iRex 800 quickly discharging

[jolka]

Here is a document with a LiOn battery dischagre profile: http://focus.ti.com/lit/an/slua015/slua015.pdf

[jolka]

Looking at the graph on page 1 - the higher the load the bigger the drop in the beginning. In Standby mode the load is minimal - so the drop would be also minimal, and the discharge curve should be close to linear.

[jolka]

Ok, there could be different electrode types in LiOn batteries: coke and graphite - they discharge diffrerently: http://www.technick.net/public/code/...de_bpw2_c02_06

[The Straven]

Originally Posted by cmdahler

Why, because actually owning an iRex device somehow gives you a deeper insight into all things Shaggy?

Or perhaps I'm just checking what Shaggy writes against my own experiences with iRex devices. For instance, I have my DR800 in airplane mode and have never experienced it turning on 3G mode by itself. I'm also on my second charge, and yes, the first one lasted for about two weeks.

That's not to say that my device won't develop the problems mgmueller and Orca Blue are having, but as of now it lends to the theory that not all DR800s are defective. If my DR800 does develop the same problems, I'll post them here.

As for the rest of it, if you really are that bitter, go on with your bad self. I took the outside chance that you didn't intend to come off that way.

[superhero]

I haven't heard mention of this but my unit never turns itself off. If I leave text on the screen and come back a few hours later, the text is still on the screen and it works normally. I thought the unit was supposed to enter standby by itself after a period of time. Is this normal?

On the other hand, my battery does not appear to be discharging in only 4 days either.

Would it be better to just let it stay on without manually putting it into standby mode so it doesn't have to refresh and wipe the screen?

EDIT: I will answer my own question. No, leaving it on does not give better battery life. In fact, it lost about 22% during the day since it never went into standby mode.

[mgmueller]

Originally Posted by TGS

Sounds odd - and wrong. After four days with at least a couple of hours use each day I'm not going below 70%, and I posted earlier that after being away for three days and not touching the unit the battery had dropped by 13% - even that seemed a bit of a heavy drain. Are IREX saying anything?

Your drop by 13% already occurs on my reader after 39 hours instead of 3 days: https://www.mobileread.com/forums/sho...2&postcount=76
I'm starting to worry a bit...

[TGS]

Originally Posted by mgmueller

Your drop by 13% already occurs on my reader after 39 hours instead of 3 days: https://www.mobileread.com/forums/sho...2&postcount=76
I'm starting to worry a bit...

I'm really interested in your test. I cannot let my unit just sit, but have been closely monitoring and it has gone from 100% to 86% in 38 hours, but that includes about 9 hours reading and quite a bit of switching between pubs. It seems that just "staying alive" constitutes the greater proportion of the drain on the battery - which makes me think we should start asking IREX if it is possible to implement an "off mode".

[mgmueller]

Originally Posted by TGS

I'm really interested in your test. I cannot let my unit just sit, but have been closely monitoring and it has gone from 100% to 86% in 38 hours, but that includes about 9 hours reading and quite a bit of switching between pubs. It seems that just "staying alive" constitutes the greater proportion of the drain on the battery - which makes me think we should start asking IREX if it is possible to implement an "off mode".

Really strange...
Of course, your reader might behave totally different from mine. I'd have to repeat your user habits on mine.
But still: About the same energy consumption in more or less the same time, you with 9 hours of reading and switching files, myself briefly turning it on 9 times for checking the load...
And still this doesn't lead to discharging in 4 days (only if I get a sudden drop within the next 3 days)...

My explanation right now: It either didn't go into standby (did flicker the switch as always and the screen went blank, but who knows about the internal processes of the reader?) or it did turn itself on again (I've used my nook quite a few times in that period. nook lies next to iRex 800, so I probably would have seen, if iRex 800 would have been on permanently)...

[TomK]

I still read too sporadically to guess how many hours my DR800SG battery is holding up, but there is no question that keeping it in airplane mode has improved the situation. I wanted to volunteer this because way early in the thread a user reported that switching to airplane mode wasn't making a difference. I also turn it off when not using and lock the switch.

[Shaggy]

Originally Posted by jolka

I once charged my DR800S to 100% and left it in standby mode. Never switched it on in two weeks. After two weeks it was still possible to switch it on - the battery was low, around 10% I think, but still the reader was operational.

Could that be that:

- the battery was not completely charged?
- the reader malfunctioned in Stanby, say it was not in Standby but in On mode?

I would try to charge it to 100% and leave it in standby for some time. Probably would switch it on once a day to monitor the battery state.

Do you expect it to run for longer than 2 weeks on a charge? It's not turned off, so it will use power while in standby, but on the other hand it will also wake up and be ready to use within a few seconds.

The way the iLiad and DR1000 work is that you have to shut them down and it takes 40 - 50 seconds to boot up every time you want to use it. Lots of people complained about that. So the DR800 does what most other eInk devices do, and goes into a standby mode instead of being turned off.

[Shaggy]

Originally Posted by cmdahler

One would think, of course, that since any particular company has control over and thus knows the discharge profile of the battery in the device, it would be fairly simple to take snapshots of the battery's voltage every few minutes or so (or with an e-ink device, every time a button is pressed), and just compare that to the battery's known voltage drop-off graph for the battery type to get a fairly accurate picture of where the battery charge is on that profile. That way the meter could display a charge level to the user in a more accurate, linear fashion that would make more sense to the average person instead of getting what HarryT described.

You assume that there is a known drop-off rate, which probably isn't true. As the battery ages the rate will change.

[Shaggy]

Originally Posted by superhero

I haven't heard mention of this but my unit never turns itself off. If I leave text on the screen and come back a few hours later, the text is still on the screen and it works normally. I thought the unit was supposed to enter standby by itself after a period of time. Is this normal?

Good question.

It's either not going into standby, or else if you let it go into standby this way it doesn't clear the screen. Not sure which.

[TGS]

Originally Posted by Shaggy

The way the iLiad and DR1000 work is that you have to shut them down and it takes 40 - 50 seconds to boot up every time you want to use it. Lots of people complained about that. So the DR800 does what most other eInk devices do, and goes into a standby mode instead of being turned off.

But does it have to be either/or? I've put a question on the IREX forum about whether it is possible to implement an "off mode" - not instead of but as well as, the sleep/standby mode. The unit is obviously doing a lot of things when it's in standby - it would be interesting to know, firstly, what these things are, and secondly, whether it's possible to stop it doing these things if one knows it is not going to be used for a while.

[penartur]

Originally Posted by Shaggy

Good question.

It's either not going into standby, or else if you let it go into standby this way it doesn't clear the screen. Not sure which.

AFAIK when PRS500 goes into standby automatically after some time of inactivity, it doesn't clear the screen.
So, actually it is the same standby as when triggered by power switch, only with not erased screen.

[Shaggy]

Originally Posted by TGS

But does it have to be either/or?

I agree. I've said in an earlier post that it would be nice to have both options so that people who know they're not going to use it for awhile can turn it off, recognizing that the trade off is a much slower startup time when they want to use it again.

I suspect that at one point they did plan on something like that, but changed it so that the longer switch would do a reset instead of a shutdown. That's probably why the manual is confusing, it was written before they changed it. Hopefully there's not a technical reason they changed it, and with enough feedback they'll put it back so a long switch does a shutdown (or maybe have a "power off" icon on the menu somewhere).

I do find it a little amusing though that with the iLiad and DR1000 everything they heard was that people hated having to shut it down. Now people are complaining that they can't shut it down.

Having both options would, I think, make most people happy though.