Hi all, after having my PRS700 for a week and having recharged it three times already, I thought I would do some research on how to care for and extend the life of the lithium-ion battery. The following is quoted from the windows help on my PC.

Note: If you frequently drain and then recharge a lithium-ion battery, it can quickly lose its ability to hold a charge. The practice of completely draining and then fully charging a battery is advice that applied to nickel cadmium (NiCd) batteries and, to a lesser extent, nickel metal hydride (NiMH) batteries. Lithium-ion batteries last longer if you charge them often, a little at a time, and maintain a minimum charge of about 40 percent capacity.

Using the sidelights on my PRS700 drains my battery quicker than expected. Reading at night with only level-1 lighting seems to drain my battery quicker than the 8 hours mentioned in the manual.

Playing with the search funtion on the PRS700 also seems to drain the battery at an alarming rate.

The term "frequently drain" may not apply to readers who do not use the lights on the reader, but it certainly applies to my need to do frequent recharges.

Since the battery is not accessible on the PRS700 (as far as I know), I thought this info might be useful for those who want to extend their battery life.

My plan, if I can, is to follow this advice and charge my battery often, a little at a time, unless someone can explain why this is not a good idea.

Long life to you and your battery:D

Now that you mention it, I've also noticed that the battery does seem to
*EDIT* NEED topping up rather quickly (especially when LED lights are used). I will have to
monitor more closely to see if it reaches Sonys' battery life claim.

so how many hours are you getting with the light at level 1?

so how many hours are you getting with the light at level 1?
I'm not quite sure how many hours I'm getting. I read both with and without the light. Since I've had to recharge 3 times in one week, and I only read about 2 hours per night with the light, I'm assuming I'm getting considerably less than the 8 hours specified.:blink:

It's the same advice for Ipods. Basically, charge at 50-40%, and then every so often let the battery drain completely. I got my 700 on Friday, and it was 1/2 charged, so I was able to explore it right out of the box. However, my holiday company wanted to go see "Australia", which is a long, but great movie, so, I put the reader on charge. I was lucky that my charger for my Casio EXILIM fit my 700, we travel, so it's cool to have one charger for two very diverse units. Since then I've read mostly with the light off, but I have read with the light on at night (lowest light works for me), and my battery hasn't gone down a tick yet. However, I have a sleep disorder, so the 700 seemed to be a godsend for me, so I'll probably keep my AC adapter bedside.

It's the same advice for Ipods. Basically, charge at 50-40%, and then every so often let the battery drain completely.
How often is every so often? Once a month, once every 3 months...is your iPod manual more specific?:)

this is something i learned with my cell phone, charge whenever you need it (i need it almost every night, or if i dont use it much, once every 2 days)

dont leave it in the charger for more than over night....THIS IS VERY IMPORTANT WITH LAPTOP BATTERIES. if you want the laptop to last, dont leave it plugged in. NEVER leave it pluged in while your using it one your lap, the cords in laptops are very sensitive (comparitivly) and the wires inside get frayed/broken and this can lead to you not being able to use your laptop while you wait from the Warrenty, or you have to spend 40-80 bucks on a new charger. with certain 3 pin chargers (dells mostly ive noticed) there is this little pin on the inside that says, Hey im a Dell Charger, if the wire gets frayed (its very small, maybe 22-24 guage on the inside of a 10-14 guage charger) or that pin gets pushed into the charger head (happened 6 times to my brother and friends with dell laptops, 4 frays and 2 pushins, ive only recently been fixing the frays by soldering cause their warrenty expired) the laptop will turn on, but not charge the battery


as for my PRS 700, if i have 2 bars or less, and if im going to sleep. i throw it on the chrager. if i have 3-4 bars i leave it off.

Li ion batteries work opposite to NickelCD.

I'd recommend to always keep them charged.
Like laptops, whenever in reach of a wall socket it is better to keep them plugged in.
The less you use them,the less they can wear out.

After 2 to 3 years of using my laptop, with plugging in always when possible, my battery (large capacity) still holds 3 of the 4 hours of batterylife!
Wouldn't have been possible with my wife's laptop which only gets plugged in when empty.

Besides, generally when a Lithium battery still has 80%left, they get slowcharged, which is more healthy for the battery.

li ion batteries dont like to stay topped off though. if you are going to not use one for about 2 weeks, i would discharge about 50% and then put it away. Li ions like to be used more than anything else i think.

li ion batteries dont like to stay topped off though. if you are going to not use one for about 2 weeks, i would discharge about 50% and then put it away. Li ions like to be used more than anything else i think.

I've written a few articles on this on other forums.
I written Duracell and they have confirmed that Li-Ion best always remains charged.
Completely emptying them could cause them to get into a state where part or even the whole of the battery never can be charged again.
A Li-Ion battery always need a remaining voltage, and the less you charge it, the less it wears out.
This resembles my experience of the past 5 years I've been using Li-Ion batteries in my cellphones.

They also recommend to at least charge a non-used battery once every 2 to 3 months (depending on the drain of the battery).
Modern batteries may only need recharging every 6 to 9 months when not used.

I've written a few articles on this on other forums.
I written Duracell and they have confirmed that Li-Ion best always remains charged.
Completely emptying them could cause them to get into a state where part or even the whole of the battery never can be charged again.
A Li-Ion battery always need a remaining voltage, and the less you charge it, the less it wears out.
This resembles my experience of the past 5 years I've been using Li-Ion batteries in my cellphones.

They also recommend to at least charge a non-used battery once every 2 to 3 months (depending on the drain of the battery).
Modern batteries may only need recharging every 6 to 9 months when not used.
So what would you suggest, ProDigit, for recharging the PRS700. What would you suggest I do at the end of each night using the following senarios:

If charge is at: 3/4 - charge overnight to be ready for tomorrow
charge is at 1/2 - charge overnight...
charge is at 1/4 - charge overnight...

..or any other scenario you can think of. I intend to use my PRS700 on a regular basis.

Can you harm the battery by leaving it charging all night when it only needs to charge for a max of 2 hours?
Thanks in advance for your advice:thanks:

I've written a few articles on this on other forums.
I written Duracell and they have confirmed that Li-Ion best always remains charged.
Completely emptying them could cause them to get into a state where part or even the whole of the battery never can be charged again.
A Li-Ion battery always need a remaining voltage, and the less you charge it, the less it wears out.
This resembles my experience of the past 5 years I've been using Li-Ion batteries in my cellphones.

They also recommend to at least charge a non-used battery once every 2 to 3 months (depending on the drain of the battery).
Modern batteries may only need recharging every 6 to 9 months when not used.

that's interesting, and yes, using a Li ion is the only way to actually keep the capacity up, but i think a topped off battery that sits is worse from my experience with many laptops.

my cell phone was the only one in the family who's battery was never replaced.

i think the best advice is if you want to Use the battery, USE the battery. a battery that sits unused will deplete faster than one that is used every day, this is what most reports ive seen has said.

as for the 6 - 9 months. Never once have I heard any body who keeps their laptop plugged in for more than 6 months go out and get more than 1 hour that their battery gives them. while with actual working laptops they work every day just fine

and my argument for batterys not being stored while full is, if they last so long full, then they would top them off before packaging, instead of giving you a 10-40% battery charge on new devices

Can you harm the battery by leaving it charging all night when it only needs to charge for a max of 2 hours?
Charging stops automatically when the battery is full, so probably not.

Actually, the usage of the reader is less that of a laptop, and more that of a cellphone.

On a laptop the battery is best preserved to,when you can, plug it in the wall when using the laptop.
That way the battery remains fully charged, and while using it,you actually use the AC instead of wearing the battery.
Though the same can be applied on the reader, due to it's enormous small powerdraw you most likely not need to plug it in always.

A reader, as with a cellphone, uses way less electricity, and the battery remains charged longer (unless you have these cheap cellphones that only last a day).

On the other hand, I own a Sony PRS-505, and can deplete it's battery in less than 1 hour, by:
- indexing a large amount of files (turn off the power saving mode for this).
- viewing large sized pictures (in my case 4MB 6Mpix photo's from my digital camera).
- opening a book, changing fontsizes to all zoom level, and proceed to the next book to change fontsizes over there,and repeat for a few hundred of books.
- Fast pageswapping through comic books in pdf format(takes little longer)

When doing such tasks I'd also recommend to keep the reader plugged in the wall, if possible.

I myself don't really need to charge the reader, since I upload,and modify plenty of books on the reader's internal memory.
When plugged in a usb port, the reader also charges.

Obviously keeping the reader plugged in at all times will cost you more on electricity (by keeping the AC adaptor plugged in,or your computer running to provide power for the usb port).

When I use it in the evening reading in my bed, I plug it in the wall (AC,not USB) when I see the battery is getting empty.
Usually by the time I finished reading the battery is charged. That way the hour I spend reading, I charged the battery without ballasting it. 2 tasks in one done!
If you can live by such strict rules, I'd recommend yo;but if not then most likely 2 years from now my battery will live 5-10minutes longer than yours on a full charge,so you won't really lose much either way. ;)
Current Li-ion batteries are pretty good.

Generally a normal charge takes less than 1 hour; it takes 2 hours to charge from a completely empty battery on the AC adaptor. Charging it via USB takes upto 4 hours, and you can not simultaneously read books. You can use the SD cardslot and internal memory of the reader to add files or something...

In my opinion it does not really matter if the battery indicator says full,1/2 or 1/4 charged.
The indicator is deceiving, in a way that upon booting the device, the battery meter may indicate that the battery is full, while in real fact it can be 15minutes away from being completely discharged.
Only after using the device a few minutes can you see the real charge.

Seeing this, it is probably safer to charge the battery while the indicator is 1/2 rather than waiting until it is empty.
But I don't really know if 3/4,1/2 or 1/4thof the battery will make much of difference.

The battery used in the reader is a single cell, with no internal hardware to keep track of charging cycles, so I might say it's safer to charge while reading, and while the battery indicates 1/2 charge.

Unplug it when you're not using the device. This saves you energy, and less chance of something going wrong:

I don't know about other products, but sony's products are generally very safe products, and i could not imagine the Sony reader catching fire, but where ever electricity comes to play in a plastic little box, there always is chance of fire.
Be it not the reader, then the adaptor, be it not sporadically, then through a lightning strike on your electricity net... the thought is a bit far fetched, but the possibility is always there.

The fire hazard of electronic devices has dropped drastically compared to electric devices, but it still is not completely nihil.

Another thing,the reader doesn't need to catch fire; but a lightning stroke can permanently damage the reader too,when being plugged in!
Chances are less that this could happen when not being plugged in.

You save the energy of the adaptor being on,using between 0,1 and 1W when not in use.
Do this for all your non-used electronic and electric devices in your household,and you can save about $75 per year on electricity cost! That'd translate in a nice dinner for two, at a fancy restaurant; or the purchase of 3 to 5 books, whichever you prefer.

The Sony reader has a build in protection circuit against over-charging the battery, so you don't need to fear about leaving it plugged in too long.

A general piece of advise is to buy extension cords with a build in switch,that can deflect (block) lightning strikes. And turn off the switch, when not using a device.
It's always greener and safer!

Actually, the usage of the reader is less that of a laptop, and more that of a cellphone.
Thanks for the info ProDigit and igorsk.

Similar discussion going on in PRS50X forum re: battery.

They also point to wiki tips on battery life, where it suggests approx. every 30th charge should be from a total drain.

They also point to wiki tips on battery life, where it suggests approx. every 30th charge should be from a total drain.

I personally would never total drain it for reasons I stated above.
A total drain is only good for Ni-Cd batteries, not for Li-Ion.

My personal opinion is that a total drain on Li-ion is harmful for the battery.
Either way noone has to agree with me. Only I'd never do such a thing on my batteries.

Also,the wiki has been created by normal people like you and me. It wasn't created by researchers or engineers.

taken from http://www.batteryuniversity.com/parttwo-34.htm

http://www.batteryuniversity.com/images/parttwo-34.gif

# Avoid frequent full discharges because this puts additional strain on the battery. Several partial discharges with frequent recharges are better for lithium-ion than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no memory. (In this respect, lithium-ion differs from nickel-based batteries.) Short battery life in a laptop is mainly cause by heat rather than charge / discharge patterns.

# Batteries with fuel gauge (laptops) should be calibrated by applying a deliberate full discharge once every 30 charges. Running the pack down in the equipment does this. If ignored, the fuel gauge will become increasingly less accurate and in some cases cut off the device prematurely.

# Keep the lithium-ion battery cool. Avoid a hot car. For prolonged storage, keep the battery at a 40% charge level.

# Consider removing the battery from a laptop when running on fixed power. (Some laptop manufacturers are concerned about dust and moisture accumulating inside the battery casing.)

# Avoid purchasing spare lithium-ion batteries for later use. Observe manufacturing dates. Do not buy old stock, even if sold at clearance prices.

# If you have a spare lithium-ion battery, use one to the fullest and keep the other cool by placing it in the refrigerator. Do not freeze the battery. For best results, store the battery at 40% state-of-charge.

so it looks like the best thing to do is
Charge Often
Store someplace cool.
if you are going to not use it for an extended Period deplete to 40% before storing