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3.7 out of 5 stars350
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on 6 February 2014
The batteries I received (from "Topwell") are red and grey (as in the current picture), say UltraFire on them and are labelled as 18650 and 3000mAh (no space).

I was surprised at how light they felt so I weighed them. They were 33gms whereas some older 18650 batteries I have are 46.5 gms.

With some NiMh batteries I find it is common for sellers to claim a high capacity where the batteries are actually of low capacity - and have a correspondingly low weight compared with good ones.

Does the same principle apply to Li-ion batteries?

To find out I made a test circuit (discharging though an ammeter and a 2.5 Ohm resistor) to measure capacity. As a control, I also tested one of my old 3860 batteries ("Asucell" and labelled as 3000 mAh and I measured the output at 2853 mAh - quite good for a well used 18 month old battery I'd have thought.

I then tested both of these Fire batteries and the capacity is showing up as just over 800 mAh - so less than 30% of that claimed.

I gather that one of the operations of the protection circuits in Lithium ion batteries is to prevent damage caused by discharging below 5% of capacity. I noticed that the old batteries I have cut out when voltage got too low - presumably the circuit is working, whereas these "UltraFire" batteries did not cut out so I wonder if they have any protection circuits at all.

Lithium ion batteries can be dangerous. As the 3000 mAh label is a lie, don't trust the "protected" label.

Avoid.
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on 11 May 2014
Arrived in good time. Packaging was fine. Put on charge, it didnt fully charge after hours, I did some research and found that these batteries where taken from used laptops, repackaged and resold... and on top of that, they didnt fit in the device I have.
Contacted the company, they gave me a full refund on return of the items.
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on 25 January 2014
I bought six of these and only two of them work

The rest don't charge properly.
Too good to be true.
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on 16 October 2013
They work but after testing them they are not 3000 mah. I would choose a different make next time due to this as it's false advertising
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on 17 November 2013
I found the capacity of these to be nowhere near the 3000 milliamp claimed, out of curiosity I 'unwrapped' them to see if the true value may be marked somewhere, no markings but what I did find beggars belief, they're repackaged secondhand cells!
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on 28 August 2014
Beware of Ultrafire labeled products. If you look on line for' fake Ultrafire batteries' you will be surprised at what is being put on the market. It is possible that a genuine Ultrafire product is reasonable but can anyone, even importers, tell which is fake and which is a genuine product.
The one that I took to pieces was full of what looked like proper cell material, no chalk packing, but what was supposed to be the safety over charging / discharging device inside the cap did not a look genuine piece of kit. Dont try this indoors or if you dont know what you are doing because even a battery that appears dead flat can still have a considerable charge if the internal safety device has operated or failed, which means that dismantling could cause fire, injury or contamination. Measuring the amp hours of lion cells cannot be done reliably by discharging with a lamp or similar load whilst measuring time and current because it will discharge below the threashold voltage of about 3 volts and the cell will be damaged or un recoverable.
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on 10 May 2014
Terrible purchase ' batteries are utter crap one of them blew up nearly hit my face as I was using it in my e-cig mod ' from the time I got them they where in the bin with 40 mins
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on 29 August 2013
I bought a cree headlamp to use when cycling to work realising it did not come with batteries i orderded two 18650 batteries as recommended I charged them the first time i used it the torch was great.Five days ago i charged the pack up only for three hours On leaving my property for some time came back to find the pack had exploded an caused asmall fire on my kitchen worktop how it did not cause unthinkable damage or injury i will never know I thought you would like to hear this and forewarn others Is there any way these could be replaced
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on 16 October 2014
My 2 year old blue Trustfire batteries have started to lose a bit of capacity, meaning they lasted about 4 hours in my flashlight when new and now only about 3 hours. Thinking these would be good replacements I ordered two. These new batteries seem to charge but last about 15 minutes before my flashlight starts to fade and begins to just blink dimly.

I'm not much of a load testing amperage metering battery tester sort of person, but I cannot possibly recommend these batteries to anyone for any reason. To put it short, these are junk. Possibly a "bad batch", but both batteries I received are equally bad. Ultrabad.
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on 22 October 2015
These batteries are rubbish! I have to charge them for over 24 hours then they last about 5 minutes, literally!! I wanted to return them as they are not fit for purpose but this was denied because I bought them at end of August. There doesn't seem to be an email address to contact Amazon so I am stuck with these rubbish batteries. I took my dog out in the dark with the newly fully charged batteries and after 5 minutes of walking the torch just stopped. I had to walk home in the dark - very dangerous as motor vehicles would not have been able to see us had any come our way. The batteries obviously do not hold the charge. My advice is: DO NOT BUY THESE BATTERIES.
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