AccuEvolution D Cells quality gone!

[jayflash]

Another Accu update. After charging 10 D cells with the Maha 808 I let them sit for two days and discharged six @ .5A & four @ .4A, both had only 7Ah capacity. This is after five charge/discharge cycles. I'll check the peak charge voltage again, but it was only about 1.43v the last time.

I'm recharging six in the Maha and four in a Titanium MD-3000 which outputs ~1.6 - 1.8A. The MD charged some Accu C cells to 1.48v which is higher than the Maha. Retesting the C & D cells will be necessary, but now I wonder whether the Maha is fully charging -- it usually stops at two hours for soft chg. with Duraloop AA's.

So far, unless more cycles are needed, it seems these Accu's have no LSD qualities whatsoever. Another test in several months may prove this, but I'm thinking enough info's been collected to contact the manufacturer or seller. Any opinions? I plan to test my 10 C cells soon, perhaps that will answer some questions or create more.

 

[jayflash]

deleted goof

 

[My2Cents]

Capacity check on older Accu Ds should be done and posted this weekend.

Meanwhile... Anyone notice that battery states 900mA for 12 hours but accu website shows 950mA for 12 hours ? Looked at the ones I have and it all show 12h/900mA. Maybe a newer one is coming ?

Also fast charge is different.

Perhaps there's 2 different versions of the this battery ? A "12h/900" and "12h/950". This might explain the difference in quality.

 

[My2Cents]

Based on discharge test on old cells, it is also possible that you received old stock.
These batteries do not have any production date or lot number.
IMHO, a manufacturer who is confident about the quality and/or consistency of their product will use some form of tracking code in case something is not up to par.

 

[jayflash]

After numerous tests since last February, the ten AccuEvo D & ten C cells are all close to one another in specs, like Duraloops, so that's a good start. Initial testing after break-in showed all cells close to specs in capacity. After sitting 30 & 60 days they had, roughly, half of their capacity. Retesting a couple days after a full charge, the D cells had about 8.5Ah with a .5A load.

The Maha 808 charged them to a peak of 1.49 volts, while a Titanium MD-3000 hit 1.52 volts. The MD charged fully charged cells from the Maha for another hour. While I'm still concerned about the poor showing for LSD properties, might the Maha be undercharging?

 

[jayflash]

Warmer weather and the outdoors have me busy on other maintenance because summer is short in Two Rivers. Here's a brief update on my slow testing progress.

Latest test on the AccuEvo C cells indicate about 3.5Ah capacity after sitting a month. The discharge curve is quite flat and they reach 1.47v immediately off charge with 1.49 - 1.52 peak charging volts. I'm letting the D cells sit for awhile longer to be more certain whether they have any LSD properties. This is time consuming and that makes it harder to get around to.

Any info from others regarding C & D LSD cell testing?

 

[LEDAdd1ct]

I have some AccuEvolution "D" cells which I would very much like to charge on my new Bantam BC8DP. My dad and I are going to craft some charging wires this evening, so I may have something substantive to contribute in the near future. :thumbsup:

 

[Groundhog]

I didn't note the date I recharged them, but I've been checking the voltage of some C and D size Powerex and Imedion. They were charged about a month ago on a Maha 808. Using a BK multimeter to check voltages.

Pretty stable results so far. Down to about 1.285v on the Powerex and 1.335v on the Imedion for both sizes. Results very stable across and between C and D sizes (rare for a reading >.002v variance from avg).

 

[357mag1]

Hope your new Imedion D cells check out better than mine. The Imedion cells I purchased are much like the new Accuevolution cells. They have excessive voltage sag under even light loads. A 2amp load will drop them down almost .1 volts under the original Accuevolution cells. This makes a huge difference in any Ican in the ROP low range or higher current draws. You probably won't notice it running a TK50 or Malkoff dropin though the lower voltage will increase current draw and deplete your cells faster.

 

[Groundhog]

Unfortunately my Imedions likely have the same magic smoke inside them as yours. I didn't notice a manufacturing lot on my batteries so kinda hard to compare. Maybe I didn't look hard enough.

I have 4 more D's and 2 C's that should have been delivered today so I guess I should to do a proper test starting this weekend. At least I can get an idea of how quickly they discharge vs Powerex.

Haven't considered testing them under a load. Makes sense though.

Will be using the cells with Malkoff 3-6D Maglite drop in, portable radio, maybe a LED camp lantern and other general/emergency use.

 

[357mag1]

For that use they should work fine but I would have saved a bunch of money and bought the Tenergy LSD D cells for a lot less money and they hold up under a load better. Almost as well as the old (Good) Accuevolutions.

 

[LEDAdd1ct]

I have some AccuEvolution "D" cells which I would very much like to charge on my new Bantam BC8DP. My dad and I are going to craft some charging wires this evening, so I may have something substantive to contribute in the near future. :thumbsup:

Well, I pulled three of the "D" cells I have, and tried discharging/charging them on the BC8DP. Regardless of the health of the cells, I can say that it will be very hard for me to go back to a charger that does not offer a detailed readout! Being able to watch the temperature, charge current, amount of charge put in, etc. is absolutely amazing, and having such control over the parameters is addicting.

The first couple discharge/charges on the cell did not get very far at all. I did a two amp discharge, and four amp charge, since 4aH is a little under 0.5C @10aH total. I tweaked the type of charge to "Reflex," and the cell seemed to like that better. I am not entirely sure what makes this algorithm different than a "regular" charge, but it took much more current before reading full. When I try the other two cells, I will install all three in my favorite 3D lantern and report back on their capacities and other stats, as well as whether the light remains constant instead of immediately dropping off as it had before.

After discharging one of the questionable batteries at one amp, I am now slow charging it at only 900mA. I'll report back when the charge completes some time next year. I am hoping the slow rate will help to "form" it as they say, and restore it to full capacity. I am hoping that after a prolonged period of inactivity, discharging the cell and then slow charging it can help to bring the capacity back up to snuff. Whether it will hold that under load...?

EDIT: Well, it's official! I am thoroughly confused. This site here suggests a slow charge is good for forming, and for bringing cells out of storage. This site here states that "...to begin with, the NiMH produces a very small voltage drop at full charge and the -dV is almost non-existent at charge rates below 0.5C and elevated temperatures."

So, if I am trying to revive these "D" AccuEvolution cells, am I better with the 900mA charge as printed on the cell label? Or, am I better going with the 0.5C at 5aH? Or, am I better off discharging the cell completely, and putting it in an old, dumb, timer charger until enough hours have elapsed to reach 10aH?

If it helps, I checked the picture earlier in the thread, and my button tops are shorter, like the cell on the right.

 

[ufokillerz]

hate to bump a old thread, i just got some Accuevolution D batteries from bearwobble recently, and the cells come off my Maha C808 @ ~1.47, after a week or so, they were about 1.37, these are the newer style cells with the taller button

 

[Zyban]

Awaiting for my AccuEvolution by Accupower D Cells 10,000 mAh to arrive tomorrow to start testing. I ran across some AccuLoop by Accupower D Cells today while searching again for a spec sheet for my old CTA 12,000 mAh cells (no luck). The AccuLoops are rated at 8,500 and are LSD with the part number AL8500. Found them on onlybatteries dot com (they carry both AccuLoop and AccuEvolution D cells) and can only find them listed on Accupower's international websites.

I first thought maybe AccuLoop was a non-USA brand since it isn't on the Accupower USA website, but Thomas Distributing carries both AccuLoop (AA/AAA) and AccuEvolution (C/D/9V) on their website. AccuEvolution with the higher capacity is marketed by a Michigan company in the USA with a partnership with Accupower in Austria. The spec sheet does show the AccuEvolution with the 10,000 mAh rating is a slightly larger diamter and heavier battery, so I doubt it is just a matter of rebranding with a new rating.

Any thoughts?

 

[gbcox]

Well crap... been looking around for a few days for rechargeable Ds and settled on the Accuevolution; then I read this thread after I've ordered from Bear Wobble. Will let you all know what I find... I'm hoping that all will be good, but after reading this thread I don't think I chose wisely... :sick2:

 

[gbcox]

Received my shipment from BearWobble today. Looks like the ones with the shorter positive terminal - but the top of the battery is somewhat flexible, so not sure if that really means much of anything. The initial voltages out of the box ranged from 1.317v to 1.321v. I'll running half through my Rayovac Sportsman Lantern to test, then charge up and take a few readings. I'll then create and post a spreadsheet with the findings. The batteries say 1.2v - so anything at or above that is what to expect, right?

 

[Mr Happy]

The initial voltages out of the box ranged from 1.317v to 1.321v. I'll running half through my Rayovac Sportsman Lantern to test, then charge up and take a few readings. I'll then create and post a spreadsheet with the findings. The batteries say 1.2v - so anything at or above that is what to expect, right?

1.2 V is completely empty, somewhere around 1.35 V is fully charged but this varies a bit depending on the particular brand of battery. 1.32 V out of the box is a good sign especially if all the batteries had similar voltages. Low (< 1.2 V) or uneven voltages out of the box is usually a bad sign.

 

[357mag1]

I received my TK70 this past week providing another test platform for the various D cell batteries in my collection.

In the turbo mode this light draws right around 8.5amps at the tailcap using the original AccuEvolution, Tenergy Premium, or Centura cells.

The new AccuEvolution cells with the larger positive button drew 9.7amps on turbo. This is a regulated light so the higher current draw indicates the batteries voltage sags much worse than any of the other rechargeable D cells.

I have found there is some variance in the quality of the Tenergy Centura cells as well but nothing as drastic as these new AccuEvolution cells.

The Imedion D cells are not much better.

The only LSD D cell I would recommend at this time is the Tenergy Centura. The Premium seems to work even better under higher current loads so consider them if you don't need LSD qualities.

 

[rich05uk]

Hi all, I've been watching this thread with interest as I'm just about to order a TK70 and will need to order a load of D cells and charger to go with it. What's the latest on this, which D cells are the best for me to order, obviously I was going to order the AccuEvolution ones originally but not after reading this, but am none the wiser as to which ones to go for instead?

Also, any recommendations for a charger, cost is not an issue?


EDIT

I've done a little bit more research and wanted to know if Ansmann are any good and if anyone has had any experience with them, good or bad:-

These are their 10,000mAh batteries http://www.ansmann.de/cms/en/consum...hargeable-batteries-nimh/mono-d/10000mah.html

And this is their battery management charger http://www.ansmann.de/cms/en/consumroot/chargers-and-power-supplies/xc3000.html

Thanks.

 

[Nadrek]

I bought four AccuEvolution D LSD's a month or so ago, and charged them on my Maha-808M immediately after. My CBA III, set for a 10A discharge rate, reports the cell almost immediately drops to 1.03V, and only discharged 7.18AH until the 0.9V cutoff voltage was reached. Needless to say, I'm unimpressed; what is the best way of contacting AccuEvolution? I'll be checking the other 3 AccuEvolution cells, as well as some older CTA 12AH and much older GI 8AH stadard NiMH cells, all charged within a few days of each other (a month ago).