trying, getting to my buddies house. Never caught. Charged battery, checked voltage, 12.4. Started bike and checked voltage 14.*. Sat confused, blamed moisture gremlins. Then turned on lights and watched voltage meter drop to 12.3 Left running with lights, rode up street a mile or so and came back, 12.2.
Looks like charging system can’t handle running with lights on and charge battery. I figure it was almost to low to start, then got drained while I was idling in yard with the lights running and battery wouldn’t charge off stator after that.
Won’t be adding anything to bike. Gonna look at LEDs to replace head and taillight, see if I can’t lower power needs. Definitely unplugging the alarm. Right now just idling for a few minutes after riding with the lights off and will be checking the voltage on the regular. I don’t really have outdoor, overnight, safe power supply to use a battery tender. Bike is being kept in a building now and not just tarp draped, for Justin Case.
Now I worry about longer rides, (Francis Marion supposedly has trails and that ain’t too far) but I did get 200+ miles of street riding with the lights on that whole time at least. Don’t know if I was running lights while doing figure eights in yard and laps in buddies field to get used to bike before getting tags and permit.

Most of the Amps drawn on these bikes is the headlight. I am not entirely sure what style of bulb the Brozz uses, but on the Hawks they come standard with a fairly low output H4 with a 35W low beam if I remember correctly. That means that at 12 volts the headlight alone draws 2.9 amps.

Combine that with a 21W/5W bulb (tail light for most) or an standard 1157 for the rear lights (about .5amps.

that's 3.4 Amps of current draw on a stator that, at best, at 1500rpm idle speed, puts out 3.5 Amps, and disclude any other system draws, and you basically end up with a bike that neither charges or discharges when sitting still. While riding though, it should be able to keep up.

The fact that your bike isn't keeping up even at idle makes me wonder if you have a 55w halogen headlight bulb, which is pulling closer to 5 amps. Combine that with any other draws on the system, let's just call it a total of 6 amps, and it would be no wonder that your bike would not charge at all.

If you really want to test this theory, see what your charge voltage does at say 7000rpm. If the previous is true then it should actually show some level of charging at that point. If not, then you may have a poor connection somewhere in the harness or at a ground point, a battery with too much internal resistance that won't take a charge, or a few other very very remote possibilities.

Most not all are an 8 coil stator and around 120 watts - shouldn't that be about 10 Amps MAX?
120W
200W
250W
300W
350W
These from memory are about what they CLAIM to be etc
Diameter and widths of stators change, first bigger diameter and coil increase Watts then wider adds more Watts is the general rule of thumb as you upgrade etc.

10 Amps at 9000rpm maybe, and even that is a big maybe. Max output means very little in most cases. The average output for most bikes that you really want to go off if is usually around 4000-5000rpm for any bike that doesn't generally go beyond 10k rpm.

In the case of the typical 8 coil stator, that is right around 5 Amps, give or take a little.