Disappointing data re: Odec C-cell batteries

I have a new XTAR Dragon VP4 Plus charger and began recording data before-and-after each charge/refresh/test cycle. I had bought 8 Odec C-cells through Amazon and was eager to see the results.

To explain what's in each column:
col 1: IGNORE, simply a # assigned to a battery
2: manufacturer
3: cell size
4: claimed mAh rating
5: date of last charge/refresh/test
6: actual mAh rating
7: charge/refresh/test (C/R/T)
8: charging rate
9: notes

004 odec C 5000 03.05.2018 4193 T 0.5 # generic flourescent, emergency light
005 odec C 5000 03.05.2018 3786 T 0.5 # generic flourescent, emergency light
005 odec C 5000 03.08.2018 3704 T 0.5 # generic flourescent, emergency light # pre-charge voltage = 1.39 IR = 038, 81% # this is just 3 days after last Tcharge # post-charge voltage = 1.45 IR = 017
006 odec C 5000 03.05.2018 4347 T 0.5 # generic flourescent, emergency light
007 odec C 5000 03.05.2018 3902 T 0.5 # generic flourescent, emergency light
008 odec C 5000 03.06.2018 3753 T 0.5 # generic flourescent, emergency light
008 odec C 5000 03.08.2018 3949 T 0.5 # generic flourescent, emergency light # pre-charge voltage = 1.41 IR = 010, 89% # this is just 3 days after last Tcharge # post-charge voltage = 1.48 IR = 015
009 odec C 5000 03.06.2018 3980 T 0.5 # generic flourescent, emergency light
010 odec C 5000 03.06.2018 4545 T 0.5 # generic flourescent, emergency light
011 odec C 5000 03.06.2018 4280 T 0.5 # generic flourescent, emergency light

These Odec C-cells claim to have a 5000 mAh rating. You'll notice that the actual ratings are substantially lower. The mean-average actual is 4043 mAh, which is almost 20% lower than claimed.

Furthermore, I noted that cells #005 and #008 had the lowest initial scores, so I retested them. Cell #005 did worse, an approximate 2% difference. Cell #008 did better, an approximate 5% difference.

I suspect my buying the Odec C-cells is an example of "caveat emptor"/"buyer beware". The Odec C-cells were quite low cost, so I suspect this was just a case of "you get what you pay for".

SLIGHTLY OFF-TOPIC: As I recently bought an Acebeam EC-50 generation 3 flashlight that came with an Acebeam 26650 cell. While I know its not fair to compare a C-cell to a 26650, they both are rated at 5000 mAh and the results from the first Acebeam battery were quite impressive:

001 acebeam 26650 5000 03.03.2018 5361 T 0.5 # acebeam ec50 gen 3 flashlight

I was so impressed, that I ordered 2 more Acebeam 26650 batteries. Similarly, the Panasonic eneloop/pro AA/AAA batteries I bought also gave me actual mAh ratings that significantly exceeded their claimed rating.

ANYWAYS, BACK TO THESE ODEC C-CELLS: I'm planning on buying 6-8 Powerex C-cells, which are substantially more expensive. Once I've bought and tested some Powerex batteries, I'll report back.

IN SUMMARY: I will avoid buying Odec batteries in the future. While they are less expensive, that cost savings amounts to an approximate 20% reduction in actual mAh rating. These C-cells will be used almost exclusively in an older flourescent-tube emergency light and given that the first time I used these C-cells, this light stayed on for approximately 8 hours... so theoretically a set of actual 5000-mAh batteries should amount to about 2 more hours of light. TWO MORE hours of basic light can mean a lot when you're depending on a lantern during an emergency or blackout.

POSTSCRIPT 1: I gave these batteries two stars (out of five stars). Three stars would've been "average, I might buy more". Two stars for me is "average, but I won't buy more".

POSTSCRIPT 2: I recognize that an even-better charger like the SkyRC MC3000 might do better at packing in a bit more power into these C-cells, it's more expensive than my XTAR Dragon VP4 Plus... but given that this XTAR charger is probably more expensive than the average consumer wants to spend, I think I can say the the raw data I collected (and decision made after) is objective, fair, repeatable and honest.

Never heard of Odec batteries, but I guess you get what you pay for.

I'd go with Tenergy Centuras, or Premiums, if I were in the market.

Chris

ChrisGarrett said:

Never heard of Odec batteries, but I guess you get what you pay for.

Click to expand...

Odec batteries are available through Amazon. Since I bought them, I did a little research... couldn't find a manufacturer's website, so no battery specs... I learned my lesson, though, and will stick with highly-rated batteries that CPF people review/recommend. Thanks for suggesting Tenergy, will check them out.

david.allie said:

Odec batteries are available through Amazon. Since I bought them, I did a little research... couldn't find a manufacturer's website, so no battery specs... I learned my lesson, though, and will stick with highly-rated batteries that CPF people review/recommend. Thanks for suggesting Tenergy, will check them out.

Click to expand...

Live and learn. Maha Energy's Imedion (Pros now?) or regular PowerEx would be an option, but they're spendy. Tenergy has a bit of a track record and while they make three levels, if I could find fresh batteries, I'd just go that route and then see what I could see.

D batteries are on my list for hurricane preps, but I have the Eneloop adapters and I even bought a bunch of alkalines in 2012, just to have for my 12vdc fans and lanterns.

Welcome to CPF and keep us posted.

Chris

ChrisGarrett said:

Maha Energy's Imedion (Pros now?) or regular PowerEx would be an option, but they're spendy.

Click to expand...

The standard HSD PowerEx are now called and labeled as Pros. The replacement for the Imedion LSD are called Precharged and labeled Precharged and READY TO USE.

DavisonDave said:

The standard HSD PowerEx are now called and labeled as Pros. The replacement for the Imedion LSD are called Precharged and labeled Precharged and READY TO USE.

Click to expand...

Thanks. That's good to know so we don't buy old stock.

Chris

ChrisGarrett said:

D batteries are on my list for hurricane preps, but I have the Eneloop adapters and I even bought a bunch of alkalines in 2012, just to have for my 12vdc fans and lanterns.

Click to expand...

You bought a bunch of alkalines in... 2012? Well, then they are now 6 years old. I'd better check on them if they're still good because alkalines, even if they don't leak, self-discharge over time as well. I think the rate is about 5.5% per year, though this might be different depending on the manufacturer. I think this was a figure given by Energizer back when they introduced their Lithium batteries back in the 90's.

david.allie said:

I have a new XTAR Dragon VP4 Plus charger and began recording data before-and-after each charge/refresh/test cycle. I had bought 8 Odec C-cells through Amazon and was eager to see the results.
...........

SLIGHTLY OFF-TOPIC: As I recently bought an Acebeam EC-50 generation 3 flashlight that came with an Acebeam 26650 cell. While I know its not fair to compare a C-cell to a 26650, they both are rated at 5000 mAh and the results from the first Acebeam battery were quite impressive:

....... Similarly, the Panasonic eneloop/pro AA/AAA batteries I bought also gave me actual mAh ratings that significantly exceeded their claimed rating.
.....

Click to expand...

This is a nice simple test, but I see a few confusing points.

While your conclusion may be correct, there are several things here that make it cloudy. First even talking about Li-Ion cells in relation too their rated capacity, in a discussion about some NiMH cell is not slightly off topic, it is completely irrelevant and means absolutely nothing.

Second, if your data is showing your Eneloops have "significantly exceeded" their rated capacity then you have only proved your data is wrong, and it cannot be trusted. However; since you didn't actually state the capacity and test parameters no one can really judge what you think is 'significant' or the value of the data.

I want to be clear, I'm not saying that given your test parameters (which would result in a 250mA discharge) one should not expect a higher capacity for the C-Cells given the manufacture's spec, it's just that you muddy the waters trying to justify the data with comparisons to other LiIon and Eneloop cells. Also the manufacture did not state the discharge rate to achieve their rating, so it's meaningless rating with out a data sheet with more information. However; at 1/20 C it is reasonable to expect the rated capacity with NiMH chemistry.

Anyway seeing as how given the price you expected as much from this test, I don't see how you can be too upset about the performance. It maybe does not meet the incomplete specification, but it's not exactly horrible. If the cells have a reasonable life-time they would actually be very good value. Not that one should necessarily have any expectations on lifetime without independent tests.

You sound like you know better than to expect more from unknown battery sellers, without a shred of test data. It's nice that you started the initial test of these cells for others though, but I don't really feel you were hurt by your purchase or have any reason to be.

Kurt_Woloch said:

You bought a bunch of alkalines in... 2012? Well, then they are now 6 years old. I'd better check on them if they're still good because alkalines, even if they don't leak, self-discharge over time as well. I think the rate is about 5.5% per year, though this might be different depending on the manufacturer. I think this was a figure given by Energizer back when they introduced their Lithium batteries back in the 90's.

Click to expand...

You want to hear something interesting?

Back in '97-'98, I bought two MagLite 6D flashlights and a bunch of blister packs of Energizer and Duracell D batteries, in 4 packs. Their expiry dates were ~2003, so at the time I bought them, that makes sense--6 years?

After about 4-5 years of not using them, I dug them out of the cupboard and one, or two, of each had leaked in their packs. I probably had 8-12 of each.

I opened them up and chucked the bad ones and just held onto the non-leaking batteriess.

Fast forward to 2017.

Hurricane Irma blew through Miami and I had a dozen D batteries from the lot, sitting in a cashew container and decided to plug them into some 12vdc 10" fans and guess what?

They worked fine.

Can't say what their capacity was/is, but I've notated their voltages over the years, on their wrappers and they worked for my 500mA fans.

You never know.

Chris

StandardBattery said:

This is a nice simple test, but I see a few confusing points.

While your conclusion may be correct, there are several things here that make it cloudy. First even talking about Li-Ion cells in relation too their rated capacity, in a discussion about some NiMH cell is not slightly off topic, it is completely irrelevant and means absolutely nothing.

Click to expand...

Thank you, StandardBattery, for pointing out my errors in testing and analyses. You're right, it was incorrect/inappropriate of me to make comparisons between NiMH, LiOn and Eneloops---they are very, very different chemistries.
.

StandardBattery said:

Second, if your data is showing your Eneloops have "significantly exceeded" their rated capacity then you have only proved your data is wrong, and it cannot be trusted. However; since you didn't actually state the capacity and test parameters no one can really judge what you think is 'significant' or the value of the data.

Click to expand...

While I did err in making some not fully accurate assumptions and conclusions, I feel we'll need to agree-to-disagree about my data collection---the numbers I did list were accurately collected and reported in the table. Perhaps the errors were in my inferences.
.

StandardBattery said:

I want to be clear, I'm not saying that given your test parameters (which would result in a 250mA discharge) one should not expect a higher capacity for the C-Cells given the manufacture's spec, it's just that you muddy the waters trying to justify the data with comparisons to other LiIon and Eneloop cells. Also the manufacture did not state the discharge rate to achieve their rating, so it's meaningless rating with out a data sheet with more information. However; at 1/20 C it is reasonable to expect the rated capacity with NiMH chemistry.

Click to expand...

Yup, I totally admit I'm a raw newbie, still very much learning. You've got me at a disadvantage as I don't understand your meaning in "However; at 1/20 C it is reasonable to expect the rated capacity with NiMH chemistry." I know I'm not understanding you as I thought that an almost 20% reduction in actual capacity vs claimed capacity (4043mAh vs 5000mAh) might be considered significant. Please clarify your meaning so I can better understand.
.

StandardBattery said:

Anyway seeing as how given the price you expected as much from this test, I don't see how you can be too upset about the performance. It maybe does not meet the incomplete specification, but it's not exactly horrible. If the cells have a reasonable life-time they would actually be very good value. Not that one should necessarily have any expectations on lifetime without independent tests.

Click to expand...

I hope you didn't think I was boo-hoo-ing (not my intention) about the overall performance of these specific Odec NiMH cells given the low price I paid. As a newbie, I was a bit surprised and, yes, a little disappointed at the difference between claimed and actual capacities. I won't embarrass myself further by claiming it was "statistically significant" when I've only tested an extremely small sample size of 8 cells! I knew inexpensive batteries would most likely never match the capacity/performance of more expensive cells... and where this was my first analyzing charger, it was very much a learning experience for me. I think my intent was solely to let other people know about one person's experiences with this specific manufacturer/batch of batteries... I've been learning a lot from the CPF and was hoping to contribute my two-cents.
.

StandardBattery said:

You sound like you know better than to expect more from unknown battery sellers, without a shred of test data. It's nice that you started the initial test of these cells for others though, but I don't really feel you were hurt by your purchase or have any reason to be.

Click to expand...

Thanks again for pointing out my inferential errors. I appreciate the feedback, realize I have a lot to learn and am glad for this forum where I can learn from others!
.

david.allie said:

StandardBattery said:

Second, if your data is showing your Eneloops have "significantly exceeded" their rated capacity then you have only proved your data is wrong, and it cannot be trusted. However; since you didn't actually state the capacity and test parameters no one can really judge what you think is 'significant' or the value of the data.

Click to expand...

While I did err in making some not fully accurate assumptions and conclusions, I feel we'll need to agree-to-disagree about my data collection---the numbers I did list were accurately collected and reported in the table. Perhaps the errors were in my inferences.

Click to expand...

Let me explain. The Capacity of envelops is well known and well tested, if you have numbers suggesting you have ones that are significantly better (and they have been some examples of over performing eneloops, but 'significant' is subjective), then there is a good chance your data is wrong. So while you think you may have collected the data accurately, the accuracy is based both on process and the equipment, the VC4 is not exactly a scientific instrument, or even what one would classify as professional.

david.allie said:

I don't understand your meaning in "However; at 1/20 C it is reasonable to expect the rated capacity with NiMH chemistry."

Click to expand...

I was saying that despite the lack of a full specification for the cell, with a 1/20C discharge rate one could reasonably expect a result closer to any appropriate specification for such a chemistry. i.e. Your test parameters were not the problem.

david.allie said:

I know I'm not understanding you as I thought that an almost 20% reduction in actual capacity vs claimed capacity (4043mAh vs 5000mAh) might be considered significant. Please clarify your meaning so I can better understand.

Click to expand...

My reference to your use of the word 'significant' was in your use of it to describe the capacity result for your Eneloop cells. if you simply stated that you felt the capacity different for the C cells was significant then there can be no objection as it is subjective. Just stating the test results for your cell would have removed all the ambiguity, but it was still not relevant to your test in the context you were trying to use it.

Yes, I think people here will certainly appreciate your contribution in providing the first test of these cells. The hard data on the tests I'm sure will be useful.