Battery usage in sleep mode

stethorn · 01-08-2013, 10:47 AM

Hi,

On some reviews I have read, the Glo was knocked down due to the battery usage in sleep mode. I have had my KK for years, and when I wasn't using it the drain was minimal in sleep, although I never used the wifi.

Is it true there is battery drain in sleep on the kobo, at times I can go for 2 weeks to a month with out reading and don't want to pick up my kobo when I finally get 5 mins to find it dead. I don't use the wifi on it, I used the wifi for about 2 mins to have a play and now its off.

I have not noticed any battery drain, in fact its stayed on 41% for the last 3 days. Is the battery percentage reliable ? I did a full reboot of the kobo in case the % was no updating and it changed by 2 %.

So far the battery in exceeding my expectations, one of the reasons why I wanted the Paperwhite was because of the 2 month battery life, the kobo was advertised at half of that. I love the fact you don't have to worry about charging it and use more electric.

Thanks in advance

Ste

ltr · 01-08-2013, 04:29 PM

My test of the battery (for the Touch model), showed in Sleep mode the battery lasted about 11 days, and when powered off it lasts about 40 days.

ltr

stethorn · 01-08-2013, 04:34 PM

Quote:

Originally Posted by ltr

My test of the battery (for the Touch model), showed in Sleep mode the battery lasted about 11 days, and when powered off it lasts about 40 days.

ltr

Was this with Wifi off ? That seems really bad compared to the kindle. When I have left my glo in standby the % doesn't change, when I powered it off and back on then it wiped 2 % off it.

Lunchtray · 01-08-2013, 04:53 PM

I haven't been overly scientific about my battery usage but I read everyday for 1-2hrs a day. Only sleep my Kobo Glo and use the Glo function 1/4-1/3 of the time and it'll last over 30-35hrs on a single charge might stretch to 40hrs in some cases.

So it'll go about a month using sleep mode while reading at 2-4x the usage rate of Kindle's* battery usage amounts before I have to recharge.

Wifi off at all times (I never turn it on)

*Kindles #'s if I recall are 30min reading per day.

Stethorn, if you're going to not read for 2 weeks to a month turn it fully off instead of leaving it in sleep mode. But it should have a decent amount of charge left after being in sleep for that long a period.

TechniSol · 01-08-2013, 10:48 PM

I have a Touch. In sleep mode, as reported by others, it seems to use very little battery power, but it also seems to use quite a lot once it finally does start to register. My thinking is that the battery gauge may not be very linear -not exactly unheard of with battery powered devices. I think the only workable way to be near accurate is to monitor uptime between fully charged and the low end cutoff (around 2.75Vdc for lithium) while accounting for varying loads based on device state. With a profile generated in that manner the device could get a fairly accurate idea of total available power upon recharging and then track remaining power based on usage and turn that into a fairly accurate % on demand. But, that has limitations as well, since batteries are often rated at C/10 or C/20 discharge rates, but fail to deliver that much capacity when used at higher loads. Basically, battery gauges are more an indication of a trend than an accurate depiction of remaining power. It's like trying to guess how much water is left in a glass by looking at how fast it's being poured out. Worse, the only time the unit can accurately estimate the total capacity is when you completely discharge it.

I would advise anyone not planning on reading for 12-18 or more hours to consider shutting the Touch off between usages if they're looking for longer run time between charges. I'd also suggest that the occasional deep discharge may not hurt the device's ability to determine total capacity and more accurately estimate the remaining charge. However, I wouldn't carry deep discharges to the extreme either. OTOH, if Kobo properly determined minimum voltages and set them a bit higher than any internal protection circuitry it should be safe to run a device all the way down until you get the recharge message and then recharge it soon.

ltr · 01-09-2013, 07:51 AM

Quote:

Originally Posted by stethorn

Was this with Wifi off ? That seems really bad compared to the kindle. When I have left my glo in standby the % doesn't change, when I powered it off and back on then it wiped 2 % off it.

That was with WiFi off. The battery meter seems to last a long time on 100%, and then it drops faster the lower it goes.

01-08-2013, 10:47 AM	#1
stethorn Connoisseur Posts: 57 Karma: 12428 Join Date: Jan 2013 Device: Kobo Glo	Battery usage in sleep mode Hi, On some reviews I have read, the Glo was knocked down due to the battery usage in sleep mode. I have had my KK for years, and when I wasn't using it the drain was minimal in sleep, although I never used the wifi. Is it true there is battery drain in sleep on the kobo, at times I can go for 2 weeks to a month with out reading and don't want to pick up my kobo when I finally get 5 mins to find it dead. I don't use the wifi on it, I used the wifi for about 2 mins to have a play and now its off. I have not noticed any battery drain, in fact its stayed on 41% for the last 3 days. Is the battery percentage reliable ? I did a full reboot of the kobo in case the % was no updating and it changed by 2 %. So far the battery in exceeding my expectations, one of the reasons why I wanted the Paperwhite was because of the 2 month battery life, the kobo was advertised at half of that. I love the fact you don't have to worry about charging it and use more electric. Thanks in advance Ste

01-08-2013, 04:53 PM	#4
Lunchtray Connoisseur Posts: 78 Karma: 107708 Join Date: Jul 2011 Device: Kobo Glo, Kobo Touch, Kobo Gen 1	I haven't been overly scientific about my battery usage but I read everyday for 1-2hrs a day. Only sleep my Kobo Glo and use the Glo function 1/4-1/3 of the time and it'll last over 30-35hrs on a single charge might stretch to 40hrs in some cases. So it'll go about a month using sleep mode while reading at 2-4x the usage rate of Kindle's* battery usage amounts before I have to recharge. Wifi off at all times (I never turn it on) Kindles #'s if I recall are 30min reading per day. Stethorn, if you're going to not read for 2 weeks to a month turn it fully off instead of leaving it in sleep mode. But it should have a decent amount of charge left after being in sleep for that long a period. Last edited by Lunchtray; 01-08-2013 at 04:58 PM.*

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01-08-2013, 04:29 PM	#2
ltr Addict Posts: 399 Karma: 104628 Join Date: Oct 2010 Location: Canada Device: Kindle PW-2	My test of the battery (for the Touch model), showed in Sleep mode the battery lasted about 11 days, and when powered off it lasts about 40 days. ltr

01-08-2013, 10:48 PM	#5
TechniSol GranPohbah-Fezzes r cool! Posts: 1,056 Karma: 3151024 Join Date: Jul 2010 Device: Nook STRs, Kobo Touch, Kobo Glo	I have a Touch. In sleep mode, as reported by others, it seems to use very little battery power, but it also seems to use quite a lot once it finally does start to register. My thinking is that the battery gauge may not be very linear -not exactly unheard of with battery powered devices. I think the only workable way to be near accurate is to monitor uptime between fully charged and the low end cutoff (around 2.75Vdc for lithium) while accounting for varying loads based on device state. With a profile generated in that manner the device could get a fairly accurate idea of total available power upon recharging and then track remaining power based on usage and turn that into a fairly accurate % on demand. But, that has limitations as well, since batteries are often rated at C/10 or C/20 discharge rates, but fail to deliver that much capacity when used at higher loads. Basically, battery gauges are more an indication of a trend than an accurate depiction of remaining power. It's like trying to guess how much water is left in a glass by looking at how fast it's being poured out. Worse, the only time the unit can accurately estimate the total capacity is when you completely discharge it. I would advise anyone not planning on reading for 12-18 or more hours to consider shutting the Touch off between usages if they're looking for longer run time between charges. I'd also suggest that the occasional deep discharge may not hurt the device's ability to determine total capacity and more accurately estimate the remaining charge. However, I wouldn't carry deep discharges to the extreme either. OTOH, if Kobo properly determined minimum voltages and set them a bit higher than any internal protection circuitry it should be safe to run a device all the way down until you get the recharge message and then recharge it soon.

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