K2 and Battery Life Issue

[emellaich]

I had some instances where my battery life was alarmingly short -- less than a day. This was sufficient that I had contacted Amazon about a return, but they never answered my email .

Anyway, after some initial problems, everything seemed to be working better, and then it happened again. That is when I realized that it was occurring on days when I was leaving my K2 connected to my laptop in order to re-organzie my library. Now, I think I have figured out the problem and I thought I would pass it on for any of you with similar circumstances.

I had assumed that leaving it plugged in to a computer USB was actually charging the unit -- as stated somewhere in the documentation AFAIK. However, I remember reading somewhere on the net about the fact that some laptop USB ports do not have sufficient power to drive some peripherals. Furthermore, I note that my K2 claims that I can read it while it is connected to my laptop if I "dismount' the unit. However, when I dismount it, it never switches over to reading mode. I assumed this was a minor software but, but now I believe it may be due to a power problem.

The power symptoms I observe would be consistent with a situation where, instead of charging while connected to the laptop, the K2 was discharging. I believe that it is using power to remain connected the entire time I keep it plugged into my laptop. I don't have time know, but I can experiment next week to see how it behaves while connected to my desktop instead of my laptop.

At this point in time I am almost positive the problem is due to connection it to my computer USB. However, I am only guesing that it is due to an underpowered USB port on my laptop -- it may be something that occurs with any computer USB. I have had no problems with charging the K2 from a normal outlet.

Have any of you had similar experiences?

Michael

[Gideon]

This would happen with the K1 if you left it attached it to any USB but no, when attached to a 2.0 USB port I've not had any problems charging my Kindle.

[Dragoro]

You have to eject the kindle as a usb drive if you want to have your computer charge it. Your computer doesnt charge it while its being used as a drive. Its in the manual

[KindleKat]

I would try and do a full charge cycle on it. Charge it up, let it die completely, charge it up, let it die and charge it up again.

[sirbruce]

Are you leaving wireless on? With wireless on my K2 only lasts 36 hours.

[Slow_hand]

Originally Posted by Dragoro

You have to eject the kindle as a usb drive if you want to have your computer charge it. Your computer doesnt charge it while its being used as a drive. Its in the manual

That's what Amazon says but I noticed mine charged up while in USB mode also. I was downloading some Calibre files when all of a sudden the charging light turns green. Of course this is attached to my desktop (homebuilt), not a laptop.

emellaich, can you try it with a desktop?

[dhill]

This what the manual says:

When you are connected to your PC, your Kindle will go into USB drive mode and its battery will be recharged by the computer.

[snipenekkid]

many USB ports (either 1.1 or 2.0) fail to provide the 5V required by the spec. So you are likely right about the issue. One way around it is to buy a powered USB hub that states if provides the proper 5V via the ports. Not ideal but it does work. I am lucky my laptops all pass that spec. My main lappy has four USB ports all of which are in active mode and provide a very steady 5V.

Somewhere I once ran across a voltage tester for USB ports but I never saved the link. You might be able to find one somewhere. It should be under $10 and is a nice tool to have if weird things happen with yur USB device. It could be an early warning sign of a failing motherboard in need of replacement or repair.

[snipenekkid]

Originally Posted by sirbruce

Are you leaving wireless on? With wireless on my K2 only lasts 36 hours.

I thought the spec was the K2 would last a week with wireless on and over 2-weeks with it off? If 1.5 days is the norm, boy did Amazon fluff that number.

[Ervserver]

Those figures as stated by Amazon are laboratory best case scenarios, in reality few people will achieve those statistics

Originally Posted by snipenekkid

I thought the spec was the K2 would last a week with wireless on and over 2-weeks with it off? If 1.5 days is the norm, boy did Amazon fluff that number.

[sirbruce]

They claim 4 days with wireless and 2 weeks without. 4 days might be true if you're in solid 3G country and you don't do anything else; if you're in an area of variable signal, the constant shifting from EVDO to 1X and back will drain the battery twice as fast. As for two weeks without, obviously this depends on number of page turns and how many hours a day you read. If you read on font level 1, your battery will last longer; I read on level 4, so it stands to reason my battery won't last 2 weeks. But even then, they must be estimating only a few hours of reading per day.

[snipenekkid]

Originally Posted by Ervserver

Those figures as stated by Amazon are laboratory best case scenarios, in reality few people will achieve those statistics

gee, thanks, this ain't my first rodeo cowboy. Used nothing but laptops since about 1993. Not a desktop to be found in my work place or home so I know manufacturers are let's say, optimistic. But to over shoot numbers that badly is, well, kinda slimy. My current laptop was indicated as having about 6hrs run time on the standard battery so I figured about 4-4.5 in real life...and that is what I got when new. With the 2nd battery wedge installed the claim was 12-14hrs, we got 9.5-12hrs I bought for the office. Most did did not drop below 9hrs until month 14. Now after almost 3yrs it's about 6hrs with both batteries. My point is Amazon seems to have been ridiculous to the point of absurdity in the estimates. Yeah, it is marketing but the over estimation is not exactly what I would call within reason either. If fact it is borderline hyperbole.

And do not take this as an anti-kindle stance. I think it is a very, very interesting device technically. Book formats are not ideal but manageable also. In fact if the screen were better background wise I would likely own one.

[snipenekkid]

Originally Posted by sirbruce

They claim 4 days with wireless and 2 weeks without. 4 days might be true if you're in solid 3G country and you don't do anything else; if you're in an area of variable signal, the constant shifting from EVDO to 1X and back will drain the battery twice as fast. As for two weeks without, obviously this depends on number of page turns and how many hours a day you read. If you read on font level 1, your battery will last longer; I read on level 4, so it stands to reason my battery won't last 2 weeks. But even then, they must be estimating only a few hours of reading per day.

that makes a lot of sense. I know my cellular broadband can stuggle even to the point of heating up in finge areas. So that would indeed use a lot more power.

Now about the font affecting power, as I understand how eink works that makes no sense. Each cell needs to be fully polarized, twice, on each page turn so the amount of power is should be the same, yes? Or am I misunderstanding the way it works?

[Sporadic]

Originally Posted by snipenekkid

Now about the font affecting power, as I understand how eink works that makes no sense. Each cell needs to be fully polarized, twice, on each page turn so the amount of power is should be the same, yes? Or am I misunderstanding the way it works?

font size 1 = smallest text/less page turns
compared to
font size 4 = bigger text which will require more page turns than 1 since there is more text on each page

[sirbruce]

Sporadic got my point, yes. What matters is # of page turns.

Anyway, I've gotten a week with wireless turned off and it was only 50% drained when I recharged it again, but I was only reading a couple of hours a day.