question Differences between Sanyo's AA eneloops and Panasonic's AA eneloops?

apairofpcs

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#1
[SIZE=+1]I'm in the immediate market for eight AA eneloop cells. The 3rd generation of Sanyo cells specifies 1,800 charges, up from 1,500 charges. Panasonic bought Sanyo's battery division and specifies 2,100 charges. The capacities are identical. Sanyo boasts 75% of charge remaining after three years in storage. Panasonic boasts 70% of charge remaining after five years in storage. What are your opinions about each cell? The prices are comparable.
[/SIZE]
 

LunarMist

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#2
Sanyo was folded back into Panasonic/Matsushita. They probably have differencs in marketing, but there are only two current types. Thee xxx are the high capacity, faster srlf duscharfe and the lower capacity lower duscharfe
 

apairofpcs

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#3
Sanyo was folded back into Panasonic/Matsushita. They probably have differences in marketing, but there are only two current types. Thee xxx are the high capacity, faster self-discharge and the lower capacity lower discharge.
I wasn't considering the XX version. But the former standard Sanyo and the new Panasonic have some differences. I still have ten of the original Sanyo AA eneloops, but I'd like spares. If the claims made by Panasonic are accurate, their eneloops will be a better choice. I admire both Sanyo and Panasonic for retaining the 2,000 mAh capacity, with all their competition hovering around 3,000 mAh. It's this 2,000 mAh capacity that allows an eneloop to demonstrate a ridiculously low self-discharge rate. I recall that when I started buying eneloops, each cell in a 4 pack of AA cells had the same voltage, to the millivolt, which is a feat after being in storage until sold. This is testimony to Sanyo's exemplary quality control. Add to this fact that they're fully functional right out of the package. Does anybody own both versions in question in my thread, and if so do they see any difference in performance between the two?
 

time

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#4
Sanyo actually bought the battery manufacturing entity from Toshiba in 2001 and named it Sanyo Energy Twicell.

When Panasonic asborbed Sanyo, it was sold to FDK, a satellite company of Fujitsu, who renamed it to FDK Twicell (FDK has now been reabsorbed into Fujitsu as a division). It was sold as a going concern, so it's the same factory with the same technology and has continued to produce all Eneloops to date. It's now acting as a supplier to Panasonic, who apparently cancelled plans to expand their own manufacturing. Note that Panasonic did not sell the larger scale automotive battery line from Sanyo.

Non-retail cells are sold as FDK Twicell instead of Sanyo Twicell, it's just the retail cells that are branded either Sanyo or Panasonic (or both) or Fujitsu.

There are small differences between the cells, but you have to realize that this is more down to different generations or variants that co-exist. The last two Sanyo-branded models progressively reduced self-discharge and increased life expectancy. Technically, Panasonic's most recent model has marginally better life expectancy, but I wouldn't lose any sleep over it (2100 cycles vs 1800).

The higher capacity (2550mAh) cells have a higher level of self-discharge, but again, that improved with the more recent version to 85% retention after one year, vs 90% for the 2000mAh cells. The only drawback for most applications is cost and weight.

I would take claims of 3000mAh capacity with a grain of salt. That *might* be achievable under laboratory conditions, but in practise their effective runtime tends to be much less than with 2500mAh Eneloops.
 

LunarMist

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#5
I wasn't considering the XX version. But the former standard Sanyo and the new Panasonic have some differences. I still have ten of the original Sanyo AA eneloops, but I'd like spares. If the claims made by Panasonic are accurate, their eneloops will be a better choice. I admire both Sanyo and Panasonic for retaining the 2,000 mAh capacity, with all their competition hovering around 3,000 mAh. It's this 2,000 mAh capacity that allows an eneloop to demonstrate a ridiculously low self-discharge rate. I recall that when I started buying eneloops, each cell in a 4 pack of AA cells had the same voltage, to the millivolt, which is a feat after being in storage until sold. This is testimony to Sanyo's exemplary quality control. Add to this fact that they're fully functional right out of the package. Does anybody own both versions in question in my thread, and if so do they see any difference in performance between the two?
The cells are mass produced so unless they made some major negative changes (which makes little sense) I'd go with the Panasonics as they are newer. Sanyo was related to Matsushita (Panasonic) years ago before all the corporate shenanigans in recent years. They have almost always made cells equal or better than their contemporaries.

Disregard my post above. I'm not sure what was up with the cell phone Androids.
 

apairofpcs

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#6
Sanyo actually bought the battery manufacturing entity from Toshiba in 2001 and named it Sanyo Energy Twicell.

When Panasonic absorbed Sanyo, it was sold to FDK, a satellite company of Fujitsu, who renamed it to FDK Twicell (FDK has now been reabsorbed into Fujitsu as a division). It was sold as a going concern, so it's the same factory with the same technology and has continued to produce all Eneloops to date. It's now acting as a supplier to Panasonic, who apparently cancelled plans to expand their own manufacturing. Note that Panasonic did not sell the larger scale automotive battery line from Sanyo.

Non-retail cells are sold as FDK Twicell instead of Sanyo Twicell, it's just the retail cells that are branded either Sanyo or Panasonic (or both) or Fujitsu.

There are small differences between the cells, but you have to realize that this is more down to different generations or variants that co-exist. The last two Sanyo-branded models progressively reduced self-discharge and increased life expectancy. Technically, Panasonic's most recent model has marginally better life expectancy, but I wouldn't lose any sleep over it (2100 cycles vs 1800).

The higher capacity (2550mAh) cells have a higher level of self-discharge, but again, that improved with the more recent version to 85% retention after one year, vs 90% for the 2000mAh cells. The only drawback for most applications is cost and weight.

I would take claims of 3000mAh capacity with a grain of salt. That *might* be achievable under laboratory conditions, but in practice their effective runtime tends to be much less than with 2500mAh Eneloops.
Thank you for the short history of eneloop cells. I've discovered that in the case of Sanyo AA eneloops, the advertised charges started at 1,000, increased to 1,500 ( still available ) and finally 1,800. The Panasonics are advertised at 2,100.
 

apairofpcs

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#7
The cells are mass produced, so unless they made some major negative changes (which makes little sense) I'd go with the Panasonics as they are newer. Sanyo was related to Matsushita (Panasonic) years ago before all the corporate shenanigans in recent years. They have almost always made cells equal or better than their contemporaries.

Disregard my post above. I'm not sure what was up with the cell phone Androids.
I agree with your recommendation. Panasonic's eneloops, offering 2,100 charges and 70% remaining capacity after 5 years, are a slightly better product than Sanyo's latest version, offering 1,800 charges and 75% remaining capacity after 3 years. Newegg sells an 8 pack of the Panasonics for $25 with free shipping and no sales tax, This is a good deal.

I fondly remember when eneloops hit the streets. They revolutionized NiMH technology by offering the first cells to have an "imperceptible" self-discharge rate. I recall my previous NiMH cells losing all of their capacity in as little as 3 months of non-use. Of course, many companies have manufactured similar cells since eneloops were released, but I'm not sure if any of them are equivalent to them in quality or reliability.

To this day, I'm puzzled as to why any manufacturer will "push" the capacity of an AA cell to close to 3,000 mAh, when the self-discharge rate will increase with capacity. The way I see portable battery power, it makes more sense to have reliable cells than high capacity cells. Since the volume of an AA cell can't be increased without reducing the can's wall thickness, thereby making the cell more vulnerable to damage, this makes no sense to me if safety is of prime importance. Knowing that the anode / cathode separator elements in a cell must be made thinner in order to increase capacity, and this process increases the self-discharge rate, why would a manufacturer do this? The manufacturers keeping their capacities in the area of 2,000 to 2,100 mAh are to be commended, because they're resisting the temptation to be competitive through higher capacities.
 

time

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#8
Can you substantiate your assertions that the increased capacity is achieved through thinner canister walls? And that that has some identifiable negative consequence?

A thinner separator makes sense, but I hadn't realized it would necessarily lead to increased self-discharge. Care to share your sources?

Unless manufacturers can continue to increase NiMH capacities, they will have no customers, because Lithium chemistry cells have double the energy density by weight, not to mention all the other advantages.
 

time

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#10
The separator thickness is measured in micrometres, but I believe tunneling doesn't occur until you are measuring in nanometres.
 

LunarMist

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#11
Can you substantiate your assertions that the increased capacity is achieved through thinner canister walls? And that that has some identifiable negative consequence?

A thinner separator makes sense, but I hadn't realized it would necessarily lead to increased self-discharge. Care to share your sources?

Unless manufacturers can continue to increase NiMH capacities, they will have no customers, because Lithium chemistry cells have double the energy density by weight, not to mention all the other advantages.
Lithium secondary cells still have many disadvantages as well, such as safety and longevity.
 

apairofpcs

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#12
Can you substantiate your assertions that the increased capacity is achieved through thinner canister walls? And that it has some identifiable negative consequence?

A thinner separator makes sense, but I hadn't realized it would necessarily lead to increased self-discharge. Care to share your sources?

Unless manufacturers can continue to increase NiMH capacities, they will have no customers, because Lithium chemistry cells have double the energy density by weight, not to mention all the other advantages.

I can't substantiate my assertions with a firm source, but I can provide scientific explanations as to why my assertions are feasible.

Since the outer dimensions of an AA or AAA NiMH cell can't be increased without destroying every industry that uses AA and AAA cells, something on the inside has to give to allow higher capacity.. If the power capabilities of the elements comprising the electrolyte, anode and cathodes in a cell are the same for 2,000 mAh cells as for 3,000 mAh cells, then there is a need to increase the volume of the electrolyte, anode and or cathode materials to allow the introduction of more of these materials to build up the capacity. If the wall thickness is not reduced to generate greater volume for more materials, then something else has to allow an increase in volume for more materials.

I've spoken to people who've stated that reducing separator thickness is one way to generate more volume for materials. In post #9, ddrueding used the term "quantum tunneling." I believe this term describes the phenomenon where materials can permeate through other materials, which is how I was explained why a thinner separator allows anode and cathode materials to combine when they more easily leak through the separators. In effect, the leaking anode and cathode materials create a low level closed circuit, which depletes the cell via self-discharge.

If my assertions are incorrect, then why would manufacturers who advertise "low self-discharge" keep their cell capacities close to 800 mAh for AAA cells and 2,000 mAh for AA cells, instead of close to the capacities of the manufacturers who are "pushing the capacity envelope"?

I agree with your statement about the need to be competitive, and many are competitive. But those that are manufacturing cells with capacities near the current maximum, are NOT advertising a "low self-discharge" rate. In my feeble mind, this trend seems to point to what I've written above. You can't indefinitely increase capacity without either introducing more chemicals in a cell, or finding more efficient combinations of chemicals.

Regarding the differences between NiMh cells and lithium based cells, we've seen how these two chemistries each offer advantages and disadvantages. Since NiMH cells are known to be safer than lithium based cells, this is probably why so many consumer devices are designed to use NiMH power sources instead of disposable ones. A smart manufacturer will design circuits to allow NiMH cells at 1.2 Vas well as disposable cells at 1.5 V, the choice being made by the user. I have many such devices.

If I'm off base in what I've written, I welcome anybody to "enlighten" me, with the knowledge that I won't be devastated. I'm as OK being wrong, as being right!

 

apairofpcs

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#14
The separator thickness is measured in micrometres, but I believe tunneling doesn't occur until you are measuring in nanometres.
I'm enjoying the technical input from you guys, because it reminds me of my education in physics, from a very looooong time ago.
 

apairofpcs

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#15
Lithium secondary cells still have many disadvantages as well, such as safety and longevity.
Ditto.....!

Consider the repercussions on all airlines using lithium ion cells in their 787 Dreamliners, when the battery pack caught fire on a few planes. We're speaking of millions of dollars of lost revenue when the entire fleet was grounded for a few months. I bought four 3 V 123 form factor LiFePO4 "safe" cells, to be used in pairs in a flashlight with a 7.1 V max. input voltage. The combined "off the charger" voltage is slightly above 7.1 V, but the manufacturer states that the circuitry can tolerate this, since the cell's voltage drops quickly upon initial use. This lithium based chemistry is the safest one out there for the consumer market.

Speaking of NiMH cells, my Panasonic 2,100 charges AA eneloop 8 pack shipment arrived a few hours ago. I forgot to inform you that I placed the order last Sunday from Newegg.

Since I generated this thread to get advice about the available eneloop varieties, I no longer need such input. But don't let this stop us from further discussing the science of NiMH cell chemistry.
 

time

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#16
No problem, I wondered if you were bringing a retired industrial chemist's knowledge to the table when you hypothesized that the increased capacity was due to increased volume!

Thinning of the container walls may well have occurred, although I suspect it would have been more of a weight-shedding exercise. Thinning of the separator is a given, but I think the obvious explanation is greater electrolyte density, balanced by reduced mass in the anode/cathode structure. The 2000mAh cells weigh in at 26g and the 2500mAh cells at 30g.
 
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#17
The separator thickness is measured in micrometres, but I believe tunneling doesn't occur until you are measuring in nanometres.
This is correct. I had no idea where the tech was inside batteries. Good to hear that they have so much room for progress. I wonder what a "price no object" AA would look like?
 

RichardS

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#18
Hi, all....
a year ago I bought the Sanyo Ni-MH battery charger (NC-MONO6U)set with 12 eneloop batteries.
Recently, I was given a gift of the new Panasonic BQ-CC55 charger and another of 12 of IT'S batteries in the package.
What I want to know is can I use ANY of those 2 dozen batteries from one set to the other? Can I charge the earlier eneloop batteries that came with the the Sanyo unit, now in the newer Panasonic unit?
Conversely, can I use the new eneloop batteries packaged in the Panasonic packaging in the older Sanyo charger?
So, now I have a couple of dozen of these eneloops, does it matter which charger I use?
thanks in advance, guys...
 

Stereodude

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#24
Any way to restore a Sanyo AA that the charger won't charge?
It probably is at too low of a voltage for the charger to recognize. Connect it in parallel with a good charged one for a few seconds. Or hook it up to a power supply set to 1.2V with a low current limit of like 100mA for a minute.
 

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#27
crap forum software reminder 1
crap forum software reminder 2
Attempting to edit my post with mobile Firefox on my tablet caused it to make another new post and leave the original in place even though I clicked Edit Post. I can't delete the extra posts, but I was able to edit them on my laptop.
I'm happy to update the forum software to something more modern like Xenforo but I have concerns that it'll upset small base of users we have.
 

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#28
What I want to know is can I use ANY of those 2 dozen batteries from one set to the other?
Regardless of battery chemistry (type), a general rule of thumb is to use cells of similar capacity, charge, and health together. Using an end-of-life cell together with a new, healthy cell will load the latter considerably and shorten its life.

There are advanced chargers that test cells and indicate their health. The two chargers you have won't do that. So in the absence of this information, it is advisable to use the old set of cells together, the new set together, and not mix the two sets.
 

time

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#29
Probably more significant is the fact that the Sanyo NC-MQNO6U is only a dual-channel charger. On top of that, it's a 'slow' charger, taking 10 hours to fully charge. Although there's some mention of being a 'smart' charger, Negative Delta V isn't reliable with low charge rates, so it's more likely the charger relies on a timer and temperature monitoring. This type of charger is not friendly to NiMH batteries, but cheap to make.

The Panasonic BQ-CC55 is a proper smart charger with 4 independent channels, although power supply limitations mean it takes twice as long for 4 batteries as 2. I would be favoring this charger for all the batteries, if possible. If you need to use the NC-MQNO6U, try to keep the batteries in pairs (label them) and don't mix them up.

You can crudely compare cells with a multimeter. You want each pair to have a similar voltage at full charge and when at least half discharged.
 

Howell

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#30
It probably is at too low of a voltage for the charger to recognize. Connect it in parallel with a good charged one for a few seconds. Or hook it up to a power supply set to 1.2V with a low current limit of like 100mA for a minute.
Thanks. Pairing it with another battery worked.
 

Stereodude

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#31
Thanks. Pairing it with another battery worked.
Glad I could help. I've done both methods myself. I was doing a runtime test of a lantern last night and found 3 of the 4 D cell NiMH batteries were under .25V this morning. I set my power supply to 1.2V, the current limit to 100mA and connected each one until they got to .8V. Took 15-30 seconds per battery. I let them sit for a little bit and then dropped them in my Maha.

For AA's I have a charger that will start charging as soon as a cell is inserted regardless of cell voltage so I can just put them in there for a minute to get the voltage up before putting them in one of my fancier chargers.
 

Howell

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#32
D-cells: I bought some AA to D adapters but I've yet to try them but I see you are using natural Ds. Do you have a preference based on experience?
 

LunarMist

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#33
D-cells: I bought some AA to D adapters but I've yet to try them but I see you are using natural Ds. Do you have a preference based on experience?
It really depends on the device power needs. What are the peak current and usage cycles?
 

mubs

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#34
I was doing a runtime test of a lantern last night and found 3 of the 4 D cell NiMH batteries were under .25V this morning. I set my power supply to 1.2V, the current limit to 100mA and connected each one until they got to .8V. Took 15-30 seconds per battery.
Where do you get D size NiMh cells? Are they LSD as well? And this kind of power supply that lets you adjust both voltage and amperage? I do have a Sanyo charger that came with my Eneloops, Model NC-MQN05U, but have never used it and don't know if it will charge regardless of battery state. I've always used the Maha C9000.


D-cells: I bought some AA to D adapters but I've yet to try them but I see you are using natural Ds. Do you have a preference based on experience?
I'm using an 1xAA to D adapter that came with the Eneloop kit I bought at Costco years ago. Works quite well. I also ordered a 2xAA Parallel to D adapter at Amazon. My regular mule (bro) will bring them to me in 3 weeks time.
 

LunarMist

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#35
There are full D cells as well as D cells that contain sub-C cells and probably other sizes. The Ah rating will be your clue. Full D are up to 8 or 10 Ah.
Here is one example of D LSD at random search.
 

Stereodude

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#36
D-cells: I bought some AA to D adapters but I've yet to try them but I see you are using natural Ds. Do you have a preference based on experience?
I'm using Tenergy Centura D cells. They's LSD and 8Ah. I saw reports on CandlepowerForums that they had lower internal resistance than the PowerEX LSD cells. NiMH D cells are expensive to get into simply because the charger costs so much.
 

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#37
Where do you get D size NiMh cells? Are they LSD as well? And this kind of power supply that lets you adjust both voltage and amperage? I do have a Sanyo charger that came with my Eneloops, Model NC-MQN05U, but have never used it and don't know if it will charge regardless of battery state. I've always used the Maha C9000.
They're sold here and there. There are LSD and non-LSD true D cells out there. I'm using Tenergy Centura D cells. They're 8Ah and LSD. PowerEX claims 9.5AH for their Imedion LSD cells, but they're a lot more money. The power supply is a benchtop laboratory style power supply. I have a few of them with different voltage and current ratings.

I'm using an 1xAA to D adapter that came with the Eneloop kit I bought at Costco years ago. Works quite well. I also ordered a 2xAA Parallel to D adapter at Amazon. My regular mule (bro) will bring them to me in 3 weeks time.
There are 3AA to D adapters out there as well. By the time you buy a decent 3AA to D adapter and stuff 3 Eneloops in it you've got more cost into it than buying a real D cell. However, decent chargers for multiple D cells are uncommon. The Maha MH-C808M is pretty much the only game for charging 8 D cells in a reasonable time. It has 2A charge for up to 8 D cells. The cheaper chargers only will hold 2, maybe 4 D cells. Some also have time limits and other things that stop them from putting 8Ah+ into a battery in one shot. So you have to start the charger a second time after it times out the first time. Of course if you're using 3AA to D adapters you've got to charge 12 AAs for a 4D cell device, so you'd need three 4AA chargers if you wanted to charge them all at once.
 

mubs

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#38
There are 3AA to D adapters out there as well. By the time you buy a decent 3AA to D adapter and stuff 3 Eneloops in it you've got more cost into it than buying a real D cell.
I hear you.

Currently my only need for a D is in the gas stove; it has an ignition mechanism that requires a single D battery. Alkaline Ds are becoming rare to find because there are so few devices nowadays that use that size. The first (and only D) I put in lasted about 16 months. When it died, I remembered the 1xAA to D adapter that came with the Eneloops, fished it out and put my lowest performing Eneloop AA in it. Been about 5 months, no hitch so far. Then I saw the 2xAA to D adapter on Amazon, which were 4 for ~ 3 USD, so I ordered a set. This should last me a lifetime now. Buying yet another charger for a D Ni-Mh is going to add to the clutter and cost, so that's ruled out. It's the reason I'm staying away from anything that requires an 18650 cell or any other form factor other than AA.
 

sechs

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#39
Which adapter did you get from Amazon? Have you tried it?

I have just one D-cell device, and buying the cells and a charger wouldn't be worth it. I also have single AA-to-D adapters, but 2 AA-to-D might be worth the cost.
 
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