PRS-650 New Owner - A few questions. - Page 4

Latinandgreek · 02-11-2011, 06:07 AM

Quote:

Originally Posted by Fortissimo

Thanks a lot Latin. I'm sure I will. How long have you been using your 505? I hope my Sony lasts for a long time!

I've had it for about 2 years, and it's built like a tank, really solid. I bought it new, but the internal calendar in it is set to 2007, though, so I guess it's actually probably more like 3 1/2 - 4 years old and sat in a warehouse for a while. I can honestly say that it is probably the best purchase I've ever made. I am going to give it to my husband (he's been asking for it), and get myself one of the new Sony readers, as I really like the touch screen and dictionaries.

Poppaea · 02-11-2011, 06:09 AM

Have you been charging all those hours??? Stop that! What are you doing there, man? Charging takes only two hours with a wall charger and three hours with a computer, and it does not take as long for you as your reader was half full when you got it. Take it off and enjoy it. Looks like you are trying to delay your handling it... it wont break just because you read with it. Believe me, it was made to be read with.

Bookworm_Girl · 02-11-2011, 08:53 AM

Quote:

Originally Posted by Fortissimo

Electrical outlets in the US don't have on/off switches?

Nope!

And, of course, switches in the UK go in the opposite direction for on/off from the US.... I attached pictures of both a US and UK outlet for comparison.

Ardjan · 02-11-2011, 09:02 AM

I have just read this thread and all the doubts about voltages and chargers and thought it might be good to try to explain how this works. First of all as mentioned before 5V is the USB standard, so all generic USB chargers should be fine. The reason the Sony Reader is specified for 3.7V is that it is probably using a Li-Ion battery.

The Sony Reader has some circuitry build-in that handles the charging of this 3.7V battery with the 5V input, this type of circuitry also prevents over-charging, so I'm convinced that it is safe to keep the reader connected to the charger for longer periods (personally I charge the reader overnight).
The mentioned rating of 940mA for the Sony Reader should probably be 940mAh which is a rating of the capacity of the battery and cannot be compared to the mA rating of the charger. A PC's USB port can output 500mA at most, so any charger rated for more than 500mA should be fine to charge the Sony Reader I guess.

Personally I use the carger of my mobile phone for my reader and this works just fine. I prefer this to charging using my computer because a computer USB port can switch from power mode causing the charging to start and stop. Since Li-Ion batteries have a limited number of charge cycles interrupting the charging process frequently reduces the life time of the battery (although this effect is probably not very big).

On hindsight this post is a bit rich on technical details (especially since this is my first post on mobileread

), so let me summarize: All generic 5V USB chargers with a rating of at least 500mA should be fine for charging the Sony Readers. Leaving the reader in the charger after the light has gone out shouldn't do any damage as far as I can see.
I hope this was helpful.

Latinandgreek · 02-11-2011, 09:16 AM

Quote:

Originally Posted by Ardjan

I have just read this thread and all the doubts about voltages and chargers and thought it might be good to try to explain how this works. First of all as mentioned before 5V is the USB standard, so all generic USB chargers should be fine. The reason the Sony Reader is specified for 3.7V is that it is probably using a Li-Ion battery.

The Sony Reader has some circuitry build-in that handles the charging of this 3.7V battery with the 5V input, this type of circuitry also prevents over-charging, so I'm convinced that it is safe to keep the reader connected to the charger for longer periods (personally I charge the reader overnight).
The mentioned rating of 940mA for the Sony Reader should probably be 940mAh which is a rating of the capacity of the battery and cannot be compared to the mA rating of the charger. A PC's USB port can output 500mA at most, so any charger rated for more than 500mA should be fine to charge the Sony Reader I guess.

Personally I use the carger of my mobile phone for my reader and this works just fine. I prefer this to charging using my computer because a computer USB port can switch from power mode causing the charging to start and stop. Since Li-Ion batteries have a limited number of charge cycles interrupting the charging process frequently reduces the life time of the battery (although this effect is probably not very big).

On hindsight this post is a bit rich on technical details (especially since this is my first post on mobileread

), so let me summarize: All generic 5V USB chargers with a rating of at least 500mA should be fine for charging the Sony Readers. Leaving the reader in the charger after the light has gone out shouldn't do any damage as far as I can see.
I hope this was helpful.

Welcome to MR, Ardjan. Very useful information.

elcreative · 02-11-2011, 10:11 AM

Just don't forget to keep a copy of your post so that you can do like the rest of us and repost periodically when the next user doesn't know how to search

and repeats the questions again... and again...

Still,good to have some people around with a bit of tech savvy...

Quote:

Originally Posted by Ardjan

...All generic 5V USB chargers with a rating of at least 500mA should be fine for charging the Sony Readers. Leaving the reader in the charger after the light has gone out shouldn't do any damage as far as I can see.
I hope this was helpful...

Pinecone · 02-11-2011, 12:03 PM

Actually it uses a lithium polymer battery.

The are rated at a nominal 3.7 volts, but like all rechargeable batteries, there is range of operating voltage from fully charged down to the maximum safe discharge. For Lipoloy (or Lipo), fully charged is 4.2 volts and fuly discharged in 3.0 volts.

So to fully charge, you need a source of at least 4.2 volts.

The way that lipos are charged is a constant current - constant voltage curve. They start with a constant current (for long life a maximum of 1 x capacity, so for a 940 mAH battery, 940 mA charge rate). Once the charger voltage reaches the fully charged voltage (4.2 volts) the charger holds this voltage until full charged. Since the charge current goes down as the battery gets fully charged, you really can't overcharge them, unless you put in too high of a voltage.

Also, a lipo life is limited by the number of charge cycles, but it is based on full charge cycles (3.0 - 4.2 volts). If you only run it down 1/2 way and charge, it only counts as 1/2 cycle. So no problem with charging when the reader is not fully discharged.

Also, as I understand it, the light goes out at 80% charge, it take another hour for it to fully charge. Although, it is hard to mark 80% and very easy to mark 90% charged. 90% charged is when the charge voltage hits the max voltage (4.2 volts).

elcreative · 02-11-2011, 01:19 PM

Just don't get confused by the tech detail about voltages... external USB PSUs are 5V devices as are USB computer ports... this is what USB provides and this is what you are supposed to supply to the reader... getting to specific voltages, for the actual battery, is handled internally...

Quote:

Originally Posted by Pinecone

Actually it uses a lithium polymer battery.

The are rated at a nominal 3.7 volts, but like all rechargeable batteries, there is range of operating voltage from fully charged down to the maximum safe discharge. For Lipoloy (or Lipo), fully charged is 4.2 volts and fuly discharged in 3.0 volts.

So to fully charge, you need a source of at least 4.2 volts.

The way that lipos are charged is a constant current - constant voltage curve. They start with a constant current (for long life a maximum of 1 x capacity, so for a 940 mAH battery, 940 mA charge rate). Once the charger voltage reaches the fully charged voltage (4.2 volts) the charger holds this voltage until full charged. Since the charge current goes down as the battery gets fully charged, you really can't overcharge them, unless you put in too high of a voltage.

Also, a lipo life is limited by the number of charge cycles, but it is based on full charge cycles (3.0 - 4.2 volts). If you only run it down 1/2 way and charge, it only counts as 1/2 cycle. So no problem with charging when the reader is not fully discharged.

Also, as I understand it, the light goes out at 80% charge, it take another hour for it to fully charge. Although, it is hard to mark 80% and very easy to mark 90% charged. 90% charged is when the charge voltage hits the max voltage (4.2 volts).

Fortissimo · 02-11-2011, 02:11 PM

Quote:

Originally Posted by Poppaea

Have you been charging all those hours??? Stop that! What are you doing there, man? Charging takes only two hours with a wall charger and three hours with a computer, and it does not take as long for you as your reader was half full when you got it. Take it off and enjoy it. Looks like you are trying to delay your handling it... it wont break just because you read with it. Believe me, it was made to be read with.

Yes, mam. By the way, I've authorized my reader. It was just a simple click like in your case. I worry too much. I couldn't figure out how to sync, so I just dragged and dropped.

Poppaea · 02-11-2011, 02:12 PM

Quote:

Originally Posted by Fortissimo

Yes, mam. By the way, I've authorized my reader. It was just a simple click like in your case. I worry too much. I couldn't figure out how to sync, so I just dragged and dropped.

Are you ready to read with it now?

Fortissimo · 02-11-2011, 02:42 PM

Quote:

Originally Posted by Poppaea

Are you ready to read with it now?

Yes I am, and I have.

Poppaea · 02-11-2011, 02:45 PM

Quote:

Originally Posted by Fortissimo

Yes I am, and I have.

Enjoy it

Fortissimo · 02-11-2011, 05:31 PM

Quote:

Originally Posted by Poppaea

Enjoy it

Haha!! You should come around some time.

Pinecone · 02-13-2011, 07:49 AM

Quote:

Originally Posted by elcreative

Just don't get confused by the tech detail about voltages... external USB PSUs are 5V devices as are USB computer ports... this is what USB provides and this is what you are supposed to supply to the reader... getting to specific voltages, for the actual battery, is handled internally...

Exactly, thanks for clarifying.

Fortissimo · 02-14-2011, 11:23 AM

Also, when you first got your reader, did you caliberate the battery? That is, by allowing it to discharge fully before you charge it again? I read in a previous thread that this is bad for LiPo batteries in general. But perhaps I have to do this the first few times I charge it?

I'm really trying to get the best out of my reader.

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02-11-2011, 06:09 AM	#47
Poppaea Lucifer's Bat Posts: 2,577 Karma: 20638583 Join Date: Nov 2010 Location: Earth/Berlin Device: Kobo Libra Colour	Have you been charging all those hours??? Stop that! What are you doing there, man? Charging takes only two hours with a wall charger and three hours with a computer, and it does not take as long for you as your reader was half full when you got it. Take it off and enjoy it. Looks like you are trying to delay your handling it... it wont break just because you read with it. Believe me, it was made to be read with.

02-11-2011, 09:02 AM	#49
Ardjan Member Posts: 11 Karma: 466 Join Date: Feb 2011 Location: The Netherlands Device: Sony PRS-650	I have just read this thread and all the doubts about voltages and chargers and thought it might be good to try to explain how this works. First of all as mentioned before 5V is the USB standard, so all generic USB chargers should be fine. The reason the Sony Reader is specified for 3.7V is that it is probably using a Li-Ion battery. The Sony Reader has some circuitry build-in that handles the charging of this 3.7V battery with the 5V input, this type of circuitry also prevents over-charging, so I'm convinced that it is safe to keep the reader connected to the charger for longer periods (personally I charge the reader overnight). The mentioned rating of 940mA for the Sony Reader should probably be 940mAh which is a rating of the capacity of the battery and cannot be compared to the mA rating of the charger. A PC's USB port can output 500mA at most, so any charger rated for more than 500mA should be fine to charge the Sony Reader I guess. Personally I use the carger of my mobile phone for my reader and this works just fine. I prefer this to charging using my computer because a computer USB port can switch from power mode causing the charging to start and stop. Since Li-Ion batteries have a limited number of charge cycles interrupting the charging process frequently reduces the life time of the battery (although this effect is probably not very big). On hindsight this post is a bit rich on technical details (especially since this is my first post on mobileread ), so let me summarize: All generic 5V USB chargers with a rating of at least 500mA should be fine for charging the Sony Readers. Leaving the reader in the charger after the light has gone out shouldn't do any damage as far as I can see. I hope this was helpful.

02-11-2011, 12:03 PM	#52
Pinecone Guru Posts: 902 Karma: 1660722 Join Date: Nov 2009 Location: Maryland Device: PRS-650, PRS-600, PRS-350	Actually it uses a lithium polymer battery. The are rated at a nominal 3.7 volts, but like all rechargeable batteries, there is range of operating voltage from fully charged down to the maximum safe discharge. For Lipoloy (or Lipo), fully charged is 4.2 volts and fuly discharged in 3.0 volts. So to fully charge, you need a source of at least 4.2 volts. The way that lipos are charged is a constant current - constant voltage curve. They start with a constant current (for long life a maximum of 1 x capacity, so for a 940 mAH battery, 940 mA charge rate). Once the charger voltage reaches the fully charged voltage (4.2 volts) the charger holds this voltage until full charged. Since the charge current goes down as the battery gets fully charged, you really can't overcharge them, unless you put in too high of a voltage. Also, a lipo life is limited by the number of charge cycles, but it is based on full charge cycles (3.0 - 4.2 volts). If you only run it down 1/2 way and charge, it only counts as 1/2 cycle. So no problem with charging when the reader is not fully discharged. Also, as I understand it, the light goes out at 80% charge, it take another hour for it to fully charge. Although, it is hard to mark 80% and very easy to mark 90% charged. 90% charged is when the charge voltage hits the max voltage (4.2 volts).

02-14-2011, 11:23 AM	#60
Fortissimo Connoisseur Posts: 77 Karma: 10360 Join Date: Jan 2011 Location: Lagos, Nigeria. Device: Sony Reader Touch Edition (PRS-650BC)	Also, when you first got your reader, did you caliberate the battery? That is, by allowing it to discharge fully before you charge it again? I read in a previous thread that this is bad for LiPo batteries in general. But perhaps I have to do this the first few times I charge it? I'm really trying to get the best out of my reader.

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