Oasis Battery Life Concern

[mezzanine]

Originally Posted by Strether

I'm not confused at all. Why should I consider them separately when they were designed to work together to provide a similar (at least) experience as other Kindles. If you're worried so much about the batterie, don't keep the Oasis and sleep better at night.

Jim

You're definitely wrong, if you're not confused.

[mezzanine]

Originally Posted by Cinisajoy

Hey on your cell phone you might want to check what is running in the background. Oh and second suggestion if yours is a smart phone, turn off location services and wifi unless you are using it.
Oh and lastly, if you are in an area with no cell reception or very spotty cell reception put it in airplane mode otherwise it will wake you up at 3 am wanting fed. (Care to guess who forgot to put it in airplane mode. Hint hubby didn't appreciate not his phone waking him up.).

It seems that my concern has been misinterpreted as a request for advice. I'm not in need of advice, my only intention has been to check my logic to see if there was something I was missing. I'm aware of the steps to take to minimize battery drain and have implemented them on my Oasis. I noticed an improvement in battery life when I went to airplane mode exclusively.

I may have been wrong in my assumption about the rate of degradation, though. I appreciate that feedback.

[Cinisajoy]

Originally Posted by mezzanine

It seems that my concern has been misinterpreted as a request for advice. I'm not in need of advice, my only intention has been to check my logic to see if there was something I was missing. I'm aware of the steps to take to minimize battery drain and have implemented them on my Oasis. I noticed an improvement in battery life when I went to airplane mode exclusively.

I may have been wrong in my assumption about the rate of degradation, though. I appreciate that feedback.

Sorry about all the advice but it was just little tidbits I've picked up over the years.
I was actually thinking more about your cell phone when you said it had battery troubles.

Oh and totally useless trivia: if you have Verizon, put your cell phone in airplane mode 30 miles outside of Brownwood, Tx. No service there.

[mezzanine]

Originally Posted by Cinisajoy

Sorry about all the advice but it was just little tidbits I've picked up over the years.
I was actually thinking more about your cell phone when you said it had battery troubles.

Oh and totally useless trivia: if you have Verizon, put your cell phone in airplane mode 30 miles outside of Brownwood, Tx. No service there.

Strether's posts are a good example of what I've observed more generally, and I don't feel it has helped uninformed users to understand what they're getting with the Oasis.

It looks like you may have hit the nail on the head with your feedback on cell batteries. I think I've been too quick to generalize from my experience with cell phones because, even though I'm charging the Oasis itself quite frequently, it's still not at the same frequency as I would a cell phone.

[Cinisajoy]

Originally Posted by mezzanine

Strether's posts are a good example of what I've observed more generally, and I don't feel it has helped uninformed users to understand what they're getting with the Oasis.

It looks like you may have hit the nail on the head with your feedback on cell batteries. I think I've been too quick to generalize from my experience with cell phones because, even though I'm charging the Oasis itself quite frequently, it's still not at the same frequency as I would a cell phone.

Ok here is a good rule of thumb for kindle batteries, they need charged between 15 and 30 hours of read time. If it says a month or two month battery life, that is figured on 30 minutes a day of reading time. Personal opinion, they used that figure because it makes it sound like the kindle battery will stay charged for a longer period of time.
Good marketing but not realistic for heavy readers.

[induna]

This thread is based on assumptions that may not be valid. The number of charge/discharge cycles a lithium ion battery can tolerate is highly dependent on the maximum and minimum states of charge of each cycle, as well the rate of charge and discharge, which can be ignored here. A battery that is kept at a state of charge between 40% and 60% can go through thousands of charge/discharge cycles without degrading. A battery that is always charged to 100% capacity and discharged close to 0% may only last 500 cycles before it's capacity is reduced to less than 80%. I don't believe that any of us know what state of charge the management system in the Oasis is designed to maintain on the internal battery. Since it will be subject to a greater number of charge/discharge cycles, it would be logical to manage the state of charge of the internal battery differently than the one in the case. If Amazon has done that, there is no reason that the battery inside the device cannot last just as long as the battery in the case, or even longer.

[mezzanine]

Does that mean that the battery status indicator could show that the Oasis itself is at 100%, even though it's only maybe at 75% in actuality, in order to increase the number of charge cycles before it's capacity becomes reduced?

The battery is small enough that the idea that they wouldn't use it's full charge capacity seems unlikely. It would reduce what is already a smart phone-like discharge rate.

Thanks for weighing in, induna. I considered contacting Amazon directly about this question, but figured I wouldn't get the kind of detailed technical explanation you've provided.

[JSWolf]

Originally Posted by mezzanine

I am referring to the device itself. I read without the cover.

Perhaps the Oasis is intended only for lighter readers? That would come closest to a reasonable explanation yet. It's strange, though, that such a high-end niche device as the Oasis would be targeted at lighter readers. It's seems self-contradictory to me.

If you're a heavier reader, and you read without the cover, my charging experience is far more similar to a cell phone. Yes, a cell phone will show little change in charge capacity in the first year of use. It's years two and beyond that will be telling.

The Oasis is intended to be used with the cover. That's why the battery is split. The Oasis should be used with the cover or you end up with a very weak battery. Also, reading without the cover means more chance of damage should it be dropped. When you bought the Oasis, you should have known it was meant to be used in the cover. If you use without the cover, you'll be plugging it in to charge many more times.

[rem736]

Originally Posted by induna

This thread is based on assumptions that may not be valid. The number of charge/discharge cycles a lithium ion battery can tolerate is highly dependent on the maximum and minimum states of charge of each cycle, as well the rate of charge and discharge, which can be ignored here. A battery that is kept at a state of charge between 40% and 60% can go through thousands of charge/discharge cycles without degrading. A battery that is always charged to 100% capacity and discharged close to 0% may only last 500 cycles before it's capacity is reduced to less than 80%. I don't believe that any of us know what state of charge the management system in the Oasis is designed to maintain on the internal battery. Since it will be subject to a greater number of charge/discharge cycles, it would be logical to manage the state of charge of the internal battery differently than the one in the case. If Amazon has done that, there is no reason that the battery inside the device cannot last just as long as the battery in the case, or even longer.

i understand your point. however, this is not practical when it comes to actual use by real people. let's say you start with a battery at 40% and it takes 30 minutes to get up to 60%. how many will be reading for a few hours to get it down to 40% and plugging it in just for 30 minutes and remember to remove it from charging in time. and with the oasis, i thought that the only way to charge the cover is to connect it to the reader itself. there is no way to charge the cover alone. trying to manage a 40% to 60% range in both the reader and the cover is not at all a practical, if not downright difficult thing to do.

[induna]

Originally Posted by mezzanine

Does that mean that the battery status indicator could show that the Oasis itself is at 100%, even though it's only maybe at 75% in actuality, in order to increase the number of charge cycles before it's capacity becomes reduced?

The battery is small enough that the idea that they wouldn't use it's full charge capacity seems unlikely. It would reduce what is already a smart phone-like discharge rate.

Thanks for weighing in, induna. I considered contacting Amazon directly about this question, but figured I wouldn't get the kind of detailed technical explanation you've provided.

The battery status indicator is controlled by software and can show anything the programmer wants it to. It could easily show a 100% charge even if the battery's maximum charge was limited to 90%. I personally don't think the capacity of the small, internal battery is that critical since it is designed to work in concert with the case/charger. It really only needs to last long enough for one reasonably long session. Once put back in the case, it is automatically recharged rather rapidly. Amazon advertises the battery capacity and duration based on the combination of the small internal, and much larger external battery. A 10%-20% reduction in the capacity of the smaller battery would not significantly reduce the combined capacity and would allow the smaller battery to support a significantly higher number of charge/discharge cycles. That's the way I would design it.

Maybe one of our experience Kindle hackers can chime in with what they know, if anything, about how what the charge levels are. The levels will be expressed in volts, with approx. 4.2 representing a 100% charge on most lithium ion cells. Some can go as high as 4.35. If the target maximum charge is less than that, say 4 volts, that would indicate the battery is being charged to less than it's maximum capacity to, presumably, increase the number of cycles it can support.

Cell phone batteries are inevitably cycled through 100% of their capacity since on screen time is a very important feature for users. Much more important than how many cycles the battery will endure.

[induna]

Originally Posted by rem736

i understand your point. however, this is not practical when it comes to actual use by real people. let's say you start with a battery at 40% and it takes 30 minutes to get up to 60%. how many will be reading for a few hours to get it down to 40% and plugging it in just for 30 minutes and remember to remove it from charging in time. and with the oasis, i thought that the only way to charge the cover is to connect it to the reader itself. there is no way to charge the cover alone. trying to manage a 40% to 60% range in both the reader and the cover is not at all a practical, if not downright difficult thing to do.

You don't have to control the charge yourself. It is done in software. All I'm saying is that Amazon could easily have decided that the internal battery be kept at a lower state of charge to increase the charge cycles the battery can sustain since it is a necessary consequence of the design that the internal battery will experience a much greater number of cycles than the external battery. The state of charge of the internal and external batteries can be individually controlled and set to different levels. This is trivially easy to implement.

[knc1]

The battery management used in the Kindles is quite sophisticated.
You can expect at least a two year life.

But of course not as sophisticated as that used in your hybrid car, where batteries start at $10,000 (and up).
With those, you can expect at least a ten year life.

- - - -

And I bet there are not a lot of people who are setting aside a $1,000/year of their savings in fuel, to replace the battery a decade from now.

[shalym]

Originally Posted by rem736

i understand your point. however, this is not practical when it comes to actual use by real people. let's say you start with a battery at 40% and it takes 30 minutes to get up to 60%. how many will be reading for a few hours to get it down to 40% and plugging it in just for 30 minutes and remember to remove it from charging in time. and with the oasis, i thought that the only way to charge the cover is to connect it to the reader itself. there is no way to charge the cover alone. trying to manage a 40% to 60% range in both the reader and the cover is not at all a practical, if not downright difficult thing to do.

The way that *real people* are using this (if they read without the cover) is that they are reading on it for a few hours (without the cover) and then putting it in the cover for 30 minutes or so. Putting it in the cover charges it, and from what Atunah has said, she is only charging the whole package (including cover) every few days.

For me, I use mine with the cover, and charge it about once every 10 days--about as often as I do my Voyage.

Shari

[mezzanine]

Does the Oasis use the cover battery before the device battery if the cover is attached?

I realize it's a basic question, but in all my worries about the device battery, I never thought that maybe the cover is used first. If the cover is used first, the device battery would have a much longer life.



***Just did some research and apparently the case battery drains first. Those tricky folks at Amazon...I don't think they intended it to be primarily used without the cover. Not impressed!

[NullNix]

Originally Posted by mezzanine

Does the Oasis use the cover battery before the device battery if the cover is attached?
***Just did some research and apparently the case battery drains first. Those tricky folks at Amazon...I don't think they intended it to be primarily used without the cover. Not impressed!

Nah. The Oasis always runs from its internal battery, but if it's attached to the cover the cover will top it up as and when the magic gnomes in the software see fit (normally around 85%, but sometimes as low as 70% before getting topped right back up to 94). There is an I2C protocol
between the cover and the Oasis itself on two of the cover pins. God knows what's passing down there, though some of it appears to be DRM to try to stop third-party cover manufacturers who might undercut them on price (God bless our new anticompetitive tech overlords, though given the quality of Chinese chargers half those cheaper covers would probably set your hands on fire too).

In practice you don't care: it's 'as if' it runs from the case battery, because the usable capacity of the thing in the cover is equal to the capacities of both batteries added together.