Oasis x Voyage

[Barbara1955]

Originally Posted by pendragginp

for this! I ordered the refurb Voyage; it arrived today and the screen is beautiful. I must admit I was a bit uncertain because of all the discussion about bad screens and light cones, but no problems with mine.

ETA: Karma as thanks

ENJOY!!!

[John F]

Originally Posted by barryem

I didn't realize that. Good information. However, it doesn't really change the calculation.



If you read the section on caring for lithium ion batteries at:
http://batteryuniversity.com/learn/a...ased_batteries

you'll see that they agree that shallow discharging cycles make a difference, as you say, but not nearly as much as you describe. It might be enough to throw my calculations off by 20% or so but these are all ballpark numbers anyway so I don't think that's enough to matter.

Barry

And if you look at figure 1, the capacity diminishes with every charge; since the battery is (much) smaller, you are charging more often, so the capacity diminishes (much) quicker.

Stating that there are two main factors seems a little strange to me, especially for a reading site such as MR (and also that one of those factors is 1/6 the size.)

[HarryT]

Originally Posted by John F

Stating that there are two main factors seems a little strange to me, especially for a reading site such as MR (and also that one of those factors is 1/6 the size.)

What do you consider to be strange about it, John? Capacity loss due to the increase in the internal resistance of the battery's cells over time is undeniably a much more significant factor than capacity loss due to the number of charge cycles for a low-current device such as a Kindle.

[John F]

Since the battery size is 1/6 the size, and this is a reading site, (i.e. there are probably some heavy readers here), saying "it is a big battery, don't worry about" seems an over simplification.

From you: "1. The number of charge cycles, as above." Don't you think how long a charge cycles lasts should be considered?

[HarryT]

Originally Posted by John F

Since the battery size is 1/6 the size, and this is a reading site, (i.e. there are probably some heavy readers here), saying "it is a big battery, don't worry about" seems an over simplification.

From you: "1. The number of charge cycles, as above." Don't you think how long a charge cycles lasts should be considered?

Number of charge cycles is a factor, John (as I stated), but for a low-current device such as a Kindle it's one which is of considerably less significance than the "age" factor.

[John F]

How about an example. I believe I've read reports that people charge there their Paperwhites every two weeks.

So after three years, they have gone through:
Paperwhite: 79 cycles (and a charge will last 13.4 days)
Oasis: 543 cycles (and a charge will last 1.7 days)

And I'm not considering loss of capacity due to aging alone. Doing a quick google I see this :

http://www.popularmechanics.com/tech...-time-6705747/

... And batteries degrade even if you don't use them. According to battery-testing firm Cadex Electronics, a fully charged lithium-ion battery will lose about 20 percent of its capacity after a year of typical storage. Increase the temperature to just above 100 degrees Fahrenheitas in a hot attic, for exampleand that number is 35 percent. ...

I have doubts about the 20% number, but if I roughly apply it, that means that after three years, a charge for the Oasis would last 0.9 days (and this is just a rough guess, I think it would actually be much lower.)

[HarryT]

Sorry, John, but I'm not sure that it is that we're disagreeing about. We both appear to agree that the capacity of a battery falls with time.

[John F]

Originally Posted by HarryT

Sorry, John, but I'm not sure that it is that we're disagreeing about. We both appear to agree that the capacity of a battery falls with time.

I think we are disagreeing about the bolded part below:

Originally Posted by HarryT

Lithium battery lifetime has two factors:

1. The number of charge cycles, as above.
2. A absolute lifespan somewhere around 5 years which is independent of the number of charge cycles. The clock starts ticking when the battery is first charged, and can't be stopped.

The second of these factors, not the first, is what will eventually kill the battery of any reader.

I interpret what is bolded, to paraphrase, as "the device is going to last 5 years, don't worry about". I disagree (or consider it misleading) with what I paraphrased.

Did I misread what you posted.

[HarryT]

Oh, sorry, I see what you mean.

The device should last roughly five years (although the lifespan of individual batteries varies enormously) before the battery flat out dies. As with any other Kindle, there may come a point before that time at which the capacity of the battery has fallen to a point at which a user finds it inconvenient, although this may perhaps be less of a consideration for the Oasis, where the intended pattern of usage appears to be to put it into the cover to recharge the internal battery after a reading session.

Tell will of course tell, but personally I'd be surprised if the usable life of the Oasis fell proportionally more quickly than that of any other Kindle model. We'll just have to wait and see.

I would note that I had my iPhone 4 for four and a half years, and that really is a device which you need to pretty much fully recharge every day, and I eventually replaced it because newer phones were so much better, not because of battery considerations. After 1500+ charges, the battery capacity had not significantly fallen to a point at which the deterioration was noticeable.

[Atunah]

I charge my kindles every 3-4 days. Always have. Oasis its usually every 4 days. So far they have all held up. I remember reading so much with my K1 that I had to plug it in at some point to continue the book. . So I think the K1 by now probably doesn't hold a charge as well as it used to. Its 8 years old and I don't think I was ever able to go 4 days on it in any case.

I only managed to run down the battery on the Oasis without the cover once since I have had it. And that was because I was in a different level of the house, left the device away from the cover, had wifi on in a spot where its not very good and was sending a bunch of books to it. So after 10 hours of reading and all the other stuff, it was dead. But just once. It never goes below 40% or so I think while I use it normally. Can't really say as I stick it in the cover every time I set it down. But I know I have had 4-5 hour sessions out of the cover and it was still half full by the time I took a break.

All this talk about its battery is pretty useless as nobody knows and wont know until the units are a few years old. Then those of us that actually own the device can talk about how its held up.

[John F]

Harrry, thank you for the clarification. I was looking at it more from a usage point of than a drop dead date.

I'm kind of the opposite of you (and I'm guessing I'm not the norm). At the end of the day, my iPhone 4s was typically down about 15% (and that was with wifi and bluetooth always on). My laptop is always plugged in. And I read more than the "average" 1/2 hour a day. So for me, I would like to know more than "don't worry about it" or "nobody knows" or "it is too complicated".

YMMV.

[JSWolf]

Because the battery in the Oasis has to be charged more often than the battery in the Voyage, the Oasis battery will come to a point where the user finds it not lasting long enough much sooner than the Voyage. It doesn't matter that the batter is being topped up by a battery in the case. That battery will flatten out as well as it has to go through a lot of charges. So overall, the Oasis battery will not last even 1/2 as long as the Voyage before it needs replacing. Given the cost of the Oasis, I would find this unacceptable.

[Shinytop]

I own both the Voyage and Oasis. Without agreeing with all that posted about battery life for the sake of argument I will post with that caveat.

The comfort of reading with the Oasis is so much more, for me, than the Voyage that if the battery's life were half I would still buy it and replace it with an Oasis. My comfort while reading is much more important than having to replace an electronic device a little sooner. Somebody with better math skills than I should compare cost per reading session.

By the way, the discussion of the size of the internal battery MAY have an appreciable effect on the life of the battery but most of us are capable of reading without the cover and simply place it back in the cover when not reading. So for those with simple adaptive skills the combined battery power is the main consideration, not just the internal battery. Every time you buy a new phone you change some habits. Why not with a reader?

[Shinytop]

Actually the figures are pretty easy. Calculating one hour per day of reading for two years the Voyage cost is $.27 vs Oasis cost of $.40. Obviously the more you read the difference between the two costs go down.

I used the full price of each reader. I did not include a cover for the Voyage so the real price for most people will be higher that what I posted above. If you buy the Oragami leather cover the price difference will be negligible

The price difference is not enough to change my mind. I kept the time at two years to placate those talking about possible shorter lifetime of Oasis battery. The longer you keep it the cost difference also becomes less.

But if you go with the Voyage and put the $.13 saving in a piggy bank for two years you will have enough at the end to make up the cost difference and you can buy the Oasis the next time you need a reader!

[JSWolf]

It's not about the price per read. It's that the Oasis costs so much and will not last long enough to justify the high price. There are lots of people who keep their Reader until it needs replacing be it batter or some other reason. There are also a lot of people out there who are not able to replace the battery. So when the battery goes, so does the Reader. That means for a lot of people the Oasis won't last all that long compared to the Voyage.

What I don't get is how many here don't agree that the battery in the oasis won't last nearly as long as the Voyage.