Huge difference between 1700 & 1800 Duracell AA's incl. w/ Power Gauge/Value chargers

KingGlamis

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Re: Huge difference between 1700 & 1800 Duracell AA's incl. w/ Power Gauge/Value char

Lots of good info here, thanks. But what about the Duracell 2650mAh AAs? I'm tempted to buy some, but wanted some input first. The package said something to the effect of "Typical charge is 270mA for 16h." But I Googled these batteries and see that Duracell makes a 30min and a 15min charger for these. Are those quick chargers any good at all?

Any clarification would be appreciated.
 

TigerhawkT3

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Re: Huge difference between 1700 & 1800 Duracell AA's incl. w/ Power Gauge/Value char

I have a Lenmar 15 minute charger, and it works well. I don't think I've put even a dozen cycles on most of my rechargeables, so I can't comment on what it does to cells in the long run.

Many users have complained about the D2650s having very high self-discharge, or sometimes not taking a charge at all. If I were in the market for NiMHs, I would go with Sanyo Eneloops or Rayovac Hybrids.
 

Lightingguy321

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Re: Huge difference between 1700 & 1800 Duracell AA's incl. w/ Power Gauge/Value char

Any 30 minute or 15 minute charger is sending a very high current for charging through the battery and that is pretty much the equivalent of blowing away someone. Batteries like to be charged at lower rates, if those rates of 15 to 30 minutes were applied, you would be putting a lot of stress on the batteries (esp heat) and most likely not charging them completely full.
 

radellaf

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Re: Huge difference between 1700 & 1800 Duracell AA's incl. w/ Power Gauge/Value char

Found a good link about charge methods here, from Duracell:

http://www.duracell.com/oem/Pdf/others/TECHBULL.pdf

while I was looking for a manual for the "value charger". I'm always curious how effective cheaper chargers can be. Never found the manual - anyone know how the CEF14 works?


As for charge termination, sounds like the recommended method is dT/dt of 1 deg C per min for the 1-2 hour chargers, but all I've ever seen is voltage drop sensing with hi-temp safety shutoff, even on Maha's MH-9000 flagship charger. I guess it's really hard to measure temperature of a cell, whereas it'd be easy in a battery pack with an embedded temperature sensor.


I do find it interesting they are still selling the 1700mAh cells, which, if Sanyo, are still what I've seen being sold as generic green wrapper industrial cells. Makes me wonder if that's not the ideal capacity to shoot for in terms of reliability. That you're getting 2000+ mAh out of them, though, makes me suspect they're mis-labeling higher cap (2300mAh?) Sanyo cells. Energizer 2300s were those, and I got good service from them, though not as long a life as the 1700 or 1850s.
 

koala

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Re: Huge difference between 1700 & 1800 Duracell AA's incl. w/ Power Gauge/Value char

Hello Turbo_DV8,

Can you please pop the 1700 and 1800 on to a scale and check the actual weight? Thanks.

Vincent.
 

mdocod

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Re: Huge difference between 1700 & 1800 Duracell AA's incl. w/ Power Gauge/Value char

noticed some flawed thinking about charge rates and charge times I would like to chime in about here:

NIMH charging is not something that happens with 100% efficiancy. if it WERE, then the method often described to calculate charge time would work: capacity/charge rate = time required to charge...

But the reality is that about 30-40% of the energy you dump at a NIMH cells goes up in heat. So you have to take your charge rate and throw some out the window to calculate charge times. Notice how one of the recommended charge methods for most cells is 0.1C for 16 hours... notice how it would have pushed the full cells capacity in 10 hours, but they suggest 16 hours, this is to makeup for lost energy to heat.

So if you take a charger rated for 400mA, you need to figure that only about 260mA is actually going INTO the cell as stored capacity. By my calculations, that's 8.5 hours for a full charge on a 2200mAH cell.

Sounds like the charger was doing pretty well after-all. Any Questions?
 

Mr Happy

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Re: Huge difference between 1700 & 1800 Duracell AA's incl. w/ Power Gauge/Value char

Well, this thread has been around for a while!

Just reading back over it, I thought I'd mention that I have the Duracell Power Gauge charger model CEF21 and I like it a lot. It may not be super fast, but in my tests it does have four independent charging channels, it keeps the cells cool during charging, and it charges more completely than the C-9000. It's also very light, moderately compact and has worldwide voltage input, so it's convenient for traveling.

See this post for an indication of how well it charges: https://www.candlepowerforums.com/posts/2303088&postcount=37
 

Turbo DV8

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Re: Huge difference between 1700 & 1800 Duracell AA's incl. w/ Power Gauge/Value char

So if you take a charger rated for 400mA, you need to figure that only about 260mA is actually going INTO the cell as stored capacity. By my calculations, that's 8.5 hours for a full charge on a 2200mAH cell. Sounds like the charger was doing pretty well after-all. Any Questions?


No questions, but a reiteration of my findings with this charger.

Even four 2000 mAh cells with a good bit of charge remaining took 6-7 hours to "top off."

The charger is packaged with 1700 mAh cells. Using your 260 mAh figure, the 1700 mAh cells should terminate in 6.5 hours. The package says "Charges in 4 hours." I do not think they were talking about 1040 mAh cells (your 260 mAh x 4 hours.) If I can take 2000 mAh cells that are close to 2/3 full, and it takes 7 hours to terminate, either it is not charging at 400 mA, or it is missing termination at the appropriate time ... period. Any questions?
 
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Turbo DV8

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Re: Huge difference between 1700 & 1800 Duracell AA's incl. w/ Power Gauge/Value char

Hello Turbo_DV8,

Can you please pop the 1700 and 1800 on to a scale and check the actual weight? Thanks.

Vincent.

I do not have the 1800 mAh cells anymore. The 1700 mAh cells weigh 27-28 grams.
 

Mr Happy

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Re: Huge difference between 1700 & 1800 Duracell AA's incl. w/ Power Gauge/Value char

The "charges in 4 hours" is the typical hyperbolic claim of marketing folks. It applies to a standard 1500 mAh cell, which we all know is not standard at all. The typical charge time for a 2000 mAh cell is 5-6 hours in my testing.

As to the independent channels, I tested this out quite a bit when I first got the charger. For example I prepared 4 cells at different states of charge: full, 3/4, 1/2, 1/4 and put them in random slots. The green completion lights came on in the expected order and approximately after the expected delays. For fully charged cells the green completion light came on almost immediately, within a few minutes at most. I tried this a few times just to check.

It is true the red intermediate lights are on 2 hr and 4 hr interval timers, but that is no big deal. They are just saying, "hey, it's 2 hrs since we started and the end of charge signal hasn't been detected yet". The green light does however appear to be an actual end of charge indicator. I always see each of the green lights come on at different times, even when starting with four empty cells.
 

mdocod

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Re: Huge difference between 1700 & 1800 Duracell AA's incl. w/ Power Gauge/Value char

yea the 2/3rds full cells taking 7 hours seems like something is wrong. But I do believe that the "4 hour" charging time on the packaging is probably hype based on a different capacity cell as Mr Happy has pointed out.

Cells that are closer to full can be trickier for a charger to find a termination "signal."

The main point I wanted to make clear was the loss of power to heat, which does help explain away *some* of the charging time phenomenon....

My vanson "Speedy" box does the same thing. It supposedly charges at 750mA, but to charge a 2000mAH cell takes about 4 hours give or take 30 minutes or so. Charging 10AH D cells on it seems to take 20-24 hours. It often misses termination so I just pull it at 24 hours, I figure charging at 0.075C it can "brush off" the overcharge with minimal wear and tear.
 

Turbo DV8

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Re: Huge difference between 1700 & 1800 Duracell AA's incl. w/ Power Gauge/Value char

Update:

Ok, so it has been 3 1/2 years since my OP. I have used my eight Duracell 1700, made-in-Japan cells every night, all night in my LED candles all that time. My original tests were conducted on the BC-900. From my earlier posts, you can see the returns were amazing. So I decided now to give them a stiffer litmus test on the Maha C9000 after 3 1/2 years of continuous use. All eight of my Duracell 1700's return over 1700 mAh on the R&A cycle on the C9000, and all within 40 mAh of each other! And these were not treated terribly well, either. When I awoke on certain mornings to turn them off, and the LED's had a high-frequency pulsation, signalling when the cells needed charging, one or more cells had gone below 0.9v for some duration of the night. Pretty rough treatment every three weeks for 3 1/2 years, if you ask me. Amazing cells. Did I mention these were not Energizers? :whistle:
 
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chewy78

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Re: Huge difference between 1700 & 1800 Duracell AA's incl. w/ Power Gauge/Value char

interesting
 
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