Battery information

[spiralofhope]

The official documentation:


http://openpandora.o...emid=31&lang=en


.. points the user to:


http://pandorawiki.o...#First_Time_Use


.. which says:

Finally, don't just leave your Pandora plugged in forever. Unplug it once every couple days while using it to allow the battery to discharge from full (to around 90% or less?). If you're not going to use your Pandora for a while, discharge the battery to around 40%, remove the battery, wrap it in a plastic bag (a Ziplock-type bag?), and stick it in the fridge.

I'm working on documentation, and one of the things which really bothers me is poorly-unsourced and possibly-disastrous information. Like the above.


Does anyone have documentation from the battery manufacturer? Perhaps they have opinions on the above. Also, I'd like technical details so I can research peer-reviewed publications. This is a new skill I'd like to develop.


Alternately, if I got some more info on the manufacturer, I could contact them myself. Mangle email addresses so spam harvesters hopefully won't get them. Also don't post personal contact info here.. PM me.


--

.. I hear that black batteries hold a charge for longer when kept below 5 degrees Celcius, but only at certain altitudes. It involves waving this special magnet counter-clockwise. I read it on the internet, and everything the internet says is true because the internet says that everything on the internet says is true. Honest. Now for only five easy payments of 9.95, you can DON'T MAKE FUN OF MY BELIEFS!!one

 

[WizardStan]

I'm working on documentation, and one of the things which really bothers me is poorly-unsourced and possibly-disastrous information. Like the above.

3 years ago I had charts and everything that clearly showed remaining capacity of several lipo batteries tested over several years: fully charged, 40% charged, completely discharged, kept in controlled cooling vs uncontrolled temperature. The test was a full charge and then controlled discharge of each battery to determine how much capacity remained over the course of a year. Long story short: the battery charged to 40% in a cool, dry environment was able to be used with 98% of its original capacity after two years; the other combinations had lost 10-40% of their total storage capacity in the same time frame.


Unfortunately, I no longer have these charts, and cursory google searches now return nothing but RC sites and forums saying the same thing about partial discharge and cool storage. Not always 40%, sometimes 50% or 70%, but whatever. Even wikipedia links to a questionable source simply saying "manufacturers store them at 40% and 15C for extended periods of time" without citing its source.

 

[Prometheus]

Also, the part about leaving it plugged in forever has, in a sense, been documented in the Support section here - a number of people had their batteries puff up a LOT (in some cases, to the point of causing breakage to the casing, if my memory serves me correctly), due to leaving them plugged in for days, weeks, months, without unplugging it.


As I'm sure you know, deformed lithium-polymer batteries are incredibly dangerous, which is, I assume, the reason for adding that part of the advice quoted.


Unfortunately, it's a bit tricky to find the links to the reported cases, due to differing descriptions of the issues that occurred.


Now, that said, more recent Hotfixes and OS revisions have apparently dealt with the issue that caused the puffing. I'm unsure if that warrants the removal of the advice regarding leaving it plugged in all the time, though, since there are probably other good reasons not to do that.

 

[spiralofhope]

There is all kinds of interesting battery advice and stories scattered all over the place. Not just the wiki but this and the gp32x forum too. This is probably going to be my first topic of research since my very first new user concerns were about the battery.


Can I plug it in? With the battery? Can I use it while charging? There's a big difference between me being told or learning that things work, and finding out later that I'm destroying my battery or risking the device. =)


Heck, I got lucky reading a post talking about missing battery clips and using a folded piece of paper to hold the battery better. My system was randomly rebooting when I applied pressure in different places. I thought it was defective.


I do think I can find research if I look through journals .. but manufacturer input, even if "unofficial", would help.


Maybe I'll begin by finding all the stuff on the wiki and these forums and building a list, and another list of questions - answered or not. Then I can keep all of that in mind while researching.

 

[Prometheus]

Can I plug it in? With the battery? Can I use it while charging?

Yes. Yes. And yes. But, if you've had some reason to take the battery out, don't put it back in whilst it's plugged in - I gather that it's not geared for that.

 

[diligentcircle]

Now, that said, more recent Hotfixes and OS revisions have apparently dealt with the issue that caused the puffing. I'm unsure if that warrants the removal of the advice regarding leaving it plugged in all the time, though, since there are probably other good reasons not to do that.

Hardly. That advice was there because the battery used to be trickle-charged (a bad idea for LiPo batteries), but now the battery stops charging when it gets full and resumes charging when it gets down to 60%. With that mechanism in place, unplugging isn't going to do anything special, because the battery is never going to remain 100% charged unless you're sitting there constantly unplugging and plugging back in the cord. (If it isn't obvious, you shouldn't try to keep the battery at 100%; this will accelerate the reduction of the battery's life. I doubt anyone would want to spend their time doing that anyway, though.)

 

[craigix]

Shit, I'd better start parking the Leaf in my fridge.

 

[Prometheus]

I think you're gonna need a pretty big fridge for that.

 

[wdt]

> Shit, I'd better start parking the Leaf in my fridge.


It is most unlikely that your leaf has a LiCoO battery (lithium cobalt oxide)


Almost certainly it will have a LiFePO4 battery (lithium iron phosphate)


These batterys are very much more rugged, but hold only 3/4 the energy of LiCoO batterys


(equal size, volume, weight)


First used in OLPC

 

[fantomid]

Hi all,


About the battery, what is the part number of the battery connector on the battery and on the pandora ?


Where could I find these informations ?


Thanks for your help.


Regards,