a little math help please

[waddup]

i have a 1 mode (high) 3xD mag with a direct drive p7 in it

and 3 X 10,000 mah tenergy batteries

approximately how long will it run for?

to 50% i guess?


thanks in advance :twothumbs

 

[The Dane]

@ 4 hours to flat.

 

[waddup]

Regulation or no regulation?

i dont know? i didnt build it, i believe its direct drive?

 

[Alan B]

This is not really a math problem. It could be but the amount of information required to do the calculation properly is more than you are going to have. Here are some of the factors:

LED Vf (forward voltage)/ Current curve for different temperatures

Thermal impedance from the LED to ambient

Ambient temperature

Resistance in the light, switch, wiring, etc

Actual cell MAH (not rated) at various currents (this is not a constant)

This is a direct drive light, so the Vf and current will change with temperature, battery charge state, etc. It makes the calculation somewhat complicated to do accurately.

It would be easier to measure it than calculate it.

You could measure the tailcap current and make an estimate of the runtime by taking cell MAH / tailcap current. It won't be precise but will give you an idea.

 

[waddup]

:thinking:




















:welcome:

 

[gswitter]

You can get a rough approximation using the expected capacity of the battery (10,000mAh) and the expected draw of the emitter at 3.6V (say 2800mA for a DSVOJ bin). 10,000mAh / 2800mA = 3.57h.

But as Alan elaborated on, the difference between a rough approximation and reality is very complicated, and would probably take you longer to figure out than just turning the light on and timing it.

 

[waddup]

@ 4 hours to flat.

You can get a rough approximation using the expected capacity of the battery (10,000mAh) and the expected draw of the emitter at 3.6V (say 2800mA for a DSVOJ bin). 10,000mAh / 2800mA = 3.57h.

But as Alan elaborated on, the difference between a rough approximation and reality is very complicated, and would probably take you longer to figure out than just turning the light on and timing it.

approximate is great thank you:thumbsup: