This is another quick review carried out on a single cell. As I have mentioned in other reviews of single cells, it is nice to test cells in pairs, to get some insight in to how well cells are matched, but there is only so much you can tell from such a small sample. If two cells are badly matched, then you have learnt all you need to know, but if two cells are well matched, who is to say whether three or four cells, or even more, would be equally well matched. So while I can't comment on cell matching, we can at least see if this one cell matches it's claimed capacity, and see how well it maintains it's capacity at different discharge rates.
Shilling and such.....
I know that there is some concern in this forum with people testing items that have been supplied by dealers, in case items are reviewed favourably, in order to keep up the supply of 'freebies'. In light of this, it is only fair to state that this battery was supplied for me to test, by UK ebay dealer big_f_d_d.
Fact is that, before there was ever any question of my being sent any cells to test, I was already a customer. I was attracted to big_f_d_d's ebay listings, as for one thing, he was in the UK. He carried a wide selection of different cells, and unusually, provides discharge curves and comparisons of a wide selection of cells. He also offers free shipping, a free box, and the opportunity to return any cells that you are not happy with.
So, if I sound positive about big_f_d_d, it's not because I am benefiting in any way from supporting him, but because having bought several batteries from him, a charger, and an XM-L P60 drop-in, I have been genuinely pleased with his service.
Having once been sent an extra cell to test (along with a selection of batteries that I had bought), I contacted big_f_d_d to get some extra details to include in the write up. Having done so, it only seemed courteous to let him know when I posted the review. In response to that he asked if I would be interested in testing some more cells, and here we are.
The cells will be tested in the same way I have tested other cells, and the measurements will be posted just as they come off the machine - I have no intention of 'massaging' the figures to make these cells look any better than they are. As it happens, big_f_d_d doesn't even have these cells listed on ebay at the moment, so there is no great advantage to him, even if I recommended these over everything else. Not to mention that you could pick these up from any number of other dealers.
Testing equipment
A quick re-cap of the equipment used for testing: -
I will be charging cells with an iCharger 106B+, and discharging and testing internal resistance with an iCharger 208B. Two chargers are used for speed and convenience – one cell can be charging while a second is being discharged (not relevant in this instance). I use the same charger for each step to ensure consistency in conditions between tests, so that results are comparable.
Voltage is measured with a Precision Gold WG 020 multi-meter, dimensions with a Precision Gold digital calliper, and weight with a Neva digital scale stated to be accurate to 1/100th of a gram.
The base of the cell is attached to the charger via a 12” 16AWG cable with a large, strong magnet soldered to it. The positive button is attached via a magnet (if it adheres well) or via a crocodile clip. In this case, the magnets adhered well at both ends.
Results at a glance
Trustfire 18650 3000mAh protected
Provided for testing by Ebay UK member ‘big_f_d_d’
Big_f_d_d does not currently have this cell listed on his ebay page, so I cannot comment on pricing, but it is freely available from other ebay dealers, or the common China/HK electronics retailers – for instance, KD, DX, DD, BIO, BOB, Manafont, et al are likely to stock these
|
Cell 1 (1) |
Storage voltage |
4.00V |
Measured length |
68.69mm |
Measured width (max) |
18.42mm |
Weight |
45.52grams |
Internal resistance at initial voltage |
123mOhm |
Capacity from storage down to 3.00V @ 0.6A |
2019mAh |
Internal resistance after storage charge |
135mOhm |
Capacity from 4.2V down to 3V @ 0.6A |
2455mAh |
Capacity from 4.2V down to 3V @ 1.0A |
2445mAh |
Capacity from 4.2V down to 3V @ 3.0A |
2402mAh |
Capacity from 4.2V down to 3V @ 5.0A |
2186mAh |
(1) This is a single cell provided to me for testing, rather than a purchase that I have made – these cells are normally supplied in pairs.
Construction
The cell has a more brittle wrap than most vinyl type heat shrink. It appears quite thin, and is stretched tightly around the protection board. Quite likely the need for a material that accepts graphics and is metallic leads to the difference in consistency.
As per the photo above, there was a small nick in the wrap. As received, the wrap was crushed at this point, but did not appear to go through to bare metal. Under the heat of the 5A discharge, this nick has split, revealing the underlying cell. The cell also had a small dent in the side, but it doesn’t look to be large enough to have caused any damage to the cells internals.
You have a standard, medium sized button. This appears to be made out of steel – a magnet will adhere to it readily. This should provide compatibility with a wide range of lights and chargers.
The cell has a foil style base over the protection circuit, which will tend to exhibit wear and tear more than a solid metal base.
Light compatibility
Light |
Characteristics |
Fits |
Functions |
Olight M20 |
Wide tube, spring at head, sprung plunger at tail cap |
Yes |
Yes |
SWM T20CS |
Short tube, dual springs |
Yes |
Yes |
Jet IIIM |
Wide tube, tail spring only |
Yes |
Yes |
Fenix TK15 |
Two-piece tube – narrow at head Short tube, short spring at head |
Yes |
Yes |
Fenix TK11 |
Narrow tube, tail spring only |
Yes |
Yes |
Eagletac G25C2 |
Wide tube, sprung plunger at head and tail (minimal travel at the head end), physical reverse polarity protection |
Yes |
Yes |
Nitecore IFE2 |
Narrow tube, physical reverse Polarity protection |
Yes |
Yes |
Charger compatibility
Charger |
Fits |
Functions |
4Sevens single bay |
Yes |
Yes |
Trustfire TR-001 |
Yes - just |
Yes |
Ultrafire WF-139 |
No (2) |
Yes (2) |
Ultrafire WF-188 |
Yes |
Yes |
HXY-042V2000A |
Yes |
Yes |
XTAR WP2 II |
Yes |
Yes |
Pila IBC |
Yes |
Yes |
Jetbeam/Sysmax Intellicharge i4 |
Yes - Just |
Yes |
(2) While the cell is too long to sit all the way down in the cradle of the WF-139 charger, with the cell sat in the bay at an angle, the positive button on the cell makes contact with the charger’s positive terminal, and charging will commence.
Internal resistance
Cell |
Voltage |
Internal resistance |
Trustfire 3000mAh |
4.00V (as received) |
123mOhm |
Trustfire 3000mAh |
3.74V (storage charge) |
135mOhm |
Ultrafire 3000mAh |
3.93V (as received) |
248mOhm |
Ridbatt 2600mAh #1 |
3.74V (storage charge) |
129mOhm |
Ridbatt 2600mAh #1 |
3.74V after initial capacity test (storage charge) |
135mOhm |
Ridbatt 2600mAh #1 |
3.74V all testing complete (storage charge) |
117mOhm |
Xtar 2600mAh #1 |
3.85V (as received) |
139mOhm |
Xtar 2600mAh #2 |
3.79V (as received) |
136mOhm |
Keeppower 2600mAh #1 |
3.78V (as received) |
123mOhm |
Keeppower 2600mAh #2 |
3.78V (as received) |
119mOhm |
Hi-Max 2600mAh #1 |
3.79V (as received) |
153mOhm |
Hi-Max 2600mAh #2 |
3.80V (as received) |
163mOhm |
I have compared the Trustfire 3000mAh with the only other cell I have listed as having a capacity of 3000mAh. The rest of the internal resistance table is bulked out with cells listed as having a capacity of 2600mAh, which seems more in line with the true capacity of the Trustfire.
Conclusion
I'm in two minds about this cell. I'm sure that the little nick in the wrap, and the little dent, where specific to my cell, so I'm not going to worry about that. However, cells that overstate their capacity are a pet peeve of mine. This cell didn't perform badly - if you think of it as being a 2600mAh cell. As a 3000mAh cell, it fell short. It maintained capacity well between 0.6A and 3A, with capacity dropping more noticeably at a 5A discharge. As these can generally be picked up cheaply, I guess it's not a bad budget choice, but if we take pricing out of the equation, I can't help but think that there are better cells available in the 2600mAh class, some not a whole lot more expensive. Continued testing of other cells (I have a few 2600mAh ones lined up), will show if this is indeed the case. So to sum up, cheap, good for the price, but they don't strike me as being the best in class, and certainly not a 3000mAh cell.