Recently upgraded all my Surefire lights to Malkoff heads. It's a big improvement. So far have been using regular disposable cells. Now I am looking to get rechargeable batteries.

On the 2 cell lights I have ordered Orbtronic 16650 protected cells and an XTAR VP4. The brand seems to have a good reputation and I've seen them recommended one the forums. I also have a 16650 rechargeable conversion for my Hogster so using the same size seemed logical.

Reading here it seems like protected may or may not be required, may or may not impact performance. Malkoff sells protected cells so that's why I went with protected.

But for my 3 cell M900s I'm not sure what to do. I have seen mention of 16500 size batteries, but in searching there are very few options, lacking button tops, or they have "fire" in the name.

I have not been able to locate a Surefire body extension that would allow me to fit 2x 16650 either.

I am aware of single rechargeable CR123 batteries with the USB charger on the cell, but imagining my charging setup would be a hot mess of cables everywhere.

Malkoff sells a dummy CR123 cell that I guess would work as a conductive spacer with one 16650? It seems like I would be missing out on battery capacity.

The Malkoff MDM4 LED conversion only listed a maximum input voltage of 12v but no minimum. Now that I think about it I don't know if a single cell rechargeable would power it?

Thanks

I prefer unprotected cells in my high drain devices. I have a Cloud Defensive MCH Duty that won’t even run on protected cells. There’s a slightly higher risk of some kind of runaway or fire issue, but I don’t leave my batteries on chargers or in devices unless I am checking them regularly.

There are rechargeable cr123s. Surefire sells them and I’m sure there are others. You lose some performance with them, I believe. But I may be misremembering.

RCR123A.

https://www.amazon.com/dp/B0BSTSQ1GW?tag=arfcom00-20

I have had good luck with these in certain devices but not others

They do power Surefire G2 with Cree head no problem

Surefire sells rechargeable CR123's. I also have some Nitecore ones. Both get charged with your typical charger. Just know that rechargeable ones have much lower capacity than non-rechargeable ones

You could see if a 17500 will fit.

What head are you going to use with the M900? That will tell you what battery options you have.

There could be a head that can use 3x 16340 batteries, 2x 14500 batteries and a sleeve, or you could be stuck with 16650 and a spacer.

FFS why nobody has mentioned replacing 3xCR123's with a PAIR of 17500's is beyond me.

Paladin

That is where I was going, but I don't know for sure that a 17mm diameter cell will fit in the tube.

The 17500's fit my nightstand Surefire 9P and G3 fine.  One has the Malkoff led installed, the other the old SF 120 lumen drop in.

Paladin

Thank you both.

Update to my upgrades:

Being not entirely sure the 17mm battery would fit in the light as 16mm were already snug, and that 16500 and 17500 size seems hard to find, and that the keeppower makes 17500 protected cells, but I already have keeppower that are way too long, I got some 16340s to try.

Also, my surefire p114 pistol light and stream light m3 win use them.

On that note, the p114 is reverse polarity, the malkoff head does not work.

I found Lumens Factory makes drop in LED conversion for both lights which I have procured and I am pleased with.

16340 are typically 750mah each. 3x750=2250mah.

A single 16650 Keeppower is 2500mah.

16650 plus spacer is more capacity and most LED lights are generally set up to run off a single 3.7v cell and not an 11.1v stack of 16340s.

Anyone who says 16500 for an LED light was probably trying to say 16650 (2×123 sized) or 14500 (AA sized) and had a typo or brain fart.

The choice is easy.

For a 3xCR123a light, a CR123a being 16mm diameter and 35mm in length, with 3 being roughly 100mm total length due to a slight nesting effect, a pair of 16500's is roughly the same 100mm total length and their 8.4v maximum voltage makes them safer to use in place of 3xCR123a's with their 9.9v maximum combined voltage, than 3x16340's and their resultant combined maximum 12.6 volts.