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Rechargeable AAA NiMh Batteries How do the High Capacity Batteries Compare?
My grandson received a digital camera last Christmas and asked me "Granddad! why can I only take a few pictures before I have to recharge the batteries"
The batteries used were 4 x AAA NiMh rechargeable and checking his particular cells I found not only did they have low capacity the internal resistance was high. The capacity rating of rechargeable batteries gives an indication as to how long they should last between charges but in power hungry devices like digital cameras the internal resistance is a major factor of battery failure. Whilst all the NiMh batteries give their capacity there is little information as to the internal resistance and the readily available cheap battery testers on the market do not test the battery under a heavy enough load and will show good a cell that has gone HIGH. I test my cells with a tester I modified with a 1ohm discharge resister, this loads the battery with just over 1amp & a good cell will maintain a voltage of well over 1.2 volts under this load.
This prompted me to check out some of the cheaper high capacities AAA cells available to see if they actually lived up to their specifications and I am testing AAA cells of 1000mAh & over and will extend these tests to AA cells of 2500mAh & over. (Click for results so far)Click the montage to see the full results  The manufacturers seem to keep their specifications to themselves and trying to find individual specs is obscured. I did find however excellent data sheets available at the Vapextech website and am using their specs as a basis for my tests.
New cells do not reach their full capacity on the initial charge and require several charge/discharge cycles to achieve their full capacity so I needed to set up a test procedure to achieve the full capacity of the cells
The Vapextech specifications for the AAA 1100mAh cells are
| | | Conditions | | Nominal voltage | 1.2 V | | | Max. charge voltage | 1.5 V | At standard charge (0.1C/20 centigrade) | | Capacity | | | | Nominal | 1100mAh | Discharge at 0.2C | | >900 mAh | discharge at 1C | | | Minimal | 950mAh | Discharge at 0.2C 1.0V end discharge voltage
Ambient temperature 20 centigrade | | Typical | 1000mAh | Discharge at 0.2C | | Max. discharge Current | 2200mA | Ambient temperature 20-50 centigrade | | Charge | Charge current | Charge time | | Standard charge | 110mA | 15hrs at 20 centigrade | | Quick charge | 550 mA | 1.8hrs for empty battery | | Max. charge | 1100mA | 50mins | | Trickle charge current | 27-45mA | (recommended) | | Continuous overcharge | <45mA | No conspicuous deformation | The charge/discharge rate is specified as a fraction of the specified capacity
For example 0.2C is 1100 x .2 = 220mA
With these figures and the equipment I have to hand I devised a method of conditioning and testing the batteries |  | As the batteries are usually used in 2s or 4s and generally come in packs of 4, each test consisted of a set of 4 cells and the average results taken.
- Firstly a Soft Charge Conditioning mode with my Maha MH-C801D charger
This can take up to 36 hours to complete the full cycle.
- Secondly a cycle/refresh of up to 5 times Using my Maha MH-C9000 or La Crosse BC-900 charging at .5C discharging at .2C (I selected the charge/discharge rates as near to these figures as possible, which were 500mA charge & 250mA discharge) I used the same charge/discharge rates for all batteries to obtain a true comparison. I cycled the charge/discharge up to 5 times or until there was less than 5% increase of capacity. This brings the cells up to maximum capacity but show a lower capacity than in the specifications.
Each cycle takes around 5 hours.
- After the refresh cycles and the batteries charged I find that the cells have only acquired 80-90% of their capacity. I then apply a Top Up charge of .05C for 4 hours and finally a Maintenance Charge of 20mA for 24 hours. (I have some old chargers that I can do this with) This top up and maintenance charge produced results which were consistent within 2%
- The cell is then tested in my La Crosse BC-900 with the discharge rate set at as near to the .2C as is possible which is 250mA with AAA 1000mAh & above cells.
This final test takes about 5 hours and in my opinion gives true results as to the batteries capacity
| Charging the batteries in sets of 4 at 1000mA & above generated quite a lot of heat and I found I needed to cool them down by using low powered PC case fans connected to a separate low voltage PSU.
Only The Duracell AAA 1000mAh achieved their stated capacity with all cells with an average capacity of 103%, some of the Energizer & GP AAA 1000mAh cells achieved the stated capacity and only the Duracell. Energizer & GP so far reached a capacity of over 1000mAh. Comparing all the cells at 1000mAh I managed to achieve 98% with the Profitexx 1300 & Vapextech 1100
BTY 1000 cells were a total flop at 21%, BB 1200mAh achieved only 60%, Unbranded POWER 1200mAh achieved only 47%, of their stated capacities. Full refunds (including postage) were obtained from the Hong Kong eBay suppliers The MAXUSS 1200mAh achieved only 58% of their stated capacity & The UK eBay supplier accepted the batteries back with a full refund including return postage.
The POWERCELL 1300mAh achieved only 42% of their stated capacity & the eBay supplier "creative*product" has offered a refund of £3.50 provided I return the batteries unopened by recorded delivery at a cost to me of £4.32. My PayPal claim was refused because I declined to pay the return postage of more than the cost of the batteries. I will NEVER deal with "creative*product" again and advise all readers to boycott their site.
One of the Energizer cells failed to condition correctly and a replacement was supplied by the UK eBay supplier. Only the initial 3 good cells are included with this test | The following table list the batteries in order of their rated capacity performance
Also showing their percentage capacity of 1000mAH | Manufacturer | Stated
Capacity | Image | Maximum
Single Cell
Capacity | Average
Tested
Capacity | Nominal
1000mAh
Average | DURACELL | 1000mAh |
 | 1037mAh | 103% | 103% | Energizer | 1000mAh |
 | 1011mAh | 98% | 98% | GP | 1000mAh |
 | 1009mAh | 96% | 96% | Vapextech | 1100mAh |
 | 995mAh | 89% | 98% | LA CROSSE | 1000mAh |
 | 923mAh | 87% | 87% | palocell | 1100mAh |
| 953mAh | 86% | 94% | FUJICELL | 1100mAh |
| 910mAh | 79% | 87% | ENCORE | 1000mAh |
| 790mAh | 76% | 76% | PROFITEXX | 1300mAh |
 | 996mAh | 75% | 98% | Battech | 1200mAh |
| 915mAh | 74% | 89% | BB | 1200mAh |
| 737mAh | 60% | 72% | MAXUSS | 1250mAh |
| 744mAh | 58% | 72% | Unbranded
POWER | 1200mAh |
| 635mAh | 47% | 56% | POWERCELL | 1300mAh |
| 557mAh | 42% | 54% | BTY | 1000mAh |
| 228mAh | 21% | 21% | The following table lists the batteries in order of their actual tested capacity | Manufacturer | Stated
Capacity | Image | Maximum
Single Cell
Capacity | Nominal
1000mAh
Average | DURACELL | 1000mAh |
| 1037mAh | 103% | Energizer | 1000mAh |
| 1011mAh | 98% | | PROFITEXX | 1300mAh |
| 996mAh | 98% | | Vapextech | 1100mAh |
| 995mAh | 98% | | GP | 1000mAh |
| 1009mAh | 96% | | palocell | 1100mAh |
| 953mAh | 94% | | Battech | 1200mAh |
| 915mAh | 87% | | LA CROSSE | 1000mAh |
| 923mAh | 87% | | FUJICELL | 1100mAh |
| 910mAh | 87% | | ENCORE | 1000mAh |
| 790mAh | 76% | | MAXUSS | 1250mAh |
| 744mAh | 72% | | BB | 1200mAh |
| 737mAh | 72% | | Unbranded
POWER | 1200mAh |
| 635mAh | 56% | | POWERCELL | 1300mAh |
| 557mAh | 54% | | BTY | 1000mAh |
| 228mAh | 21% | The discharge rate I used was 250mA for all tests. 250mA is .25C of 1000mAh and .2C of 1250mAh so the lower than expected figures with some of the lower capacity batteries can be contributed to the higher discharge rate, This is the same for all tests to give a true comparison of capacity between different brands. Charging was done at 500mA which is as near as .5C as was possible and was the same for all batteries. I could have charged up to 1C for quicker results but the higher charge rate & temperature produced is likely to reduce the capacity & hence the effective life of the batteries, I recommend the 2 hour or more charge rate to prolong the battery life.
CONCLUSION
From the batteries I have tested 1000mAh seems to be the maximum capacity obtainable (perhaps 1100mah in extreme circumstances). All the Duracell 1000mAh were the only batteries to achieve over 100% of their rated capacity & the three highest capacity brands are all rated at 1000mAh. The so called 1100mAh & above are no higher capacity than the lower 1000mAh batteries.
The cheap so called high capacity batteries available direct from Hong Kong appear to be very low grade and I recommend avoiding them at all costs
The well known Duracell came out top of the list but any of the 6 brands which came out above 90% of 1000mAh are the ones I can recommend
Any battery suppliers or manufacturers who feel I have left them out of the tests Please contact me to submit your batteries to be added to these charts. | Friday, June 12, 2009 Reviewer: Flashhits: 2217
Posted by Flash on Jun 16, 2009 - 12:13 PM
La Crosse by Component-Shop
Thanks for the info.
I don't know who makes the Lacrosse batteries, as we are effectively selling a charger with a few batteries thrown in.
The results for the Vapex batteries do interest me - we are the main UK importer and agent for Vapex Technology, in fact Component-Shop is the retail end of Vapex Technology Ltd (Europe) Both companies being based in our North Wales warehouse.
As you discharged the 1100mAh battery at 250mA which equates to 0.227C it would give a lower capacity than at 0.2C, I would have expected the capacity to actually come out around 1030 - 1090mAh. In keeping with the current method for classification, this capacity is rounded to the next 100mAh increment.
1100mAh is the maximum that any manufacturer can achieve at the moment - look at Sanyo as the industry leaders in this type of manufacturing, spending millions every year on R&D so if they can only manage 1100mAh you can bet that no little Chinese manufacturer has bettered them.
That being the case, you must wonder about these highly dishonest companies who label their product 1200, 1300 etc I even came across one joker with AAA cells labeled 1800mAh! If a manufacturer is prepared to lie about the capacity, then the chances are they are just going to use any cells, as you can see with the "Power" & "BTY" brands.
I am familiar with the "Profitexx" & "Fujicell" brands (Note Fujicell is nothing to do with the Fuji camera company) Interestingly, these cells are manufactured in a factory which is literally across the road from the Vapex Technology factory. The factory producing these cells is Shenzhen Better power who offered me cells with "whatever label I wanted" on them! So an 900mAh cell is cheaper than an 1100, but the 1100 obviously sells better, hence your results. Vapex Technology do not do this & if we ever received batteries which did not meet their rated capacity we would simply reject them - quality is everything. We have had customers who went elsewhere because they could get a cheaper product, but then came back because they realized that it isn't cheap if it doesn't work properly.
Anyway, I hope that this helps, as I said, I am not too concerned about the Lacrosse batteries, but I am more than happy to answer questions relating to Vapex Technology products.
Best Regards,
Iain Lewis.
Posted by Flash on Jun 16, 2009 - 12:19 PM
Profitexx by budpak Hi many thanks for letting you know your findings and I do appreciate your comments. As requested I will send your findings over to Profitexx for any opinions. Only one thought with your analysis, would be to compare like for like capacities which would be a more true comparison. Also include discharge rates which can seriously impact run times in high drain items like digital cameras etc. Regards Garry - budpak
Posted by Flash on Jun 16, 2009 - 12:23 PM
Palocell
Interesting results our cells fared well.
I did read that you were going to test AA's please let me know if you would like to test our AA's too. I can also supply data sheets if your interested in looking at them. Many thanks Paul
Posted by Flash on Jun 16, 2009 - 12:31 PM
Fujicell by makes_scentz
As requested, comments from the manufacturers below. The manufacturers are chinese so the english isn't perfect! except capacity, the quality factors of batteries has several ones, such as life cycle, internal resistance, self-discharge rate, high drain discharge performance, and especially the discharge rate , If it is not meaning, higher capacity of batteries last longer, but better discharge rate(stage) last longer time discharge rate means the Voltage from full capacity voltage to 1.0V, better cells has stable and nice rate, bad batteries has higher capacity but short rate, short curve. discharge curve means the Voltage from full capacity voltage to 1.0V, better cells has stable and nice curve, bad batteries has even higher capacity but short rate, short curve. Some batteries even with higher capacity, but when you storage in warehouse or shop, the voltage is going down quickly, That is not so good batteries, Normally the customers only need the higher capacity , thinks higher capacity must higher quality, but not completey right If you look as well he has done the tests based on a nominal capacity of 1000 so even the percentages are not true and vapex 850?s when based on 1000 of course will have a higher percentage. Additionally the equipment you really need is lab based and not achievable on a home unit. It?s a shame to see he did not do the same results with the duracells, uniross, gp etc to get a better reflection
- makes_scentz
Posted by Flash on Jun 16, 2009 - 06:52 PM
MAXUSS by midlandmobilephones
These are manufacturers label . This 1250mah batteries capacity is what the manufacturers have told me I can not guarantee. Thank you.
- midlandmobilephones
Posted by Flash on Jun 18, 2009 - 06:03 PM
POWERCELL by creative*product
Acutally the web site information is incorrect, That is personal views, But doesn't matter, If you not accept the item, Please return,I hope you don't open the packing,I need you return the original packing back to me, But I will not offer the return postage, Because my return police explain detail.
Posted by Flash on Aug 09, 2009 - 10:15 AM
In reply to Fujicell by makes_scentz
Thank you for your informative reply. From your comments I have removed the Vapex 850 from the tests & added Duracell Energizer & GP. These came out the best. The discharge rate was kept at a constant 250mA which is .25C for 1000mAh & .2C for 1250mAh. Results are shown for actual percentage of the cells declared capacity and also a percentage of 1000mAh which appears to be the maximum achievable, this gives a direct comparison to the batteries performance. To keep the tests fair all batteries were tested at the same charge discharge rates and the final comparison compares the capacity (hence performance) of each individual manufacturer.
I am currently testing AA NiMh batteries in a similar manner with the addition of high charge/discharge to simulate high usage. My chart so far can be viewed
here
The consumer is not interested in lab based test, they need to know how they will perform under domestic use.
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