I'm hoping someone might be able to tell me what's going on here. This afternoon I took out a couple of lights just to play around with. One was one of the costco 150 lumen tactical ones and the other was a nebo redline. Last time I used either of them was maybe two weeks ago and they both had relatively new batteries with maybe 15 minutes of use. Both of them run on three AAA batteries. I have regular Duracell alkalines in them.
So today I pull them out and I turn on the costco tactical light. It comes on at a very dim level then fizzles out and turns off in about 2 seconds. I initially thought that maybe I had accidentally put it in the drawer still turned on and the batteries died. Then I take out the nebo redline, turn that one on, and the same exact thing happens. Now I'm completely stumped.
I then put brand new batteries in both of them, tried again, and now they both worked perfectly. hrmm......
Next thing I did was test the old batteries with my DMM. Here's what I got - both lights had the exact same results. Two out of the three batteries were fine and one out of the three was dead.
The two good ones gave me a voltage reading of between 1.38 and 1.4. The dead one read about 0.3. I got almost identical results on the batteries that came from both lights. Each light had one dead battery and two perfectly fine ones.
Now, I've heard that some lights have parasitic drain and pull a little bit of current even when they are turned off, but is it possible that something like that could drain only one of the batteries and leave the other two completely untouched?
Or is it possible that each light coincidentally ended up with one bad battery in them?
Get lights that take lithium?..... Seriously though it happens to me with other things as well. I have a battery powered soap dispenser with 4 aa's. It seems to drain one battery more than others.
Ok what gives?!?!?! Tonight while I was walking the dogs I noticed that my trustfire Z5 which runs on two 18650 batteries was getting a little dim so when I got back I checked the batteries with my DMM. One of them read 3.6v, the other one read 0.26v. Why are the batteries in all of my lights discharging unevenly?
Aren't the batteries supposed to discharge evenly? Why is this happening on all of my multi-cell lights? And isn't it supposed to be dangerous to have two 18650 cells that are at completely different charge levels in the same flashlight? What's going on here??
Also, is it safe to recharged the battery that discharged to 0.26v? I thought it wasn't safe to let these get below 2.5v. I have it on the charger right now but am I risking blowing it up or something?
Ok, have some more info. I tried charging the 18650 that was reading .025v and it won't charge. The status light on the charger looks like it's just a solid green (I'm assuming that's what it is....I am colorblind and have a hard time telling the difference between red and green LEDs but I put the other presumably good battery in the charger by itself and the light seemed to turn red, or at least it was darker and looked like a different color, so I'm assuming it's red and that one is charging.) I also checked the bad one with the DMM after it had been sitting in the charger for a couple of hours and it didn't pick up a charge.
So, it looks like one of my 18650 batteries has died an early death. Hell, I just bought this thing! Is there any way to revive it and get it to charge again?
The 18650s I have right now are unprotected. They are the blue ultrafire 2400mAh ones that came bundled with my trustfire Z5.
Would a protected battery not have died like this? What can I do to prevent this? Was it just a bad battery and things like this happen from time to time?
And I'm still mystified as to how the exact same issue happened on three of my multi-cell lights. One battery discharges completely and the others hardly lose any charge at all.
At least AAA batteries are cheap. 18650s, not so much, and if one discharges too much, it's ruined. If this is what I have to look forward to with 18650 lights, I think it's gonna be a very short lived hobby for me.
I would not recommend charging an unprotected lithium battery that you've discharged as low as even 2.0V. It is dangerous to recharge them at that point, possibly resulting in a fire or small explosion. Certainly don't charge such batteries while not in the room or next to any flammable materials.
Protected batteries are supposed to cut the circuit at around 2.4V +/- (though sometimes the protection circuit fails to do so, especially at low current draws). Most recommend stopping using them a bit before the protection kicks in, but relying on the protection is certainly better than letting it get all the way to 0.2V! Many midrange or high-end lights have undervoltage protection built-into the driver, but it relies on your cells being matched in charge/voltage to work correctly. I'd verify your charger is working well by checking the battery voltage after the green light comes on. Protected batteries might read 0V after the protection circuit kicks in. In that case, your charger will reset the circuit and get the charge flowing again through the battery.
Bundled batteries have a reputation for being unreliable, so maybe you just got a dud or two. It has happened to me even with midrange batteries like the Trustfire flames.
Wait a minute.. Are you saying that someone is selling UNprotected batteries together with a multi-cell light? That's so dangerous that it should be illegal!!
No, if the protection works normally.
Just buy GOOD protected batteries like XTAR 2600, especially for multi-cell lights, and you will be both safe and happy.
This is what I have. http://www.ebay.com/itm/1600-CREE-T6-LED-Bike-Bicycle-Light-Flashlight-Torch-K4-/300603005767?pt=LH_DefaultDomain_0&hash=item45fd55db47
I don't see anywhere that says these batteries are protected.
So is there any way to revive this thing? I've tried leaving it on the charger for a little while but the status light on the charger just stays green and it doesn't charge it.
And anyone have any ideas as to why on all of my multicell lights, one battery discharges but the other ones stay almost fully charged?
Most likely, you have ruined or dud batteries. The way to test that theory is to try two known working batteries in the same light. If an unprotected battery was used in the light until the light died, the battery is most likely ruined, unless the light's driver has a low-voltage safety cutoff. Once a battery is drained that low, I'd just dispose of or recycle it. It is fairly common for inexpensive/bundled batteries to be unreliable and not matched in capacity/voltage. I've received new batteries that were just plain DOA, and that might have also happened to you.
The other less likely option is a malfunctioning charger. To test that theory, try another working charger from a friend, etc. That test is a little dangerous with a battery drained so low, so I can't really recommend it unless you watch it closely and monitor the battery temperature. Many intelligent 18650 chargers will refuse to charge batteries drained that low, since it can lead to fires. The general suggestion here is to get a decent charger (Xtar WP2, etc.) and some decent protected batteries (Xtar, Hi-Max, TF Flame, etc.) to start with. They aren't that much more expensive than the unprotected Ultrafire batteries and more generic charger you have, but they are a lot more reliable/consistent. It seems odd suggesting more expensive gear on a budget forum, but in this case I think most everyone would agree it is worth the few extra dollars, since a charger can last for years, and mishandled or malfunctioning lithium batteries can be a safety issue.
It is very unlikely the flashlight is at fault, unless there is some kind of short in a battery cage/tube that somehow only affects one battery yet still allows the light to function, but you can inspect the battery area and springs for debris, shorts, loose wires, bad connections, loose solder blobs, etc.
Here's a possibly stupid question. It looks like the battery is definitely dead. I've had it on the charger for almost the entire day and nothing. It's stuck on about 0.5v and not even getting warm.
Now, the two batteries that came with this light are the only two 18650 batteries I have. Can I still put this one in the light along with the good battery so I can at least run the light with one battery and have the bad one act essentially as a spacer, or am I risking an explosion by doing this?
From what I'm able to figure out, I was most likely running the light this way for a while anyway without any problems. Since the other battery wasn't discharging at all until this one was fully discharged, it seems that this one was discharging and eventually running with almost no charge while the other one stayed charged.
hrmm...I think instead of new batteries, or rather in addition to new batteries, I should just get a new light and stick to single 18650 cell lights. These multi-cell ones look like they require way too much attention to use safely.
I currently have a UF-2100 on the way from DD. I was hoping to at some point get one of the trustfire 3-xml lights but I'm having second thoughts about it. But I do want a super-bright light. What's the brightest single 18650 budget light out there? I prefer a floodier beam.
I'm using multi-cell lights and consider them "pretty safe". But here's my approach to them:
Prerequisities:
- a DMM (almost any will do)
- decent batteries (I use mostly XTAR 2600, even some Trustfire "flames")
- good charger (for example XTAR WP2 II)
Safety measures:
- measure the voltage of batteries
- when you get them (trying to match pairs - and keep them paired)
- before charging (making sure they are not dead, but remember that 0V reading from protected is ok)
- after charging (check that they are not overcharged)
- before inserting them to flashlight (check that the voltages are equal, for me 0.02V difference will do)
- after use (if the voltage is way different, try to match a better pair)
- keep "known good" pairs together (and don't use them one-by-one in other lights)
- dispose (/recycle) any malfunctioning cell
In case of emergency (haven't done this for a flashlight, yet - but for RC car batteries), meaning that if you hear any strange noise from flashlight or it gets uncomfortably hot:
- try to turn it off quickly
- back off (or throw it to "safe" place)
- if noise stops -> wait some time, let it cool down properly, then approach the flashlight and check batteries etc.
Whether this is "too much attention" or not, well, it depends.. I like powerful multi-cell lights and am willing to take the above mentioned steps. Actually it doesn't even bother me at all.
But then again: I wouldn't suggest multi-cell lights for any new flashaholic. There's much to learn and enjoy this hobby even with single cells.
For a good, a bit floodier single cell 18650 light I would suggest KD C8. Great light, good value for money. Just used it as a bike light for my 20km ride during morning twilight. Suits well also that purpose. :)
Bro, those packaged blue cells (ultrafires?) are JUNK. I got a pair with my X9 and both of them discharge about 2-3V a day. One discharges faster than the other. I am pretty sure (based on other posters) these are crappy salvaged cells. I mean really crappy since I have about 12 good salvaged cells and know that salvaged laptop cells can work nicely. I will eventually take the cells apart and verify myself.
Try a Keygos Ke5 (ke-5). I just received mine a couple days ago. (will do a writeup soon) With a 40mm reflector it's supposed to be a thrower, but compared to my X9, I find the beam pretty floody at distances greater than 20 yrds. It can be had for less than $25.00 on ebay.
And based purely on reflector size, the TF-2100 that dinodirect is offering right now seems like a great floody light. It's only $15.00 too. I should be getting mine soon. (hopefully)
If you have 2 good cells that have similar capacities (and charge state's) you have really nothing to be concerned about with 2 cell lights. It's only if the cells aren't matched that you encounter problems like in the links above. So why not use your nice $35 light and get a pair of Xtars ($13.50) or Himax ($12.00). I would get some good cells before buying another light, since you will need good batteries anyway with another 18650 light.
And don't all cells in series have this problem of 1 cell being more discharged? This is why I never run down a battery pack or multi-cell device. I only use to about 50% and recharge. Laptop batteries do this. RC batteries do this. My Audiovox handhelds do it (4 AAA's). Just don't run down 3 or more cells to the end in any device. You should be ok.
Tenergy 2600mAh, pack of 4 for 14.99 shipped. They ship from the US so I'll have them in about 3 days or so.
On the thread in the batteries forum someone said they were decent and from what I could tell in the review, they are ok. I hope they don't blow up on me.