I am trying to find out the Watt draw of the First Generation Duracell flashlight Costco sold.The 3&4 cell using C battery.Bafang bbs02 compatible?

[James340]

I recently installed a Bafang bbs02 kit and it has a 6 volt headlight circuit.It only has 3 Watt current though.I don't want to damage the controller pulling to many Watts

 

[RunForTheHills]

Watt is a unit of power and not current. Watts = Amps (current) X Voltage. So 3W at 6V would be 0.5A of current. If you have a multimeter, you can measure the current while the light is on. Select the current function on the multimeter and choose DC. Put the probes in series with the circuit.

 

[James340]

In series? That would be+ -?

 

[James340]

Watt is a unit of power and not current. Watts = Amps (current) X Voltage. So 3W at 6V would be 0.5A of current. If you have a multimeter, you can measure the current while the light is on. Select the current function on the multimeter and choose DC. Put the probes in series with the circuit.

Thanks for the help

 

[RunForTheHills]

https://www.allaboutcircuits.com/textbook/experiments/chpt-2/ammeter-usage/

 

[James340]

https://www.allaboutcircuits.com/textbook/experiments/chpt-2/ammeter-usage/

I didn't know that. Thank you

 

[James340]

My Multi Meter only goes to 300 ma but it pegged before I even turned on the light.

 

[RunForTheHills]

300 mA is less than a third of an amp. So you won't be able to measure the 0.5A (500mA) that you are estimating for your light. It should have been zero if the light wasn't turned on. There is short in your circuit somewhere.

 

[James340]

The light functions.Has Low.High.Strobe.

 

[scianiac]

Just based totally on a guess, they say "500" on the side and from the very blurry photo of the front I'm guessing those are Cree XM-L or XM-L2 LEDs so if that 500 is lumens which is a reasonable level for these LEDs considering it's a alkaline powered light that would mean about 4-5w not including driver losses. But those are just guesses and you can drive those LEDs much harder, like 15-20W if you are doing some serious hot rodding, but those lights are not and you can't get that much from alkaline batteries and that 500 may be optimistic. Honestly I would just get a separate bike light that can put out some actual light, lighting is safety equipment and the last thing you want is to be going potentially quite fast and not being able to see very well.

 

[James340]

Just based totally on a guess, they say "500" on the side and from the very blurry photo of the front I'm guessing those are Cree XM-L or XM-L2 LEDs so if that 500 is lumens which is a reasonable level for these LEDs considering it's a alkaline powered light that would mean about 4-5w not including driver losses. But those are just guesses and you can drive those LEDs much harder, like 15-20W if you are doing some serious hot rodding, but those lights are not and you can't get that much from alkaline batteries and that 500 may be optimistic. Honestly I would just get a separate bike light that can put out some actual light, lighting is safety equipment and the last thing you want is to be going potentially quite fast and not being able to see very well.

This is a drop bar bike & it's a hassle to attach a switch.It would be convenient to have the display turn on the light.

 

[Chalo]

This is a drop bar bike & it's a hassle to attach a switch.It would be convenient to have the display turn on the light.

You can use a solid state relay to turn on a light that runs on your full battery voltage. The spec for the control signal on those is usually 3 to 30V, so 6V is just right. Switching an SSR draws low current on the control wire, and will not overtax your circuit.

https://a.co/d/d21XGFE

 

[James340]

You can use a solid state relay to turn on a light that runs on your full battery voltage. The spec for the control signal on those is usually 3 to 30V, so 6V is just right. Switching an SSR draws low current on the control wire, and will not overtax your circuit.

https://a.co/d/d21XGFE

I ordered a light for another bike & will be installing it this way.I have the flashlight's sitting on a shelf and it was worth a shot to see if it would work.