Glo Battery drained by faulty SD card/reader

GeoffR · 01-07-2013, 01:29 AM

Going by other's reports of good battery life, my Kobo Glo battery wasn't lasting as long as it should have, but I think I have found the cause of the problem:

I had a 4GB card in the Glo's micro SD expansion slot, and I was getting about 8-9 hours reading time with WiFi off. It didn't seem to matter whether the book I was reading was on the external card or not.

Yesterday I replaced the Glo's internal 2GB card with an 8GB one, and removed the 4GB card from the expansion slot. (I did this because images were not being cached properly for books residing on the external card, greatly slowing the display of thumbnails). Since then my power consumption appears to have dropped dramatically.

It'll take some time to work out exactly how much it has changed, but based on the last day's use I might now get 30 hours or more reading time per charge.

I can't imagine it is normal for a micro SD card to use so much power, so I guess either it was a faulty card, or a fault with my Glo such as a short-circuit in the card reader. I'd need to buy another card to test which.

voidoid · 01-07-2013, 01:48 AM

Quote:

Originally Posted by GeoffR

Going by other's reports of good battery life, my Kobo Glo battery wasn't lasting as long as it should have, but I think I have found the cause of the problem:

I had a 4GB card in the Glo's micro SD expansion slot, and I was getting about 8-9 hours reading time with WiFi off. It didn't seem to matter whether the book I was reading was on the external card or not.

Yesterday I replaced the Glo's internal 2GB card with an 8GB one, and removed the 4GB card from the expansion slot. (I did this because images were not being cached properly for books residing on the external card, greatly slowing the display of thumbnails). Since then my power consumption appears to have dropped dramatically.

It'll take some time to work out exactly how much it has changed, but based on the last day's use I might now get 30 hours or more reading time per charge.

I can't imagine it is normal for a micro SD card to use so much power, so I guess either it was a faulty card, or a fault with my Glo such as a short-circuit in the card reader. I'd need to buy another card to test which.

Please keep us posted about any conclusions or even strong suspicions that you reach. This is interesting stuff.

GeoffR · 01-20-2013, 02:04 AM

I have been testing a new micro SD card (Sandisk Ultra 16GB) for a few days and there seems to be little difference in power consumption compared to no card at all. I estimate about 30-35 hours reading time with wifi off. (Can't be exact without a much longer trial).

But when I put my old card (Kingston 4GB) back in the slot it is clear within a few hours that the battery is being drained at a much higher rate. Even with no books on the card, just having it in the card slot is enough to cause the drain. So it seems clear that the fault is with the card itself.

PeterT · 01-20-2013, 02:52 AM

@GeoffR; just wondering if you could watch the Glo with the old card in and see if it ever does sleep? I'm curious as my experience on my Touch was that the unit would start to sleep, and then wake right back up again,

Thanks!

GeoffR · 01-20-2013, 12:59 PM

Quote:

Originally Posted by PeterT

@GeoffR; just wondering if you could watch the Glo with the old card in and see if it ever does sleep? I'm curious as my experience on my Touch was that the unit would start to sleep, and then wake right back up again,

The bad card doesn't stop the Glo sleeping, and I didn't see it wake up unexpectedly. In fact the bad card didn't seem to have any noticable effect on the function or stability of the reader other than using a lot of power.

TechniSol · 01-21-2013, 02:31 AM

Perhaps a process gets started identifying or reading the card's contents and fails to shut down despite the ereader going into sleep mode? Maybe it's some sort of minor hardware or software compatibility issue with certain brands or the firmware has a bug that only shows with certain cards -might even be the card doesn't somehow follow the spec... though it seems likely Kobo could bulletproof whatever routine gets stuck with a timeout of some sort, or an override that shuts the microSD hardware down anyway. I think I recall seeing other posts about this sort of thing happening only with a certain brand/size card, possibly with the Touch.

01-07-2013, 01:29 AM	#1
GeoffR Wizard Posts: 3,821 Karma: 19162882 Join Date: Nov 2012 Location: Te Riu-a-Māui Device: Kobo Glo	Battery drained by faulty SD card/reader Going by other's reports of good battery life, my Kobo Glo battery wasn't lasting as long as it should have, but I think I have found the cause of the problem: I had a 4GB card in the Glo's micro SD expansion slot, and I was getting about 8-9 hours reading time with WiFi off. It didn't seem to matter whether the book I was reading was on the external card or not. Yesterday I replaced the Glo's internal 2GB card with an 8GB one, and removed the 4GB card from the expansion slot. (I did this because images were not being cached properly for books residing on the external card, greatly slowing the display of thumbnails). Since then my power consumption appears to have dropped dramatically. It'll take some time to work out exactly how much it has changed, but based on the last day's use I might now get 30 hours or more reading time per charge. I can't imagine it is normal for a micro SD card to use so much power, so I guess either it was a faulty card, or a fault with my Glo such as a short-circuit in the card reader. I'd need to buy another card to test which.

01-20-2013, 02:04 AM	#3
GeoffR Wizard Posts: 3,821 Karma: 19162882 Join Date: Nov 2012 Location: Te Riu-a-Māui Device: Kobo Glo	I have been testing a new micro SD card (Sandisk Ultra 16GB) for a few days and there seems to be little difference in power consumption compared to no card at all. I estimate about 30-35 hours reading time with wifi off. (Can't be exact without a much longer trial). But when I put my old card (Kingston 4GB) back in the slot it is clear within a few hours that the battery is being drained at a much higher rate. Even with no books on the card, just having it in the card slot is enough to cause the drain. So it seems clear that the fault is with the card itself. Last edited by GeoffR; 01-20-2013 at 02:04 AM. Reason: spelling

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01-20-2013, 02:52 AM	#4
PeterT Grand Sorcerer Posts: 13,698 Karma: 79983758 Join Date: Nov 2007 Location: Toronto Device: Libra H2O, Libra Colour	@GeoffR; just wondering if you could watch the Glo with the old card in and see if it ever does sleep? I'm curious as my experience on my Touch was that the unit would start to sleep, and then wake right back up again, Thanks!

01-21-2013, 02:31 AM	#6
TechniSol GranPohbah-Fezzes r cool! Posts: 1,056 Karma: 3151024 Join Date: Jul 2010 Device: Nook STRs, Kobo Touch, Kobo Glo	Perhaps a process gets started identifying or reading the card's contents and fails to shut down despite the ereader going into sleep mode? Maybe it's some sort of minor hardware or software compatibility issue with certain brands or the firmware has a bug that only shows with certain cards -might even be the card doesn't somehow follow the spec... though it seems likely Kobo could bulletproof whatever routine gets stuck with a timeout of some sort, or an override that shuts the microSD hardware down anyway. I think I recall seeing other posts about this sort of thing happening only with a certain brand/size card, possibly with the Touch.

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