Oasis Separate Charging Cover

[Atunah]

Originally Posted by badgoodDeb

Do remember that Atunah is putting the Oasis back into the cover for tiny recharges every time she* gets up for a break. She said that, repeatedly. Dunno if that fits with your calculations or not.


* Sorry if I've remembered/guessed your sex wrong.

You got it right.

yes, that is exactly how I use it. Even though I read a lot each day, I keep putting it in the cover each time I take a break, or go eat, take out the trash, run an errand, etc. So it never goes all the way down really. Then I charge it with the cover to full each 5 days and repeat the process. I was just wondering if topping off a battery like that will wear it out the same as a full charge cycle each times its topped, or if so many toppings equal one full charge.

[John F]

Originally Posted by badgoodDeb

Do remember that Atunah is putting the Oasis back into the cover for tiny recharges every time she* gets up for a break. She said that, repeatedly. Dunno if that fits with your calculations or not.


* Sorry if I've remembered/guessed your sex wrong.

I bumped it down from 5% to 3% to compensate. And again, also note the 7 vs 9 hour capacity.

[HarryT]

Originally Posted by Atunah

You got it right.

yes, that is exactly how I use it. Even though I read a lot each day, I keep putting it in the cover each time I take a break, or go eat, take out the trash, run an errand, etc. So it never goes all the way down really. Then I charge it with the cover to full each 5 days and repeat the process. I was just wondering if topping off a battery like that will wear it out the same as a full charge cycle each times its topped, or if so many toppings equal one full charge.

No, it does no harm at all to "top up" a lithium battery. Essentially 10 X 10% charges will be the equivalent of one full charge.

[Atunah]

Cool, thanks everyone.

[disconnected]

Originally Posted by John F

I bumped it down from 5% to 3% to compensate. And again, also note the 7 vs 9 hour capacity.

Unless you keep the light level very low even 7 hours sounds wildly optimistic to me. Of the few reports I've read where people actually mentioned actual times I don't think anyone has mentioned anything above six. I think nullnix reported four hours at level 10-12. With the light at 17 I got times ranging from two and a half to just under six hours.

I'm very happy with the Oasis but I've had to adjust my thinking about the ways I'll use it. I'd been planning on carrying the Oasis around in a lightweight sleeve or third-party cover and now I know that I won't ever leave the house without the charging cover. If you want to be able to read for more than a few hours without ever at least putting it in the cover to top it up I don't think the Oasis is a good fit for you.

[schulzmc]

Has anyone mentioned the fact that, with a Paperwhite or a Voyage when the battery degrades you are stuck, but with an Oasis you could (potentionally, if Amazon sells them as some point) buy a new cover and in a sense replace over half your battery with a new, fresh one? Reading time out of the case would still be reduced, but I'm guessing never to the point that it was unusable.

[disconnected]

Originally Posted by schulzmc

Has anyone mentioned the fact that, with a Paperwhite or a Voyage when the battery degrades you are stuck, but with an Oasis you could (potentionally, if Amazon sells them as some point) buy a new cover and in a sense replace over half your battery with a new, fresh one? Reading time out of the case would still be reduced, but I'm guessing never to the point that it was unusable.

That's a good point. And although I'd been worried about the weight of the Oasis cover it turns out that the Oasis with the charging cover on it is still a bit lighter than my Voyage in a lightweight third-party cover.

[jbjb]

Originally Posted by HarryT

No, it does no harm at all to "top up" a lithium battery. Essentially 10 X 10% charges will be the equivalent of one full charge.

In fact it's better than that - shallow charge cycles generally have proportionally less effect on Li Ion battery life than deep ones (so 10x10% charges could shorten the lifetime less than 1x100% charge), so a pattern of frequent top-ups (which I suspect is likely to be a common usage pattern with the Oasis) could significantly extend the battery lifetime.

As I said in a previous post, it's possible the Oasis designers could further enhance lifetime by exploiting that usage pattern. When used this way, the actual capacity of the device battery less crucial - if it's mostly going to be topped up after partial discharges, it doesn't really matter too much if the total capacity is a bit lower, so the designers could greatly extend the battery lifetime by reducing the maximum charge level. Battery lifetime roughly doubles for every 0.1V the float voltage is reduced below 4.2V (a change which knocks only ~14% off the capacity).

[John F]

Originally Posted by disconnected

Unless you keep the light level very low even 7 hours sounds wildly optimistic to me. Of the few reports I've read where people actually mentioned actual times I don't think anyone has mentioned anything above six. I think nullnix reported four hours at level 10-12. With the light at 17 I got times ranging from two and a half to just under six hours.

I'm very happy with the Oasis but I've had to adjust my thinking about the ways I'll use it. I'd been planning on carrying the Oasis around in a lightweight sleeve or third-party cover and now I know that I won't ever leave the house without the charging cover. If you want to be able to read for more than a few hours without ever at least putting it in the cover to top it up I don't think the Oasis is a good fit for you.

For some more numbers...

For 7 hour starting capacity, 5% decay, 6 hours a day:

After first year: Capacity is 5.8 hours, went through 365 cycles
Second year: capacity is 4.3 hours, 777 cycles
Third year: capacity is 1.7 hours, 1502 cycles

[John F]

Originally Posted by disconnected

Unless you keep the light level very low even 7 hours sounds wildly optimistic to me. Of the few reports I've read where people actually mentioned actual times I don't think anyone has mentioned anything above six. I think nullnix reported four hours at level 10-12. With the light at 17 I got times ranging from two and a half to just under six hours.

...

For me (on my Kobo HD), I always just leave the light on, and switch to night mode at night. Maybe Amazon should bring the adaptive lighting back (so that during daylight hours the light would be off)?

[John F]

Originally Posted by jbjb

In fact it's better than that - shallow charge cycles generally have proportionally less effect on Li Ion battery life than deep ones (so 10x10% charges could shorten the lifetime less than 1x100% charge), so a pattern of frequent top-ups (which I suspect is likely to be a common usage pattern with the Oasis) could significantly extend the battery lifetime.

As I said in a previous post, it's possible the Oasis designers could further enhance lifetime by exploiting that usage pattern. When used this way, the actual capacity of the device battery less crucial - if it's mostly going to be topped up after partial discharges, it doesn't really matter too much if the total capacity is a bit lower, so the designers could greatly extend the battery lifetime by reducing the maximum charge level. Battery lifetime roughly doubles for every 0.1V the float voltage is reduced below 4.2V (a change which knocks only ~14% off the capacity).

I agree, Amazon could do a lot. Looking at table 2: http://batteryuniversity.com/learn/a...ased_batteries it looks like 50% is the better discharge level, so they could achieve that.

What about users who want to read without a cover? A quick charge when plugged into the cover, and quick charging puts more stress on the battery.

[disconnected]

Originally Posted by John F

For me (on my Kobo HD), I always just leave the light on, and switch to night mode at night. Maybe Amazon should bring the adaptive lighting back (so that during daylight hours the light would be off)?

Not for me.

I tried unlit ereaders (K3 and Touch and a Sony) and I could hardly read on them at all. I kept switching back to my phone or Pocket PC. I don't normally read outside and in a reasonably well lit room I like my ereaders to be quite bright. I've been leaving my Oasis at 17.

If the battery goes bad really quickly Amazon is going to get a lot of complaints, particularly as the user guide has no advice on best practices for charging.

[Shinytop]

Worse case scenario, the charging time for the Oasis without cover degrades in two years below an acceptable level. Again worse case, Amazon does not have a cost effective solution. I buy the current Kindle and keep on reading. Two years of reading with the Oasis comfort level is worth 150/year. I think the battery degradation is overblown but I will not let worry about it affect how I use the Oasis. I bought it to read books, not to win battery marathons.

[webjunk]

Originally Posted by John F

Again, I'm interested in the larger numbers, as that is similar to my habits. Your "averages" don't really interest me. I think the math doesn't work to favorably for the heavy reader who doesn't like to charge as often.


Would you please help a fellow member with poor math skills? What is a rough rock bottom battery life expectancy (for the smaller battery of the Oasis) using it for six hours of reading a day without the cover.

Who says people are running "the battery right down?"
That is the point you refuse to grasp: with a larger battery, who cares? You can go for long periods between charges, and still not abuse the battery.

The Oasis is going to be a great device for some people; for some it won't. Why not just present the numbers so people can make up their own mind?

500 charge cycles. 500 days then it starts to decrease. Easy as easy.

I do grasp the point. The point is that there is an ideal way to use the battery to get the maxiimum life out of it - especially if you are using the battery to its projected life i.e. A very heavy user. Going for long periods between charges is irrelevant - that's personal choice. If you go a long period then the battery must be being run down and not being optimally used.

[John F]

Originally Posted by webjunk

500 charge cycles. 500 days then it starts to decrease. Easy as easy. ...

I don't think you are correct, could you provide a link/reference please? From the one I provided (battery U) it looks to me like the decrease starts with the first charge cycle, and is relatively linear.

...
I do grasp the point. The point is that there is an ideal way to use the battery to get the maxiimum life out of it - especially if you are using the battery to its projected life i.e. A very heavy user. Going for long periods between charges is irrelevant - that's personal choice. If you go a long period then the battery must be being run down and not being optimally used.

Again, could you provide a link please? From what I read, 50% looks like a good charge interval. Some people are reporting "short" reading times before needing to recharge, say 5 hours. So You should only read for 2.5 hours, stop reading, and wait for it to charge; rinse, wash, repeat? No thank you. Or do you think they should only go down by 10% and limit there reading sessions to 30 mins between charges?