Battery concerns / conservation question
 

I'm giving the N810 I'm having a chance and am trying out some things with it and so far I must say I'm as in love with this device as one can be without breaking some state-laws..

One thing that I would want to get some input on is the battery life/consumption I'm experiencing.

Ex: Last night I had the battery at about 90% when I went to sleep.
Seven hour later, when I woke up, it was at 5% and when using it for 10-15 mins I get a battery/charge warning and the device shut down 10 secs later.

What I had running: Gmail notifier (set to check every 30 mins), Weather forecast applet, RSS reader applet, Mauku was running (icon shown in the left hand side), Skype was also running (icon in left side), I had an active WiFi connection but no BlueTooth - I also noticed that the GPS icon was showing in the top and seemed active.

So, reading some threads here on the forums it seems like this might all be explained by the apps I had running (or am I wrong?).

I really like having things like gmail notifier, mauku, rss reader, weather reader active - but do I have to close them all every time I go to sleep/don't intend to use the tablet for some time?

Is there a mode that "disables them" but keeps them on my tablet and hence preserves my battery (but allows for the alarm clock to still work)?

I guess the question is,
a) Does my apps listed above fully explain the battery drain, and
b) how do you guys 'turn the device off' in the evening and/or when you don't intend to use it for a couple of hours?

Re: Battery concerns / conservation question
 

I leave mine running when I'm not doing anything. However, I don't leave apps running without it at least plugged in. Especially anything that uses hardware such as the GPS or leaves the screen on. The NITS are designed to run for up to 10 days on standby with the screen off, so if you're running short on power, it's likely from the wifi, since you had gmail notifier and all those other web apps on, which would have at the very least ate your battery from being on.

My suggestion is that if you're gonna have all those on, you need to set them to either only run when the wifi is on, or set the wifi to auto timeout after 5-10 minutes. When I'm traveling, the wifi is on for as little time as possible. If an app needs the internet for something, then tough beens. It has to wait until I connect again.

On a side note, as for the stuff in your sig about "want to get" for the case, get the HP Jornada case from Overstock. It's just $5 and it fits the nit like a glove.

Re: Battery concerns / conservation question
 

Oh, is there a way to setup all applets (RSS, Weather, etc) to only be active if there is a WiFi connection?

I'll look at setting the WiFi to time-out after 10 mins as well if that is such a battery drain.

Re: Battery concerns / conservation question
 

I don't understand this part of your question. Closing an application does not remove it from the tablet. You simply need to start the program again the next time you want to use it.

I leave Gmail notifier and WiFi running continously, but exit other application when I am not actively using them. I always connect the table to AC power at night to be assured the battery is fully charged the next morning.

Re: Battery concerns / conservation question
 

GPS can drain batteries quite quickly in my experience. Also, applets that are constantly active (for example if the reader constantly scrolls of fetches content). Note about rss - appLICATION or appLET ? Skype is also a hog, but to a lesser extent.

I just enable offline (a.k.a. flight) mode. That usually is enough for the usual suspects to refrain from causing trouble and in my case I loose less than 10% of battery through the night.

Likely, yes. It's a good idea to install a CPU load applet at least while you're 'new' to the device to get a feel what uses battery and what doesn't.

Re: Battery concerns / conservation question
 

The quality of your WLAN access point heavily influences the N810 battery drain. For example, I noticed that my new Zyxel ADSL+WLAN box caused the N810 to drain its battery in a matter of hours. The tablet was warm to touch the whole time. On the other hand, an old WRT54GS v1.1 allows the N810 to remain in standby for days, even with IM presence set to "online" for most of the time.

Re: Battery concerns / conservation question
 

My comment was on Lord's statement "you need to set them to either only run when the wifi is on, or set the wifi to auto timeout after 5-10 minutes."

The way I understand it is that applications can be run in two ways on the tablet;
a) As an applet that runs on your homescreen (example: RSS reader), and
b) As an application that can be 'minimized' to the left side of the screen as an icon, showing that it's still active (example: Mauku).

I understand that closing an application doesn't remove it from the tablet - my question was if there was a way to make applets/applications dependent on a wifi connection for them to start running.

Re: Battery concerns / conservation question
 

I use the Applet that continously scrolls.
If that is an issue..how does people use that, or similar applets then? Do you go to the menu and de-activate the applet on your home page every time you go to bed? :)


Thanks, I'm going to try the 'flight mode' tonight and see how much it drains over night.

Re: Battery concerns / conservation question
 

Lucky for me we got the WRT54G :)

Re: Battery concerns / conservation question
 

Can't you just turn the internet tablet off at night? I always turn my tablet off and put it on the charger every night.

Re: Battery concerns / conservation question
 

I've noticed sometimes my tablet will disconnect from internet services (usually shown when the Presence icon switches between green and red) but will still stay connected to the WiFi signal. This seems to really drain the battery. I thought had the problem solved by setting the Idle Time, but that only sometimes works.

Its usually not a problem. Most nights I run FlipClock with battery power and only drop at most 10%. However last night was one of those nights where I started at around 65% and woke up to 0.3%. Not a huge problem though, as its a rare occurence.

Re: Battery concerns / conservation question
 

Will the alarm clock still kick in even if it is turned off?
If so, I'll try that as well tonight. Thanks!

Re: Battery concerns / conservation question
 

With the rss feed applet you can turn the scrolling off by going to home press the menu key > applet settings > rss feed reader > and untick the automatic scrolling. I've found that I get much better battery life with it not scrolling.

Re: Battery concerns / conservation question
 

If I do have a battery issue I may be tempted to get one of these: http://shop.eten.hu/mugen-power-1800...e71-p-212.html

At least the spec looks good.

Re: Battery concerns / conservation question
 

@silvermountain

dude, i would say unless that foo's gonna send u a new battery as well, you really should makem him refund you.

Here's what I did with my N810 yesterday...

Went to the campus to talk to advisor, register for summer, and get my ID pic taken. (listening to music in between the key parts)

Rode with my Grandmother to run some errands, also listening to music the whole time. Also, played Doom, Bo Jackson's Baseball on iNes, and messed with the GPS for about 20 minutes, before I realized I didn't have the maps for where i was at when i was messin with it.... still listen to music.

Got home, put down the NIT. Periodically went outside to smoke, listened to it each time.

Before bed, I watched part of Bela Fleck and the Flecktones: Live @ The Quick (excellent dvd) on it... about 20 mins.

Then put it down and went to bed (left it on, didn't put it on charge).

It now has...5 days / 3 hours left on the battery.

It shouldn't matter how nice the guy is. He obviously sold it cuz it wasn't working right for him and the battery kept dyin.

Just my 2 cents.

Re: Battery concerns / conservation question
 

I run with wi-fi on, on battery alone, with basically all those functions you mentioned except Mauku or GPS (as I have an N800 not an N810, so no built-in GPS), all day (~ 9-10 hours) with no battery problems. I used to be able to do that for at least 30-50 hours in the past, but now after > 2.5 years of constant use the battery is not as good as it was. So, on the second day, the battery drops down a bar.

Re: Battery concerns / conservation question
 

Things that will kill the battery:
YouTube videos played in the browser. Battery soon dead.
Modest when it gets confused and claims you have no mail: Battery soon dead.
Mauku reports an error fetching tweets: Battery soon dead.

Please note that the last two will not show any undue activity in the status bar cpu load applet. I'm not sure if this has been corrected in the latest mauku release, in my case I killall mauku whenever I see that error message.

Any animated desktop applet:

Mail, mauku and/or RSS refresh rates that are frequent. Scale that ish back. The less frequently an app updates over the net the better.

To a lesser extent mmc booting can have adverse effects on battery life because the card itself can be an "additional" draw. It's been discussed here before and the effect varies with the quality of the card.

Re: Battery concerns / conservation question
 

I got it for $170 and still with time to inspect it when I get the cable to reflash it this week. The battery seems to be working much better after I set a WLAN idle time of 10 mins. I've been using it for 2-3 hours now, downloading things, playing games, taking notes, etc, etc and the battery bar is still full and shows 6 hours left so I'm happy with that.

It's an amazing device. Love it :)

Re: Battery concerns / conservation question
 

Some facts:

• GPS was probably the problem in your case. Deactivate (i.e. close any running GPS app) when not in use.
• A good quality access point supporting "PSM" will mean your tablet can stay on 24 hours or more connected to it.
• The scrolling RSS home applet stops updating (as all good apps do) when the screen blanks, to save power.
• Turning the tablet on & off takes *masses* of battery; leaving it on, but idle, is generally better.
• Some apps & applets aren't well behaved and will wake the device up every minute; or keep updating the screen even when it's off. It's difficult (currently) to identify these without some trial & error.

HTH.

Re: Battery concerns / conservation question
 

Silver ... good for you !
It really is a wonderfull device !

Very often people come here to ask about battery life issues ... that came from applet/GPS/cheap wifi access points. It means that except those problems that are not Nokia's and Maemo team fault ... our tablets really rocks !

Re: Battery concerns / conservation question
 

Bad, but often repeated advice. A reboot cycle takes at most as much power as 4 hours of idle, probably a lot less. You need to factor the chance that some runaway process will eat your battery while you sleep against the minute it takes to boot when you want to use it, but the battery wasted by turning off/on is a myth that should die.

Re: Battery concerns / conservation question
 

I second Matan, he already told this before and tested precisely, turning ON/OFF doesn't suck so much power.

Re: Battery concerns / conservation question
 

4 hours sounds like quite a long time to me (I've not seen your research which totololo references, and have been going off the comments of senior engineers like Igor) . But then, I'm very careful about trying to minimise the runaway processes which may exist on my tablet.

Re: Battery concerns / conservation question
 

that's been my experience, too.

Re: Battery concerns / conservation question
 

A short calculation:

The battery should last 10 days of idle time, that is 240 hours. In my testing it can last 3 hours of playing video over wifi with high brightness (probably as much power draw as possible). I measured 20 seconds for shutdown and one minute for bootup.

All thah data comes up to: off/on eats about 0.75% of the battery which is equivalent to about 2 hours of idle time.

While two hours might sound a lot, it is less then the sleep period of almost all human beings.

Re: Battery concerns / conservation question
 

Well, right now my N810 freezes about every 5-10 minutes. Sometimes after 1-2 minutes. It becomes inoperative, then the screen dims..and after about a minute it resets.

I can't seem to tie it to a specific event and it has happened when WiFi has been on..and off..

I'm hoping that when I get the cable for it on Friday I can re-flash it and see if that resolves the issues :(

Re: Battery concerns / conservation question
 

Well, I completely disagree with Matan about the on/off/boot vs. idle case. When your battery gets older, as the one in my N800, you'll find that rebooting completely floors the battery. It drops down 3 bars and stays there.

I absolutely prefers to leave my N800 on at all times. I had the occasional runaway-during-the-night problem in the past, but that all disappeared after I got rid of the maemo crawler application. It has never happened again. A couple of months back I reported that my N800 had been dead a couple of times, it turned out that this was caused by a mechanical problem which momentarily disconnected the battery and had nothing to do with the old problem.

Conclusion: Absolutely no software runaway problem ever again for me. And even if there were, the cost of a powerdown/reboot cycle every morning is outrageous compared to a hypothetical runaway case every few months.

Re: Battery concerns / conservation question
 

This has been discussed a few times. The battery can't physically lose over 50% percent within a minute, as that equals a draw of over 150W for that minute. What you actually see is incorrect battery level measurements.

Re: Battery concerns / conservation question
 

No, it is not. It is a battery which has increased internal resistance due to not being new anymore. And even when it was newer it took quite a bit of capacity to boot. It is not incorrect battery level measurements, because that is simply a voltage measurement. In fact I am now, at this moment, charging a battery that dropped down after a reboot. It's been charging for an hour.

Re: Battery concerns / conservation question
 

This is simple physics:

"holding an N800 for a minute while it goes through half a battery is like holding a working 150W light bulb for a minute -- not something you can do with bare hands."

Re: Battery concerns / conservation question
 

i just rebooted, before I did the built-in battery expectation was 1day idle or 2 hours use, has now dropped to 1day/1 hour. The estimation of a reboot = 4 hours idle seems reasonable. We all have different configurations and applications, and no common language or tool-set to measure battery use. I am sure mine is worse because of my wireless router, and plan to reinstate my old WRT54G. I re-flashed, installed no software, took out my memory cards and by far, the biggest influence is connection to my SMC barricade, apparently a crappy router. What routers do other people have?

Incidentally, another piece of research says a cell-phone battery has a life of charge/drain cycles (or absolute total current of discharge), and since the N800 runs off the battery, even when charging, leaving it in standby WiFi-connected (looking for e-mail, updating RSS) and charging overnight, is wasting battery life.

Re: Battery concerns / conservation question
 

I never ever shut it down, but because of a different reason. I have burned myself (several :( ) times by not having enough juice to boot up the unit, which in turn sent it into a nasty boot loop. I'm pretty certain there was enough ENERGY in the battery but am not really sure how the Power Management section reacts to the high-draw case of a boot with a far-less-than-full battery.

For example, I had 20% battery power, and the power on did not manage to go through. If there really WAS 20% in the (2 months old) battery, that would have been also a quited heated event. So why risk, just leave the thing on, it's <10% through the night anyway.

Re: Battery concerns / conservation question
 

SD cards seems to be the problem for my battery drain in idle/standby (offline) mode. I removed all of my user installed programs. This had no affect on saving battery power. Nokia N800 would only last 2 days in idle/standby (offline) mode, even with no user programs installed. I then removed both of my SD cards and there was basically NO battery drain for 7 days. Battery lasted 16 days and probably could have gone another day for 17 days in idle/standby (offline) mode. Using two Kingston Elite Pro 2GB 50X SD Cards. I've seen other threads that say Kingston are good cards for battery usage.

http://talk.maemo.org/showthread.php?t=29146

Re: Battery concerns / conservation question
 

There are only three or four companies in the world that actually manufacture SD cards: Panasonic, SanDisk, Toshiba, and possibly one more. Kingston--and everyone else--is just applying stickers to what they buy in bulk from one of the real manufacturers.

So, Kingston almost certainly switches up manufacturers for different models of card depending upon available deals from the manufacturers and what quality/speed/price point Kingston wants to hit with a given model. In fact, I'd not be surprised if the manufacturer of one particular model of Kingston card changes over time.

Also, the latest, fastest card from a given manufacturer is almost certainly going to draw more power than a slower card of the same capacity from an older line from the same manufacturer.

In the end, it's impossible to say that all cards from a given company have a given trait such as sipping power.

Re: Battery concerns / conservation question
 

Don't want to get off topic. My only point is SD cards can affect battery life in a major way. The other threads indicated that cheap unknown SD brands may have problems related to battery life. (Why is the real question and what if anything can be done about it.) They were saying Kingston has high quality and tests and checks everything they sell. They also were saying it had to do with software on the SD card related to sleep mode. Not sure if this could be true or not. Kingston has a Co-Logo program where they design and apply labels with your brand name to bulk purchases. So if Kingston is good these would be good also.

Kingston Technology Company, Inc. is the world’s largest independent manufacturer of memory products. Kingston designs, manufactures and distributes memory products and Flash memory products. Kingston has established five manufacturing facilities around the world to meet the needs of the memory market on a global scale. These manufacturing facilities are strategically located in the U.S., Taiwan, Malaysia and in China (Shanghai +Shenzhen ). Each facility serves the memory needs for Kingston and the top tier system manufacturers that employ Kingston to make their system memory. Kingston has more than 50 state-of-the-art Surface Mount Technology (SMT) lines that build more than eighteen million customized modules each month for servers, desktops, notebooks, workstations, printers, personal digital assistants (PDAs), hand-held PCs, graphic cards, digital cameras and cell phones. Kingston has the world's largest memory module manufacturing facility in Shanghai, China.

iSuppli ranks Kingston as world's number-one memory module manufacturer for the third-party memory market for the fifth consecutive year. Kingston receives Intels Outstanding Supplier Award for Exceptional Support, Quality and Timely Delivery of FB-DIMM Products. Kingston released the world's first 128GB USB Flash drive. The 128GB drive is build-to-order only.

Re: Battery concerns / conservation question
 

I set up the Linksys WRT54G v2 yesterday and had the N800 online, in standby for more than 8 hours with negligible impact on the battery, then able to download and play TWIT podcast this morning. Connected through the SMC7904WBRA2 would see the battery drain in four hours. (The Linksys provides the wireless access point; it is connected to the SMC which still supplies DHCP and Internet gateway routing etc).

Re: Battery concerns / conservation question
 

No, it's not that easy. What a light bulb does is mostly convert energy into heat. You can make electronic devices which consume 150W and don't convert that much energy onto heat, but in something else.

Re: Battery concerns / conservation question
 

Actually, no. Energy can never disappear or be created, only converted to some other form of energy. Doing that it might do some work for you, but work by itself (i.e. calculations) is not energy. Electronic devices only have limited options here, so almost everything is converted to heat energy. A little bit may be converted to chemical energy (charging the battery), an even tinier bit may be stored in capacitors on the board, but then you're out of options.

Re: Battery concerns / conservation question
 

A proportion will be RF EM energy...

Re: Battery concerns / conservation question
 

Indeed, that's true. Still tiny though.. the wi-fi transmitter transmits up to 100mW, and some of that will be heat too. The BT transmitter even less. The N900 can transmit some power through its GSM radio. Some photons escape via the LCD screen and won't become heat until they're absorbed by a wall or something.