SST90 M@g vs. 5761?

[GarageBoy]

Love the insane brightness of the 5761, but can I get it in LED form for longer runtime?

 

[flashfiend]

You know in its optimal Mag form the sst-90 draws the same current as the 5761?

However in a 3D NiMH setup the sst-90 will give better runtimes.

 

[ma_sha1]

SST-50 driven at 5 Amp will give you 5761 in LED form, the run time on same battery would be similar thou.

SST-90 driven to 8/9 amp will blow away 5761.
But with less run time on same battery.

 

[flashfiend]

SST-50 driven at 5 Amp will give you 5761 in LED form, the run time on same battery would be similar thou.

SST-90 driven to 8/9 amp will blow away 5761.
But with less run time on same battery.

Can you remind me how you're calculating the above? Using 2 Li-Ion IMRs the 5761 draws 5.6A.

Using Power = Voltage x Current a sst-90 (Vf = 3.87v per spec) driven to 9 amps shoots out 34.83 Watts. Divide that by the 7.4v of 2 Li-Ions gives 4.71A drawn from the batteries in a regulated setup. Am I calculating something wrong? Looks like the sst-90 should last longer in a regulated setup with the same batteries.

SST-90 given 9A to the LED will blow away the 5761 though.

 

[hoongern]

SST-50 driven at 5 Amp will give you 5761 in LED form, the run time on same battery would be similar thou.

SST-90 driven to 8/9 amp will blow away 5761.
But with less run time on same battery.

Just for clarification & numbers:

SST-50 @ 5A, Vf:3.6V Power: 18.00W
SST-90 @ 9A, Vf:3.87V Power: 34.83W
5761 @ 5.6A, V: 7.4V Power: 41.40W

Runtime is calculated from power, not current. Thus, on the same battery, SST50@5A would last longest, followed by SST90, and then 5761.

 

[flashfiend]

Thanks for clearing that up hoongern.