Rechargeable Batteries Compatibility (new guy)

[eraursls1984]

I've noticed that some lights say they are not compatible with rechargeable batteries. Also I see lights from the same manufacture where one says rcr123, cr123 and another just says cr123. I don't want any lights I can't run rechargable lights in. Right now I have eneloop aa and aaa and plan to get rechargeable cr123 and 18650s when I get more lights. I'm looking at a few Foursevens lights, mini ml, qt2l-x, m2a, and mmu-x will I run into problems if I use rechargable batteries in any of these?

 

[Joe Talmadge]

I've noticed that some lights say they are not compatible with rechargeable batteries. Also I see lights from the same manufacture where one says rcr123, cr123 and another just says cr123. I don't want any lights I can't run rechargable lights in. Right now I have eneloop aa and aaa and plan to get rechargeable cr123 and 18650s when I get more lights. I'm looking at a few Foursevens lights, mini ml, qt2l-x, m2a, and mmu-x will I run into problems if I use rechargable batteries in any of these?

In the spirit of "teach a man to fish" :) ...

If a light isn't advertised explicitly for RCR/18650 etc, you might also look at the manufacturer's input voltage range in the specs. If it says 4.2V (or 8.4V in the case of 2xRCR, etc), you're good. Sometimes the light supports 4.2V but for whatever reason, Li Ion support doesn't make it into the manufacturers supported battery list.

The other thing to note is that even though there are lights that *officially* support only primaries, there are many lights that *can* support Li Ion, and the only reason the manufacturer doesn't support this config (i.e., the circuit can handle it) is because the light gets hot on high and there is worry about LED or circuit damage -- but forearmed with this knowledge, you can safely run Li Ion as long as you take the light off high when it starts getting hot. For example, my Klarus XT1C officially is supported only for primaries, but I contacted Klarus, and they told me "safe to run Li Ion but take it off high when it gets hot". The thing is a barn-burner on high on Li Ion, I love it. Some of the 4sevens lights also have this feature -- circuit can handle the voltage, but you risk damaging the light if you run it too hot -- but I don't know offhand which ones, since I don't have any 4sevens lights anymore. You can search the forums or ask on 4sevens' forum on cpfmarketplace.

 

[eraursls1984]

In the spirit of "teach a man to fish" :) ...

If a light isn't advertised explicitly for RCR/18650 etc, you might also look at the manufacturer's input voltage range in the specs. If it says 4.2V (or 8.4V in the case of 2xRCR, etc), you're good. Sometimes the light supports 4.2V but for whatever reason, Li Ion support doesn't make it into the manufacturers supported battery list.

The other thing to note is that even though there are lights that *officially* support only primaries, there are many lights that *can* support Li Ion, and the only reason the manufacturer doesn't support this config (i.e., the circuit can handle it) is because the light gets hot on high and there is worry about LED or circuit damage. For example, my Klarus XT1C officially is supported only for primaries, but I contacted Klarus, and they told me "safe to run Li Ion but take it off high when it gets hot".

Ok, I've seen "primaries" but didn't know what it meant, I'm guessing it means non-chargeable. So the reason some lights don't support rechargeable batteries is because they are higher voltage, this is why my Preon 2 gets hot as hell after a few minutes on high (which is because of the clicky switch accidentally turning on in my pocket)

 

[lensman]

I've noticed that some lights say they are not compatible with rechargeable batteries. Also I see lights from the same manufacture where one says rcr123, cr123 and another just says cr123. I don't want any lights I can't run rechargable lights in. Right now I have eneloop aa and aaa and plan to get rechargeable cr123 and 18650s when I get more lights. I'm looking at a few Foursevens lights, mini ml, qt2l-x, m2a, and mmu-x will I run into problems if I use rechargable batteries in any of these?

It is primarily voltage for compatibility between primaries and rechargeables, but also note that not all rechargeables are the same.

NiMH - 1.2 volts, rechargeable
primary alkaline - 1.5 volts
NiZn - 1.6 volts, rechargeable - note that these are relatively easy to overdischarge and kill
primary lithium - 3.0 volts
LiFePO4 - 3.0-3.3 volts, rechargeable, lower energy density than Li-ion.
Li-ion - 3.7 volts.

Note that I list nominal discharge voltages, not charging voltages.

I also prefer rechargeables. If I do find a light that doesn't like rcr123, I will just substitute a LiFePO4 battery and take my chances. I tend to not need long runtimes.