Warning: really long post and mild rant! Does anybody else hate overdischarging batteries as much as I do?

Regardless of chemistry…

I have one of those infrared motion sensing lights that uses 4xaaa. It has a low battery warning light that just came on today. I took out the eneloops to check voltages before charging, and 3 of them were between 0.8-0.9v which is normal for being depleted, but the fourth was at –0.04. |( Yes, negative. That’s no good… On the bright side, I did get them all recharging again by doing the “channel jumping” trick on my bc-9009. BTW, this is not the first time that I’ve had to use that tactic.

Also, a couple weeks ago I lent my TK35 and chinese 50w HID to my friend for a camping/animal spotting trip in the national forest/jungle. That was my first mistake, giving out flashlights and not going along to supervise their usage :davie: … he is definitely not a flashaholic or as careful (read anal) as I am. Anyways, I got a text from him asking if it was normal for HID’s to just cut out suddenly. I told him probably yes if the battery was too low (even though I personally have never pushed the limit), and that it would probably be a good idea to charge up the battery pack asap. I really have no idea how well designed the circuits are in those things.

Later after the trip, when he returned the lights to me, I checked them over. The HID’s battery pack had been recharged, and it was working fine. sigh of relief The TK35 lit up in low, med, and high, but not turbo. I thought, sweet!, some kind of way to tell that the batteries are getting low. So I pulled out the batts to see how low they were. One was at 3.6v and the other was at 0v. :frowning: I know you’re probably thinking tripped protection circuit! But that was not the case because the light still lit up on the lower modes, remember? Unfortunately, my second mistake was putting in unprotected cells. I usually have protected Hi-Max’s in it, but I got the request for the lights on short notice and didn’t have time to charge them up, so I put in some fuller unprotected Panny’s thinking they would last longer. I will never do that again…

From my experience, it seems that most of the time, the culprit is the use of multiple cells (and inattention to runtime). Surely, single cell applications have fewer problems with overdischarging. This is why I have been hesitating on the quark deal. I would hate to have to deal with overdischarged cells at that price/quality level. And now that the L3 Illuminations L10 is out, it’s hard not to just get two single cell lights for the price of one 2 cell light (emitters, lumens, and other specs aside). But a quark is a quark! The similarities between the two are they both run on aa’s and have a moonlight/firefly mode. These are the two features I’ve been after recently, mostly because I’ve been looking into lights for long camping trips (weeks) for normal people (non-flashaholics) where runtime is important and there is a risk of overdischarging cells and not being able to immediately recharge them thereby inducing permanent damage. Logically, that means I should go with some L10’s, but for some reason I can’t seem to get over the quark deal.

So how do I prevent overdischarging in the future? In the case of the PIR lamp, there really is no way for me to tell battery status, short of pulling out the cells weekly and checking them, since the warning light is unreliable. But I’m too lazy for that. For the TK35, I wish I had the U2 version with the step-down and low voltage warning. They really should have included that on the original. But, I’ve definitely learned the lesson of using (or not using) unprotected cells in a multi-cell in-series light. Never again… Never again.

When it comes to primaries, I love to squeeze out every last bit of juice. But with rechargables, nimh or li-ion, it really really bothers me when they get overdischarged or when the voltage goes into the negative. It’s even worse, when I can’t recharge them immediately. I can’t help but think about how much I’m killing them. In the end, I guess they’re just batteries. But I still like to take care of my stuff as best as I can. It’s too bad I can’t really trust other people to do likewise. Anybody else feel the same as I do or have a similar frustrating story? I know kriesler has one. BTW, if you made it all the way through this post, thanks for reading. At least it wasn’t as long as one of kriesler’s reviews :wink: … I hope it was somewhat enjoyable/entertaining. If not, sorry I wasted your time… I mean you should have stopped reading after the first paragraph! :stuck_out_tongue: I did warn you didn’t I?

Loaners only get protected cells out of the Casa De X - I don't like pitching out cells either.

Do Not Give Non-Flashaholics Flashlights Containing Rechargable Cells .

Wow, you're friend is certainly lucky the TK-35 didn't explode. That could have easily lead to reverse charging.

> PIR lamp

I’ve been wondering if putting a solar cell on outdoor devices, with say a sheet of copper foil as the contact tucked between the end cells and the device’s battery box contacts, could feed enough of a trickle charge to rechargeable cells to keep them out of reversing range.

I have definitely learned something and adopted stricter rules since the last fiasco. Usually I’m pretty cautious and paranoid. I check battery voltages all the time to make sure things are evenly matched and charged. Honestly, I don’t like lending out any of my lights. I just don’t trust people with using them. In the future, I might even go as far as only lending single cell aa lights unless I tag along. That’s the main reason why I’ve been looking for decent aa lights recently. All of my current ones are weak on nimh and have average-to-awful runtimes. I usually use 14500’s with them anyways. OTOH I don’t really want to deprive other people of the joys of li-ion lights either. I guess I just have to supervise from now on, even though sometimes I still get a little nervous even if I am around.

You’re right. It really was a dumb move on my part. I totally regret it, and would never do it again, at least with unprotected cells. I guess I should have coached him more or given him a different light or kept the protected cells in it despite being half used. The thing is, he has borrowed the TK35 on more than one occasion previously, with the protected Hi-Max’s, without incident. Never has he drained the batteries down like this last time. Actually I lent him a single cell MCE P60 light for this particular trip too, but apparently that one didn’t see as much use. I really do try to keep it as safe as possible for anybody who may be using my lights. I know it is my responsibility and I would feel just awful if anybody was injured because of my actions.

I have shown him my collection and tried to explain stuff to him before. He’s just not that interested. I guess that should have been a clue. The problem is, he’s like my boss… he needed lights, so I gave him my best and brightest ones. I knew/know about the dangers of multiple (unprotected or otherwise) cell li-ion lights, but couldn’t think of another option at the time given the short notice. Until now, I never really thought about the reality of the potential danger that he could have experienced given the circumstances. Honestly, thanks for pointing that out. That’s something new to be thankful for. I am glad that things turned out okay. With quoted runtimes of 170 hours on low and 16 on med, I just didn’t think that he would ever drain the batteries all the way down in just one night. I guess he couldn’t resist the turbo. I was surprised how different the terminal voltages were. I’m pretty sure they were well matched when I put them in.

What about lending out lights w/ nimh’s? I always thought that was pretty safe. I don’t think alkalines would cut it and lithium primaries are too expensive especially for extended camping/trekking trips. I would think it would take multiple reloads. Now I’m even getting paranoid about non-flashaholics using multiple nimh lights. I know which would be safer for the average user, but which would be better to use and better for the health of the batteries in keeping with the original idea of this thread in the event of (accidental) overdischarge: a multiple aa light like the Jetbeam PA40 and Quark AA2 or a single 18650 light with, of course, a protected cell. Keep in mind the circumstances (long usage time without ability to recharge) and the fact that I hate overdischarging any kind of battery without the ability to immediately recharge it resulting in leaving it in an overdischarged state for possibly up to a week. Which is the lesser of two evils? I would assume nimh is always safer and more resilient. Is there any way around this problem besides single aa lights (which may be inadequate on nimh) or lights with low voltage warnings? Or am I answering my own questions?

Wow! I am really long winded when it comes to posting. I’m really not like this at all in person… weird. I couldn’t imagine spending more time on BLF than I already do, but this posting business is really time consuming. Maybe I’ll just go back to reading and lurking…

Never lend hi-quality worked hard to acquire expensive stuff to anybody when ya got decent-enough-equal-enough-idiot-proof-cheaper-stuff to lend them so that when they break it, abuse it, or lose it, nobody gets upset and ruins the friendship which ultimately is the most valuable thing ya needed to worry about to begin with if ya have any common sense.

So if any of you wanna borrow my Ferrari, take a hike. :open_mouth: :stuck_out_tongue:

Yeah I agree. Friends over Flashlights! Would that be blasphemy here? :open_mouth: That’s why I gave up the good stuff in the first place. If I lent him weaker lights, I don’t think he would have been able to spot the wildlife that he did.

But like I said earlier, its just batteries and flashlights. It’s all just temporary stuff. Doesn’t even start to compare to a random person/stranger, let alone a friend. I don’t think he has anything to worry about in terms of our friendship regardless of what happens (as long as one of my flashlights doesn’t blow off his arm. In that case I should be the one worrying…) :~ All this other stuff is just me and my incessant flashaholic OCD.

5 Sippy 68 $6 clones wrapped in velcro ribbon and he’ll be able to spot 50 civets and a partridge in a pear tree.


Unfortunately, that probably would have taken about 3 weeks if I had tried to go that route. Also, remind me never to borrow a car from you. :wink: I wouldn’t mind hitching a ride though…. to lightstock of course.

+1 But if you do give out Li-Ion flashlights, only protected and only single cell lights.

Welcome to BLF, lateotter.

I'll second Betweenrides I only give/lend out single cell lights. I generally don't bother with protected though as not much can go wrong with a single cell.

While having 1 cell at 3.6 and the other at 0 is dangerous it does happen and rarely will lead to an explosion. This is the second documented case of what should have lead to reverse charging but didn't. (The other one being mine) I think even good unprotected cells will not reverse charge. My current theory is the thermistor in them (magical little thing ) will prevent them from reverse charging because they would heat up from that. The real danger is the crapfire cells.

Thanks for the welcome. I’ve actually been following this forum from way back in the day, circa the introduction of xp-g when BLF was on the old domain. I don’t remember why I registered last year, and still don’t know why I started posting recently. But I’ve definitely enjoyed my time here, even as just a lurker.

If you are right scaru, I’m glad I was using quality panasonic cells, if that was indeed the reason my friend didn’t get his hand blown off. All of my unprotected 18650’s are either panasonics or samsungs. What brand did you have in your DRY during your incident?

Sanyo 2600 mah 18650s.

I ran 4 eneloops flat in my PA40, I left it on all night til it was moonlight mode.

Then when I cycled them they only held about 1800mAh, but after the break in mode they were just under 2000mAh again.

As for remotes and clocks etc, I don’t think eneloops are good for low drain devices.

For some reason, I put batteries in my Wii remote and don’t use it. Weeks later when I go to use it they are flat. I don’t know what to do about that other than take the batteries out every time but thats a pain in the butt.

I think Lumatic hit it spot on with his posts +1…. :bigsmile:

Did you happen to check voltages? When you say flat, does that mean ~0.9v or closer to 0v? Which charger do you have? Did it have any trouble recognizing and charging the cells? My Lacrosse charger will refuse to charge if the voltage is too low.

I hate loaning out flashlights because people don’t understand them. They don’t realize they aren’t a $10 flashlight from the supermarket. But I do have a few sk68’s for loaning out. They are great for kids too. This one family I know got their kids Minimag incans, probably 15-25 dollars. The kids lost both of the lights after 2 or 3 weeks. I’m gonna try recommending the sk68 due to their cheap cost and effectiveness.

I don’t remember but I was worried about the batteries at the time so I would say it was something not good for them, I made a post about it somewhere on here asking if I killed them. Ill see if I can find the post but I doubt it.

Letting non-flashaholics borror your lights will ultimatively lead to deep, sad, and lasting disappointment of one kind or another.

First you’ll have to keep inquiring about your property repeatedly, and when you finally get your torch back, it is either smeared with cooking fat or chocolate, or the ano has been scuffed in places, or clip bent out of whack, or the lens scratched, or any combination of the above. Oh yes, and cells are usually seriously dead.

I still give away lights as gifts sometimes, but I do not lend somebody any of my own personal ones anymore.
Don’t lend out - make someone a nice gift, instead! *- and save yourself the hassles of having to deal with depleted cells, worn ano, dinged battery tubes, once well-maintained and greased threads now dull and binding from dirt and sand, punctured tailcap boots, missing maglite switch covers, … I could go on for quite a while.