Oh right… my calcs above neglected Vload<Vno-load for each cell.
Under load cell-V drops and the calculation looks like this with estimated Vload=3.5V (I normally use Vnom = 3.6V for calcs like this)
4A x 10.5 = 42 W pulled from cells
42 x .80efficiency(typ) = 33.6W into LED array
33.6W / 7LED = 4.8W/LED
4.8W / 3.4Vf = 1.41A per XML (assuming 3.4Vf)
Slightly less than the previous calculation at 4.2Vbatt
Anyway the Solarstorm is not driven that high, at 2700L OTF as the 2A driver is not “stable”. So not sure which one to aim for. But i’ll surely use protected cells here which i’d test conscientiously!
To give an idea on the heat levels, the Trustfire TR-3T6 triple XM-L with 1300L OTF is driven to such levels. This light has 7 T6 but quite a bit bigger. 1.12kg is no joke with most of it at the head. TK70 is 769g. But i suspect that 1.12kg is in error.
You guys are are assuming its more efficient, or brighter overall with higher Vin. It should be noted that lights like the TR-J12/18 are brighter at 8.4Vin than 12.6
It seems that in this case for 3S it could very well be brighter than 4S. 4A for 3S and 9.6A for 4S. There would be more voltage sag for 3S and hence 3S should give a higher reading, but if the cells are good then 4A shd still not sag a lot. Could be the case for J12….difference of about 5% in output.
This is confirmed a > 3000L light, just a matter of 3200, 3300 or 3400L OTF. Pity no UCL size.
Shipping to SG is $29.18, paypal is $3.16. Thailand shd be similar.
You wanna get one? I think 4 x 18650 still is very comfortable for XTAR 2600s or TF flames 2400s. Protected is ok. Well for me i have the PVC sleevels from J12 and my 2 26650 Shadow lights.
You place order first w/o paying. They will invoice you with a xls in an email and you PP. They are the same guys as bestinone.net, you know the generic IMRs. And sz-eyoung.