Have you seen this type of counterfeit 18650 battery before? UltraFire

5.7v? Thats much too high. Its dangerous. Put it in a metal cash box (ends taped) or outside.
What charger did you have it in?

It would not be two 16340s together (in series).

Any one know anything about the Ultrafires being sold by Battery Junction? For most things they seem to be a major web seller and I know that they are a dealer member of CPF. The listed capacities sound reasonable so are these the genuine article, the mythical “genuine Ultrafire” batteries or more total junk?

Even 4.5V is dangerous for a 4.2V cell, especially if you start hitting the cell.

Yeah must be in series to get that voltage, but that would also mean there are 2 empty 16340, 5.7/2=2.85V

The lesson I learned is that its very hard to trust batteries with “fire’ in their brands. I have a good Marsfire 26650 (marked 5000 mAh but does 4321 mAh in my tests) which I bought from DX. All the other ‘fire’ cells that I have, however, are best thrown into the fire.

Never charged it, bought it locally with a cheap but fairly powerful “q5” flashlight. So i guess the led in that is overdriven to hell? I does warm up but nothing abnormal. Also throws like a champ since it’s a zoomie.

Dealer member of CPF means nothing. Just throw some money at CPF & you can be one too.

I have posted several links to US and German dealers on EBay that sold huge numbers of nonexistent capacities, why have they chosen to sell those? I do not think they are oblivious to the reality like some people said, nor I think they should be taken seriously just because they are in US or Germany.

As technology advances Ultrafire cells start to make more sense to people but they do not realize that when the top cell was 2900mAh Ultrafire still had cells claiming 3500mAh.

Is it a single battery that measures 18mm diameter by about 65mm long?
Picture?

Are you sure it's 5.7V? MCU should have issues at that voltage (like die), cell could blow up at any time.

So we can have HKJ's latest Ultrafire 5000mAh review linked here too. You get 1000mAh at 3A load and 600mAh at 5A load, not to mention possible issues with such cells.

Test/Review of UltraFire TR18650 5000mAh (Blue)

There you go. I know, not the most glamorous DMM.
pic 1
pic 2

Try a new battery in your DMM.

Is that the only cell you have that shows an out of spec voltage?

If other cells also aren’t measuring right, try a new battery in your DMM.

If that one is the only cell that shows a bad voltage,
Seriously
tape the ends of the cell AND put it outside in a metal box and read up on what to do about it.

When the reaction rate of the electrolytes increases, it continues to increase;
there’s a problem with the separator between the chemicals that can only get worse.

once that starts to happen that cell’s dangerous.

NOTE that page at batteryuniversity keeps being improved.
If you haven’t read it recently, check it again.

” What every battery user should know

A major concern arises if static electricity or a faulty charger has destroyed the battery’s protection circuit. Such damage can permanently fuse the solid-state switches in an ON position without the user knowing. A battery with a faulty protection circuit may function normally but does not provide protection against abuse. …I would caution against using an unidentified lithium-ion battery from an Asian source …”

Thank you.
Of course it was the battery in the DMM. With a fresh 9v it now shows 3.7v on the Ultrafire. Thank you.

its a sad mentality of those sellers/manufacturers who continue to make so many fakes of an already crappy brand that is known for so many fakes and counterfeits. its probably because of the zillions of un-aware & uneducated buyers who buy these dangerous crappy fake cells thinking they are getting a great deal.

great.now lets get you pointed towards some decent batteries and a charger.those $1.50 ebay ultrafires and noname potentially dangerous chargers gotta go.
since it came with a cheap light i would expect both to be crap.laptop salvage cells are 10x safer and better!

“… Fire investigators say that when the e-cigarette reached its charging limit, it overheated and shot parts everywhere, including onto the furniture.

“It blew the end cap off and blew fragments off and on to the couch and ignited the couch in the house,” said the county fire marshal.

The more we catch wind of these stories, the more clear it becomes that the e-cigarette industry needs to make some important changes. Designing devices that can charge and then shut off when they’re full so they don’t overheat would work, but until manufacturers get around to doing that, never leave a charging e-cig unattended and unplug it as soon as it’s done charging.

Barring that, even a simple warning to consumers on the packaging would be the responsible thing to do. If my hair dryer tells me not to drop it into the bathtub full of water, surely companies can advise consumers how to safely operate their cigarettes….”

Manufacturers don’t care. Throughout history, companies have never cared until they are held responsible.

Yeah I’ve got like 18 laptop pulls and I’ll borrow a buddy’s Accucell to see if I can revive them. Too scared to use some Catchonfire charger.

If the voltage is too low its best to trash them instead. Low voltage causes internal damage. Options vary on the cut off point for trashing a low voltage cell. Some people would rather take the extra risk then toss the cell.

I would toss anything below 2.5v.
Also unprotected batteries such as laptop pulls should only be used in flashlights that have low voltage warning.