Turbo DV8
Flashlight Enthusiast
Sorry, no fancy graphs and charts to be found here. You'll just have to read the whole story :sleepy:to see the big picture! I have 56 ROV Hybrid AAA cells that I purchased in Feb 2007. They are almost all in use in various applications, kept charged and never allowed to stay in a deeply discharged state. My Hybrid AAA cells are basically used very lightly and have gone through perhaps a half dozen charge cycles since 2/07. I happened to have available three back in August that I took out of rotation and decided to do a capacity check to see what type of degradation the Hybrids experienced in a year and a half of easy-cheesy life.
The batteries were in an LED candle, used regularly. I use the LED candle until it begins to pulsate, at which point the battery voltage is about 1 volt, then I charged them on the BC-900. The first thing I noticed was that one of the cells finished charging after only 398 mAh had gone "into" the cell. So I did the discharge half of the refresh mode @ 250 mA discharge, and the cell only delivered 329 mAh. On the second discharge, the capacity jumped to 664 mAh. I charged it a third time and decided to let it sit for two months, and measure the capacity. I tested it yesterday, and it ain't looking good.
After sitting for two months, the cell was only able to deliver 460 mAh @ 250 mA discharge current. I have also a couple other ROV Hybrid AAA cells that will no longer properly terminate on the charger at 200 mA charge rate. I must use the 500 mA rate. These are just a slice of the picture, but when I note the general trend of how the capacities of my ROV Hybrid AAA cells has declined much faster and less evenly than my Eneloops AAA's (purchased at the same time) I have to come to the conclusion the Hybrids are not as robust. When new, my Hybrids appeared to have substantially more capacity than the Eneloops. Almost all were over 800 mAh, with many approaching 850 mAh. The Eneloops more closely, and tightly, mirrored their rating, between 800-820 mAh. However, of the Hybrids I tested recently, capacity has dropped to between 710-760 mAh (not including the 664 mAh cell) while the Eneloops are between 790-810 mAh. I note the Eneloops are deteriorating much more gracefully than the Hybrids. Where the Hybrids came out of the gates appearing stronger than the Eneloops in terms of capacity, they have dropped faster and farther, and with more disparity between cells, than the Eneloops. The Eneloops have never failed to terminate at 200 mA charge rate, and have never given me any indication to suspect high self-discharge or development of high internal resistance.
The fact that the Eneloops are turning out to be more robust than the ROV Hybrids doesn't surprise me, and probably won't surprise others here, either. What does bother me (because I own 56 of the little buggers) is the rapidity these cells are deteriorating so quickly with such few charge cycles on them.
The batteries were in an LED candle, used regularly. I use the LED candle until it begins to pulsate, at which point the battery voltage is about 1 volt, then I charged them on the BC-900. The first thing I noticed was that one of the cells finished charging after only 398 mAh had gone "into" the cell. So I did the discharge half of the refresh mode @ 250 mA discharge, and the cell only delivered 329 mAh. On the second discharge, the capacity jumped to 664 mAh. I charged it a third time and decided to let it sit for two months, and measure the capacity. I tested it yesterday, and it ain't looking good.
After sitting for two months, the cell was only able to deliver 460 mAh @ 250 mA discharge current. I have also a couple other ROV Hybrid AAA cells that will no longer properly terminate on the charger at 200 mA charge rate. I must use the 500 mA rate. These are just a slice of the picture, but when I note the general trend of how the capacities of my ROV Hybrid AAA cells has declined much faster and less evenly than my Eneloops AAA's (purchased at the same time) I have to come to the conclusion the Hybrids are not as robust. When new, my Hybrids appeared to have substantially more capacity than the Eneloops. Almost all were over 800 mAh, with many approaching 850 mAh. The Eneloops more closely, and tightly, mirrored their rating, between 800-820 mAh. However, of the Hybrids I tested recently, capacity has dropped to between 710-760 mAh (not including the 664 mAh cell) while the Eneloops are between 790-810 mAh. I note the Eneloops are deteriorating much more gracefully than the Hybrids. Where the Hybrids came out of the gates appearing stronger than the Eneloops in terms of capacity, they have dropped faster and farther, and with more disparity between cells, than the Eneloops. The Eneloops have never failed to terminate at 200 mA charge rate, and have never given me any indication to suspect high self-discharge or development of high internal resistance.
The fact that the Eneloops are turning out to be more robust than the ROV Hybrids doesn't surprise me, and probably won't surprise others here, either. What does bother me (because I own 56 of the little buggers) is the rapidity these cells are deteriorating so quickly with such few charge cycles on them.
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