Battery For Pandora


chame

Member
Joined
Dec 19, 2008
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110
hi everybody
I want to suggest something for pandora. I work with this type of battery lithium polymer. they dont need steel case like the li-ion ones, so they are lighter. lipo stops charging when voltage = 4,2v when li-ion stops at 4,1 and thats the only difference when charging.

there are a variety of models out there

this one has 5000 mAh power and 3,7 volts
dimensions: 130x50x7 milimeters

lipo01cb4.jpg
 
I think it might be a little late in the day...
 
A battery isn't necessarily a hardware feature, and it's replaceable. If the charging curve/voltage is programmable it might be possible to use a lithium polymer battery. For a later replacement this is interesting. Not as a replacement for the included battery, which is 'set in stone' supposedly.
 
mali said:
A battery isn't necessarily a hardware feature, and it's replaceable. If the charging curve/voltage is programmable it might be possible to use a lithium polymer battery. For a later replacement this is interesting. Not as a replacement for the included battery, which is 'set in stone' supposedly.
A battery set in stone? Wouldn't that be incredibly heavy? *rimshot* :D
 
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Yes, this would fall under the modding category.
But if it can be made to work, you'd get probably 2.5X the run time.
As the stock battery is supposed to be 1800mAh, if I recall correctly.
YAY!
 
mali said:
A battery isn't necessarily a hardware feature, and it's replaceable. If the charging curve/voltage is programmable it might be possible to use a lithium polymer battery. For a later replacement this is interesting. Not as a replacement for the included battery, which is 'set in stone' supposedly.
Uh sure, if you don't mind completely modding the charge circuit, and possibly the case itself, why not.
 
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OK, I thought I remembered 1800, but thanks for the correction.
4000mAh, that is a big battery.
The Pandora is going to be half battery.
All the better to run for long periods of time.

mechanizeddeath said:
j.pickens said:
As the stock battery is supposed to be 1800mAh, if I recall correctly.
YAY!
http://www.gp32x.de/board/index.php?showt...mp;#entry630241

Over twice that actually! 4000mAh! But hey, this one is 5000.

But I'm still waiting for one that is over... 9000. :lol:
 
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hedwards said:
mali said:
A battery isn't necessarily a hardware feature, and it's replaceable. If the charging curve/voltage is programmable it might be possible to use a lithium polymer battery. For a later replacement this is interesting. Not as a replacement for the included battery, which is 'set in stone' supposedly.
Uh sure, if you don't mind completely modding the charge circuit, and possibly the case itself, why not.


I've highlighted the important part of my post ;)
Nowadays a charging circuitry doesn't consist of a bunch of transistors and resistors any more. It's a smart and maybe even multi-purpose chip fitting for various situations.

Edit:
This is the chip used for charging:
http://focus.ti.com/lit/ds/symlink/tps65950.pdf
 
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mali said:
I've highlighted the important part of my post ;)
Nowadays a charging circuitry doesn't consist of a bunch of transistors and resistors any more. It's a smart and maybe even multi-purpose chip fitting for various situations.
it is possible to charge a lipo with a li-ion charger without any change. the only drawback is because li-ion stops charging at 4,1v, the resulting charge has about 8% less power.

a 5000mAh lipo in a li-on charger results in about 4600mAh power (the battery is underused)

the opposite is not possible, li-ion on a lipo charger will damage the battery (maybe heating or even explosion)
 
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chame said:
it is possible to charge a lipo with a li-ion charger without any change. the only drawback is because li-ion stops charging at 4,1v, the resulting charge has about 8% less power.

a 5000mAh lipo in a li-on charger results in about 4600mAh power (the battery is underused)
But it is still more than 4000mAh right?
Besides doesn't that result longer battery life by not charging it full?
 
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A quick peek at the datasheet confirms, that the chip can do both li-ion and polymer. Mweston is the one to tell us, if the charging voltage can be changed on the fly, if someone wants to try it out.
 
GoaLitiuM said:
But it is still more than 4000mAh right?
Besides doesn't that result longer battery life by not charging it full?
no, lipo & li-ion like to be 100% charged and if possible charged slowly. leave one of those discharged too much time and they will be damaged.

in fact both can be charged to 70% in about 30 minutes, but in order to get 100% and better life time they need more time, the last 8% is important

charging time depends on the charging power of course

I didnt see the specs of the case, but seems to be at least 16cm wide, maybe could fit pretty well
 
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Tozarian said:
Vegeta,what does the scouter say about the voltage and milliamps?
*SMASH* THEY ARE OVER 9000!!!!!!
 
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chame said:
no, lipo & li-ion like to be 100% charged and if possible charged slowly.
Actually, about 40% charged will yield the greatest lifespan. Full charge and higher temperatures will make a battery die faster.

If you follow the very strict charging profile you can actually charge them quite quickly without ill effect (as long as they stay cool, which is the main limiting factor) but of course even a little overcharging will make them go boom.

Edit: I'd just like to mention that you should see far better lifespans out of the pandora battery than you will from a laptop battery, simply because the P will run so much cooler than a laptop does. And you don't have to do anything special! :)
 
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There's some incorrect information in this thread.

Li-ion doesn't "stop charging at 4.1V". First, no battery stops charging by itself (until you reach the safety voltage of 4.30V as every li-ion/li-poly battery should have built-in). The charging stops when the charging circuit in the _device_ decides to stop.
Secondly, where's this 4.1V coming from? My Palm devices charge to 4.24 V, with lithium-ion batteries. For the one where I have replaced the original battery with a lithium-polymer battery it of course charges that one to 4.24 volts too.

And I have never seen anywhere that lithium-ion batteries should be charged to a lower voltage than lithium-polymer. However, for both of them they will last slightly longer if you charge them to 4.10V instead of higher, e.g. 4.20V. But Palm charges to 4.24V anyway (it drops relatively quickly to 4.21V after you unplug) because this lifetime effect is really really small after all.

In short, we've got a good battery already (4000mAh lithium-ion), I see no point in going for something else..
 
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