Warning: don't leave your Pandora plugged in for too long

[Exophase]

Or you run the risk of your battery literally expanding. I don't know exactly what happened, but zodttd told me that his battery was literally bursting and bent his back cover, so I checked mine and indeed the back cover was bulging out.


Now, when I say "too long" I mean a LONG time. My uptime was 73 days. zodttd says he had his plugged in for over 4 months. The consequences seem pretty.. unsafe to be sure. I'm sure most of you are out there using it and don't just have them sitting around for development purposes like we did. But I recommend regularly checking for this, and I guess the best thing to do is to every once in a while unplug the thing and let it discharge. Honestly I don't really know. The whole issue is kind of scary.


Don't know what I'm going to do with my battery yet.. don't feel comfortable trying to use it anymore of course, and even getting the cover back on would be kinda hard. Probably going to pitch it and see if OP will send me a new one, if not I guess I'll be buying one. But I might hold off and wait until more can be explained as to why this is happening and how to prevent it.

 

[zodttd]

Yeah. I took a picture after I put it in a trash bag. The battery is going in the garbage tomorrow. Kinda freaky. The Pandora works fine on AC still.

 

[Exophase]

Text snippet for what could be causing this:


"Pressure effects


These problems relate to sealed cells only.


Increased internal pressure within a cell is usually the consequence of increased temperature. Several factors can play a part in causing the temperature and pressure rise. Excessive currents or a high ambient temperature will cause the cell temperature to rise and the resulting expansion of the active chemicals will in turn cause the internal pressure in the cell to rise. Overcharging also causes a rise in temperature, but more seriously, overcharging can also cause the release of gases resulting in an even greater build up in the internal pressure."


My battery wasn't nearly as bad as zod's, but still bulging, and you could feel the increased pressure/trapped gasses by pressing on it.

 

[WizardStan]

According to the TPS spec sheet, when the chip detects that the battery is full (which occurs when the charge rate drops below 80ma apparently) it is supposed to actually shut off the charge. I've detected this on mine, and I know other people have reported similar. Not everyone seems to be experiencing this behavior though. It's kind of odd.


Anywho, when it does this it cycles down to 80% before charging back up to 100% again. Are you aware if this is what your Pandora was doing while plugged in, or was it in a constant state of trickle charge?

 

[Exophase]

According to the TPS spec sheet, when the chip detects that the battery is full (which occurs when the charge rate drops below 80ma apparently) it is supposed to actually shut off the charge. I've detected this on mine, and I know other people have reported similar. Not everyone seems to be experiencing this behavior though. It's kind of odd.


Anywho, when it does this it cycles down to 80% before charging back up to 100% again. Are you aware if this is what your Pandora was doing while plugged in, or was it in a constant state of trickle charge?

I have absolutely no idea what it was doing, sorry. I can't imagine that it was constantly trickle charging or it would have probably gotten a lot worse a lot sooner. Maybe its cutoff threshold is simply too high and it kept hitting against it bit by bit.

 

[Link]

I try not to ever let mine charge overnight let alone 4 months?


Pandora


"Don't Charge for more than 2 Months™"

 

[TitanUranus]

Several ideas.


1. Bung it in the freezer and see if it contracts over night.


2. Try popping it with a pin and let some pressure out.


3. Try flattening it out by pummelling it with a hammer.


IMPORTANT: I take no responsibility for anyone insane enough to listen to what I just said. Prior blinding yourself and permanently destroying your upper limbs by doing any of these, could you please pop your Pandora in a postal box and send it to me for safe keeping.

 

[Exophase]

I try not to ever let mine charge overnight let alone 4 months?


Pandora


"Don't Charge for more than 2 Months™"

Not highly applicable I'm sure but still a legitimate warning. If you just use it to develop and don't have much need for gadgets on the go much why unplug it? I know most of you got a Pandora because you wanted to use it like a normal person but hey

 

[MWeston]

It has been explained before that the TI chip does not allow the battery to be isolated from the power input circuit, therefore trickle charging is continuous. As Wizardstan points out, if you can get the AC input draw down to below 80mA, then the charging circuit will be shut down but since the battery is not isolated, that means the entire system plus the battery trickle charging has to be under 80mA which is pretty much impossible. I don't even know if the power save mode can go that low but if it does, that would be the only logical reason charging would EVER stop.


The fact that charging stops at all for some people feels like some undocumented errata issue in the chip TI will never acknowledge as I have said before. Pandora was designed to be used as a portable gaming system that comes off the charger each day to be used, not sit plugged in for months. It seemed obvious but I guess we'll have to make that more clear.


Even if the battery did stop charging and drop to 80% and then charge again, leaving it for months would destroy the cell because maintaining a battery on a charger above 4V for long periods of time is supposed to do irreparable damage. That's why the charge current is set to about 0.2C at best (800mA out of 1000mA setting with LCD off, idle, etc) because the battery will spend more time slowly ramping up the voltage over the entire cycle rather than a higher current charge (ie. 1C) which will pull the cell up to nearly 4.2V quickly and keep it there for most of the charge cycle leading to early failure.

 

[Exophase]

Maybe if Pandora could operate without a battery I wouldn't have left one in at all, but alas it can't. I'm sorry to inform you but leaving a portable device plugged in indefinitely being unsafe for the battery is not common knowledge. Why would you think something like that would be obvious? It's about as obvious as the gotcha that you shouldn't insert the battery with the AC plugged in, which is something you may end up doing without really thinking about it if you have to pop the battery in order to reset the thing because nothing else would take it out of a hard lock (happened several times to me in the past).


Anyway, I don't really know the RMA procedure, but I'm not sending in the Pandora (much less the battery), can I expect a replacement battery will be sent to me or are am I going to have to pay for one?

 

[Link]

Maybe if Pandora could operate without a battery I wouldn't have left one in at all, but alas it can't. I'm sorry to inform you but leaving a portable device plugged in indefinitely being unsafe for the battery is not common knowledge. Why would you think something like that would be obvious? It's about as obvious as the gotcha that you shouldn't insert the battery with the AC plugged in, which is something you may end up doing without really thinking about it if you have to pop the battery in order to reset the thing because nothing else would take it out of a hard lock (happened several times to me in the past).


Anyway, I don't really know the RMA procedure, but I'm not sending in the Pandora (much less the battery), can I expect a replacement battery will be sent to me or are am I going to have to pay for one?

Isn't there some kind of test mode that the Pandora can be plugged in without a battery? Not official but possible?


I could be stoned too.

 

[Yannick]

Somehow i start to understand the whole apple non removable battery issue

 

[EvilDragon]

Maybe if Pandora could operate without a battery I wouldn't have left one in at all, but alas it can't.

It's an undocumented feature of TI's chip. So far, I've only seen a few Pandoras (two to five) out of a few hundred that DO NOT work without a battery.


Most do.

I'm sorry to inform you but leaving a portable device plugged in indefinitely being unsafe for the battery is not common knowledge. Why would you think something like that would be obvious? It's about as obvious as the gotcha that you shouldn't insert the battery with the AC plugged in, which is something you may end up doing without really thinking about it if you have to pop the battery in order to reset the thing because nothing else would take it out of a hard lock (happened several times to me in the past).

Well, we're going to need to change the manual and warn about this. It's nothing that can be changed, as it's TI's charging chip.


And I'm pretty sure A LOT of the modern mobile phones or similar mobile devices won't survive 4 months permanent charging either...

 

[darfgarf]

And I'm pretty sure A LOT of the modern mobile phones or similar mobile devices won't survive 4 months permanent charging either...

or old ones for that matter, there should be some way to shut the charging circuitry off from software, obviously someone at TI didn't think about this eventuality


though they probably didn't expect it, most things do have a statement somewhere that says 'if unit is not in use for extended periods, remove batteries' etc, something like that should cover it, without making everyone panic over leaving it charging overnight


...though i should check mine, it's been sat charging on a desk for a few weeks now XD

 

[Prometheus]

Gracious me, those batteries... :blink:

It's about as obvious as the gotcha that you shouldn't insert the battery with the AC plugged in, which is something you may end up doing without really thinking about it if you have to pop the battery in order to reset the thing because nothing else would take it out of a hard lock (happened several times to me in the past).

When it locks up like that, you don't need to pop the battery out - just hold the Pandora button and flip the power switch as you would when powering it on. It does a hard reset.


Of course, that's moot if even that wouldn't get it out of such a state, but I've not come across that myself.

 

[THB]

I've noticed it getting hot after just a couple of days on charge.

 

[elwing]

I'm sorry to inform you but leaving a portable device plugged in indefinitely being unsafe for the battery is not common knowledge.

it's really something they avoid to advertise, but it's knowns for years... keeping a battery plugged in literally kills it (through they normally don't inflate like that...)

 

[JayFoxRox]

When it locks up like that, you don't need to pop the battery out - just hold the Pandora button and flip the power switch as you would when powering it on. It does a hard reset.

That's not true (for my Pandora at least). This only works in some cases for me.


Especially when the SGX locks up I have to remove the battery which happens really really often for me.


- Scary stuff about the batteries. I had mine at the charger all the time before Uni started too, so this could have happened here too.


And especially with the Pandora this shouldn't be a problem because some people might use it as a stationary console for retro games.


I guess we will be seeing this more often in the future if it's not solved before.


Not sure why you would assume that people don't keep it in a charger for a long time. It works fine with all of my other devices - so why shouldn't it with the Pandora?

 

[Bosbeetle]

I only have mine on the charger when I sleep. And I run it down to about 10% every day.


My battery looks fine but still this is scary stuff.

 

[tsh]

So is it possible to have a daemon re-configure the charging chip if it can detect charge has been at >98% for an hour, and allow the battery to discharge (for 30 min or till it reads <90%)? Not sure if this actually makes life better for the battery or not (is active +/-Q better than static 100%?).