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View Full Version : Sync WITHOUT charging ?


Prolet
08-04-2008, 04:17 AM
Hello, folks... ;)

Is there any way to sync the PRS-505 with the PC WITHOUT triggering the charge feature ?

Here's why: We all "know" that modern batteries like LiIon or LiP batteries don't suffer of the infamous memory effect and could be charged just as you like.
This is as true as politician's promises prior to elections.
Every charge will degrade the battery, the more often you charge the battery, the sooner it will be down and cry for replacement, even if charging duration is quite short as with synchronizing the Reader.

I thought about cutting the +5 V line of the USB plug, but I fear this is used for signalling the presence of the USB connection.

Any ideas, anyone ?

gwynevans
08-04-2008, 07:26 AM
Just on the off-chance you're open to correction, you might want to take a look at sources such as this (http://www.batteryuniversity.com/partone-21.htm).

To summarise, deep discharge wears Li-ion batteries more than frequent charges - they age whether used or not, but wear best when topped up little & often. Don't expect NiCad 'best practice' to apply to different battery technologies, any more than you needed to top-up your Duracells like you would have had to with a Lead-Acid car battery.

acidzebra
08-04-2008, 07:28 AM
I agree with Gwyn, and was about the cite the same page :)

Prolet
08-04-2008, 10:21 AM
I deeply feared reactions of the above kind. :D

Of course I read about the theories and things people claimed to know by hands-on experience - but this does not match with my own practical experience with LiIon batteries.
I used two identical types of LiIon batteries with my Nokia cellphone:
One I recharged after the phone switched off itself due to low battery capacity only, another one I recharged whenever I thought about charging the thingy.
The first one is still ok, the second one is trashed.
Same results with notebook batteries (Acer Travelmate 800LCi), same results with LiIon batteries used with PDAs (Handspring Visor Edge).

Of course this might be pure coincidence, but I just don't believe in that. :)
Also there might be quite some differences in LiIon batteries - some that "know" how to behave properly according to public theories supporting LiIon battery manufacturers and some that don't.
But how to find out what kind of battery is used in the reader ?

So is there any chance to sync the Reader without charging ?

Catire
08-04-2008, 11:52 AM
The easiest way to add books without charging would be to use a memory card.

jakewastaken
08-04-2008, 02:16 PM
The easiest way to add books without charging would be to use a memory card.

This is your best bet. You could also maybe daisy chain one or two usb hubs together or plug other devices in - I think lowering the available power to under 5V would thwart the charger.

DrMoze
08-04-2008, 07:32 PM
It's not just opinion and wives' tales out there--there has been scores, no, hundreds of detailed, controlled, scientific studies and analyses of this battery chemistry, as well as huge resources used to develop and characterize them. What people have posted are not off-the-cuff 'personal experiences,' but references to the results of these substantial efforts in developing and understanding batteries.

Also, it is well-known that many cheap-o Li batteries (like the ones you buy from eBay for under $10, or other aftermarket products) are cheaply made and may not hold/maintain a proper charge. (Were your batteries name-brand ones, or "made in China"?)

My suggestion would be to charge and synch whenever the mood strikes, and to not let the meter get below 2 bars for very long before charging. But it's your Reader, so it's your call. :chinscratch:

porkupan
08-04-2008, 08:57 PM
Were your batteries name-brand ones, or "made in China"?
It's no longer either-or: all the name brand stuff is made in China now-a-days. :(

However, I agree that the crazy attempts to "prolong the life of the battery" by some users do look ridiculous. This is not a cellphone, which needs to be recharged 3 times a week, and even the cellphone Li-Ion batteries last for several years these days.

Prolet
08-05-2008, 02:13 AM
Thank you for your thoughts, Catire and jakewastaken. ;)

If there was a chance to copy books from the memory card to the internal memory to reduce the increased battery drain caused by inserted memory cards without the need of a PC connection, this would be it.
Maybe with the next firmware update... :)

HarryT
08-05-2008, 04:13 AM
It's no longer either-or: all the name brand stuff is made in China now-a-days. :(


Why do you say that as though it were a bad thing?

DrMoze
08-05-2008, 08:13 PM
It's no longer either-or: all the name brand stuff is made in China now-a-days. :(

Perhaps true. What I meant, more precisely, is that the OEM batteries are generally produced (wherever!) to more stringent quality standards than some of the cheap-o eBay replacement batteries. Despite the same technology, poorly-made batteries often exhibit poorer performance. (Yes, *some* aftermarket batteries may be as good as, or better than, the OEM versions!)

seajewel
08-06-2008, 12:38 AM
I do have a question, though.. when I connect my Reader for a few minutes to add books, does that count as a "charge" that reduces the life of the Reader? I've been itching to add books I'm trying to wait as while I was messing with the flasher I literally had to connect and unconnect the Reader tens of times in the span of like 3 days..

gwynevans
08-06-2008, 05:13 AM
My understanding is that with Li-Ion, a 'charge' counts as the amount of charge needed to fully recharge from 'empty', although even that's misleading, as Li-Ion batteries start degrading from the time they're manufactured - it's not the number of 'charges' that count.

stasys
08-06-2008, 11:53 AM
Maybe we shall pass this charging-degradation topic to Mythbusters?:))

jakewastaken
08-06-2008, 04:30 PM
Maybe we shall pass this charging-degradation topic to Mythbusters?:))

I'd really like to see that. Maybe snopes too, while we're at it.