Replace 2xCR123A with a 16650 Battery

Hi, I'm a bit of a noob to the flashlight world. I have an old Mag-Tac (Crowned Bezel) laying around that I wanted to use rechargeable batteries in. I bought a 16650 battery, and tried it, but it appears that the drivers won't accept 3.7v.

How difficult would it be to swap the drivers for something that will operate on the lower voltage? Would it be worth swapping the drivers, or is there a different rechargeable cell that will replace 2xCR123A batteries.

Thanks

You can get rechargeable CR 123s. Google search RCR123.

Edit: And welcome to CPF!!

Thank you!

Feel free to correct me, but it was my understanding that because of the way the batteries were constructed the rechargeable CR123s ran a higher voltage than the disposables, and I would prefer not to risk damaging the light. I'll start looking into what's available.

Do you have any recommendations on a decent quality battery? With so many batteries flooding the market it's hard to tell what's decent and what's not.

I guess now I'll have to get another light that will work with these 16650 cells...

RCR123 runs at 3.7v while primary CR123 runs at 3v..
You may wanna look for LiPo cells, they are 3v cells & are a good replacement for primary cells.
Just that their capacity are quite low.

DellSuperman said:

RCR123 runs at 3.7v while primary CR123 runs at 3v..
You may wanna look for LiPo cells, they are 3v cells & are a good replacement for primary cells.
Just that their capacity are quite low.

Click to expand...

And they need a special charger as well.

Look at the Lumens Factory Seraph 6 if you decide to go to a different light. Just as bright as yours, three modes, standard emitter is Neutral White, you can get a 90+ CRI instead by emailing them and requesting it after placing your order. Best of all, they are on sale right now for $35 + shipping. Nice little light, comes with both twisty and forward clicky tail caps. Accepts 18650 but with a little judicious wrapping a 16650 won't rattle around inside at all. I've had mine for years, and it is quite reliable.

What's the likelihood that using the higher voltage would damage the light? Would it be possible to use a resistor to drop the voltage down to something that the light can use? I believe the drivers would keep the current draw of the LED fairly consistent. I'm just not sure how I can find the resistance or current of the light itself in order to calculate the value of the resistor I need. I'm also not sure how I could package the resistor neatly enough to that it wouldn't become a bother. Perhaps adding it in to the tailcap?

I would look online for the light manual to see if you can figure what voltage its designed for. If the light is important to you, try the 3.7 v RCR123s. If it damages the light, then just go the mod route you already thought of as an option Some lights say don't use anything but primaries, but sometimes the reason is that they expect a shock load from a weapons mount, etc. I have some 3v RCR123s (Watson makes them) that as stated above require a different charger. They work fine in my light that requires those types of cells. I found mine at B&H, but i'm sure you can find them elsewhere. Turns out the driver in that light was able to also run 16650s though, although the 2 cells are a little brighter i believe.

Welcome to the forum and hope this helps

LRDII said:

What's the likelihood that using the higher voltage would damage the light? Would it be possible to use a resistor to drop the voltage down to something that the light can use? I believe the drivers would keep the current draw of the LED fairly consistent. I'm just not sure how I can find the resistance or current of the light itself in order to calculate the value of the resistor I need. I'm also not sure how I could package the resistor neatly enough to that it wouldn't become a bother. Perhaps adding it in to the tailcap?

Click to expand...

Voltage supplied-voltage required
___________________________
Amps
=Ohm rating for the resistor.

The manual for the light was not helpful. I'm going to try to get on the phone with Maglite support, and see if the light can handle the higher voltage. The manual did say that the light has "voltage control," but did not elaborate. If I don't get a good answer from Maglite I'll probably go the Watson route. It looks like $34 will get me a charger + four batteries.

edit: Maglite said it would damage the light because the voltage was too high. It looks like I'll go the Watson route. What sort of runtime do you get off of those cells?

I used the light for general purposes and haven't done a full out test on runtimes, but it lasted enough for those purposes. This is actually what got me started on my recent flashlight update binge (which hasn't stopped yet BTW), so even though i really like that light, i have been testing other lights right now and that particular light has been feeling lonely . The capacity isn't great on those, but i also ordered 4 of them and some extras and just stuck them in the charger on a frequent basis (every couple days or so) so it wasn't a big deal. Now you have me wondering, so i'll see what the runtime is on those. I now also have a few single CR123 lights that i use these in and they don't have that bad of a runtime. Then again, i still feel thankful that i have gotten away from primaries, so even if it was much less runtime wrt to primaries, i feel its a great tradeoff...