2.8 amps with AW Protected 18500?

[recDNA]

I got a new Fivemega 18500 body today and I'm using it with a Surefire bezel and Surefire Z41 tail with McClicky and brass. I added a Solarforce clip and an extra o-ring to keep the clip in place. I plan on putting the Nailbender 3 mode 2.8 amp SST-50 in it. I know I won't be able to run it on max for very long due to the small sized body.

My real question is should I use a protected 18500 or an IMR18500? I prefer to use the protected cell to add heat and over discharge protection but I don't know if 2.8 amps with AW Protected 18500 is too much of a draw?

Thanks

 

[flashfiend]

LiCo batteries are rated at 2C and the AW protected 18500 capacity is 1500mAh. This means max discharge should be 3.0 amps. A 2.8 amp module should be fine.

 

[recDNA]

Thanks. Should be safer with protected cell than IMR. I'll use the IMR18500 as a backup. Strangely, it seems to look a little brighter with the IMR18500 than the RCR18500.

 

[flashfiend]

I actually look at the IMR as safer because of the chemistry. Remember, protection circuits can fail but the batteries chemistry won't change. IMRs handle heat better and higher discharge currents and afaik are less prone to exploding.

 

[ElectronGuru]

+1

RCR's get all the attention, but IMRs are superior in a number of ways. In this case, 2.8a is so close to 3.0a that the black cell is working like a jogger out of breath. 3a, the IMR is just getting warmed up.

The key thing with IMR discharge is simply to recharge soon after.

 

[flashfiend]

Thanks for re-affirming my preference for the IMRs EG.

Btw, when I did a comparison between a Redilast 2900 mAh Protected and AW IMR18650 with a 2.8A regulated MC-E, the IMR still delivered slightly more current. This was true of all my regulated and direct drive modules.

The only light with no significant (if any) increase in current was a Strion bulb using FM's D26 socket. Both batteries would only deliver ~1.7A. Must be the limit of this bulb at single li-ion voltages. Although, I am uncertain this bulb can handle higher voltages. Likely not.

 

[Battery Guy]

Thanks. Should be safer with protected cell than IMR. I'll use the IMR18500 as a backup. Strangely, it seems to look a little brighter with the IMR18500 than the RCR18500.

IMR are usually designed for higher current, higher power applications. This is one of the advantages of the LiMn2O4 cathode material. I suspect that the reason that your light is brighter with the IMR cell is that the voltage under load is higher than the RCR.

Cheers,
BG

 

[recDNA]

That makes sense...I'm just sure I'll over discharge the IMR by accident so I think I'll stick to the protected cell despite lower brightness and perhaps even shorter runtime.

 

[Darvis]

Not me, I've completed my shift to IMRs and am not looking back. I've routinely discharged mine to 2.7v in some applications and have not had any issues recharging them at all, I do try to recharge them ASAP, though, as low open voltage is not a good thing.

The only dislike is the length, most are too short to make contact in certain setups and I've had to get creative with switches.

 

[recDNA]

There is a lot of talk about how much safer the IMR's are because they will not explode however the hydrofluoric acid released if they vent is pretty deadly too. It can penetrate your skin and turn your bones to goo so imagine what it would do if you breath it or get it in your eyes.