[Q] NST replacement battery will not charge

The original battery in my Nook had gotten to the point where it would only run for a day or so. I ordered a replacement battery and installed it. The system came up and indicated a 85% charge. Put in on the charger for the evening and then started using it in the morning. After more then a month of use the Nook indicated it was getting low so I placed it back on the charger. It was then I noticed that while it detected it was on a charger (got the large battery icon) the device/battery never switched from 'discharge' to 'charging', only to 'not charging'. Left it on over night but no change.

Thinking I perhaps had a bad battery (and not being able to return it) I purchased another one from a different source. Upon installing this one (at a 75% charge) I noticed it would show the same thing 'not charging'.

Putting the Nook original battery back in made everything happy.

I have tried different cables and power plugs, reboots, hard reboots, pulling the battery holding the power down for 60sec, even doing the factory reset re-register. Nothing seems to help.

Has anyone else seen this type of behavior with a new battery?

Possible that both are bad? Or is there some value that is not getting cleared?

Any help or pointers will be appreciated.

Thank-you

Renate NST said:

Did you try using UsbMode.apk (in the signature)?
(You'll need superuser to run that.)
Try setting the current to 500 mA and see if it will start charging.

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Thank-you for the fast reply. I haven't rooted the Nook yet but seeing that nothing else is working I have no problem trying. I will download your app and give it a try.

Thanks again

dsfraser said:

Thank-you for the fast reply. I haven't rooted the Nook yet but seeing that nothing else is working I have no problem trying. I will download your app and give it a try.

Thanks again

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Well I did the NookManager root and sideloaded your USBMode.apk. Changed the setup from Auto to 500mA, but it makes no difference. The status says 'Not charging' (switches to Discharging if I unplug). Health - Unknown, Reg - enabled, Max current - 500 mA, Battery - 3.963V 69%, Temp - 28F (which is odd as it's about 70 in here) Problem with a temperature sensor?

I've toyed with the idea of swapping the little battery circuit card from the old battery to my new one, good or bad idea?

Thanks for your assistance.

Renate NST said:

B&N screwed up on the temperature measurement.
The were supposed to report it as in integer, scaled 10X Celcius.
So for a normal 23°C the number should be 230, B&N blew it and delivers 23.
UsbMode.apk uses fingerprints to determine if it should handle it as a bug.
There is a problem with that, there are many Nooks with different fingerprints.

In any case 28°F is below freezing, below 0°C.
If the scale were off by a factor of 10, it would still be cold.
If the charging circuits thought the battery were cold it would not charge.
Since the thermistor in the battery pack is NTC, that means it's probably open.

The resistance from yellow to black at room temperature should be near to 10K.

Those little boards are tiny and it would be easy to short the battery before the Battery Protection Module.
I'd just pick up a new battery if the yellow/black measurement is way high.

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You are probably right about just getting another new battery, third times the charm? I tried to swap the circuit cards between the old, still sort of functioning, and the new 'no charging' one but to no avail. Didn't get any voltage out at all. Any recommendations about whom to buy a new battery from... I obviously haven't made very good choices the past two times.

Thanks for the help

Renate NST said:

It still could be the charging system on your Nook.
(But you say that your old battery charges ok. What does the temperature say?)

It would be nice to figure out exactly what the problem is.
Do you have a meter to measure the yellow to black resistance?
Moreover, is the yellow wire next to the red wires?

If they switched the thermistor and the ID resistor wire 30K would probably give a freezing indication.
See: http://xdaforums.com/showpost.php?p=42552349&postcount=5

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First off... Thank-you, thank-you, thank-you.

Now the story. I more or less (OK, more) destroyed my original and first replacement battery swapping the circuit cards around. I followed your suggestion and put a meter on the plug wires. My colors ran RRYWBB. Sure enough I had 27K where I should have 10K, and 9K where it should read 30K. Using a X-acto knife I was able to pry the plug locking tabs up and swap the Wht / Yel leads. Bingo, the Temp now reads 72F and when I plug in the charger I immediately get the battery icon with the lightning bolt and the status switches to 'Charging'. I'm guessing the first replacement battery had the same issue. These were from different companies and were packaged differently, but perhaps they all come from the same manufacture and that manufacture screwed up.

So again, thank-you for all your help.