Do I have a problem with my MH C9000 or did I buy some "super cells!?"

[mikekoz]

I have some generic AA NIHM cells. They are actually CVS Drugstore brand. They sometimes have them on sale for half price, and we get coupons from CVS all the time and they end up being really cheap! I have actually had very good performance from them up to now, but have I think I bought a bad batch. After charging some of them in a Targus charger and putting them in a new light, the light would go dim after about 30 seconds of turning it on. I put the cells in the CH9000 and they charged, but only showed a capacity of about 600 mAh!! I removed them and put in a few more, and they took about 3-4 hours to charge, and were showing a capacity of just under 3500 mAh!! They are rated at 2450 mAh. I am charging them at 700 ma. What would cause this in the CH 9000 where it would show a cell with a 3500 mAh capacity? Also, if I cycle the bad ones with this charger, can I repair them?

 

[snakebite]

you simply missed termination.
run a break in on these and get back here with the results.
new cells sometimes miss termination or terminate early.

 

[mikekoz]

you simply missed termination.
run a break in on these and get back here with the results.
new cells sometimes miss termination or terminate early.

Thanks for the reply. If I understand correctly, the cells that did not fully charge and were at 600 mAh when the charger finished with them terminated early, and the ones that charged to 3500 missed?

 

[Mr Happy]

Also, when you run a break in on those cells, do not enter the capacity as 2400 mAh -- the cells are most likely not that good. Enter a break in capacity of 2000 mAh and see what the results are.

Also remember the rule of thumb for using the C9000: charge AA cells at 1000 mA and AAA cells at 500 mA. 700 mA is a bit low for a (supposedly) 2450 mAh cell.

 

[ToddC]

mikeko - You need to do a discharge to see cell capacity. What you're (likely) reporting is what the charger outputted (charge rate * time ... implies to me you had a 5 hour charge)

 

[mikekoz]

you simply missed termination.
run a break in on these and get back here with the results.
new cells sometimes miss termination or terminate early.

Well, after breaking in 3 of them, I am still not sure of the results. They ended up as 1763, 447, and 457 mAh and 1.38, 1.35, and 1.35 volts. I have not used this charger very often, so I am not sure I set it up correctly. Going to give them another full charge and see how they do. Thanks for all the help!