I went to use one of my chargers and found the sliding positive tip was loose with no tension. It wasn’t like that when I last used it, so it apparently failed while not in use. Here’s the back of the non-branded, single cell charger.
This may have been very fortunate. I was somewhat surprised to see that the negative blade and positive current through the spring end were perhaps a millimeter apart with nothing but air separating them. A very slightly bent negative could easily short the spring while it was connected to the positive lead.
When I took it apart, I found the post that the non-moving end of the spring was hooked to had broken off. Note that in this picture, the spring is now hooked to one of the screw holes instead of the post which was formerly between the two screw holes.
And here is the board inside the charger. This one would overcharge a couple hundredth of a volt if left on past the light changing to green.
I mostly use a ML-102 when doing single cells, but I’ve kept the cheap one for small cells. Not a big loss as pennies worked fine as spacers.
I had a cheap one break on me. The part that broke was the piece of plastic the tensioner spring was attached to. It was a thin flimsy piece- at least that piece looks beefier.
In my opinion - none! These cheapo chinese chargers are dangerous and should not be used for anything but project parts, or alternatively, showing others how poorly made they are. Some might say that there are some good ones, but the majority are poorly designed and manufactured. If you're buying good cells, why not buy a good charger?
I dont know about that gross generalization, Trustfire TR-006 is reliable and consistent and pretty cheap, I have two of them working every other day to daily for almost 6 months with no issues. They do charge to about 4.14-5 and the other 4.16 instead of 4.2 consistently, but that only helps to extend battery life.
*edit: of course this doesnt apply to those super cheap ones above, I have some too I used once and put aside. Only addressing comments saying the $10-15 TR006 is too cheap.
Some pretty bad reviews of the tr-006 on Amazon. One fellow bought three and only one worked, and only on 12v DC. Another fellow was so unhappy he called his a POS.
You're right, its dangerous to generalize. But in this case I would rather be safe than sorry. Aside from poor materials, bent sliders and other physical defects, these very inexpensive chargers are often poorly designed and do not use a proper CC/CV charging profile.
They often do not have sufficient isolation between the high voltage AC section and the low voltage DC parts - parts that you will be touching with your hands when the charger is plugged into the AC power.
They seldom terminate correctly and will continue to trickle charge the cell. This is bad because over time it damages the cell and increases the likelyhood of a vent with flame.
Note that what is important is not the voltage that the cell is charged to (comes off the charger with), but rather the voltage that the charger applies to the cell while charging it. Cells age with time and one of the results is that the cell will no longer accept as much charge, and if charged properly, it will terminate at a lower and lower voltage as it ages. If your charger is detecting this and allowing the cell to say "I've had enough" then it is doing its job.
The cheap chargers that do not terminate properly may go on charging the cell, trying to force more current into it and causing invisible damage in the cell while doing so. This is dangerous because you can't see that the cell is becoming less stable and more prone to having a catasrophic failure. If you don't know what I mean by that you may want to search youtube for "lithium fire" for some rather eye-opening videos.
If you would like more information about the poor quality of some of these cheap chargers, have a look at some of HKJ's charger reviews: http://lygte-info.dk/
Please understand that I'm not trying to knock your charger. Yours may be doing a good job for you. But while we play with cells that can be reasonably safe when handled correctly, it is easy to forget that they contain a lot of energy and can react violently if mistreated.
Well, yes you are right in general. But, with these chargers, several things: first off the Amazon average is 4/5 stars over just 9 reviews, and I know some of those negative claims are really odd and wrong for the chargers I have (working off 12v?, only charging with two cells in it?, not fitting snugly?). From my research and from people’s comments even on this forum, some are found to be built to run off 240/220 and not 120, and Chinese sellers are notoriously not “careful” with this kind of stuff (shipping the wrong plugs etc), its very likely that the wrong unit was shipped and that there are 220/240V + 120V +12V DC versions around (also thereby eliminating just about all the low reviews in one swoop—>seller not product issue).
What I know for certain is this: for several months I tested 26650 (some 18650) batteries every time as they came off the charger, and leaving them in extra time does not seem to increase voltage when I tested this, so trickle overcharging does not seem to be an issue (I generally take them off once finished quickly though). They charge very consistently to between 4.14 - 4.16V, and I have not really seen any decrease over about 6mo of use with TWO chargers going each time.
Its possible I got “lucky”, but with 2 of them running almost every other day with no issues, and experience (positive) with a third, I think thats highly unlikely and 220/240V versions shipped instead of 120 and/or some “copycats” is more likely.
Also note when I do use them I have safety in mind and never completely “trust” them, and using what I use without caution like I do I wouldn’t recommend: I am always around when charging, I take cells off very soon after they are done (very rarely would a cell get more than an hr sitting with a green light in the charger), and I semi regularly check voltages before and after charging. I actually would prefer a 4x26650 charger if one were available (or at least 3x26650), but the chargers I have seem to work perfectly so far with lots of use.
…I really thought I found an informative review of this charger before somewhere too and cant find it now….I’d love HKJ to review it.
It won't, because once fully charged, the cell cannot accept any more charge. But if the charger has not fully terminated it may still be applying a voltage to the cell. If so, it can cause plating of metallic lithium on the anode. This is invisible, can not be detected by a DMM and is dangerous because as it accumulates over time it causes the cell to become unstable.
This is where the problem is. Doing it once or twice likely won't be a problem. But if it happens repeatedly the cell is being damaged as described above.
I beat this subject to death a couple years back, so I won't do it again. You can even do a simple practical test to see if your charger is continuing to apply a voltage to the cell after termination. See this post and some of the discussion prior to it for more info.
Yes, I’ve heard this before, but this is where you are wrong in this case, the cells can accept more voltage at 4.14 to 4.17 range, at least to 4.20 — the charger stops at these sub 4.2 voltages, not the cell (I’ve tested this on several 18650s, they also come up to the same range, but after transfer to my Xtar wp2 they increase to 4.2V, so it is the charger stopping charge and I should be seeing an increase in voltage if it does keep charging).
I remember while testing laptop pack pulls, noticing one cell dropping to 4.13 and being recently off the charger about the same time others and then remembering I started that charger earlier. So I attributed that loss to sitting on a “finished” charger longer…but I’ll check more officially today, its still a good idea to test officially for a longer period.
Tks photon its always good to check your charger out thoroughly. I did want to note too that after responding about my theory there are 3 versions of this charger that are not labeled, and that this is what causes a lot of “POS it doesn’t work” complaints, it occurred to me to show others that may consider the TR-006 that there is some deductive “proof” of the “3 versions” as well: the TR-006 charger has an input cord which is not permanently attached. There is a “flange” on the input to charger plug on one side only, which would allow the cord to be plugged in one way only. The input cable on mine however does not have this flange, so it can fit in either side, and, this should not really matter if you are dealing with AC, however…if you are dealing with DC in some cases it WOULD matter. This coupled with the reviews stating some chargers work on 12V DC indicates there IS a DC version and either seller inattention or mislabeling causes some to be sent out the wrong model. Also, there are several reviews over other sites (and this one) saying the charger did not work, but when they sent it back the seller said it works fine: this indicates there probably are 240/220V charger variations as well as 120V, which also get sent out sometimes to the wrong recipients.
So, it appears the TR-006 is actually has 3 versions: 240AC, 120 AC and 12V DC. And it is either disorganization on the seller’s side, or poor marking on the manufacturing side that causes people to receive the wrong model, and causing negative reviews, no matter what the reason is.
**If anyone knows how a charger could be “configured accidentally/poorly” with the same parts used to run on 120V, to instead suddenly work only on 240AC or 12V DC, please tell me, I’m assuming this is not possible.
Please note that I said "...once fully charged, the cell cannot accept any more charge." If your charger is terminating early and the cells are not fully charged then lithium plating isn't much of a risk - unless your charger does not really shut off and you leave the cells in the charger. You won't know for sure until you test your charger.
I have a few of these cheap chargers that I got before doing some reading on this subject. I eventually stopped using them because they are so poorly made. None of them shut off properly. But when I was using them, before I got a couple hobby chargers, I watched them like a hawk and never left a room with one running.
Well, it does appear that the TR-006 does not terminate correctly, it actually stops at about 4.10, then creeps up, depending on how long you leave it on the charger, one gaining +0.05 in 1hr, and the one I use more gains +0.09 in one hour. This means I must be pretty consistent in getting to it at around 30mins after it switches off, because I have taken voltages many times, always at 4.14-4.17 range. However, with the way I watch them, this is fine. I have tested the cells on the Xtar charger again, all cells do come up to 4.20, a few to 4.21, so, as long as I continue to pull them off relatively quickly as I always do, so there is no plating effect.
Its not going to change what I do any, but anyone considering them should go by the standard advice: always watch your charger, be around constantly and take them off as soon as they turn green.
Yeah, I assumed it may in the beginning and that’s why I religiously pull the cells within an hr, never got around to the testing part, so its good that I finally did I’m not sure how I kept pulling them at about the same voltage range over a time of 6 months, that surprised me since it really had been many many voltage reading tests and I assumed they had to be 4.14 /- .01 and 4.16/- .01 and it had to be very low trickle charge or no trickle charge. It also makes me wonder if trickle charge is different depending on whether its a direct connection to the outlet, or through a surge protector and varying with how many devices/cables are feeding off of it.
You can even do a simple practical test to see if your charger is continuing to apply a voltage to the cell after termination. See this post and some of the discussion prior to it for more info.