Battery Charger

[pelrun]

I would put it in the fridge, not the freezer..

Doesn't matter - Li-Ion electrolyte freezes at about -40C, far colder than your household freezer will get.

 

[pcklee123]

Could use this
http://www.sparkfun.com/commerce/product_i...products_id=674

 

[Monk]

Just to intercede on what you seem to be implying: there is nothing inherently dangerous about the Pandora batteries specifically.

I'm implying? Actually I was thinking firstly that if you need a Pandora to charge it then a spare is less use than I'd anticipated because, at that time, I hand't thought about pre-charging a battery with the pandora not in use before swapping and pre-charging the second one. As for the "bomb" jokette, I was bearing in mind comments like this one from pelrun:

Even slight damage to a Li-Ion cell can cause an internal short circuit, leading directly to the same unstoppable explosion and fire as previously mentioned.




I commend you to pelrun's other posts.



Chaps, what's the idea of the fridge/freezer? To reduce the chance of ambient temperature (direct sunlight and so on) from being any possible issue?



I'm wondering actually how OpenPandora are going to package spare batteries for shipping - I hadn't thought, at time of ordering, that the batteries might not have a rigid shell.



Ta,

 

[WizardStan]

You're confusing chemistries - AA lithium cells are lithium iron disulphide, not rechargeable, and nowhere near as dangerous as Li-Ion.
Aye, you're right, I was confused. I was sure I had a charger with a NiMH/LiIon switch on it. Turns out it's the charger for my RC truck, not a standard charger I thought I had. The point is still the same, though.

Chaps, what's the idea of the fridge/freezer? To reduce the chance of ambient temperature (direct sunlight and so on) from being any possible issue?
I think it's to slow chemical reaction, actually. All I remember is a chart showing voltage levels after extended periods of time at different temperatures. Keeping the battery cold not only made it maintain it's charge longer, but also increased it's life at that charge.

 

[lulzfish]

If you keep a li-ion in the fridge, it doesn't age quite as quickly.
Also, it keeps your fruits and vegetables smelling fresh.

 

[Monk]

fridge answers... ah, ta.



@lulz the battery keeps your fruit and veg fresh?



Curiously, sometimes refrigerating a fruit can make it go off faster, not slower. Try banannas, for example



Ta

 

[pelrun]

Chaps, what's the idea of the fridge/freezer? To reduce the chance of ambient temperature (direct sunlight and so on) from being any possible issue?
I'm wondering actually how OpenPandora are going to package spare batteries for shipping - I hadn't thought, at time of ordering, that the batteries might not have a rigid shell.

Li-Ion/LiPo (from what I'm reading, the Pandora battery must be LiPo) lose capacity as they age, but they lose it faster if they're hot or if they're fully charged. Storing them at 40% charge and below room temperature gives them the longest lifespan.

Shipping the cells shouldn't be a problem; in a box or padded bag should be sufficient. Shaking them isn't a problem, shorting them or puncturing them (which causes an internal short) is.

The point is still the same, though.

Not really - LiIon/LiPo are in a class of their own when it comes to exploding. You are getting a higher energy density than anything else, after all.

Curiously, sometimes refrigerating a fruit can make it go off faster, not slower. Try banannas, for example

That's more to do with locking them up in an airtight container than temperature, as they give off ethylene gas which ripens fruit (so don't keep bananas next to other fruit either )

 

[Monk]

Curiously, sometimes refrigerating a fruit can make it go off faster, not slower. Try banannas, for example

That's more to do with locking them up in an airtight container than temperature, as they give off ethylene gas which ripens fruit (so don't keep bananas next to other fruit either )

Actually, as with some other tropical and subtropical fruits, bananas additionally suffer from "chill injury". Below about 10 degrees C spoilage is accelerated because the cells' internal membranes are damaged, releasing enzymes and stuff. This is seperate from the blackening of the skin which, as you say, is accelerated by keeping ripening fruit close together (fruit can be stored tightly packed provided none of it has started to ripen, although we used to wrap our apples in newspaper as an extra barrier (esp. from light) when it was tightly packed. Still, once one apple goes the others are rarely all that far behind.

 

[WizardStan]

Not really - LiIon/LiPo are in a class of their own when it comes to exploding. You are getting a higher energy density than anything else, after all.
The point was that the Pandora battery is not unique in it's dangers, we're already surrounded by high energy batteries which need their own special chargers. I stand by that statement.

 

[hobbyman II]

LiPo packs are safe if you don`t abuse em, you have them all over the place already, in your phone, laptop, Mp4 player, UPS, satnav, bluetooth headset, model aircraft/boats/cars etc, just don`t abuse em and you will be fine, stick a knife through it though and you will suffer the wrath of the Pandora, you have been warned, neglecting or abusing her (Pandora) will cause you pain, she ain`t that kinda girl

anyway, the cells safety is part of the CE process (they only inspect the completed unit remember, no exceptions like "we forgot the battery"), you don`t think they are going to pass an exploding battery do you?

in fact, look at the label thread, they already have the CE logo on the wrapper, so the battery is already tested, since the battery manufacturer has made this sort of thing before you can assume they know how to make 'em safe

 

[Monk]

you don`t think they are going to pass an exploding battery do you?

Personally? Yes. That doesn't mean that Pandora batteries will be any more or less explosive than those which have exploded in personal computers from BBC Micros to Apple or, IIRC, Sony gear.

 

[Chip]

Nearly everything that is thin and handheld is powered by a LiPo battery. If you own an Ipod (any version), a DS, a PSP, or a cell phone (unless it's a Zack Morris phone), you already have a device which contains a LiPo battery. Other than capacity, there is nothing different between the batteries in these devices and the Pandora battery. It is no more or less safe, fragile, or prone to explosion. Treat the Pandora battery as you would the others. As long as you don't do anyting spectacularly stupid, it will be just fine.

 

[pelrun]

Most of those batteries are either completely internal or have a hard casing (either plastic or metal or both). And the terminals of the removable batteries usually have plastic ribs between them, which helps prevent accidental shorts. I didn't think the Pandora battery was quite that well encased.

But yes, they will be perfectly safe inside the Pandora, and if you've got a loose one, you just need to treat it with some respect.

 

[BackAssward]

Nearly everything that is thin and handheld is powered by a LiPo battery. If you own an Ipod (any version), a DS, a PSP, or a cell phone (unless it's a Zack Morris phone), you already have a device which contains a LiPo battery. Other than capacity, there is nothing different between the batteries in these devices and the Pandora battery. It is no more or less safe, fragile, or prone to explosion. Treat the Pandora battery as you would the others. As long as you don't do anyting spectacularly stupid, it will be just fine.

There is one difference of note: Length vs. Width. A cell phone or other battery has a higher thickness to length ratio. Therefore, a lot harder to break in half (re: leverage). I have no fears myself, but I can see someone not so careful (say, tossing an extra in a backpack, or w/e) splitting an extra Pandora battery in two. Perhaps the OP team should come up with some sort of hard carry case for spare batteries, and either sell them, or include them in any spare battery purchase (good for publicity to keep people from splitting their spare batteries).

I don't know the dimensions, but it looks to be what, 6mm thick and 134mm or so in length (a few mm shy of the case length), so a 1:23 ratio (or so). Whereas my cell phone battery is 5.14mm thick and 46.45mm long, so a 1:9 ratio (or so). Not to mention it would be hard to get any leverage on such a small battery, compared to how easy it would be on such a long Pandora one. I imagine even dropping the Pandora battery off a table could be enough to crack it (worst case scenario), whereas other portable device batteries wouldn't have such a problem (better ratio, much lower weight, designed to take abuse). Is product safety part of the CE and FCC tests, I wonder?

Conclusion: Not a deal breaker, but certainly not "nothing different" than other devices. Possibly one reason certain portable products have batteries you can't remove (think of the Apple slim laptop battery for example, it probably also has a high length to thickness ratio, and they didn't want to have to encase/protect it like other laptop batteries, so as to keep the laptop slim).

Edit: I was being generous on the 6mm thickness and 134mm length, it is quite possible it is thinner than this, I have no data to go on. Whoever has one could enlighten us, if they wanted.

Edit 2: It's too bad they aren't attached to the cover itself, that would add some rigidity. The cover would have to be slightly different, so the side of the case was part of it and could slide out, and the sticker would have to have the printing on the other side. The cover would have to be more like (side view):

|
|______________________________________________________

 

[Monk]

Nearly everything that is thin and handheld is powered by a LiPo battery. If you own an Ipod (any version), a DS, a PSP, or a cell phone (unless it's a Zack Morris phone), you already have a device which contains a LiPo battery. Other than capacity, there is nothing different between the batteries in these devices and the Pandora battery. It is no more or less safe, fragile, or prone to explosion. Treat the Pandora battery as you would the others. As long as you don't do anyting spectacularly stupid, it will be just fine.




It seems the Internet dooms ALL conversations to maximum absurdity in every direction.



I don't own most of those things, though I have recently dwapped to an old mobile phone that my partner has discarded as part of an upgrade in order to include a camera upon my person with the minimum amount of extra baggage because my Pandora - if and when it ever arrives - will not have one, and I could do with a camera in my PDA. HOWEVER, I do not have any spare batteries for it, so do not need to take care of the battery outside of the mobile phones own casing, and even if I bought one (which wouldn't be a bad idea, the battery doesn't seem to last as long as the one in my older, camera-free phone) it is incased in a hard shell and is verfy small, minimising the protection I would need to provide it.



A spare Pandora - the topic of my query - would not have a Pandora wrapped protectively around it (making it different from my phone battery). When outside the equipment it powers, it does not have a hardened protective shell (making it different from my phone battery). In terms of physical size it is larger and therefore more prone to real world stresses than my phone battery. In terms of capacity, the pandora has the potential to hold much more energy - it's like saying that there is no difference between a 9mm bullet and a canonball. While the general principles may be very similar, the results are of a different magnitude.



I dislike the standard Internet Polarity which leads to posts such as this. I have never meant to imply that the Pandora batteries are inherantly extremely dangerous - not having the knowledge or experience to suggest this. However, in light of revelations (such as "it has no hard shell" and so on) it seemed fair to question whether the original idea of purchasing a spare battery just as I have for my Digital Camcorder seemed to be such a wise move after all. It seems to me increasingly as if the pros - to ME, personally - are starting to be outweighed by the cons to ME personally.



Ta.

 

[Tor]

I think the simplest answer is that you probably won't need a spare battery -- you'll find that you're almost never using it, unless you're a frequent traveler on transcontinental flights (the _really_ long ones). I don't need a spare battery for my Nokia tablet, however a few people need them. But as that battery is 1500mAh and the Pandora battery is 4000mAh you're much better off to start with.

 

[Monk]

I think the simplest answer is that you probably won't need a spare battery -- you'll find that you're almost never using it...




I think that's pretty much the conclusion I was coming to - and the idea of buying a "spare" for when the original dies seems redundant if the spare is going to age significantly when not in use. Now, I just need to find out how to cancel part of an order and whether I get my money back. Sigh - possibly time for us to email the Pandora ladies (after a conflab with my partner, who bought this for my birthday last year)!

 

[azurege]

I ordered a spare battery also, hmmmm.....perhaps i dont need it now. Guess the devs are going to get some more funds from my cancelled spare battery.

 

[BackAssward]

It seems the Internet dooms ALL conversations to maximum absurdity in every direction.
...
A spare Pandora - the topic of my query - would not have a Pandora wrapped protectively around it (making it different from my phone battery). When outside the equipment it powers, it does not have a hardened protective shell (making it different from my phone battery). In terms of physical size it is larger and therefore more prone to real world stresses than my phone battery. In terms of capacity, the pandora has the potential to hold much more energy - it's like saying that there is no difference between a 9mm bullet and a canonball. While the general principles may be very similar, the results are of a different magnitude.

I think we had the same point.

I ordered a spare battery also, hmmmm.....perhaps i dont need it now. Guess the devs are going to get some more funds from my cancelled spare battery.

Unless they provide a hard case for spare batteries, or attach the battery to the cover itself (though that would require a case redesign).

 

[Monk]

I think we had the same point.

Shh. Don't tell anyone, but I agree with are in agreement on a significant number of points. Mum's the word!

Meanwhile, one could probably get dimensions from Ed's Blog post where he has provided a cut-out-and-keep battery model, along the lines of the cut-out Pandoras that we've had floating around for a while now.

CODE
http://www.openpandora.org/images/PandBattery3.jpg


Ta