Mobileread
Jetbook battery life
#1  Ham88 06-14-2009, 07:21 PM
I was just curious what other Jetbook users were getting for battery time before recharging. Mine averages around two 300 page books.

How long does yours last?
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#2  smithno 06-14-2009, 08:00 PM
The battery is rated 20-24 hours. A charge last me about a week.
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#3  wodin 06-14-2009, 11:58 PM
Quote smithno
The battery is rated 20-24 hours. A charge last me about a week.
That would be about right, although I've never let mine get below two bars.
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#4  Kris777 06-15-2009, 01:04 AM
Quote smithno
The battery is rated 20-24 hours. A charge last me about a week.
yes, this information is correct. I charge my jetBook one time per week too.
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#5  rgeorg 06-15-2009, 01:32 AM
I charge mine in about 10-12 days. Am I correct in remembering that it is good to discharge lithium batteries all the way about once a month, or perhaps once every 10 charges on the long-life batteries?
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#6  jgray 06-15-2009, 02:03 AM
Quote rgeorg
Am I correct in remembering that it is good to discharge lithium batteries all the way about once a month, or perhaps once every 10 charges on the long-life batteries?
Nope. Lithium batteries should never be fully discharged, even under normal use. You can ruin a Lithium battery by doing deep discharges. I don't remember the source, but a few years ago I read a very detailed writeup by a major battery manufacturer about the proper charging of lithium batteries. They specifically warned against deep discharging.

The practice of periodically deep discharging rechargable batteries comes from the days of NiCad batteries, where it sometimes helped with what was called "memory effect". The newer NiMH batteries are not prone to this "memory effect" and don't require periodic deep discharge. Although not needed, I understand that this practice will not destroy a NiMH, as it will a lithium.

Lithium batteries are usually rated about 1000 recharge cycles. From what I read, a partial recharge only counts partially toward one of these recharge cycles.

From my own experience with cell phones, which I charge every night, I typically get 3+ years before the capacity of the battery drops significantly. The battery is not dead, but it no longer has the capacity of a new battery. If you take the 1000 hour figure and divide by 365 days, you get 2.74 years. From this, it seems that the 1000 hour figure is probably conservative.
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#7  jgray 06-15-2009, 02:09 AM
And now back to our regularly scheduled program

As to how many hours I get from my jetBook, I haven't timed it, but it seems that the 20+ hour figure is about right. I've read 4-5 lengthy short stories and only charged it once since the initial charge after unboxing it.

Adding to what I said in the previous post, I would suggest using the jetBook until the low battery warning appears and then recharging. This should give the longest life from the battery. If you don't want to be interrupted in your reading, then any time after the battery meter drops to one bar and you are done reading should be fine.
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#8  Lanx 06-15-2009, 05:22 AM
was reading it the whole day, think i finally killed a bar.
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#9  rgeorg 06-15-2009, 12:54 PM
Oops - hope I haven't been ruining my batteries! I'll have to be more careful.
Thanks for the info.
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#10  Ham88 06-15-2009, 07:41 PM
The only battery information I saw before I bought was the number of page turns on the jetbook website, which I thought was useless as it was LCD, so its good to know that mine is doing fine cause I have the worst luck with rechargeable batteries.
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