Panasonic Evolta AA NiMH

Batteries and Chargers Rechargeable Batteries
1

A place well known to all UK cheapskates, 7dayshop had these cells on offer for about 20% less than they are asking for AA Eneloops (Price works out at $8.41 for 4 at today's exchange rate). Or less than half what they are asking for the XX Eneloops. So I thought they'd be worth a try. I really don't need any more LSD AA's as i already have 40 Eneloops, 16 Eneloop Tones, 20 Vapex Instants (Not all that great unless they are very, very cheap), 8 Camelion 2100, 4 Hybrios somewhere. I own enough lights to take about 60AAs so I'm still not going to run out any time soon.

So it's no big deal doing long-term testing on these Pansonics. They claim a 1600 cycle life - might be interesting to try that out, but I hope we'll have something way better than NiMH by the time any of these LSDs come anywhere near their cycle life. It might be interesting to see how long they'd survive being blasted by a 15-minute charger but I don't feel like being that cruel to them. Unless they turn out to be not very good.

Pics:

The back of the packaging - these are Chinese made cells.

The cells

With other LSDs I had sitting around. I'd have used more if I could have found them - there are some Hybrios about somewhere. The black Tronic branded ones cost very little from Lidl - my initial opinion is that they are barely worth the very little I paid for them (less than half what an Eneloop would cost.)

Positive contacts - the slightly "squared off" look of the + contact is very reminiscent of the Eneloop Tone one on the far right. This is hardly surprising as Panasonic owns Sanyo, I believe.

The negative contact isn't link any of the others - but Panasonic has been making (or at least commissioning the manufacture of) cells for a long time. Presumably, even though they own Sanyo they prefer to use production techniques and processes well-understood by them (or their contract manufacturer)

Initial Voltages were within a few millivolts of each other, between 1.282 and 1.286V

Initial Voltage
Cell V
1 1.285
2 1.284
3 1.282
4 1.284
5 1.284
6 1.286
7 1.286
8 1.284

This suggests to me the cells were made a while ago, the claims about cycle life date from 2010 and it wouldn't surprise me if these have been in a warehouse for a couple of years. The voltage was a bit below what I expected. The first discharge should be done in about three hours.

The plan is to run five full cycles and take the average of the first five cycles as the baseline. Discharging is at 550mA, charging at 2A followed by at least 4 hours trickle charging a Maha C808M charger.

2
Cell V mAh
1 1.285 1592
2 1.284 1608
3 1.282 1579
4 1.284 1526
5 1.284 1584
6 1.286 1636
7 1.286 1671
8 1.284 1620

Assuming 2050mAh capacity those numbers look right for two years since first full charge - or maybe they were not fully charged at manufacture. These claim a lower self-discharge than Eneloops which may, or may not turn out to be true - we'll see. I'll be interested to see what sort of actual capacity I measure from them.

I think I read somewhere that the lower the self-discharge, the lower current the cells are capable of holding their voltage at. So it may be that these have higher impedance than Eneloops - though i certainly can't afford the kit to find this out.

3

Promising first results. What discharge rate did you use?

I just bought 240 AA and 80 AAA eneloops (for work) because of their proven long-term reliability but it's always intresting how the cheaper alternatives perform.

Any specific reason you are not satisfied with the Tronics? I found that they perform very similar to my Recykos but haven't really tested their LSD characteristics.

4

Thanks Don. I'm going to check out the local stores here to see if they have them. I can always use extra batteries. :bigsmile:

5

The discharge is 550mA which is what my Angeleyes chargers offer. They were a third of the price of the C9000 at the time so I got two of them for less than one C9000. But they aren't quite as flexible.

The Lidl cells last no time in my cordless trackpads and mice. Neither of these are high current devices. I really should do more detailed testing on them. I have a little Canon camera that really doesn't like NiMH cells all that much - it claims an Eneloop is dead after about two weeks - the Lidl cells last less than two days. In both cases the cells are fine once you cajole the camera into actually taking a picture when it realises there is plenty of juice left.

I suspect they don't hold their voltage as well under load (First generation Eneloops were said to be able to hold their nominal voyage at 8 amps according to several people in the Other Place) which I can check easily enough in a bright AA light - the EastwardYJ J09 which is very voltage sensitive and really means it about a maximum of 1.5V. It pulled 4.3A from a freshly charged (~1.9V) NiZn cell. I can check the current draw and output with assorted cells I have lying around.

6

I'll probably pick up some of these, even though I have no need for any more at the moment.

Are the tronics cells from Lidl? Not seen any in our local branch, but I do have quite a few "ActivEnergy" NiMH (non LSD) cells from Aldi, which seem to perform quite well in cameras and torches, although I've not got a charger with test functions to back this up.

7

That's strange. I've had two sets of the Lidl cells in two different lights (LD40 and HP11) since the beginning of January and although the HP11 has a parasitic drain (~73 µA) and I have used both lights for walking the dog I can still switch between all four brightness modes. Maybe you got a bad batch? Mine are marked HR06 HRM 15/51 and are manufactured 2011/06. They were cheap as dirt and I regretted buying only two sets when they were available.

8

Just charged four of the Lidl cells and got.

1759
1878
1889
1865

Not all that great but I'm now giving them the same regime as the Panasonics (Which cost nearly twice as much) and I'll include the results here.

Mine have the same manufacture date and markings. I see they recommend 7 hours at 420mA - mine get a bit over an hour at 2A - maybe that is too much for them..

9

That's a possibility. I usually charge with the standard protocol (16 h at 0.1 C) if I'm not in a hurry (and after I switched to LSD NiMH that hasn't happened very often). Maybe they don't like higher charge currents.

Will measure capacity after next charge for comparison.

Maybe I don't have to feel sorry I didn't buy more? :p

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Cell
1
2
3
4
5
6
7
8

So I now have a baseline for capacity. Cycle 2 got left out as I got the charge timing wrong and the results were a lot lower. As in 10% down on what they can hold. I'll try a couple of them a day this week as I seem to remember reading that LSD cells lose a bit easy then the self discharge rate slows down. These have, so far been moved from charger to discharger straight away - which is not representative of normal use for most folks.

The regime - charge at 2A in a Maha C808 charger and leave for at least four hours (normally it'll be overnight) after it says they are charged to make sure they are fully topped off. Discharge at 550mA in one of the two Angeleyes chargers I own. I don't get to choose the discharge rate - that is what it gives me. It seems not to vary depending on how many cells are in it. Unlike the charge rates which are 1062mA with one or two cells, 710mA with three and 528mA with 4.

Once I've a week's worth of daily discharges, I'll switch to weekly discharges and so on till a couple of them have been left for a year since charge.

11

Looks good, but the price seems to have risen - your link shows them to be £7.99 now. They have eneloopsfor only £10.09 for 2 packs of 4.

I've been getting eneloops from iCell via Amazon, and again, the pricing is all over the place. I just noticed 4 packs of AA for £25, which I paid £18 for on 1st March.

12

If they cost more than the Eneloops, then I doubt that they are a better bet in any way. I really ought to set aside some Eneloops and run the same tests. And some of the Lidl LSD AAs as well.

13

Maybe 7dayshop is monitoring Don's analysis and if the results are good the price goes up? :D

I had my tronics finally charged and discharged. Both sets are the same age and have the same amount of cycles (4 or 5, don't remember exactly). First set got standard charge (0.1 C for 16 hours), second set charged with 2A (about 1C, took about 40 min till "done" in the C9000, batts left in the charger for topping-off until the voltage sank again).

Set 1 [mAh]: 1973, 1958, 1962, 1993.

Set 2 [mAh]: 1771, 1763, 1746, 1730.

When I bought the Tronics last year I did a break-in and all of them were around 1900 mAh and quite close to each other, so the difference between the two sets seems to come from charging the second set with 2A.

So these cells seem either not to like rapid charging or not to work well together with Maha's charging algorithm.

Now I'm wondering if this applies to other cells as well? As I posted earlier I normally use the standard charge for LSD NiMH, but I would like to know if the C9000 is maybe not getting full charge at higher charge rates (because of some over-the-top safety protocol to prevent overcharge) which would be a little weird for such a sophisticated charger.

I will repeat the test with Recykos and eneloops to control if it's only the Tronic cells or if it is an effect of the charging algorithm, but maybe anyone here already has done similar measurements or knows if this is a known weakness in the Maha software?

14

I know it's getting further OT (forgive me, Don) but I thought some might like to know the results of my eneloop charge testing (haven't done the Recykos yet, and am not sure that I will because it occupies my charger so long and I already came to a conclusion for myself, see below).

These are new eneloops (HR-3UTGA) out of the box (2 sets á 4). Charging/discharging was made with the Maha C9000.

Discharged initially at 0.2 C (=400 mA):

Set 1: 1397, 1385, 1397, 1393

Set 2: 1386, 1393, 1390, 1399

I used the break-in mode of the C9000 to charge Set 1 with the standard charging protocol and to register the available capacity. Set 2 got charged with 2000 mA and left for four hours in the charger after the last slot indicated "done" to allow the 2 hours top-off charge at 100 mA plus 2 hours rest before discharging at 400 mA.

Available capacity was:

Set 1: 2016, 2018, 2012, 1983

Set 2: 1823, 1882, 1853, 1819

The difference of available capacity between the two sets is not much different from the Tronic cells leading me to the assumption that the Maha charging algorithm is not giving the cells a full charge at higher charging rates.

I am a little disapointed of the C9000 performance at this point because I thought a "smart" charger should not only prevent the cells of getting overcharged but also be able to charge the cells as full as possible and safe. Please comment if this is old news or something that I should have expected.

15

I bought 8 for $28 on eBay from Australia, I wonder if they will be identical to the ones in your pictures.

16

Intersting.. I was looking for some more info to see if there was diffrent versiosn.

First I found a 1800 recharge version:

Then I found this:

Apparently just released on April 30 this year (11 days ago)

1900mAh and 1800 recharges, the lowest price I can find is around $45 so far but I am looking for cheaper.

Very tempting.

17

I’d forgotten about these cells - they are now on discharge seven months after being charged. They appear to have self-discharged at the same rate as they were all at 1.289V according to the charger.

Discharge is at 550mA.

Results in a few hours.

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Cell No. Original capacity (mAh) Measured capacity (mAh) %age remaining after 7 months
1 2084 1582 75.93
2 2069 1576 76.19
3 2060 1559 75.67
4 2039 1558 76.40
5 2063 1514 73.40
6 2049 1498 73.11
7 2069 1518 73.37
8 2026 1477 72.89
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Those numbers are pretty good. Thanks Don.

Now I wish that I bought Chibi's rainbow evolta's.

20

& this