PRS-350 battery issues

[acanthicus]

Hi everyone!
I'm still using my 505, 650, 350 and T3 alternately. I love them, so a recommendation to buy a newer reader will be fruitless .
Over the years I changed the battery in the 505, 650 and 350. The T3 is still strong. The replacements were never so good as the original batteries, so I wanted to change them a second time in the 650 and 350. But every battery I bought was not charging because of a non existing heat problem. Some kind of "thermal resistor" missing or wrong according to some infos in the internet.
So, did someone of you bought a working battery recently? Or have an idea what to do? I found some instruction to remove the resistor from a working battery and put it in the new one, but that is a bridge, I don't want to cross...
Thanks in advance.

[rcentros]

Originally Posted by acanthicus

...So, did someone of you bought a working battery recently? Or have an idea what to do? I found some instruction to remove the resistor from a working battery and put it in the new one, but that is a bridge, I don't want to cross...

I haven't bought a Sony battery but, if you live in the U.S., NewPower99 supposedly gives a year warranty. I know they're more expensive, but maybe their batteries actually have the needed resistor?

https://newpower99.com/products/sony...eplacement-kit

[acanthicus]

Hi rcentros, thanks for your suggestion. The replacements I have now in use are newpower99 if I recall correctly. So I bought the new ones from them, too. Unfortunately they do not work. I tested two kits. I tried another brand with no luck. Maybe they are all manufactured in the same factory, and only labelled differently. Recently products of newpower99 have vanished at amazon germany.

[John F]

Just to check, did you try putting in a known good battery?

[acanthicus]

If I understand you correctly, the readers work fine with the old replacements (some years old), but not with the new replacements. I use them every day. I wanted to replace them again, because the battery live decreases and those batteries are easy and relatively cheap to buy. Battery change is easy in 650 and 350, very tricky in 505.
The problem is, that the new batteries will not charge. The reader says something about it overheating. That is because the new batteries have the wrong thermistor, whatever that is... Based on the info I found in the internet, they use a standard thermistor and Sony used a special one. So the new battery delivers a wrong temperature to the reader, which stops the charging.

edit: this problem occurs with 650 and 350. I did not try to change the battery in the 505 a second time (because tricky...)

[John F]

Originally Posted by acanthicus

If I understand you correctly, the readers work fine with the old replacements (some years old), but not with the new replacements. I use them every day. I wanted to replace them again, because the battery live decreases and those batteries are easy and relatively cheap to buy. Battery change is easy in 650 and 350, very tricky in 505.
The problem is, that the new batteries will not charge. The reader says something about it overheating. That is because the new batteries have the wrong thermistor, whatever that is... Based on the info I found in the internet, they use a standard thermistor and Sony used a special one. So the new battery delivers a wrong temperature to the reader, which stops the charging.

edit: this problem occurs with 650 and 350. I did not try to change the battery in the 505 a second time (because tricky...)

Just to make sure...

On the 650: it works fine with an old battery. The new battery throws a temperature error. You put the old battery back in and it works fine?

[acanthicus]

Hi John F
yes, it works fine with an old battery, which is already a replacement with decreasing battery time. It does not work with two different brands of new batteries because of the temperature error. I put back the old one and use the readers since then daily.

[Sirtel]

I know you said that you don't want to get a newer ereader, but unfortunately you may be forced to do it eventually, as Sony readers are very old by now and getting older. They're not going to last indefinitely. So even if you can still use them at the moment, I'd start to look around a bit, to find out what else out there might be to your taste. Just in case.

[Renate]

If the supply of replacement batteries give you the wrong temperature, there are ways out. That is, if you are competent and safety conscious.

Is there any way to report what the device thinks the temperature is? This is important for battery maintenance, but also many devices use that for waveform selection for Eink. I guess that this isn't Android, so you can't use a normal app for that?

You can reuse the BMS from the old battery and use the cells from the replacement battery. If you don't understand this, get some reliable tech friend to do the job for you.

Please don't burn down your house or injure yourself.

[acanthicus]

Thank you for your suggestion. I have no idea, which temperature the device is thinking to have. The old sony readers with which there are the battery problems, use a proprietary firmware, only the 'newer' ones, T1-T3, use Android.
I read about changing the bms, or to insert a resistor, or something like that, but even if I'm normally very experimental, I will not try that. So I'm safety conscious but not very competent in this area ...

[kwik]

Originally Posted by acanthicus

Hi everyone!
I'm still using my 505, 650, 350 and T3 alternately. I love them, so a recommendation to buy a newer reader will be fruitless

for what it's worth, I feel much the same. I hope you get your issue solved.