Nova 2 Battery Repair/Replacement

Knusperkeks · 05-14-2023, 07:14 PM

Hi,

i successfully replaced a dead battery (after just 2,5 years

) on my Onyx Boox Nova 2 and want to share my experiences with you. Note that if your battery starts to degrade, it is very fast and finally the device does not boot any longer! Powering a Nova 2 only via USB does not work for some reason (at least not on mine).

Opening the device is similar to the Nova Pro and was already documented here:
How to dissamble Onyx Nova Pro
NOVA Pro - How to disassemble an change the accu
Thanks a lot for the information!

The back cover does flex quite a bit, so using a piece of plastic in the thickness of a credit card does not work too well to release the snapping points. Something with double the thickness is preferred.
The battery is mainly fixed by two horizontal adhesive stripes, but there are also some cutouts in the grey base plate where sticky foil comes through. Be careful not to damage one of the two flat flex cables located underneath the battery, they might stick to the adhesive.

I guess the battery model name (CLP259297) is related to its dimensions -> 2.5x92x97mm??? Mine actually measured more like 3mm in thickness, but it might already be swollen up a bit. After some research i found a quite similar replacement type, which is also easily available and reasonably priced (for example on ebay). Be sure to choose one with actual wires and not a flat flex cable type. Replacement options:

MC-308594 for Amazon Kindle Fire 7 5th generation
MC-308695 or ST28 for Amazon Kindle Fire 2019 9th generation

I went for the latter one, as it was cheaper and more recent. It comes with a 6 pin connector having 2 positive pins (internally shorted together), 2 negative pins (internally shorted together), one id pin (30k resistance?, not needed) and one 10k NTC (it is expected by the ereader). Mine measured a thickness of 2.7mm which fits nicely inside! As i just installed it a few days ago, no long term data about the quality or potential issues are available to me. I can only say that my ereader works fine again an can be charged as normal

By the FCC teardown pictures, an Inkpad Color PB741 should have a very similar battery, dimension wise. However i did not find any source, but maybe this could be an alternative or a potential target for the Kindle battery as well.

Hopefully this is useful for anyone suffering a battery death!!! If you have any questions, feel free to ask. Lets save some Novas!

I made some photos comparing the original battery with the kindle one for your illustration, please look below.

Greetings!

Pajamaman · 05-15-2023, 06:56 AM

Im surprised you went for a Fire battery. I bought a battery marked for a Nova Pro on Ali Baba.

Renate · 05-15-2023, 07:39 AM

It's odd that Onyx populates the battery connector on the PCB but doesn't use it.
Has anyone ever found the matching plug?

sifidthewhite · 11-03-2023, 10:16 AM

Thanks for the information. It helped me replacing my Nova2's battery. Mine died in about 3 years

. Are all of BOOX devices like this?

I bought a replacement battery from here, but I don't recommend them. They claim shipping out within 1 day, 3800 mAh capacity and some replacement tools, but the shipment started after a month

and arrived with only a useless phillips-type screwdriver and 3500 mAh capacity

. But at least size matches to the original battery. Pic1 is a comparison before I detached the original battery:

About my experience: not having something better, I opened the case using a kitchen knife. Not so gentle but with a bit of patience it worked (though it left some dents on the edge...). My main struggle was removing the old battery. Two strips of double sided tape underneath were quite strong and I was afraid of damaging something (e.g. flat cables), but it was doable, with a credit card and patience (Pic2). First I briefly tested the device by connecting the new battery via the connector. It worked (meaning device turned on) but eventually I soldered wires to keep it as done by the manufacturer. So far my Nova2 seems fine (back to normal battery life, no freeze, no sudden battery drop, no shut down). However, it didn't charge to 100%. It stopped charging at 90%. I suspect this is because of battery calibration; Nova2's original battery is 3150 mAh and 3150/3500 = 0.9...

Renate · 11-03-2023, 12:49 PM

Yes, the batteries can be glued in something fierce.
I actually damaged the power button flex cable that went underneath on my Poke3.
I was pretty careful too.
If in doubt, unmount the power switch and let it flop.
Other times I poured a little isopropyl alcohol under the battery and let it sit a while to take some of the tenacity out of the glue strips.

trurle · 08-16-2024, 10:18 AM

thanks for posting this. I wish I had found this before I started replacing the battery in my nova 3.

my original battery did not last long either and made the book behave erratically. looking at the battery, it doesn't surprise me, it seems of very poor quality. the thickness of the original battery is not 2.5mm, it's ~3.6mm.

I opened the case by carefully inserting a wide thin stanley blade and prying slightly just enough to put the thin plastic lever in the gap, then carefully moving it around the case. since the original battery was fecked, I used a thin flexible filling knife to gradually bend and separate it from the frame, but be very careful of the two flexes that go underneath it.

as for the replacement, I took the same approach and started looking for other mass-produced batteries for tablets/ereaders as I don't trust cheap compatible batteries from aliexpress. unfortunately I did not find MC-308695/ST28 and opted for MC-347993/ST08/58-000084. Its dimensions are 78x93x3.5. I measured its capacity and it was true 3500mAh.

as it turned out, the protection circuit in that battery is set to cut-off at 4.2V (I forgot to check that the original battery was 4.35V), which meant that the reader wasn't able to reach full charge (cycled between charging and charged, stuck at 86%). It would work of course but annoying nevertheless. so I removed the protection circuit and replaced it with the one from the original battery. I understand that the new battery may not be specced for 4.35V but in my experience all mass-produced li-polymer batteries are these days, and after charge is complete, the battery holds this voltage, which is a good sign. I will keep an eye on it heating up or puffing.

another problem with ST08 is that it's got a 47KOhm NTC, so replacing the protection circuit solved that problem also.

BTW the OP suggested MC-308594 is also 4.2V (judging by the label), and it's worth checking the NTC is actually 10KOhm.

next time I am going to use MC-308695 as this seems the best fit (although lower capacity).

05-14-2023, 07:14 PM	#1
Knusperkeks Junior Member Posts: 1 Karma: 10 Join Date: May 2023 Device: Onyx Boox Nova 2	Nova 2 Battery Repair/Replacement Hi, i successfully replaced a dead battery (after just 2,5 years ) on my Onyx Boox Nova 2 and want to share my experiences with you. Note that if your battery starts to degrade, it is very fast and finally the device does not boot any longer! Powering a Nova 2 only via USB does not work for some reason (at least not on mine). Opening the device is similar to the Nova Pro and was already documented here: How to dissamble Onyx Nova Pro NOVA Pro - How to disassemble an change the accu Thanks a lot for the information! The back cover does flex quite a bit, so using a piece of plastic in the thickness of a credit card does not work too well to release the snapping points. Something with double the thickness is preferred. The battery is mainly fixed by two horizontal adhesive stripes, but there are also some cutouts in the grey base plate where sticky foil comes through. Be careful not to damage one of the two flat flex cables located underneath the battery, they might stick to the adhesive. I guess the battery model name (CLP259297) is related to its dimensions -> 2.5x92x97mm??? Mine actually measured more like 3mm in thickness, but it might already be swollen up a bit. After some research i found a quite similar replacement type, which is also easily available and reasonably priced (for example on ebay). Be sure to choose one with actual wires and not a flat flex cable type. Replacement options: MC-308594 for Amazon Kindle Fire 7 5th generation MC-308695 or ST28 for Amazon Kindle Fire 2019 9th generation I went for the latter one, as it was cheaper and more recent. It comes with a 6 pin connector having 2 positive pins (internally shorted together), 2 negative pins (internally shorted together), one id pin (30k resistance?, not needed) and one 10k NTC (it is expected by the ereader). Mine measured a thickness of 2.7mm which fits nicely inside! As i just installed it a few days ago, no long term data about the quality or potential issues are available to me. I can only say that my ereader works fine again an can be charged as normal By the FCC teardown pictures, an Inkpad Color PB741 should have a very similar battery, dimension wise. However i did not find any source, but maybe this could be an alternative or a potential target for the Kindle battery as well. Hopefully this is useful for anyone suffering a battery death!!! If you have any questions, feel free to ask. Lets save some Novas! I made some photos comparing the original battery with the kindle one for your illustration, please look below. Greetings! Attached Thumbnails

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05-15-2023, 06:56 AM	#2
Pajamaman Wizard Posts: 2,835 Karma: 10700629 Join Date: May 2016 Location: Canada Device: Onyx Nova	Im surprised you went for a Fire battery. I bought a battery marked for a Nova Pro on Ali Baba.

05-15-2023, 07:39 AM	#3
Renate Onyx-maniac Posts: 3,141 Karma: 12537601 Join Date: Feb 2012 Device: Nook NST, Glow2, 3, 4, '21, Kobo Aura2, Poke3, Poke5, Go6	It's odd that Onyx populates the battery connector on the PCB but doesn't use it. Has anyone ever found the matching plug?

11-03-2023, 12:49 PM	#5
Renate Onyx-maniac Posts: 3,141 Karma: 12537601 Join Date: Feb 2012 Device: Nook NST, Glow2, 3, 4, '21, Kobo Aura2, Poke3, Poke5, Go6	Yes, the batteries can be glued in something fierce. I actually damaged the power button flex cable that went underneath on my Poke3. I was pretty careful too. If in doubt, unmount the power switch and let it flop. Other times I poured a little isopropyl alcohol under the battery and let it sit a while to take some of the tenacity out of the glue strips.

08-16-2024, 10:18 AM	#6
trurle Junior Member Posts: 1 Karma: 10 Join Date: Aug 2024 Device: onyx boox nova 3	thanks for posting this. I wish I had found this before I started replacing the battery in my nova 3. my original battery did not last long either and made the book behave erratically. looking at the battery, it doesn't surprise me, it seems of very poor quality. the thickness of the original battery is not 2.5mm, it's ~3.6mm. I opened the case by carefully inserting a wide thin stanley blade and prying slightly just enough to put the thin plastic lever in the gap, then carefully moving it around the case. since the original battery was fecked, I used a thin flexible filling knife to gradually bend and separate it from the frame, but be very careful of the two flexes that go underneath it. as for the replacement, I took the same approach and started looking for other mass-produced batteries for tablets/ereaders as I don't trust cheap compatible batteries from aliexpress. unfortunately I did not find MC-308695/ST28 and opted for MC-347993/ST08/58-000084. Its dimensions are 78x93x3.5. I measured its capacity and it was true 3500mAh. as it turned out, the protection circuit in that battery is set to cut-off at 4.2V (I forgot to check that the original battery was 4.35V), which meant that the reader wasn't able to reach full charge (cycled between charging and charged, stuck at 86%). It would work of course but annoying nevertheless. so I removed the protection circuit and replaced it with the one from the original battery. I understand that the new battery may not be specced for 4.35V but in my experience all mass-produced li-polymer batteries are these days, and after charge is complete, the battery holds this voltage, which is a good sign. I will keep an eye on it heating up or puffing. another problem with ST08 is that it's got a 47KOhm NTC, so replacing the protection circuit solved that problem also. BTW the OP suggested MC-308594 is also 4.2V (judging by the label), and it's worth checking the NTC is actually 10KOhm. next time I am going to use MC-308695 as this seems the best fit (although lower capacity).