KX4 on lithium ion rechargeables

A buddy is asking about making his 6P LED rechargeable, he looked at the Surefire kit and wasn't crazy about it, so I suggested he try some AW protected cells...

My question is which ones will give better performance a single 17670 or two RCR123s? By performance I figure both will give the same output but what about runtime?

Specs from AW's sales thread, some calculations:

RCR123A's are 3.7V like any li-ion and 750mAh, two in series will double the voltage and capacity will stay the same

17670s are also 3.7V of course and have a 1600mAh capacity.

R123A x2 = 3.7x2V * 0.75Ah = 5.55Wh
17670 = 3.7V * 1.6Ah = 5.92Wh

Obviously these are just comparative numbers, the voltage varies according to charge state and so and so, finding the actual capacity would be more complicated.

Theoretically it looks like the 17670 will pack more punch. I have no idea about the voltage range of the KX4 and its regulation though.

Yea since the KX4 is designed to run on two or three primary cr123s I'm just wondering if 8.4 volts would keep it in regulation longer than 4.2 volts

FWIW a new KX4D pulled about 390 or 400 mA's from a pair of protected 17500's. It's on a G3 body for now, which is only used intermittently to check the back yard for our "pet" Bufo toads which my 90# hell hound likes to lick and get buzzed from.:sick2:

Another KX4 is on my goto house carbine fed by 3 primary cells. I don't think you will get full output from a single Li-ion cell.

Paladin

Paladin said:

Another KX4 is on my goto house carbine fed by 3 primary cells. I don't think you will get full output from a single Li-ion cell.

Click to expand...

You don't think so? I had read that a 17670 will run the P60L in regulation...

Mikeg23 said:

You don't think so? I had read that a 17670 will run the P60L in regulation...

Click to expand...

A single 17670 won't run the P60L in regulation - my experience is that it will be less than 50% of rated output.
(Malkoff M60's/M61's are much better in this regard.)

At this time, it is unknown how close to maximum output the updated SF KX4 will attain on a single LiIon cell ??

A single AW 17670 does contain ~45% more energy than 2x AW RCR123's (which are somewhat exaggerated in capacity).

Interesting thread!

I've recently started getting KX4s and I've been running them on 17670s. To me it's seemed like they've gotten dim quite quickly after use compared to fresh off the charger 17670s.

It's hard to be sure about such things without a way to actually measure though so I've wondered if it was just in my head.

Perhaps I'd do better running them on primaries.

Kestrel said:

A single 17670 won't run the P60L in regulation - my experience is that it will be less than 50% of rated output.
(Malkoff M60's/M61's are much better in this regard.)

At this time, it is unknown how close to maximum output the updated SF KX4 will attain on a single LiIon cell ??

A single AW 17670 does contain ~45% more energy than 2x AW RCR123's (which are somewhat exaggerated in capacity).

Click to expand...

That's mostly what I needed to hear so I guess the question is how long will it run in regulation on two RCR123... I told my buddy we may just have to try it because I have all the different cells he just lives kinda far away not too far though