wonderful! once you think up another excuse to buy more we can help again 
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I just thought I’d let you folks know that it’s been almost three months to the day and the Convoy M21F is running fantastically. It’s perfect for our needs, exactly what we wanted. The missus and I couldn’t be happier (and we still can’t get over how bright that lil light is).
Thanks, yet once again, to all you kind and knowledgeable folks who guided me through this. Very much obliged.
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Thanks for the updates! Glad you like the light! It’s always good to see people come back and review their purchases.
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Well our son liked the Convoy so much we’ve ordered him one exactly like it. I do have one question. On their site, under “Basic Introduction”, in the “Construction” section, under “switch” category they state the following: “The electronic switch is located on the side of the head, pay attention to the flashlight using the electronic switch has standby current, if it is possible that you will not use the flashlight for more than a week, please loosen the tail of the flashlight to avoid the risk of battery damage.” I’m not exactly clear on the meaning. We use ours several time a night but our son won’t be. Should he keep the tail cap loosened a few turns? Here’s a link to the light FYC: Convoy M21F gray 21700 flashlight
The light’s got an e-switch so has to keep the microcontroller awake to “listen” for clicks.
This being on could eventually drain the cell down to a level that might cause damage, it would take a long time though.
I’d not overthink it, most of my lights I lockout by half turn of the tailcap anyway, to prevent pocket activation.
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most lights have a decently low drain, batteries taking 1-6 years (from full, calculated, depending on size) for anything bad. but in long long term storage it is good to do. for example mechanichal switches, are mechanichal, and they physically break the battery connection so you dont need to do this (besides accidental activation also).
Thanks @gravelmonkey What I take from this is if you don’t use it, top off charge it once in awhile or maybe remove the battery and rubber-band it to the body? I tried it with ours just now and a ¼ turn will shut it off so a ½ or more is good. IDK what my son’s plans for it are or where or how it’ll be stored so I can’t say. When it does get here, I will use silicone grease and coat the threads and O-rings for him. I do this with all my aluminum bodied lights and it makes a big difference.
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I received two of those same lights (well, it’s the exact same body/host anyway) for free and they are quite useless to me.
I swapped a Getian blue emitter (5050 led) into one, and an SFH55.2 (9090 LED) into the other. There is absolutely no shelf for the MCPCB to sit on, it’s sitting on a hollow tube or “pill” with the driver beneath. Absolutely zero thermal path anywhere.
Even with the 10000K actual rated lumens of the SFH55 and a high drain 26650, it barely hits 1000lm by guesstimate. And for who knows how long? It’s a zoomie so most of the output is wasted. It’s has the standard garbage firmware/UI of H-M-L-Strobe-SOS-Off.
It’s kinda fun with the blue LED zoomed in, but still completely useless overall.
For a light to reach out with I would recommend a Convoy C8+ (IIRC the sofirn C8L is basically the same host but with dual switches) with SFT-25R or maybe SFT-42R, even SFT-40 3000K if you want a nice warm beam. Convoy L21A or M21A same emitter. They’re all under $50 shipped. SFT-25R in a big reflector will have a very narrow and punchy beam.
I mean I haven’t read all the way through this thread, but there will be a lot of great recommendations I’m sure
ETA sorry if you said you preferred side switch and I missed that
Personally I’d just top off every (quarter?) or if you want to “set and forget”, just 1/4 to 1/2 turn the tailcap.
I’d leave the cell inside the light, it might be damaged on the outside.
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Roger that, @gravelmonkey and thanks, again.
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I’d second that. Whatever you do, make sure it’s protected. An unsecured lion battery is a fire hazard.
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It probably doesn’t matter.
But if you have a DMM (digital multimeter), measure it yourself. Put it into a mode to measure mA, take the tailcap off, and hold the probes so the black one touches the “-” end of the battery and the red probe touches a bare aluminum part of the body tube. It should be able to tell you how much current the light uses in standby mode.
For example, let’s say it measures at 0.1 mA.
Then do a bit of math. If the battery is 5000 mAh and standby is 0.1 mA, then 5000 mAh / 0.1 mA = 50000 hours of standby time. Then 50,000 hours / 24 hours = 2083 days, or 5.7 years.
Or let’s say it measured at 2 mA standby power. Then it would work out to about 104 days.
In one of these cases, the light should be fine if left in a drawer for literally years at a time with the power connected. In the other case, it would drain itself in about 3 months.
I don’t know about this specific light, but most lights with an e-switch have a standby drain of like 0.03 mA, which means they’re fine for several years. It’s still a good idea to measure it though, to find out.
For li-ion batteries, if it won’t be used for a while, it’s better if you don’t top it off. They should be about half full when stored long-term. Anything from about 3.5V to 3.9V is probably fine for storage.
Charging it to 100% before storing it will age the battery faster. So try to avoid a full charge unless you’re actually going to use it. Or to maximize battery life span, maybe avoid ever doing a full charge. If you stop at like 4.1V instead of 4.2V, it can last for hundreds more recharges.
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@Perception thank you, I’ll make a note of that. Incidentally, I do keep my spare cells, Ni-MH and Li-Ion, in sealed plastic cases.
@ToyKeeper I appreciate the assistance. The missus and I have no problems with any of this because we use the light(s) on a regular basis, like nightly. My son will probably use his far less frequently. Maybe it’ll be in his truck or maybe the nightstand drawer, IDK. I was looking for a simple SOP for it. At this point, I’m thinking of “set it and forget it”.
I do have a DDM and your drain test peaked my interest. I’ll run it on his just to see. Insofar as charging goes, he’ll only have the lights built in charger to work with, so charging to a specific level is out. I/we are end-users and not into the technical aspects of these lights. That’s why this long thread in the first place. I remember well when incan Mag-Lites were the hot new ticket. The only thing we had to worry about was the alkaline batteries leaking. So, yeah, a simple SOP is what I/we’re after.
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