6p + p90 + (2 * li-ion CR123) = 1 fine light ???

[across the pond]

just like the equation says...

is it feasible to run a 6p (or other 2 cell surefire) plus 2 of those rechargeable 123s from jsburlys and a p90 lamp?

the cr123s give 7.2v or so when settled down. would this be ideal to run a p90? (not sure what run time would be)?

 

[Alan]

I don't think you could put 2 of rechargeable CR123 for p90. You would blow the lamp in seconds. I don't know why it was named or referred as "rechargeable 123" and might lead people to think it works like a CR123. In fact, it's not. It's nothing like a CR123 except its size and its name.

I wouldn't image how many cpf members would blow lamps or burnt LEDs when the product becomes available.

Alan

 

[across the pond]

That's why I thought of using a p90 lamp. The standard 2 cell lamp is a p60 which, according to brock's excellent chart, runs at 4.8v under load. Obviously no match for 2 li-ion cells... but the p90 from a 3 cell lamp runs at 7.35v. Seems like a match made in heaven... /ubbthreads/images/graemlins/grin.gif

The p91 high output lamp may also be good, but I don't know if the current drain would be too high and make run time ludicrously short...

 

[PeterB]

I would also assume, that this combination works great. An alternative would be the Pila 3.7V LA with a 168S cell. I think the Pila solution would give more runtime, but the P90 should be slightly brighter.
I have also tested the Pila 3.7V with one R123 (E1E+E2C+C head). Works also fine and is impressive, but I didn't dare to run it continuous since the current draw is about 2A.

 

[mohr]

hi,
its a perfect combination. i use the P91 in a G2Z and the P90 in a Z2. both powered with rechargeable cr123a. you have to be carefull not to damage the cells and dont drain them under 2,5 v. if you want to try this combo just wait for the new cr123a rechargeable that are on preorder at js.
the new cell should have build in discharge and overcharge protection and must do a better job. the runtime with the P90 is about 30min and with the P91 about 10min before the lamp starts to dim.
christian

 

[Alan]

Oops... just jump in too fast and mixed with p60, my bad. In fact, I have been using C3 w p90 on Pila for a few months. It works great. I don't know how well the smaller 123 version handle the load.

Alan

 

[MXDan]

Wow! So now we're looking at the potential to run a P91 lamp in a tiny G2 or Z2 body? And with no battery cost!! I am suddenly 100x more interested in the rechargable 123s. Until I read this, I figured the voltage output made the light worthless in most of my applications.

I would love to hear real quantified confirmation of this application.

 

[ResQTech]

How can 2x123(rechargable) which equals 7.2v sufficiently power a lamp(P90 or P91) that normally uses 3x123(lithium) at 9v? Something doesnt quite add up...

 

[fivemega]

3x123 (lithium) produce nominal voltage of 9 volts but drop to about 7.2 volt under load (1.2 Amp.)
2xLithium ion cells have maximum voltage of about 8 volts and will drop to about 7.2 volts under load.
Actually, most of bulbs design to work with 2.4 volt per Lithium 123 cell when load is about 1.2 Amp.
All above numbers may vary from case to case and depend on load, type of battery, state of charge, temp and ...

 

[mohr]

the rechargeable cr123a is 4.2 v if charged with the modded charger. you can read all about the cr123a if you do a search on cpf. some people mention not to use the cells in a 2 cell flashlight but i have had no problems with that combination. i use it as a small powerfull backup light during my nightshifts as a german policeofficer.
christian

 

[albert]

Christian is right! /ubbthreads/images/graemlins/thumbsup.gif A single rechargeable 123 cell is 4.2v fresh off the modded charger, so 2 pieces is 8.4v in a 2-cells bodies like C2/6P/D2/Z2 and is enough to drive a 9v lamp. This way you will get a more powerful light with a shorter body. /ubbthreads/images/graemlins/buttrock.gif

 

[Topper]

Sounds like A workable combination to me when the "New protected" ones come out I intend on trying it out.
Topper /ubbthreads/images/graemlins/smile.gif