Poll: Battery Life Target

[DeadlyDad]

#1. Unit must be able to charge in ANY state from a Standard 5 Volt 0.5 Amp DC (Universal Serial Bus) Power source. The connector should ideally be a Mini Or Micro USB port (using the device storage access port makes sense)

Due to the possibility of drawing a large amount of current (cpu at full load, wifi enabled, etc) then I'd say its only practical to charge via usb (500mA) when the device is powered off. If the device is switched on, charging stops and unit is powered from the batteries.

If large current draw is the problem, then why not use a 1000mA supply? Is there a problem with the USB specs that won't allow that?

Considering how often the unit might be used with external power, I would also switch to more of a UPS power scheme. (i.e. When the unit is powered externally, it uses that source, while charging the internal battery. Once external source is lost (or drops below a certain level (e.g. external battery pack/solar panel/etc.), the internal batteries are used.

#2. Accurate (to the minute) Internal Cell status, Not a 78% left message. Say 3H 53M type indication, at current power usage and known battery charge / age.

This can be done in software at a later date. I'd say the first firmware will simply give a rough percentage, emu and games can tap into this and auto-save/etc when battery falls below 10% or whatever. Due to the fact cpu load can change constantly, an accurate time indication will not be possible, it will always be "At the current cpu load, estimated time is blah blah blah."


I, for one, would appreciate a popup along the lines of "Battery power approaching critical. Go into hibernation?", which would save everything exactly as it was, thus avoid the "What? WHAT?!? NOOOOOOOOOO!!!!!!!!!!" and the ensuing clean up and out-of-warranty repairs.

 

[Balzac2m]

Yes, according to the USB specs, USB devices are only allowed to draw 0.5A from USB. Which is 2.5W.

 

[pupnik]

#1. Unit must be able to charge in ANY state from a Standard 5 Volt 0.5 Amp DC (Universal Serial Bus) Power source. The connector should ideally be a Mini Or Micro USB port (using the device storage access port makes sense)

Due to the possibility of drawing a large amount of current (cpu at full load, wifi enabled, etc) then I'd say its only practical to charge via usb (500mA) when the device is powered off. If the device is switched on, charging stops and unit is powered from the batteries.

If large current draw is the problem, then why not use a 1000mA supply? Is there a problem with the USB specs that won't allow that?

Considering how often the unit might be used with external power, I would also switch to more of a UPS power scheme. (i.e. When the unit is powered externally, it uses that source, while charging the internal battery. Once external source is lost (or drops below a certain level (e.g. external battery pack/solar panel/etc.), the internal batteries are used.

#2. Accurate (to the minute) Internal Cell status, Not a 78% left message. Say 3H 53M type indication, at current power usage and known battery charge / age.

This can be done in software at a later date. I'd say the first firmware will simply give a rough percentage, emu and games can tap into this and auto-save/etc when battery falls below 10% or whatever. Due to the fact cpu load can change constantly, an accurate time indication will not be possible, it will always be "At the current cpu load, estimated time is blah blah blah."


I, for one, would appreciate a popup along the lines of "Battery power approaching critical. Go into hibernation?", which would save everything exactly as it was, thus avoid the "What? WHAT?!? NOOOOOOOOOO!!!!!!!!!!" and the ensuing clean up and out-of-warranty repairs.


A hibernation trigger (user selectable) would be awesome especially for those emus that do not support save-states (Dosbox!)

Seeing the comments from mweston, i think they're going to give us really good battery life. The main unknown for us right now is what variety of OMAp3430 they will get - the high drain `1ghz or the lower drain ~600mhz. Beyond that it's up to the OS and app programmers to make good use of the dynamic clocking. IIRC nokia's implementation of power saving / cpu throttling used 4 seperate clock rates on the OMAP 2420, and did more aggressive throttling in their latest OS2008.

It will be fun to find out how TI's kernel handles this .. or maybe we won't? TI has the ability to force certain kernel portions to be closed source. So i hope people don't flip out if not every little piece of pandora's underlying drivers aren't open...

 

[DeadlyDad]

Seeing the comments from mweston, i think they're going to give us really good battery life. The main unknown for us right now is what variety of OMAp3430 they will get - the high drain `1ghz or the lower drain ~600mhz. Beyond that it's up to the OS and app programmers to make good use of the dynamic clocking. IIRC nokia's implementation of power saving / cpu throttling used 4 seperate clock rates on the OMAP 2420, and did more aggressive throttling in their latest OS2008.

It will be fun to find out how TI's kernel handles this .. or maybe we won't? TI has the ability to force certain kernel portions to be closed source. So i hope people don't flip out if not every little piece of pandora's underlying drivers aren't open...

I wonder if it would be possible to keep track of an application's CPU usage history? That way, you could fairly easily add up the usage of all programs currently running and drop the CPU speed to match that level. I realize that that wouldn't be optimal, as a lot of programs have definite peaks where they use a lot more than any other place, but logic tells me that those peak would have definite precursors, like starting and stopping the program, which can be taken into account. Another method would be to look for idle cycles and drop the speed until they are eliminated, but that method could require a lot of tweaking, I suppose.

 

[Squidge]

Linux already knows what processes are using the processor and at what rate. Goto any Linux box and use the "ps" or "top" commands and you'll get a linux including processor usage.

For it to work however, people need to avoid busy loops. For example, in a typical game you would check the joystick, update the screen and then sleep until the next time period. Linux would then take the action of putting the processor into a light sleep until something happens that requires its attention.

 

[Hyperpc]

7 hours plus. Could we just use the ds battery pack which i think has up 15hours of play i think

 

[Squidge]

7 hours plus. Could we just use the ds battery pack which i think has up 15hours of play i think

Sure you can use the DS battery pack, but don't expect more than 2 hours of play* from it as the Pandora is slightly more powerful than a DS

* Maybe assuming Wifi is disabled. Else < 2 hours.

 

[Series-8]

Sure you can use the DS battery pack, but don't expect more than 2 hours of play* from it as the Pandora is slightly more powerful than a DS

Why not, USE TWO?

Also it allows some on-the-fly battery swapping fun.

 

[Karel Jansens]

Why not, USE TWO?

Also it allows some on-the-fly battery swapping fun.

Why stop there? I vote "car battery".

And casters... B)

 

[Peter R]

Are you meant to connect more than one li-on in parallel? The DS battery is only like 850mAh. The Pandora one is going to be many times that, I believe.

 

[mafia-man]

I want mine powered by an unlicensed nuclear accelerator strapped to my back, and to play the Awooga waltz when the battery runs low

 

[sephiroth111]

Why not, USE TWO?

Also it allows some on-the-fly battery swapping fun.

Why stop there? I vote "car battery".

And casters... B)


i want 3 PCI ports, and enough power to run an Nvidia 8800GTX B)

 

[Lazy8s]

I suspect the CPU runs at 550 MHz and the GPU at 110 MHz.

 

[imec]

Are you meant to connect more than one li-on in parallel? The DS battery is only like 850mAh. The Pandora one is going to be many times that, I believe.

I thought it was more along the lines of 1200mAH?

7 hours plus. Could we just use the ds battery pack which i think has up 15hours of play i think

Sure you can use the DS battery pack, but don't expect more than 2 hours of play* from it as the Pandora is slightly more powerful than a DS

* Maybe assuming Wifi is disabled. Else < 2 hours.


And, what is it exactly that you are talking about, fanboy? The Nintendo DS is way ahead of the Pandora. I mean, it can't even do GameGear or NES emulation, and my DS can. Really, the Pandora can't do a single thing, and everyone is so hyped up about it. What is up with that? You guys need to get back to your magical mushroom farms, freaking junkies.

 

[quote]

^^^^ heh, you're kidding, right??!? ^^^^

 

[b._.o._.b]

<snip> *please* ban me post </snip>

 

[imec]

I are robot cat, robot cat unable to express sarcasm. Sarcasm is the cause of all wars, we robot cats must cleanse it from this earth, as well as any of those that practice it.

 

[markiej]

I think that as long as you can have INEXPENSIVE charged spares, the life isn't super critical. For example, I am flying to Denmark tonight and will bring 10 fully charged 2500mah AA batteries. I am not the least bit concerned about running out of batteries on my journey, including lay-over.

For me, this is *the* critical app for the gp2x - trans-oceanic journeys, with full video/music/ebook/audiobook/games-up-the-wazoo.

That's the problem with portable dvd players, each has a propietary battery that lasts barely one movie, and costs almost as much as the player.

I think 10 hours for mp3, 4 hours for video, 3 hours for gaming is fine. but the real key is affordable spares. And a reliable battery meter.

 

[cowai]

7 hours plus. Could we just use the ds battery pack which i think has up 15hours of play i think

:lol:

 

[Chip]

I think that as long as you can have INEXPENSIVE charged spares, the life isn't super critical. For example, I am flying to Denmark tonight and will bring 10 fully charged 2500mah AA batteries. I am not the least bit concerned about running out of batteries on my journey, including lay-over.

That's not going to be an option with Pandora's lithium batteries: http://www.engadget.com/2007/12/28/dot-ban...ies-on-flights/

Yay NTSB! Way to carry on your grand tradition of over-compensating and under-thinking.