Clara HD battery unreliable when below 30%

Cactus Chef · 06-15-2022, 11:30 PM

I've been having repeated issues where if my Clara HD shows a battery at 30% or below, I can more or less guarantee it will be dead by morning. 30% is apparently the new 5% for my Clara.

I've done everything I can to try to eliminate ambient drain. I turn off WiFi unless I'm syncing something. I keep the screen at no brighter than 5%. I have a sleep cover, but I turned the sleep cover functionality off because I suspected maybe it was inadvertently waking it up somehow. So now sleeping is completely manual, and I hit the power button every time before I close the lid, and confirm that the backlight turns off.

No luck. I don't understand what could be causing it. And surely if the battery reading were inaccurate, the battery would have recalibrated itself by now, because it has done this for my last five charges (that is to say, I found my Kobo completely drained before recharging it, so that should have been five full cycles).

It's driving me nuts, because on weeknights I generally don't check my Kobo until I'm settling down in the evening for bed, at which point I find it's dead, and I can't use it until the following day because I have to wait for it to charge.

What else can I do?

davidfor · 06-16-2022, 02:01 AM

I can think of two things.

One is that the battery is starting to fail. The behaviour is what I have seen with older Li-Ion batteries in other devices. They seem to have a charge but it runs out a lot quicker than expected. Whether this is likely depends on how old the battery is and how it has been used or abused. In these devices, you would need to read constantly to shorten the life by a lot. But, if you are reading or storing the device in hot conditions, it will shorten the battery life. But, the longer you have had the device, the more likely this is the case.

The other possibility is a hung or runaway process. That can be triggered by particular books. If this has only started since you started a new book, then that is likely to be the case. A test for this is to restart the device after finishing reading. That will stop everything and you can see what happens with the battery usage.

Also, I doubt it is the case. There have been some issues in the past, but, I haven't heard of anything recently. It could be because of the case if there is something that might be affecting the magnet and sensor nearby. I've been caught like this when I put one of the devices to near another device with a magnetic cover.

Phil_C · 06-16-2022, 01:11 PM

This seems to be typical behavior with the Clara after about 30 months. I can't speak to other Kobo models. See my comments in another thread:

https://www.mobileread.com/forums/sh...6&postcount=11

I have not one Clara, but two. Both were purchased 3 years ago. One was in daily use 90% of the time, the other only sporadically when I fiddled with options and patches or when unit #1 was charging. Yet BOTH now have the same battery capacity -- with the almost instant dropoff below 35% or 30%. So the one with very light use has had its battery degrade as rapidly as the one with heavy use. That is what I find odd.

Lithium Ion batteries do last a long time on a charge, but then drop rapidly at the end. No argument there. That's normal behavior. Maybe the displayed percentage Kobo gives us is not very accurate. Maybe 30% is really 5%. Dunno.

But years ago I used this same system with several Sony readers. Those batteries lasted way longer (in years) than the Kobo's. Also, a Sony reader I had basically in storage for a couple of years acted like brand new when I put it in use. It did not exhibit the deterioration of the stored Kobo.

Meanwhile, the Clara is the best reader I've ever had. So, while I think the batteries could be better, I'll just accept the reality and move on.

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06-15-2022, 11:30 PM	#1
Cactus Chef Evangelist Posts: 491 Karma: 6655750 Join Date: Apr 2019 Device: Kobo Sage, Kobo Clara HD, Galaxy Tab S5e, Kindle 4th Gen	Clara HD battery unreliable when below 30% I've been having repeated issues where if my Clara HD shows a battery at 30% or below, I can more or less guarantee it will be dead by morning. 30% is apparently the new 5% for my Clara. I've done everything I can to try to eliminate ambient drain. I turn off WiFi unless I'm syncing something. I keep the screen at no brighter than 5%. I have a sleep cover, but I turned the sleep cover functionality off because I suspected maybe it was inadvertently waking it up somehow. So now sleeping is completely manual, and I hit the power button every time before I close the lid, and confirm that the backlight turns off. No luck. I don't understand what could be causing it. And surely if the battery reading were inaccurate, the battery would have recalibrated itself by now, because it has done this for my last five charges (that is to say, I found my Kobo completely drained before recharging it, so that should have been five full cycles). It's driving me nuts, because on weeknights I generally don't check my Kobo until I'm settling down in the evening for bed, at which point I find it's dead, and I can't use it until the following day because I have to wait for it to charge. What else can I do?

06-16-2022, 02:01 AM	#2
davidfor Grand Sorcerer Posts: 24,905 Karma: 47303824 Join Date: Jul 2011 Location: Sydney, Australia Device: Kobo:Touch,Glo, AuraH2O, GloHD,AuraONE, ClaraHD, Libra H2O; tolinoepos	I can think of two things. One is that the battery is starting to fail. The behaviour is what I have seen with older Li-Ion batteries in other devices. They seem to have a charge but it runs out a lot quicker than expected. Whether this is likely depends on how old the battery is and how it has been used or abused. In these devices, you would need to read constantly to shorten the life by a lot. But, if you are reading or storing the device in hot conditions, it will shorten the battery life. But, the longer you have had the device, the more likely this is the case. The other possibility is a hung or runaway process. That can be triggered by particular books. If this has only started since you started a new book, then that is likely to be the case. A test for this is to restart the device after finishing reading. That will stop everything and you can see what happens with the battery usage. Also, I doubt it is the case. There have been some issues in the past, but, I haven't heard of anything recently. It could be because of the case if there is something that might be affecting the magnet and sensor nearby. I've been caught like this when I put one of the devices to near another device with a magnetic cover.

06-16-2022, 01:11 PM	#3
Phil_C Addict Posts: 274 Karma: 391602 Join Date: Oct 2009 Location: Chicago, IL USA Device: Sony PRS-350; Kobo Clara HD; Kobo Clara 2E; Kobo Clara BW	This seems to be typical behavior with the Clara after about 30 months. I can't speak to other Kobo models. See my comments in another thread: https://www.mobileread.com/forums/sh...6&postcount=11 I have not one Clara, but two. Both were purchased 3 years ago. One was in daily use 90% of the time, the other only sporadically when I fiddled with options and patches or when unit #1 was charging. Yet BOTH now have the same battery capacity -- with the almost instant dropoff below 35% or 30%. So the one with very light use has had its battery degrade as rapidly as the one with heavy use. That is what I find odd. Lithium Ion batteries do last a long time on a charge, but then drop rapidly at the end. No argument there. That's normal behavior. Maybe the displayed percentage Kobo gives us is not very accurate. Maybe 30% is really 5%. Dunno. But years ago I used this same system with several Sony readers. Those batteries lasted way longer (in years) than the Kobo's. Also, a Sony reader I had basically in storage for a couple of years acted like brand new when I put it in use. It did not exhibit the deterioration of the stored Kobo. Meanwhile, the Clara is the best reader I've ever had. So, while I think the batteries could be better, I'll just accept the reality and move on.