Mr Happy
Flashlight Enthusiast
-or-
Some musings on high internal resistance and charging modes of the MH-C9000
On Monday I noticed some AA size eneloops and Hybriloops that had been sitting around charged for a while, and out of curiosity I decided to run them through a 1000 mA discharge on the C9000 to see what condition they were in.
One eneloop and one Hybriloop held voltages in the 1.25 - 1.30 range during the first quarter of the discharge, but the other Hybriloop started out at a lower 1.15 V and the remaining eneloop showed a steady 1.05 V for the whole discharge! In spite of the varying voltages, they all showed very similar discharge capacities in the 1800 - 1900 mAh range.
What amused me about this was that the eneloop had such a low voltage even though its capacity was undiminished. Thinking that this situation was no good at all, I set out to see what might bring the eneloop back to full voltage.
First of all I put all four batteries through two cycles of 1800 mA charge and 1000 mA + 100 mA discharge(*). This got the voltages up a bit, but the low eneloop was still discharging in the 1.15 V range and the low Hybriloop was still not keeping up with the voltage of its companion.
(*)The 100 mA discharge part means doing a second discharge after the 1000 mA part finished.
Since the fast cycling was showing little further gain, I went for a conditioning charge using the break-in mode set to 1900 mAh. I ran the conditioning charge of 0.1C for 16 hours from empty and let the 0.2C discharge finish, but stopped it there. Then I charged all four at 1800 mA again, let them sit on the charger while I was at work during the day, and just tried another 1000 mA discharge this evening.
This time there was a big difference, and all four cells registered equal high voltages right the way through the discharge, starting out at 1.30 V in the beginning and staying above 1.20 V for the first half of the discharge.
What is interesting about this? Well, firstly without the voltage display of the C9000 the performance of two of these cells in use would have seemed disappointing, but with the cause remaining a mystery.
Secondly, some ordinary refresh cycles helped a bit, but they did not restore the poor cells to full vibrancy.
Thirdly, it seems like the break-in or conditioning charge really does have a positive effect.
It just goes to show how much is hidden about what your batteries might be doing during their everyday life of charge and discharge.
Some musings on high internal resistance and charging modes of the MH-C9000
On Monday I noticed some AA size eneloops and Hybriloops that had been sitting around charged for a while, and out of curiosity I decided to run them through a 1000 mA discharge on the C9000 to see what condition they were in.
One eneloop and one Hybriloop held voltages in the 1.25 - 1.30 range during the first quarter of the discharge, but the other Hybriloop started out at a lower 1.15 V and the remaining eneloop showed a steady 1.05 V for the whole discharge! In spite of the varying voltages, they all showed very similar discharge capacities in the 1800 - 1900 mAh range.
What amused me about this was that the eneloop had such a low voltage even though its capacity was undiminished. Thinking that this situation was no good at all, I set out to see what might bring the eneloop back to full voltage.
First of all I put all four batteries through two cycles of 1800 mA charge and 1000 mA + 100 mA discharge(*). This got the voltages up a bit, but the low eneloop was still discharging in the 1.15 V range and the low Hybriloop was still not keeping up with the voltage of its companion.
(*)The 100 mA discharge part means doing a second discharge after the 1000 mA part finished.
Since the fast cycling was showing little further gain, I went for a conditioning charge using the break-in mode set to 1900 mAh. I ran the conditioning charge of 0.1C for 16 hours from empty and let the 0.2C discharge finish, but stopped it there. Then I charged all four at 1800 mA again, let them sit on the charger while I was at work during the day, and just tried another 1000 mA discharge this evening.
This time there was a big difference, and all four cells registered equal high voltages right the way through the discharge, starting out at 1.30 V in the beginning and staying above 1.20 V for the first half of the discharge.
What is interesting about this? Well, firstly without the voltage display of the C9000 the performance of two of these cells in use would have seemed disappointing, but with the cause remaining a mystery.
Secondly, some ordinary refresh cycles helped a bit, but they did not restore the poor cells to full vibrancy.
Thirdly, it seems like the break-in or conditioning charge really does have a positive effect.
It just goes to show how much is hidden about what your batteries might be doing during their everyday life of charge and discharge.
