Battery on Kobo Aura H2O went from 30 % to 0 % very fast

bonaldo2000 · 01-17-2015, 09:23 AM

Hi

I have just got a Kobo Aura H20 which I am generally very happy with. The battery life has been extremely good and one charge has lasted me several months. However, I just noticed that when it reached about 30 %, in about a day it went to 0 %. Is this just the battery indicator that is buggy or do I have a problem? It's slightly annoying that I cannot count on the indicator. I mean the first 30% took maybe 3-4 weeks, the last 30 % took hours...

Barcey · 01-17-2015, 10:00 AM

Mine behaves the same way so either we have the same problem or the battery indicator isn't accurate for the last 30%.

I agree that it's annoying that you can't rely on it but at least you can read while it's charging. I just charge mine every couple of weeks.

bonaldo2000 · 01-17-2015, 11:13 AM

Thank you for the reply!
Yeah, it's no biggy. We just have to sort of count 30 % for 0 %!
By the way, can I just charge it with an iPhone or iPad charger? A bit annoying having to plug it into a computer...

meeera · 01-17-2015, 11:21 AM

Quote:

Originally Posted by bonaldo2000

By the way, can I just charge it with an iPhone or iPad charger? A bit annoying having to plug it into a computer...

Yes, no problem. I've used other USB charge plugs also without any issues.

robko · 01-17-2015, 12:09 PM

Quote:

Originally Posted by bonaldo2000

Yeah, it's no biggy. We just have to sort of count 30 % for 0 %!
By the way, can I just charge it with an iPhone or iPad charger? A bit annoying having to plug it into a computer...

Yes very typical to drop very fast in last bit of gauge.
Other chargers will work, but i-thing chargers are slightly different and may not work. I use various other phone chargers to charge my Kobo's.

JSWolf · 01-17-2015, 12:31 PM

iPhone chargers do work. You just have to tell the Kobo you are not connecting to a computer.

bonaldo2000 · 01-17-2015, 02:57 PM

Ok, thank you guys.

jackastor · 01-17-2015, 03:28 PM

Quote:

Originally Posted by bonaldo2000

Ok, thank you guys.

There are a number of H2O that have bad batteries. My first unit had one, the only course of action is to return the unit and get a new one. BTW spent many hours and days trying to sort this. Save your self a headache and time.

regards

Jack

rwhe · 01-19-2015, 04:58 PM

Quote:

Originally Posted by jackastor

There are a number of H2O that have bad batteries. My first unit had one, the only course of action is to return the unit and get a new one. BTW spent many hours and days trying to sort this. Save your self a headache and time.

regards

Jack

I partly agree with Jack. My first H2O couldn't hold a charge. I returned it and and was happy I took his advice to. However, that old unit would go from 100% to 0% in a day or two. Yours seems as though it can hold a charge for a good long time, but doesn't know where 0% really is. This sounds more like a calibration problem to me. I wasted a lot of time calibrating my first H2O, but it might not be a waste of time in your case.

GeoffR · 01-19-2015, 11:03 PM

My Glo is similar to the OP's: the battery life overall is excellent, but the meter drops very quickly after it gets down to about 25%-30%, so I just read 30% as time to recharge.

rcentros · 01-20-2015, 01:43 AM

Quote:

Originally Posted by GeoffR

My Glo is similar to the OP's: the battery life overall is excellent, but the meter drops very quickly after it gets down to about 25%-30%, so I just read 30% as time to recharge.

I guess I've never let mine get down that far. I'll have to watch for that.

TechniSol · 01-20-2015, 02:25 AM

The fast dropoff from 25-30% to the recharge point is pretty common, not just for Kobo devices. The issue is that the battery voltage falls off at a different rate as the battery is discharged. When you get down near the end of the curve the battery voltage falls off VERY rapidly compared to a nearly straight line slope for most of the charge. The algorithm determining remaining charge is probably based on a linear or straight line approximation rather than modeling the curve.

If Kobo employed either a lookup table or derived the equation for the battery curve, they could give a lot more accurate picture of remaining power... As it is, I assume 25-30% is the end of the line and figure 65% is really about 50%, etc. I usually charge before I get anywhere near the low end because it tends to be easier on the battery and you can probably charge twice as many times if you're only subjecting the battery to mild to moderate discharges. I think deep cycles are A LOT harder on lithium batteries based on my day to day experience with the batteries in my cell phones over the years. I recall that most of the battery literature points this out as well.

01-17-2015, 09:23 AM	#1
bonaldo2000 Enthusiast Posts: 33 Karma: 13208 Join Date: Aug 2008 Device: prs-505	Battery on Kobo Aura H2O went from 30 % to 0 % very fast Hi I have just got a Kobo Aura H20 which I am generally very happy with. The battery life has been extremely good and one charge has lasted me several months. However, I just noticed that when it reached about 30 %, in about a day it went to 0 %. Is this just the battery indicator that is buggy or do I have a problem? It's slightly annoying that I cannot count on the indicator. I mean the first 30% took maybe 3-4 weeks, the last 30 % took hours...

01-20-2015, 02:25 AM	#12
TechniSol GranPohbah-Fezzes r cool! Posts: 1,056 Karma: 3151024 Join Date: Jul 2010 Device: Nook STRs, Kobo Touch, Kobo Glo	The fast dropoff from 25-30% to the recharge point is pretty common, not just for Kobo devices. The issue is that the battery voltage falls off at a different rate as the battery is discharged. When you get down near the end of the curve the battery voltage falls off VERY rapidly compared to a nearly straight line slope for most of the charge. The algorithm determining remaining charge is probably based on a linear or straight line approximation rather than modeling the curve. If Kobo employed either a lookup table or derived the equation for the battery curve, they could give a lot more accurate picture of remaining power... As it is, I assume 25-30% is the end of the line and figure 65% is really about 50%, etc. I usually charge before I get anywhere near the low end because it tends to be easier on the battery and you can probably charge twice as many times if you're only subjecting the battery to mild to moderate discharges. I think deep cycles are A LOT harder on lithium batteries based on my day to day experience with the batteries in my cell phones over the years. I recall that most of the battery literature points this out as well. Last edited by TechniSol; 01-20-2015 at 02:35 AM.

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01-17-2015, 10:00 AM	#2
Barcey Wizard Posts: 1,531 Karma: 8059866 Join Date: Oct 2007 Location: Canada Device: Kobo H2O / Aura HD / Glo / iPad3	Mine behaves the same way so either we have the same problem or the battery indicator isn't accurate for the last 30%. I agree that it's annoying that you can't rely on it but at least you can read while it's charging. I just charge mine every couple of weeks.

01-17-2015, 11:13 AM	#3
bonaldo2000 Enthusiast Posts: 33 Karma: 13208 Join Date: Aug 2008 Device: prs-505	Thank you for the reply! Yeah, it's no biggy. We just have to sort of count 30 % for 0 %! By the way, can I just charge it with an iPhone or iPad charger? A bit annoying having to plug it into a computer...

01-17-2015, 12:31 PM	#6
JSWolf Resident Curmudgeon Posts: 73,983 Karma: 128903378 Join Date: Nov 2006 Location: Roslindale, Massachusetts Device: Kobo Libra 2, Kobo Aura H2O, PRS-650, PRS-T1, nook STR, PW3	iPhone chargers do work. You just have to tell the Kobo you are not connecting to a computer.

01-17-2015, 02:57 PM	#7
bonaldo2000 Enthusiast Posts: 33 Karma: 13208 Join Date: Aug 2008 Device: prs-505	Ok, thank you guys.

01-19-2015, 11:03 PM	#10
GeoffR Wizard Posts: 3,821 Karma: 19162882 Join Date: Nov 2012 Location: Te Riu-a-Māui Device: Kobo Glo	My Glo is similar to the OP's: the battery life overall is excellent, but the meter drops very quickly after it gets down to about 25%-30%, so I just read 30% as time to recharge.

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