EEVblog Electronics Community Forum
EEVblog => EEVblog Specific => Topic started by: Barny on April 12, 2019, 06:26:53 am
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https://www.youtube.com/watch?v=5Q1MPrgea1M (https://www.youtube.com/watch?v=5Q1MPrgea1M)
Are you getting ripped off with Energizer and Duracell D cell NiMH rechargeable batteries? Why is a D cell NiMh the same capacity or lower than the smaller C or even AA cell? Teardown time!
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Ca. 1995 I got D Cells from Hofer (Austrian version of Aldi).
They where Sony branded (I think).
They had standard AA cells stuck in place.
By the way, Dave got really lucky.
Clive took NiMh apart and they ot really exiting.
https://www.youtube.com/watch?v=tBg4ximDrsk=related#t=16m10 (https://www.youtube.com/watch?v=tBg4ximDrsk=related#t=16m10)
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He said he fully discharged them before disassembly; I think he is quite aware of the danger if you skip that step.
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Well, I'm sold :-)
Not sure if this holds for all brands etc but this is similar to finding out what is inside a 9V battery, and why such poor capacity !
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He said he fully discharged them before disassembly; I think he is quite aware of the danger if you skip that step.
Big Clive discharged those AAs before disassembly also!!
That's part of the reason why he was so surprised when the flames erupted... Big Clive isn't often at a loss for words, but he was absolutely flustered at about 18m into the video. :)
Just because a cell is in a discharged state doesn't mean there isn't still the potential for chemical reactions and energy release from the materials composing said cell!
What's inside Eneloop and LIDL NiMh cells (fire, apparently)
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I thought that discharging the cells completely would avoid little unexpected combustion incidents.... I was wrong.
https://youtu.be/tBg4ximDrsk?t=980
I was rather disappointed that Dave didn't even need an Explosion Containment Pie Dish... ;)
No flames even? I suppose we should all unsubscribe! ;D
Edit: I did get a good chuckle when at 12m Dave said "I won't pretend to know the exact chemistry inside..." because it was very reminiscent of Big Clive's "Ok... Right... Yeah... Not, not sure the science of this, but this is all going on fire quite rapidly. So, that's quite an exciting chemical. Oh, this isn't necessarily quite good. Where is my Explosion Containment Pie Dish?"
:-DD
But then there were no flames....
Of course, I suppose to fit the 2500 mAh into the AA size case instead of C, they have to do things a tad bit more "energetically"?
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I took a Duracell apart some years ago and it had an AA cell inside so at least they have increased the capacity over the last seventeen years or so since then.
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Eneloop uses smaller 3xAA for D, or 4xAAA for C size.
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The D cell in these 80's rat shack batteries was a C cell with a tall nipple & lager plate spot welded to the bottom.
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Well, I'm sold :-)
Not sure if this holds for all brands etc but this is similar to finding out what is inside a 9V battery, and why such poor capacity !
I have seen 9V battery half full of button cells
but back in the day a 9V battery had a Full deck of cards dipped in wax.
also
I remember a time when I was only 5yro
I remember a time when "D" Dry cell batteries had a graphite rod cathode inside t
from the 1960s and 1970s radio and telephone use
http://archive.siliconchip.com.au/cms/gallery/article.html?slideshow=0&a=110151&i=12 (http://archive.siliconchip.com.au/cms/gallery/article.html?slideshow=0&a=110151&i=12)
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This is actually very common. I've seen many D (and even C) NIMH cells which are constructed from smaller physical cells.
It stems from the fact that "back in the day", The commonly used carbon/zinc batteries had a relatively high internal resistance, and you needed physical size of elements to get higher currents. As a result many applications where D cells were spec'd were more for current capability and less for longevity.
Alkaline cells improved on this, but not enough to change the practices. Along comes NICAD and NIMH and now you can get a lot of current from a much smaller cell.
Add to that the fact that you need a smart (& beefy) charger to charge a 10,000mah cell in a reasonable time, and for many consumer applications the "reduced" D cells almost-kinda make sense. They are (maybe) lower cost, can be recharged with a simpler, cheaper charger (the kind a typical non-EEVBLOG consumer is likely to buy), and operate higher draw devices as well as and often better than non-rechargeable cells. Sure they may not last as long, but they are rechargeable and the consumer will smile about how much money he's saving every time he recharges them.
While I don't fully agree with it, I don't think the reduced cells are a blatant scam... they are fitting new technology into an old form factor in a way that for some applications is reasonable.
They could be more up-front about it, but like most products "Caveat emptor" - you really need to know what you are buying.
A better (at least more up-front) alternative is that you can buy adapters to convert smaller NIMH batteries into larger form factors for cases where doing so makes sense.
Dave
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Well, I'm sold :-)
Not sure if this holds for all brands etc but this is similar to finding out what is inside a 9V battery, and why such poor capacity !
I have seen 9V battery half full of button cells
That is not common for primary cells. I took a lot of them apart here:
https://lygte-info.dk/info/BatteryDisassembly9VAlkaline%20UK.html
And did not find a single button cell
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The pricing is also interesting. GP ReCyko+ ready-to-use NiMH cells for example, a double pack of D cells with 2200mAh is EUR 10.70, double pack of 2000mAh AA cells EUR 5.40 and the double pack 2600mAh AAs just EUR 8.20. You pay a premium for the "larger" cell despite having a low Ah rating. Varta seems to be reasonable, double pack ready-to-use D cells with 3000mAh for EUR 8.99 and the double pack of AAs with 2600mA is EUR 7.25.
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I have done some performance test on C & D cells, both NiMH and Alkaline: https://lygte-info.dk/review/batteries2012/CommonCDcomparator.php
Comparing them to AA can be done here: https://lygte-info.dk/review/batteries2012/CommonAAcomparator.php
The low capacity D cells are better than AA cells at high current.
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That makes perfectly sense when you consider that the nearly C sized inner cell with 2.x Ah has more surface area than a AA with the same Ah rating.
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Perhaps there is a safety issue here as well? - A product with 12 "real" D cells inside it could release quite a lot of energy if something went wrong?
For those that know what they are doing, there are thankfully "real" batteries available...
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Old news. That has been the case since they first introduced NimH batteries. A true D cell is at least 5000mAh.
D-cells are on their way out. apart from flashlights very little stuff uses that, and with the advent of powerful LED lights the flashlight marked has moved to LiIon rechargeable. You can find many adapters to convert C to D or 3 or 4 AA or AAA to D.
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That Duracell battery with it's electrolytic capacitor rolled design is much different then the ones in the late seventies that I took apart as a kid. Back then it was a full battery compartment of black wet powder with a big carbon rod in the center as the positive anode.
This video real shows how consumer battery technology changed in the last forty years.
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Almost all D cell rechargeable batteries have a sub-C or in modern types even a AA inside, this has been standard since the beginning. You can buy true D cell NiMH batteries but they are much more expensive and quite hard to come by. At least these list the true capacity on them.
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The pricing is also interesting. GP ReCyko+ ready-to-use NiMH cells for example, a double pack of D cells with 2200mAh is EUR 10.70, double pack of 2000mAh AA cells EUR 5.40 and the double pack 2600mAh AAs just EUR 8.20. You pay a premium for the "larger" cell despite having a low Ah rating. Varta seems to be reasonable, double pack ready-to-use D cells with 3000mAh for EUR 8.99 and the double pack of AAs with 2600mA is EUR 7.25.
Its fair to charge some premium as the cell is larger in size and probably not sold in such a high quantity. 2x seems quite a bit though.
Tenergy D 8000mAh - $5.87
Energizer D 2500mAh - $4.00
Energizer AA 2300mAh - $3.00
Alkaline D 12-18kAh - $1.00
So, Energizer is overpriced, if they actually made a full D cell they would probably charge $10 for it, which may be too much for consumers to stomach.
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The Tenergy cells I've had were garbage and did not meet quoted capacity, it's possible this has changed though.
I'm thankful for modern chargers that measure capacity, it is making it a lot harder for companies to screw people by lying about the capacity.
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That Duracell battery with it's electrolytic capacitor rolled design is much different then the ones in the late seventies that I took apart as a kid. Back then it was a full battery compartment of black wet powder with a big carbon rod in the center as the positive anode.
You're thinking of primary cells like zinc carbon or alkaline. Rechargeable batteries have the roll construction instead for low internal resistance.
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The Tenergy cells I've had were garbage and did not meet quoted capacity, it's possible this has changed though.
Yeah their normal cells are crap, I should have specified its the Tenergy Centura low self discharge, which are a bit better.
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... That is not common for primary cells. I took a lot of them apart here: https://lygte-info.dk/info/BatteryDisassembly9VAlkaline%20UK.html
Very handy / informative sites, including links. Great work
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When I needed several D cells to run for several hours, I got the AA to D adapters and used eneloops. Worked great for the time I needed them.
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I do that too, although it can't match the capacity of a true D cell which is handy in some applications.
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By the way, Dave got really lucky.
Clive took NiMh apart and they ot really exiting.
https://www.youtube.com/watch?v=tBg4ximDrsk=related#t=16m10 (https://www.youtube.com/watch?v=tBg4ximDrsk=related#t=16m10)
Metal hydrides are pyrophoric. mikeselectricstuff has also experienced this, in a slightly different product:
https://www.youtube.com/watch?v=y48wCuC3KcA#t=47m20s (https://www.youtube.com/watch?v=y48wCuC3KcA#t=47m20s)
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Not a ripoff, they're clearly marked and also cheaper than the "real thing"
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Not a ripoff, they're clearly marked and also cheaper than the "real thing"
EEVblog #1200 - CONFIRMED! Energizer & Duracell NiMH meet stated capacity.
Get real. If those scumbags make a battery with air inside they should have made it smaller.
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Get real. If those scumbags make a battery with air inside they should have made it smaller.
Wouldn't really fit as a replacement for a D-cell then would it? |O
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Incredible that this kind of firms could do these....
Are an appreciable price difference between RS one and the “mass market” others?
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Let's agree on "naughty". They could simply sell a AA or C cell plus a D cell adapter. Hiding everything in a D cell package is naughty since most consumers don't know much about Ah ratings and might be pleasantly surprised about the low price. This could be the marketing strategy behind it.
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It's slightly shady but as I mentioned earlier it's been this way for ~40 years almost universally, the standard sub-c cell being the most common. There have long been some true D rechargeable cells available but they have always cost a lot more, seems like they were around $25 each in the 90s.
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Ah, i was wondering what the deal is.
Thought there was some sort of a law limiting the capacity of the "legit" ones - i could only get 8-10 Ah ones from lesser known and unknown brands but they tested up to spec rather than being rip-offs typical for off-brand 18650s.
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But then, there are very few applications that require D cell. Boom boxes, flashlights and toys. Anything high drain high energy moved to Lithium, and this is just to keep an old market alive. Sources claim that is was like 2-3% of the battery market a decade ago. Most battery never gets charged 10% of its claimed lifetime...
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When I needed several D cells to run for several hours, I got the AA to D adapters and used eneloops. Worked great for the time I needed them.
I brought a bag of those dual AA enclosures/adapters many years ago and they are very handy as I use many rechargeable AA'S
I had a collection 2500 mah Energizers but they went flat after a week and I replaced them with Annsman 2850 but they were wern't 2850 mah more like under 2500mah and they held charge for about a month.
I brought some big Annsman D cells in 2007 for a torch. They did discharge up near 10,000mah when I got them but they kept on going flat and eventually they bulged on the negative plate and stopped accepting a charge. I was a disappointed as they cost a lot but now I use the AA enclosures to fit C and D cells.
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Get real. If those scumbags make a battery with air inside they should have made it smaller.
Wouldn't really fit as a replacement for a D-cell then would it? |O
noun: irony
the expression of one's meaning by using language that normally signifies the opposite, typically for humorous or emphatic effect.
;)
Dave was have a bit of fun winding up mock outrage. You can tell from the first few minutes. I'll quote him.
"In addition to having them clearly marked on the batteries themselves, in the datasheet, everything's legitimate. It is marked on the packaging, there it is, 2500mAh..."
"These are legitimately less capacity"
and he proceeds to bounce them in a manner akin to his video on alkaline cells as a capacity test.
It wouldn't surprise me if he was flirting with this idea as some form of April fool prank but he couldn't quite figure out how to make it work to his satisfaction.
Of course I could be quite wrong.
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I had a collection 2500 mah Energizers but they went flat after a week
I have some of those, but 2300 mAh. These were pre low self discharge technology.
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I retired all of my non-LSD batteries, they're just too much hassle compared to the ones I can charge and put in the drawer ready to go.
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Old news. That has been the case since they first introduced NimH batteries. A true D cell is at least 5000mAh.
D-cells are on their way out. apart from flashlights very little stuff uses that, and with the advent of powerful LED lights the flashlight marked has moved to LiIon rechargeable. You can find many adapters to convert C to D or 3 or 4 AA or AAA to D.
Even before NiMH, NiCd batteries were this way too. The inside cell is actually a standard size sub C. sub C cells were also used directly in devices where the cells were welded into a pack or permanently connected into a device with a built in charging circuit. Cordless drills and electric shavers were typical application of sub-C NiCd batteries. There is a good chance that if you disassemble a 'C" battery you will also find a spacer with a smaller internal cell size.
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I have found an interesting article written a while ago about the pricing when they did put AA's in D cells:
https://www.theinquirer.net/inquirer/news/1041965/energizer-rechargeable-d-batteries-rip (https://www.theinquirer.net/inquirer/news/1041965/energizer-rechargeable-d-batteries-rip)
Energizer rechargeable "D" batteries are a rip-off
Really just "AA" cells inside
Egan Orion
07 November 2007
A CONSUMER ACTIVIST took a closer look at Energizer brand rechargeable "D" size batteries and found that they provide only "AA" battery capacity, at four times the price.
Rechargeable nickel metal hydride (NiMH) batteries are great. They can be used over and over again up to 1,000 times, avoiding the need to buy, and then later throw away, a lot of nonrechargeable alkaline batteries.
Sure, they're expensive, but recharging them repeatedly makes their use more economical in the long run than buying many disposable batteries. If you fully discharge them each time before recharging, they can last practically indefinitely without degrading due to battery memory effects. But battery companies would rather sell lots of alkaline batteries, naturally, because they make a profit on each one of those sold.
So NewsTarget took a look at one of the most common sizes of rechargeable batteries sold by a leading US brand, the Energizer "D" cell used in most full-sized household flashlights, among other applications. What intrigued them was that the battery's stated capacity is only 2,500 mAh, the same capacity as given for the physically much smaller "AA" size batteries.
They took apart one of Energizer's "D" batteries and found that it contained a much smaller battery inside, comparable in size to an "AA" battery, surrounded by empty airspace and a plastic shell. The "D" cell actually turned out to be just an "AA" cell inside a larger casing.
Since Energizer's rechargeable "AA" battery costs only about $3, but its rechargeable "D" battery costs $12, or four times as much, they reckon you're getting ripped off every time you buy a rechargeable "D" battery from Energizer. It would seem they've got a point. µ
Energizer 2500mah for the same capacity:
D cell costs $12
AA cell costs $3
The adapters cost me about I think I brought a bags of them years ago for £10 but they seem a lot cheaper now.
https://www.amazon.co.uk/Size-Battery-Adapter-White-Case/dp/B0092XYLP6 (https://www.amazon.co.uk/Size-Battery-Adapter-White-Case/dp/B0092XYLP6)
8 AA to D cell adapters for £2.22.
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Energizer 2500mah for the same capacity:
D cell costs $12
AA cell costs $3
Yeah uh, at $3 you can get 18650 size 3000mAh lithium cells (NCR18650B), I don't know in which part of the world AA/C/D cells are still common. It feels like such a ripoff paying $3 for a small ni-mh that self discharges in a month and holds little energy. Here even flashlights and toys use 18650s.
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Here even flashlights and toys use 18650s.
Isn't that a problem when shipping products or travelling by air?
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Yeah uh, at $3 you can get 18650 size 3000mAh lithium cells (NCR18650B), I don't know in which part of the world AA/C/D cells are still common. It feels like such a ripoff paying $3 for a small ni-mh that self discharges in a month and holds little energy. Here even flashlights and toys use 18650s.
AA cells are still used everywhere, I do have some high power flashlights that use 18650s but for the most part I prefer AAs since they're so universal. They don't self discharge rapidly anymore and they don't catch fire if overcharged or get damaged by over-discharging. I have >50 NiMH AA's circulating around my home in various devices.
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Dave's Duracell D rated 2,200mAh but "Standard Charge 220mA for 16h" which is 3,520mAh.
NiMh charge acceptance is only 63%?
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Old news. That has been the case since they first introduced NimH batteries. A true D cell is at least 5000mAh.
Even before NiMH, NiCd batteries were this way too. The inside cell is actually a standard size sub C. sub C cells were also used directly in devices where the cells were welded into a pack or permanently connected into a device with a built in charging circuit. Cordless drills and electric shavers were typical application of sub-C NiCd batteries. There is a good chance that if you disassemble a 'C" battery you will also find a spacer with a smaller internal cell size.
This has been the rule for consumer grade NiCd D-cells and then NiMH D-cells since the beginning and sellers went to some effort to conceal it by making any capacity markings, if they existed at all, as inconspicuous as possible. An easy way to identify the crippled D-cells is by weight which is easy enough to distinguish by hand. If you knew where to look, you could always buy full capacity D-cells at a premium; I used to pick up grey market ones from the battery guy at the TRW amateur radio swap meet and they were glorious to use.
True standard NiCd D-cells are about 4 amp hours and NiMH D-cells are about 8 amp hours. The fake NiCd D-cells had of course the C-cell capacity of about 1.2 amp hours. I had not seen the AA and AAA versions but AA to D adapters have been around for a while.
Incidentally, a stack of 10 true NiCd D-cells has no problem starting a car.
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Incidentally, a stack of 10 true NiCd D-cells has no problem starting a car.
150 amps?
I'm pretty sure that one of the reasons for the "fake" cells is - safety.
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The Energizer uses ans SUB-C cell an industrial standard used in power tools or emergency light systems.
There are several types of cells, Standard, High discharge rate and High temperature. Each one has it's specific application. Here seems like it's just a standard subc cell with 2500mAh.
http://sub-c-cell-size.rambobattery.com/ (http://sub-c-cell-size.rambobattery.com/)
;)
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Incidentally, a stack of 10 true NiCd D-cells has no problem starting a car.
150 amps?
I'm pretty sure that one of the reasons for the "fake" cells is - safety.
It wouldn't do much good, even AA NiCD cells can produce enormous current for a short period, NiMH usually less. It still quite a lot. Back when RC cars used NiCD sub-C packs the guys racing them would drain a pack in <2 minutes, that requires some serious draw.
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Incidentally, a stack of 10 true NiCd D-cells has no problem starting a car.
Well, the battery pack for the 1st generation honda insight was just a (taller) stack of NiMH D cells, and that could move the car not just start it despite the higher resistance of the cells vs. NiCd.
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Incidentally, a stack of 10 true NiCd D-cells has no problem starting a car.
150 amps?
I'm pretty sure that one of the reasons for the "fake" cells is - safety.
It wouldn't do much good, even AA NiCD cells can produce enormous current for a short period, NiMH usually less. It still quite a lot. Back when RC cars used NiCD sub-C packs the guys racing them would drain a pack in <2 minutes, that requires some serious draw.
I have had a few fires involving NiCd AA cells. The cells remained undamaged.
The only reason for the fake cells is cheapness.