Anyone else besides Aleister reported issues with this cell?
I've had mine for a few weeks now and been using them quite frequently. As I recall I've discharged 4 of them and all came out around 2600 mAh. Other than the lower than expected capacity I thought they were fine especially for the price. I originally bought the TFs to be used in the DRY but ended up using Hi-Max instead. Reason being was that I had 6 Hi-Max to choose from based on their discharged capacities. Of the 4 TF, the capacities were all quite different +/- 50 mAh or so.
hi guys,
I just found out that 1 of my trustfire flames 3000mah 18650 cell is getting ever hotter when charged. Its feels just about too hot to touch. I have tried chargers like xtar mp1 and wp2 II,But its still as hot. I dun have a hobby charger so i dun know its capacity. Though it ran brightly about 1.5hr in 1 of my 1.25amp xml light.
Any suggestions? should i dump this cell?
Well I'm charging it with my Xtar MP1 right now n its showing 46.1 degree Celsius on the Ex cheapo thermometer,and at 4.1v. Got this cell from DinoD*****.
This symptoms started after I charged it by my Hp touchpad USB wall charger.
I highly suspect it outputting more than 5v Bcos my wp2II can't USB charge my touchpad due to insufficient voltage.
This quote from Shadowww is incorrect. Cells charging each other in parallel can absolutely lead to explosion. There is afterall, no current regulation that prevents the discharge rates of the higher voltage cells or the charge rates of the lower power cell from being far, far exceeded. Consider what would happen if you were to load a 3-in-parallel cell light with two fully charged cells and one fully discharged cell.
Be weary of non-experts (or non-validated experts, or selfproclaimed experts) dispensing safety advice in unmoderated forums.
I still don't own any multi-18650 lights because of my phobia re: explosive Li-on's.
But my laptops all have them and I can't remember reading about anyone with a laptop going infertile because his battery pack exploded on his lap.
If it was not for the 'waterproof' factor, our flashlights would be safer if they had a small hole drilled in them allowing them to vent off interior pressure.
Actually nothing, I just tried doing it with two charged Sanyo 2600mAh’s and one discharged one, surge current was ~5A but it quickly dropped off to 2A (which is under 1C for a 2600mAh cell).
Also note how with parallel cell configuration things can only go bad while putting cells in, and not when cells are already sealed inside a potential pipe bomb (like with cells (of unbalanced SOC) being connected in series).
Your example also involves user error - so it's not really good example at all. Getting explosion by using multiple cells in series doesn't requires any user error, all it requires is protection circuit being crappy/broken and cells not being perfectly matched.
For non hard cased LiPo/Li-Ion batteries there is, any RAPID swelling of the batteries during charging or discharging can be a sign of imminent failure.
My biggest mod light was powered by an 8s2p LiPo battery pack, 10Ah and 33 volts, running 1150 Watts into a 1000W sealed beam filament lamp, producing around 28,000 Lumens. Lamp life expectancy was only 10 hours when overdriven.
I am not disputing the fact that unbalanced cells in series is dangerous, or even that it's more likely to be dangerous than a parallel cell configuration. I am calling into question the statement that "The charging that occurs in parallel connection is not dangerous..." By your own example, in a controlled environment using test leads and good cells, the charge rate was initially 4x the recommended rate (if the capacity of the cell is actually as rated), and then settled in at ~2x the recommended rate. What do you suppose those rates would be if the cells were in contact with each other by the short sheet metal contacts of a high drain carrier instead of using leads, and the discharged cell was say, a lower capacity xxfire cell that had been overdischarged, had high internal resistance or was degraded in some other way?
I think my example is a good example because it involves user error. Generally speaking, almost all the battery catastrophes that happen, do so as a result of user error or user inexperience. Blanket statements like "it's not dangerous, period" lull inexperienced, unsuspecting people in to a false sense of security, and that's when accidents happen.
We're dealing with devices that expel deadly hydrofluoric acid when things go wrong. Better to dispense overly cautious advice than the opposite, don't you think?
Basically -- might could maybe be some clues but no certain warning that you can wait for before taking precautions.
The only one I've had go bad just wouldn't charge, so I set it in a metal tin -- wasn't warm, nothing apparent.
A few days later I remembered and put a lid on the tin. No sign of problems, just being cautious.
A while after that I took the lid off and the battery had vented, stains outside the vent holes at the positive end.
Why the delay? Something about slow growth of crystals that eventually penetrate a membrane and then stuff mixes rapidly putting out gas and heat once that happens.
The initial surge was at just 2.5 times the recommended charge and it settled at just over the recommended charging rate (1.7A per Sanyo datasheet), although I doubt that even 5A is anywhere near “deadly” because I often charged those cells at 6A when in hurry.
Also, if those were crappy cells with high IR, it'd actually be even safer, not more dangerous like you are implying - because, due to high IR, full cells would quickly sag in voltage / empty cell would quickly gain in it, resulting in way smaller current flow. Should I test it for you with old, worn blue Trustfires? :P
Oh, by the way, there's way worse user error can occur with parallel installation - putting one of cells in reverse directions. I wouldn't test what happens even in controlled environment ;)
5V (±5% based on USB specs -> up to 5.25V) at approximately 2A is not nice for any Li-Ion cell expecting to receive around 4.2V. It's no wonder if it got some internal damage during charging with that!
if its rusty , bulge from side, any burnt smell chuck it .. always charge it away from where u are and inside a box these are like little grenades when they go off ;P
