Solarforce L2 and masterpiece tailcap amp findings..need explanation

[pounder]

hey guys..I have an L2 with an R2 led and just got my masterpiece with the mce led..I checked amperage at the tailcap and found some very weird things...

L2

1mode = 1.3 amps

Masterpiece

High = .570 a
Med = .210 a
Low = .60 a


Now the Med on the Masterpiece has more light output vs the L2, but draws less than a fifth of current..the high is so much brighter than the L2 and draws a third of it's current..

is the MCE really that efficient? or is there another reason for these findings..many thanks for the help..

 

[rice rocket]

What's the voltage of the Masterpiece?

 

[MrGman]

yes are you running the masterpiece with 2 rechargeable batteries so in essence at the lower current draws the voltage is probably up at 8.2 to 8.4V and on the L2 you are running 1 battery at 3.7V and so the current is higher to keep the "Power" at the right level.

Voltage X Current is watts. If you run higher voltage then the current will be lower to keep the watts constant. Watts / voltage = current.

 

[dirtech]

Vbatt x Ibatt = Vf x If + losses

V=volts, I=current

Vf and If are voltage and current at LED respectively.

OR

Vbatt*Ibatt*Eff. = Vf*If

Same formula except using Eff=efficiency instead of losses. use Basic assumption of 80% if you don't know.

This helps explain the relationship between current drawn from the batteries (from the tailcap) to what the LED is seeing at its forward voltage.

Hope this helps you out. I had a similar question once and the CPF community was nice enough to post these equations to make sense of it all.

ETA-can someone please proof read to make sure I don't confuse the OP.

 

[ichoderso]

Masterpiece

High = .570 a
Med = .210 a
Low = .60 a

this can't be correct, the current is around 0,2/0,45/1,3A on the 3 levels, please check it...

Jens

 

[kramer5150]

Perfectly normal if you are running the masterpiece with 2xcells. Double the Vin will cut the I draw in half.

 

[pounder]

ahh nice thanks guys..I thought about the 2 cells vs 1 cell and remembered from school that VxA=watts..higher voltage would be less amps for equal wattage..but was not completely sure that was the cause or reason..

many thanks for the explanations..