Battery hot swap and external charger


CrazyIvan

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Since pyra will have less battery life than pandora it's interesting to look at options to increase it. Because ED told that he's a little afraid to order another type of battery from manufacturer that means some slice battery (something like thinkpad slice batteries of extended battery for nintendo 3ds by mugen) that are attached to the bottom of device is probably out of question. Another alternative is just to carry some more batteries and the ability to change it without turning off the device actually can make this option much more attractive.

Neo900 guys claim to implement such option for this board (see  http://neo900.org/#features) so I think it's possible to implement such feature in pyra.

And it would be nice to have a small portable battery charger so it would be possible, for example, to operate a pyra without ever connecting it to some charging cable.

What do you think?  What could be the best implementable solution for pyra to prolong battery life while remaining portable and pocketable?
 

LEOXD

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This can be done by having a small battery that can carry the system for a short amount of time. However, I don't think that there is enough space for such a feature inside the case.

Another method would be having an external battery via USB that can carry the system a while. This is probably useful; if you can carry around a second battery, you can probably also carry around a mobile charger/external battery as well.

But if you're carrying around a mobile charger (these range from around 7000 mAh to 500 mAh as far as I've seen), you probably can just charge the battery inside the pyra as well. And if you don't want to have 2 things in your hands, use duct tape.

The first 2 cases would require a redesign of the charging system of the pandora* that can switch between use-battery and use-[external power supply|small battery] seamlessly, I think.


Another way might be that you swap the battery very fast (<1/50th second) so that the power from the battery isn't interrupted, but...


* implying that the circles of the pyra are based on the circles of the pandora; charging system of the pandora according to the wiki:

When a battery is inserted, the power goes into the battery, charges it and the battery powers the Pandora. When no battery is inserted, the power goes through the charging circuit directly into the Pandora. [...]
If you powered the system without a battery, shut it off before sticking the battery back in!
 

Askarus

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I think this is the way to go:

1: You have to go into standby mode

2: Be fast and swap the battery

3: Exit standby mode

4: Every time you exit standby mode the battery chip is restarted to check the new battery level.

If not in standby the power consumption would be too hight I think

If not set it manually you need a switch that detects when the battery lid opens -> adds cost

If the battery chip isn't told to check for a new battery it still behaves like the old battery would be inside.
 

CrazyIvan

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If the battery chip isn't told to check for a new battery it still behaves like the old battery would be inside.
and what would that mean? does it really matter when the battery is discharging?

It could be possible to reset battery status when charger is connected I think. Or am I wrong?

But if you're carrying around a mobile charger (these range from around 7000 mAh to 500 mAh as far as I've seen), you probably can just charge the battery inside the pyra as well.
 

It's not pocketable and cables or ports may break. And I have two mobile charger - one is 50wh and another is about 70wh. Good for long trips and could be used to charge pyra batteries.

And basically this thread is not intended to discuss hot swap implementation (unless someone have some information on neo900 implementation) but rather other options to increase runtime without sacrificing pocketability/portability much. Hanging cables and duct tape are therefore unsuitable solutions
 
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Askarus

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If the battery chip isn't told to check for a new battery it still behaves like the old battery would be inside.
 
and what would that mean? does it really matter when the battery is discharging?

It could be possible to reset battery status when charger is connected I think. Or am I wrong?
On FOSDEM EvilDragon told me that there is a problem with the battery chip.

I think the Pandora wouldn't recognize that there's a full battery inside if it would support hot swap.

Can't tell you exactly what it is.

GTA04 has to tell how it's done in the Neo900 to get proper information.
 

CrazyIvan

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On FOSDEM EvilDragon told me that there is a problem with the battery chip.   I think the Pandora wouldn't recognize that there's a full battery inside if it would support hot swap.
I think we need some clarification. Can new battery be used to power pyra? If that's the case then what kind of degraded mode should we expect?

If that means it'll show wrong charge level until it's reset then it's fine.

And it's not clear whether battery chip could be reset without interrupting power delivery?

Another thing is how this chip powered? If it's powered directly by battery (or charger) and delivers power to the unit then it will reset itself when changing battery because it won't be powered without battery if hot swap capacitor is placed between the chip and the device.

Maybe I should change thread title to better reflect that I primarily mean neo900 hot swap implementation...
 
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Mr_Loon

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What I'd like to see is the option of a larger battery for those who value longer battery life over a decrease in portability / pocketability. The larger battery pack could perhaps contain 2 standard batteries thus eliminating the requirement of the design / manufacture of a new battery.

It would be good to see some official discussion relating to this backed up with figures relating to expected battery life for Pyra under common usage scenarios.
 

Askarus

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What I'd like to see is the option of a larger battery for those who value longer battery life over a decrease in portability / pocketability. The larger battery pack could perhaps contain 2 standard batteries thus eliminating the requirement of the design / manufacture of a new battery.

It would be good to see some official discussion relating to this backed up with figures relating to expected battery life for Pyra under common usage scenarios.
As soon as the final data of the case is out there will be a way to wire 2 batteries together and print an extended case.

Maybe one that gives a Wii U gamepad like feeling.

But I think it's not a replacement for battery hot swap.
 

levi

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I think the thread title is fine. It'd be a nice thing to have whether it's done the Neo900 way or the Psion organiser way or whatever.


Personally I never understood why people bought spare batteries with their order. Sure, you could reboot when your battery runs out, but who wants to do that all the time these days?
 

mcobit

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Maybe you only need some pretty big capacitors that can hold the system in low power mode to swap the battery.


You would only have some seconds though.
 

Askarus

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Maybe you only need some pretty big capacitors that can hold the system in low power mode to swap the battery.


You would only have some seconds though.
5 Seconds are far enough to swap the battery.
 

Grench

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Since pyra will have less battery life than pandora

...
Mmm - task for task I think you'll find that the Pyra will have at least as long or longer battery life than the Pandora.

What gave you the idea that it would be less?
 

Binky

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Since pyra will have less battery life than pandora
Really?

Modern SOCs have a higher max. power drain, but are more efficient.

The Pyra will last longer if doing the same work as the pandora on the same battery
 

Grench

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Let's go on with the hot swap discussion :) .
1.  True hot swap requires two batteries.  We'll only have one.

2.  Battery life should be 5-20 hours depending on tasks.  Standby power should be measured in days.  It isn't a huge inconvenience to expect the end user to shut down, replace the battery then reboot once every ~10 hours of continuous use.

Based on the above, I move that battery hot swap in the Pyra be declared silly scope creep, excluded, and we move on with realistic requirements.
 

Hồng Thất Công

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Isn't it the new SoCs of the same family are more efficient than the old ones?  Isn't that one of the goals SoC manufacturers trying to achieve - lower power consumption?  So with same battery and same task, Pyra would last longer. 

Edit:  Ooops: 5th person :D
 
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CrazyIvan

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Doing the same as on Pandora it gives more battery life.
No offence, but this sounds like a typical marketing phrase. My Pandora does the same as Pandora and already here. Why do I need another system?

I'm talking about battery life for typical usage for a system. Of course typical usage of Pyra will be more computationally intensive because it allows it and in mobile space we didn't reach 'good enough' stage especially for games

1.  True hot swap requires two batteries.  We'll only have one.
You can buy as many as you like, right now, https://www.dragonbox.de/en/pandora/53-pandora-ersatzakku-platinfarben-1.html'>here

2.  Battery life should be 5-20 hours depending on tasks.  Standby power should be measured in days.  It isn't a huge inconvenience to expect the end user to shut down, replace the battery then reboot once every ~10 hours of continuous use.
It's true for you and most of the time it's true for me. Most of the time I also don't need pandora, laptop or even cell phone. Also almost everyone most of the time don't need a toilet for example. But there are times when they do. 

Pyra will have enough computer power to use it as a computer, make long calculations for example or even play a game that doesn't allow to make saves everywhere.

It's a corner case but it's important and neo900 implements this feature so it's not that hard to do it in pyra (unless there are some very specific problems). Actually it can be easier since the board is much bigger.

Neo900 is also small team, money constrained project so it's theoretically possible within budget.

As soon as the final data of the case is out there will be a way to wire 2 batteries together and print an extended case. Maybe one that gives a Wii U gamepad like feeling.
 

I thought about simple electric pairing of batteries but there are some problems with balancing when charging/discharging. Or maybe our batteries have charging controller integrated that does all this?

Two batteries could push worst case runtime beyond 10 hours which s enough for a day if this dual battery setup could be fully recharged during night.

So

 - SoC efficiency != SoC power

 - battery hot swap is an interesting feature that is at least feasible for pyra's budget

 - maybe there are others ideas how to increase pyra battery life that is possible within pyra development budget AND still maintain pocketability?
 
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