What would happen to battery

Smartie · 06-15-2014, 10:40 PM

Say I have a kindle as a gift,I never turn on. After 2 years,how's battery condition looks like? Good or bad for battery in this case(I mean never used). In craigslist, most sellers consider this is an advantage because it's brand new in box,but I think battery condition is worse than the one used regularly.

Thanks

HarryT · 06-16-2014, 04:08 AM

This is very, very bad. If the charge falls below a certain critical level, the battery cannot be recharged. If you're storing a device with a lithium battery long term, keep the charge at about 40% and top it up about once a month.

Smartie · 06-16-2014, 07:39 AM

Quote:

Originally Posted by HarryT

This is very, very bad. If the charge falls below a certain critical level, the battery cannot be recharged. If you're storing a device with a lithium battery long term, keep the charge at about 40% and top it up about once a month.

That's what I thought,but sellers keep telling me it's brand new

So for those kindle stocks that are in amazon or retail warehouse ,if they stay there long,then battery condition should deteriorate to,right?

Ian.M · 06-16-2014, 09:40 AM

A high quality LiPO battery designed for C/10 or lower loads can have a self-discharge rate as low as 1%/month. Start at 55% charge and that gives you over two years in a cool climate controlled warehouse to 30%. After that, its time to hold a special sale to shift the overstock.

OTOH if a private seller has kept it unopened in a warm place and the initial charge was on the low side, it could well be dead.

I wonder how many of Amazon's refurb kindles are simply ones that have been sitting around too long and had a battery replacement.

ApK · 06-16-2014, 10:26 AM

Man, to all you chemists out there: we (as a society) REALLY need some new battery tech! Please get on that.

HarryT · 06-16-2014, 10:51 AM

Quote:

Originally Posted by ApK

Man, to all you chemists out there: we (as a society) REALLY need some new battery tech! Please get on that.

Lithium/Air batteries are the "next big thing" in battery technology, offering about 3x the energy density of LiPo, but they're probably still a good 5 years from commercial production.

ApK · 06-16-2014, 10:54 AM

Quote:

Originally Posted by HarryT

Lithium/Air batteries are the "next big thing" in battery technology, offering about 3x the energy density of LiPo, but they're probably still a good 5 years from commercial production.

Weren't we supposed to be using methanol micro fuel cells by now?

And I still don't understand why we can't recharge our devices with all that ambient rf energy that is supposedly affecting our brains. Or with cosmic rays, like in "The Girl, the Gold Watch and Everything."

HarryT · 06-16-2014, 11:15 AM

Quote:

Originally Posted by ApK

And I still don't understand why we can't recharge our devices with all that ambient rf energy that is supposedly affecting our brains. Or with cosmic rays, like in "The Girl, the Gold Watch and Everything."

The energy density is too low to be useful.

ApK · 06-16-2014, 11:34 AM

Quote:

Originally Posted by HarryT

The energy density is too low to be useful.

Are you sure? Maybe SAIC thought they were on to something.

Quote:

If an array of energy harvesting antennas is used to receive the RF energy, the power collected from all channels (i.e., the power density at all antenna inputs) can be combined, rectified and forwarded to the trickle charger 164. The power available in each channel is comparable; thus, for example, if 100 N nW is required for a load, the power collected in N channels at 100 nW each can be combined to generate the required power.

HarryT · 06-16-2014, 12:17 PM

You'll notice they're talking about nanoWatts. A charger typically requires 5W - ie a billion times more

.

ApK · 06-16-2014, 01:20 PM

Quote:

Originally Posted by HarryT

You'll notice they're talking about nanoWatts. A charger typically requires 5W - ie a billion times more

.

They're talking about about N times 100 nanowatts, so we're only talking about at most 50 million times more. It's just a matter of the value of N.....

Seriously though, while I only skimmed the patent, and I don't know how big this thing currently is, or the practical values of N at this point, the patent is not talking about an invention that is a drop in replacement for current chargers. And it does say:

"The Energy Reclamation System or ERS of the present invention can provide sufficient power (e.g., 0.1-1 mW) to perpetually operate low power wireless devices without external recharging."

That's already on the order of powering a BLE device, say.

fratermus · 06-16-2014, 07:41 PM

Disclaimer: don't try this at home. Safety first, fire extenguisher nearby, stop/drop/roll, etc.

I had a K3 that sat long enough the battery was unchargeable through normal means. As an experiment I took the battery out and used a hobby grade multi-chemistry charger on it.

I monitored the charging and there was no swelling or warming. The battery has behaved normally in the ~year since the reanimation. It may be an outlier (and few will have reason to buy a hobby-grade charger but that was my experience.

For the curious, chargers like this are used to charge batteries for serious model airplanes, cars, etc. Not toy R/C.

06-15-2014, 10:40 PM	#1
Smartie Addict Posts: 285 Karma: 1150760 Join Date: Apr 2011 Device: Kindle PW,KOBO H2O	What would happen to battery Say I have a kindle as a gift,I never turn on. After 2 years,how's battery condition looks like? Good or bad for battery in this case(I mean never used). In craigslist, most sellers consider this is an advantage because it's brand new in box,but I think battery condition is worse than the one used regularly. Thanks

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06-16-2014, 04:08 AM	#2
HarryT eBook Enthusiast Posts: 85,544 Karma: 93383043 Join Date: Nov 2006 Location: UK Device: Kindle Oasis 2, iPad Pro 10.5", iPhone 6	This is very, very bad. If the charge falls below a certain critical level, the battery cannot be recharged. If you're storing a device with a lithium battery long term, keep the charge at about 40% and top it up about once a month.

06-16-2014, 09:40 AM	#4
Ian.M Connoisseur Posts: 71 Karma: 57134 Join Date: Aug 2013 Device: Kindle 3 GB 3G	A high quality LiPO battery designed for C/10 or lower loads can have a self-discharge rate as low as 1%/month. Start at 55% charge and that gives you over two years in a cool climate controlled warehouse to 30%. After that, its time to hold a special sale to shift the overstock. OTOH if a private seller has kept it unopened in a warm place and the initial charge was on the low side, it could well be dead. I wonder how many of Amazon's refurb kindles are simply ones that have been sitting around too long and had a battery replacement.

06-16-2014, 10:26 AM	#5
ApK Award-Winning Participant Posts: 7,316 Karma: 67862884 Join Date: Feb 2010 Location: NJ, USA Device: Kindle	Man, to all you chemists out there: we (as a society) REALLY need some new battery tech! Please get on that.

06-16-2014, 12:17 PM	#10
HarryT eBook Enthusiast Posts: 85,544 Karma: 93383043 Join Date: Nov 2006 Location: UK Device: Kindle Oasis 2, iPad Pro 10.5", iPhone 6	You'll notice they're talking about nanoWatts. A charger typically requires 5W - ie a billion times more .

06-16-2014, 07:41 PM	#12
fratermus e-bookworm Posts: 86 Karma: 630090 Join Date: Sep 2012 Device: PW2, K3, KF2, Touch (dying)	Disclaimer: don't try this at home. Safety first, fire extenguisher nearby, stop/drop/roll, etc. I had a K3 that sat long enough the battery was unchargeable through normal means. As an experiment I took the battery out and used a hobby grade multi-chemistry charger on it. I monitored the charging and there was no swelling or warming. The battery has behaved normally in the ~year since the reanimation. It may be an outlier (and few will have reason to buy a hobby-grade charger but that was my experience. For the curious, chargers like this are used to charge batteries for serious model airplanes, cars, etc. Not toy R/C.

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