|
Research Topic: Which Battery Will Do?
On this page: Battery Testing | Conclusions | AA NiMH Cells | AAA NiMH Cells Rechargeable (Secondary) Battery TestingAA and AAA NiMH cells are the most common type of rechargeable battery, so I've started testing some that are available in New Zealand. This testing raises the question do these NiMH cells break fair trade laws? Many of the used cells do not have the claimed capacity, some falling short by a wide margin. There is also doubt that they last anywhere near as long as the 1,000 cycles often claimed for NiMH cells. The consistency of cells in a single packet gives an idea of the quality and consistency of the manufacturing. Cells which all test very close to each other for capacity are probably high quality and should thus give the best long term performance. The "variation" figures listed in the detailed results give an idea of the consistency of a batch of cells. It is simply the percentage difference between the best and worst cells in a batch, calculated from max/min - 1. ConclusionEneloop AA 2000. Testing has shown these to be great cells that have a very long service life. Off the shelf capacity of 71.3% (8 months after manufacture) is pretty good since Sanyo has said they only charge Eneloop cells to about 75% before they leave the factory. Eneloop AAA 800. Again, both initial and ongoing testing shows them to be great cells. Like all new Eneloops, they appear to have had a ¾ charge at manufacture. Others. Steer clear of generic and house brands. Dick Smith AA NiMH & NiCd CellsNew cellsEneloop 2000mAh. "Typ. 2000mAh (Min. 1900mAh)". Low self discharge/long shelf life NiMH, with a claimed 85% charge after one year - an untested claim. The claim of a higher voltage during discharge than other NiMH cells (and therefore greater power) is true, although it's often by only a tiny amount. Regardless, the 1st through 3rd generation are highly recommended. However, the 4th generation available in New Zealand is made in China, not at the factory that made the earlier generations, and in tests on other sites they perform no better than any other LSD batteries. Eneloop XX 2500mAh. 2500mAh, "Min. 2,400mAh". Low self discharge/long shelf life NiMH, with a claimed 75% charge after one year – an untested claim. Highly recommended, except possibly for daily use. GooP 3000mAh. I did not buy these! Given to me in May 2014. The claimed 3000mAh is too good to be true. Packaging claims "ISO9001:2000", which seems rather suspect considering the claimed capacity, and "Up to 1100 cycles", which is certainly rubbish. This brand not recommended because they simply lie about their capacity. Solar Magic. Bought (not by me!) from Bunnings Warehouse in November 2012. On the cell is "Cat no. SMB1000". Apart from that there's just instructions and no other cell markings on these things, almost like they aren't a serious cell. On the packet is "Distributed by Merlin Distribution Pty Limited" and "Made in China". Also on the packet is "Batch Code: BATCH 1X" – again, not a serious batch number. They are marketed specifically for solar garden lights. They have absolutely horrible consistency and are basically molded mud. Varta. Bought new in October 2017 but unknown age. Some of the packets look a bit tatty so they have probably been sitting around for a while. The claimed 2100 mAh is a little optimistic but they seem to have reasonable LSD properties since they still have a good charge out of the packet. Made in China, not Germany, sadly. Used cellsCamelion AlwaysReady 2100. Cell labeling "NH-AA2100RR typ.2100mAh 1.2V AA HR6". Low self discharge NiMH. DS Eneloop 3rd gen. These are the same cells as tested when new in October 2017, after not much use. As expected, they have even better capacity now. Eneloop XX 2500mAh. Gave them a break in cycle as "Min. 2,400mAh". They did not stack up well at all, but did better with the post-break in 500mA discharge. Because they had improved I thought I'd give them a bit of cycling, but that resulted in the highest capacity cell dying with great heat (84 °C), melting its label. There is a small amount of surface rust visible on a couple of the three Maybe they just like to be used, and the self discharge construction passivates them without regular use. Regardless, these are really not bad for nine and a half year old cells. GooP 3000mAh. I did not buy these! Given to me, new, in May 2014. Because of the capacity lies (labelled as 3000mAh not 2100mAh) they are not trusted and thus have not been used much. They have lost a little capacity. GP 1800mAh. Each cell has the claim "min. 1750mAh" printed on it, along with "Standard Charge 16Hrs at 180mA". Also has "180AAHC". These have lasted quite well. Powerhaus 2500mAh. Some quite used cells that are probably very representative of high capacity NiMH cells. They maintained a moderate capacity but have seriously bad voltage sag under load. This is likely why so many people don't like rechargeables. Not recommended – they will just be a source of frustration, not power. Used cells are listed in italics with a gray background.
New AA Cells - Click for Notes/Detailed ResultsUnless otherwise mentioned, capacity results are in ascending order, not in slot order. The ranking order between particular tests may vary. Sanyo Eneloop 2000Bought from Thomas Distributing (8 cells), manufacture date May 2006; bought from Online Shop Singapore (4 cells), manufacture date November 2006. Packaging for Online Shop cells labeled RWPrince,... Singapore, although the cells shipped from Hong Kong. As delivered they were partly charged, with an average cell voltage 1.308V (from TD), while the newer cells (from OSS) were all 1.310V.
Testing the charger's effectiveness at fast charging these cells, I also ran some other tests on the 8 TD cells.
The first break in capacities seemed pretty good but to see if they would all go over 2000 mAh I restarted the break in cycle after the discharge rest, and sure enough, the 1999 mAh cell was up to 2005 mAh. The second break in with the second set of 4 left just one cell below 2000 mAh, at just 1977 mAh, but strangely the same cell gave 1987mAh at a 1 amp discharge (both in outside slots on the charger). With the best two cells from the second set, the best cell was always the one positioned in slot 2 or 3, while the other was in slot 1 or 4. Update 20 June 2007: I've just put one set of Eneloops through another break in and was pleasantly surprised to see the results, both for their high capacity and for their consistency, within 1.1% of each other.
Update: Another six Eneloops have been tested (exact date unknown). Variation figures not shown for these because they are not from a single packet, and thus may or may not be from the same batch or manufacture date.
Update April 2008: Another four Eneloops are being tested, with the date stamp June 2006. These results have not been included in the results shown in the table because they were made using an analyser from a different batch. These capacities all in slot order.
Update October 2017: A bunch of four year old 3rd gen Eneloops (manuf. code 13-09SA), which have just been sitting around unopened.
I've posted some notes on the slot consistency for these Eneloops on the MH-C9000 page. Eneloops get a ¾ charge when they are made, so those capacities represent 83% of their original charge! Not bad for four year old cells, and I fully expect those to increase at least 100 mAh after a few cycles. Also, each pack got really good consistency; 3rd gen Eneloops are very well made. Eneloop XX 2500Bought online from Intl Outdoor Shop, which no longer sells them. The XX was rebranded the Eneloop Pro at the end of 2011 but is still sold in some markets as the XX (powered by Eneloop Technology), normally referred to as Eneloop XX. Battery model HR-3UWX. Date code "11-10 HM", October 2011; 5 months old at time of test in March 2012. Four Eneloop XX cells have been tested.
GooP 3000 mAhWith such a high claimed capacity I don't hold high hopes for these. (A claimed capacity which is simply a lie indicates a poor quality manufacturer.) Sold by DealExtreme here (sold out), although I didn't buy them.
These voltages (and later, the off the shelf capacities) are high enough for me to think they could have some LSD ability, which doesn't fit with the claimed capacity (the higher the capacity, the less low self discharge ability cells have). The variation of the off shelf capacities is getting quite high.
That consistency is actually quite reasonable; the capacities are not all over the place. The voltage on discharge was a little low, though, down to about 1.17 V after the first 500 mAh. My present thought is that they are clearly not as good as Eneloops, and should have been marketed as 2100mAh or 2200mAh, certainly no more than that. As they are, especially with the claimed 3000 mAh, they rightfully deserve the name "GooP". One hour after the break in had finished I started the 1 A discharge. At the end of that discharge the cells all rebounded to 1.14V. That's a little low. Next tests, both after a 0.5C charge.
Solar MagicBought (not by me!) from Bunnings Warehouse in November 2012. (Also tested that month.) On the cell is "Cat no. SMB1000". Apart from that there's just instructions, and no other cell markings on these things, almost like they aren't a serious cell. On the packet is "Distributed by Merlin Distribution Pty Limited" and "Made in China". Also on the packet is "Batch Code: BATCH 1X" – again, not a serious batch number. They are marketed specifically for solar garden lights. The basic advice for these is simply do not buy! These are the most pathetic brand new cells I have ever tested. I didn't have most of them for long enough to try a full Break In, but did do a bit of 300mA testing, which showed they're all over the place. The thought occurs to me that Eneloops cost less than twice as much, have more than twice the capacity, and have consistency a couple of orders of magnitude better. The single cell I did do a break in on definitely improved, but very few people have a charger capable of doing that, or of testing cells to get a matching set. So most people using these things in their 3 cell solar light would have been picking three cells from the four at random; there would have been a 75% chance the worst cell would have been selected.
Varta Ready to Use 2100Straight out of the packet, loaned for test.
These don't have the consistency of Eneloops (even four year old Eneloops), but they don't look too bad. The front of the packet equates 1 of these cells with 175 alkaline cells implying they'll last that many cycles, but the back of the packet claims 300 cycles. Another couple of packets – look very slightly tatty (for example, the cardboard is fraying at the corners).
Used AA Cells - Click for Notes/Detailed ResultsUnless otherwise mentioned, capacity results are in ascending order, not in slot order. The ranking order between particular tests may vary. Camelion AlwaysReady 2100Loaned from a caver to see just how well they perform. More details are on the LSD Shootout page.
Eneloop 2000, 3rd genTested when new in October 2017, these are back for a retest.
The capacity of Eneloops increasing after a few cycles is well noted, so this increase is expected. Eneloop XX 2500Retested after intermittent use, and possibly some abuse. Three of the cells have a small amount of surface rust on the exposed metal surfaces. I gave them a break in, followed by a 500 mA discharge.
Seeing that the capacities had increased, I attempted to cycle them three times at 1 amp charge, 500 mA discharge. I got back to the charger later to find the backlight was off and cell 3 was hot – very hot. My thermal camera saw 84 °C. It has resulted in the label shrinking and probably internal damage, although it measures 1.350 V. Did the charger miss charging termination and also miss over-temperature termination, or did it only respond to the temperature when the cell got extremely hot? Did the charger keep charging after thermal shutdown? As soon as I took the overheated cell out of the charger, the charger rebooted, recognised the other three cells, and proceeded to charge them without any further input from me (as it does if just left with newly inserted cells in it). The charger reported charging values ~2000 mAh, so they've taken a fairly full charge. I set the three surviving cells to discharge at 500 mA (19 April 2021), then figured I'd try discharging the overheated cell as well. As soon as I inserted it the charger turned off. I pulled it out again and the charger returned to normal. There's definitely something wrong with that cell, but not completely short circuit, since it measured 1.350 V. There appears to be something wrong with the charger too. Instead of 500 mA the cells are discharging at 552 to 557 mA. This is much more than the normal variation-from-nominal of the MH-C9000. The discharge went well, though, and it appears that the three cells have been completely revived. Even with a minute or two of discharging that was "lost" when the charger reset as the bad cell was inserted, they have come out very well.
Update 23 April 2021: It's not the cell causing the MH-C9000 to turn off. It's the channel itself; the charger turns off when any cell is inserted in that channel. My MH-C9000 has lost channel 3! The toasted cell apparently charges fine when inserted in different charger. Goop 3000These appear to have some LSD ability but are not used much. Their typical voltage under load is only 1.15V.
GP 1800Sold by Dick Smith First set of four had one cell that died a few months after purchase, leaving only three in that set. The remaining three have performed quite well in a shaver over the years, and have been observed to have a low self discharge rate – not bad at all for cells predating Eneloops by years, showing how bad the capacity race was for reliability. The three were tested in about 2007 or 2008 then again in 2017. They've lost a lot of capacity in that nine or ten years.
The GP battery charger rejected the faulty cell as defective so it hadn't been used since, but for reasons best understood by squirrels it was kept. It showed 2.4 ohms and 0 volts before the semi-successful attempt was made to resurrect it. That the 500mA test capacity was larger than the 0.2C rate (360mA) indicates that the cell still needs a bit of cycling, but since its self discharge is so high it's due for recycling.
Four more cells from an identical batteries/charger set were tested in March 2011. They were given two full break in runs (each with two slow charges) plus a 500 mA discharge between.
Powerhaus 2500Supposedly high capacity cells that are no longer driving a digital camera, but otherwise still seem to work. Testing in March 2011 showed the inability to power the digital camera was due to one cell that was dying well before the others, combined with serious voltage sag on all cells. In particular, the voltage sag on the worst cell was so severe that it was dropping straight to 0.9 V, at which point the MH-C9000 terminates its discharge. I put the cell into a single cell LED torch and ran it for a while, then tried another discharge. The cell performed better, and didn't terminate immediately. Instead, its voltage slowly recovered then stayed steady at 0.94 V, even after 75 minutes. Voltage recovery on the other cells was about 0.2 V. A fair bit of cycling of the four cells ensued, followed by two break in runs with a 500 mA discharge in between.
That first cell is heading downhill. These results highlight the need for testing of under performing batteries. The best 3 cells make quite a good matched set, at least for capacity. Having matched capacities doesn't do anything about fixing the seriously bad voltage sag. AAA NiMH CellsEneloop 800mAh. New. "Model HR-4UTG 1.2V Typ.800mAh, Min.750mAh". Highly recommended. Energizer 900mAh. Set of two, new in unopened packet but unknown how long since purchase. "NH12 AAA 1.2V NiMH HR03". Both cells stamped "0407" – manufactured in April 2007 perhaps? Tested in March 2011; possibly 4 years after manufacture. After hearing the initial test results the owner joked he wanted his money back. These cells and this brand not recommended. EniTime 800mAh. New. "AAACS 1.2V Min.750mAh HR11/45". The packet claims they will have 80% capacity after one year. Powertech 800mAh. Used. "Standard Charge: 80mA for 15hrs". This is the Jaycar house brand, and not to be confused with Maha PowerEx. These cells and this brand not recommended. Powertech 900mAh. Used, solder tag. These were used in a cellphone battery and were so bad they were just recycled without being tested. These cells and this brand not recommended. Used cells are listed in italics with a gray background.
New AAA Cells - Click for Notes/Detailed ResultsUnless otherwise mentioned, capacity results are in ascending order, not in slot order. The ranking order between particular tests may vary. Eneloop 800Premium brand low self discharge AAA made by Sanyo. First set of 4, manufacture date April 2006, so they're one year old.
8 more, manufacture date October 2006, tested September 2007; about 11 months old.
8 more, manufacture code 06-07 00 (July 2006), tested January 2008; 18 months old at time of testing.
4 more, manufacture code 09-10 S0 (September 2010), tested March 2011; 6 months old at time of testing.
In April 2011 I managed to retrieve 3 AAA Eneloops that were in a headlamp I'd loaned to someone for a caving trip 20 months earlier. After the caving trip they sat around doing nothing. So I discharged them at 200 mA (0.25C) to see how they fared. While their discharge (under load) voltages seemed a little low, they did very well, especially with being used for about an hour on the caving trip.
Energizer 900The first result in a Google search for "energizer aaa 900 pathetic" (without quotes) was a page on Energizer's own web site. Pretty much sums it up. (The 6th result was a page on this site, Aqualab.)
Did some cycling to see if I could bring that up.
EniTime 800Inexpensive brand supposedly made by GS Yuasa (a reasonably reputable Japanese brand) but actually made by Yuasa (Tianjin) Technology Ltd, China. Sold by DealExtreme here. No date code on cells. Tested January 2013.
They have a good capacity but the variation between cells is quite high, indicating manufacturing tolerances are a bit loose. These are not Eneloops! I do not expect them to last particularly well. The packet is marked "Ready to Use" but with such low capacities out of the packet it's a somewhat questionable claim (assuming a reasonable charge to start with). Further testing turned up a capacity for cell 2 of 920 mAh – a great capacity for an AAA cell, but at which point the LSD ability and/or the cycle life of the EniTime must surely be suffering. Retested May 2015.
The four cells had been in a clock, used to power RGB LEDs on demand. Their initial recharge times varied from 75 minutes to 155 minutes. How could discharged capacities be that uneven? My guess is that their LSD ability greatly varies and some of the cells had gone much flatter than others. Used AAA Cells - Click for Notes/Detailed ResultsEneloop 800These were in a headlamp loaned to a friend who didn't return the headlamp to me for 20 months. They had an unknown amount of use at the beginning of that 20 months, so the "off shelf" capacity isn't of much value, other than showing they still had a good charge. The high break in capacities show they hadn't suffered for their lack of use. Update 8 October 2018: This next batch of three AAA Eneloop (HR-4UTG, first generation) had apparently been sitting around doing nothing for years and were resisting the idea of being used again. Basically, they would only provide only about 3 mAh thanks to some sort of high resistance problem causing bad voltage sag and very quick voltage rise on charging. They got woken up not too badly by a break in cycle.
Update 30 December 2018: This batch of four AAA Eneloop (HR-4UTGA, second generation) had (also) been sitting in a torch doing nothing (or not much?) for years. They gave some strange figures upon charging – much longer charge times than the amount of charge put into them, and not a high enough voltage when fully charged; it seems the MH-C9000 had reduced the charging current at some point – so I put them through a break in cycle. Three of these cells are not performing well. Time for some slow cycling.
Update 21 September 2023.
Powertech 800Sold by Jaycar Electronics. Used regularly, seems to have quite a high self discharge. Many also have high impedance - to the point that the MH-C9000 refuses to charge 4 of the 12, and had issues with several more before eventually deciding they were OK. They haven't had several hundred charges, so at this point I cannot recommend these cells.
Other testing, to see how well charger works with these cells:
Powertech 900 (untested)Solder tag cells – sold by Jaycar Electronics. These were installed in the battery of a cellphone in May 2005, and were basically abandoned in February 2007 as being too unreliable to power the phone. They were recharged every 2-3 days on average so probably had only about 250-300 cycles, and far fewer than 200 cycles before their capacity noticeably decreased. Not good. The two previous sets of cells each lasted over three years (a respectable 500+ cycles for each set), and while the earlier cells had a lower claimed capacity (eg, 650 mAh for the initial set), the runtime of the phone with the supposedly 900 mAh set of cells did not seem appropriately longer. So it seems as though the quality of the Powertech cells is decreasing – this is probably a direct result of the higher capacity – so once again, I cannot recommend them. A few battery shoot-outs are mentioned on the More Info & Links page, or get information on the charger/analyser I use. Read on for suitable uses for particular battery types.
Contact:
|