Thread: Pocket Pro battery issue?
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Old 10-02-2009, 06:44 AM   #141
theducks
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Posts: 31,134
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Join Date: Aug 2009
Location: The Central Coast of California
Device: Kobo Libra2,Kobo Aura2v1, K4NT(Fixed: New Bat.), Galaxy Tab A
Quote:
Originally Posted by Var View Post
I have received my PP5 right before the Labor Day. I was very excited, but since I was very busy, I didn't have time to play with it.
Right out of box it came with the battery already installed. It was showing it as FULL, but I did follow the instructions and charged it - it took about 10 hours.
Yesterday I turned it on and it was only one bar short from full. It made sense since the total time it was used was around 20 min max.
Today I took it to the office to show it to my co-worked. I have turned it on and all I got was four short beeps. Reset didn't work. After coming to home (I didn't have the power adapter with me since I was not expecting I was going to need to charge the battery) I connected to the power adapter and it did start. The battery was EMPTY!

Right now it's charging. But I am worried a little bit: it was fully charged 9 days ago and the total usage time was only about 20 minutes. Yesterday it was showing (FULL-1) bar (I just checked and turned it OFF). Today is was EMPTY!

What are your comments - is this normal? I do understand that new batteries need a few full cycles before becoming 'normal', but still... No extreme conditions (temperature, ...).

I will see how it goes and I will update the forum.

Thanks,
You have found Li-ion's dirty little secret .
It is called high "Self Discharge". It loses 10% or more the first day off charge.
Note: Every battery normally has a "Self Discharge Rate". The rate varies by many conditions of use and storage. The product designer should make their choice of battery technology to use, based upon many factors required for the device being powered.

Li-ion's claim to fame is high power to weight ratio. This is great in a device like a Laptop or Camera that needs to grab good sized chunks of power right now.

Your common Alkaline battery is noted for it's great "shelf life" (just look at the "use by" dates), but it suffers more if you do fast discharges (Camera flashes,Talking on your Cell).
I suspect that Peak power (needed for page turns) and light weight and form factor were controlling choices, not really long times between charges.
Bottom line: Charge Li-ion batteries just before use. Carrying a "Charged Spare" for the PEZ on a long term trip is just carrying a "paper weight", carry a "rollup solar" charger instead http://www.inhabitat.com/2007/11/19/...adget-charger/
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