Canuke
Enlightened
I was running a batch of 6 Eneloops in my Canon 5D with battery grip, in part because I was testing an issue with this camera where it would go "schizo" after the battery voltage went to "half"; once it did that, it wouldn't come back even after the battery was recharged. It was back from Canon's third try at the problem, so I wanted to be sure they got it this time.
Since 6 NiMH's have .2 V less than the 7.4 Li-Ions it usually takes, I decided to run the camera on the Eneloops to see if it got squirrelly again. When I put the Eneloops in, they were pretty close in voltage, but were nonetheless a set of four plus a set of two from different (brief) applications with slightly varied discharge states. I also didn't expect the camera to be that hard on the cells, especially in light of its previous voltage pickiness (although in hindsight, it was designed for the 7.4V "intelligent" li-ions, with the AA battery option as backup only, and probably counts on the battery to say "stop").
No such luck. Whatever they swapped out fixed the earlier problem, but almost too well -the camera sucked the batteries all the way down to the point where two batteries measured .9V and the other four -- 90mV (yes, that's milli- with an "m"). Interestingly, the grouping did not match up to what went in -- of four "A" and two "B" group cells, one "A" and one "B" were at .9, the other four at <0.1V
This was discovered yesterday, with the last photo session being a week ago when I shot some pics of the weird orange sky from the wildfires. So, I'm *hoping* that the cells bottomed out on the relatively small current draw the camera has when "off", as I find it hard to believe that the camera shot pics glitch-free on 2V or less.
So, not knowing whether those four were reversed or not, I charged the zeroed cells in the four-cell charger that comes in the Costco kit, and the .9V pair in my Lacrosse BC-900 at 700mA. Charge appears to have terminated normally, and all six cells are "resting" now.
Was that the right thing to do? What's the right way to charge up NiMH cells that have been bottomed out, to minimize the damage?
Since 6 NiMH's have .2 V less than the 7.4 Li-Ions it usually takes, I decided to run the camera on the Eneloops to see if it got squirrelly again. When I put the Eneloops in, they were pretty close in voltage, but were nonetheless a set of four plus a set of two from different (brief) applications with slightly varied discharge states. I also didn't expect the camera to be that hard on the cells, especially in light of its previous voltage pickiness (although in hindsight, it was designed for the 7.4V "intelligent" li-ions, with the AA battery option as backup only, and probably counts on the battery to say "stop").
No such luck. Whatever they swapped out fixed the earlier problem, but almost too well -the camera sucked the batteries all the way down to the point where two batteries measured .9V and the other four -- 90mV (yes, that's milli- with an "m"). Interestingly, the grouping did not match up to what went in -- of four "A" and two "B" group cells, one "A" and one "B" were at .9, the other four at <0.1V
This was discovered yesterday, with the last photo session being a week ago when I shot some pics of the weird orange sky from the wildfires. So, I'm *hoping* that the cells bottomed out on the relatively small current draw the camera has when "off", as I find it hard to believe that the camera shot pics glitch-free on 2V or less.
So, not knowing whether those four were reversed or not, I charged the zeroed cells in the four-cell charger that comes in the Costco kit, and the .9V pair in my Lacrosse BC-900 at 700mA. Charge appears to have terminated normally, and all six cells are "resting" now.
Was that the right thing to do? What's the right way to charge up NiMH cells that have been bottomed out, to minimize the damage?
