Multi 18650 cell lights?

[bigstick1973]

Iv been looking at a few lights by ultra fire that have extensions that can be added to add cells. my question is iv seen up to 2 18650 cells can be added to some of these lights for a total of 3 18650 cells. so wouldnt this increase the voltage going to the driver? also would this voltage be droped steped down by the driver or would this be running full tilt at 3.7v x3?
Thanks.

 

[StorminMatt]

Adding more cells in series would DEFINITELY increase the voltage to the driver. In a light that accepts cells in series, the driver would NEED to be a buck driver that can accept a wide range of input voltages.

 

[Chodes]

Check out Malkoff website. Clear, precise, honest information provided.
Many manufacturers have mis information in specs for their lights that can lead you astray when trying to learn.

Here are some extracts from Malkoff blurb on the M61SHO dropin which has a very good answer to your question:

This is the Malkoff Devices M61 High Output dropin...
The input voltage is 5.5- 12 volts.
The current draw is 1000ma at 6 volts.
On three cells the current draw is 600ma
On four cells the current draw is 450ma

(Output claimed as 385 Lumens for all 3 examples)
Malkoff is using 3V per cell for these examples, CR123 primaries.

So while volts and current vary, power is constant:
6V x 1A = 6Watts
9V x 0.6A = 5.4 Watts
12V x 0.45A = 5.4Watts.

With 2 cell example, cell voltage would sag more under 1 A load, power is probably closer to 5.4Watts...

 

[bigstick1973]

My plan is to get one of these 2x18650 lights then remove the led only and then replace it with a SST-90 in red. because i cant seem to find a red drop in for these lights at 3-9 volts
thanks

 

[Chodes]

My plan is to get one of these 2x18650 lights then remove the led only and then replace it with a SST-90 in red. because i cant seem to find a red drop in for these lights at 3-9 volts
thanks

Unless you really want to do the mod yourself, I would contact either Vinhnguyen54 or Nailbender.
For whatever budget you have and or cost from either source I'm sure you'll get the best result.

 

[bigstick1973]

thanks!