9-cell battery (71.28Wh) only holds 66.90Wh (had 6 cycles).

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Chatbox · #1 Post by **Chatbox** » Mon Jun 28, 2004 4:29 pm

My 9-cell battery doesn't seem to be able to hold the full designed capacity of 71.28Wh, and only 66.90Wh. I only had 6 cycles on it.

What's wrong with it? Anything I can do to improve the situation or shall I ask for a replacement?

eriqesque · #2 Post by **eriqesque** » Mon Jun 28, 2004 4:41 pm

Seems perfectly nornal to me
The more you use the batteries the more they will consume power
meaning the futher you discharge the battery the more Whrs you will lose
this is a normal usage pattern for batteries.
This is exactly why Li-Ion batteries should NOT be conditioned(fully discharge and recharge) they prefer a more shallow cycle.

Chatbox · #3 Post by **Chatbox** » Mon Jun 28, 2004 4:50 pm

But that's a 6.1% degradation after only 6 cycles...

Or am I just too picky?

#4 Post by **K. Eng** » Mon Jun 28, 2004 5:02 pm

How deep were your discharges? I discharged to 1% once and lost 4 watt/hrs of capacity in that cycle

I have heard that Li-Ion batteries should not be discharged below 10% often if you wish to extend the life of the battery.

Chatbox · #5 Post by **Chatbox** » Mon Jun 28, 2004 5:22 pm

Oh, crap. I discharged the battery pack until it won't power up the laptop (won't complete POST), then further drained the battery with a 80mm computer case fan over night until the fan won't turn. Guess I should have RTFM when I switched from Ni-MH batteries

.

Bye bye to my 4.38Wh capacity.

Voodle · #6 Post by **Voodle** » Mon Jun 28, 2004 5:36 pm

Just discharge it to about 3%, keep an eye on the battery voltage - 10.80 volts is the absolute minimum, less than that and it's about flat.

The batteries are smart and can recover capacity, especially after just 6 cycles. Just watch for it to stick at a certain percentage level for a while, it was usually 6% that it would stick at with my T23. Once its spent too long at that percentage and drops, just charge it up again and it should recognise some extra capacity.

edit: just read that you discharged the battery overnight... yeah that's EXTREMELY bad for the battery, li-ions do not like to be completely discharged unlike nimh batteries.

Chatbox · #7 Post by **Chatbox** » Mon Jun 28, 2004 8:03 pm

Oh, so it will self-recover? Cool...but I'm not clear as to how I should go about it. Can you clarify?

9-cell battery (71.28Wh) only holds 66.90Wh (had 6 cycles).

9-cell battery (71.28Wh) only holds 66.90Wh (had 6 cycles).

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