Author Topic: Batteries  (Read 3308 times)

Offline Ed Lolington

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Batteries
« on: October 20, 2013, 10:35:18 PM »
I can't remember if it was the previous episode (11) or one of the ones before that, but Jacob and Joe at some point talked about the usable capacity ranges of batteries for EV cars. If you missed it, the short story is that some (all?) EV cars operate in the mid-range of their battery's total capacity and only a fraction of their total capacity is available to the user. The user might see empty or full, but in actuality the battery's available capacity is still somewhere in the middle. This keeps the stored capacity away from the extremes (full,empty), and extends the life of the battery. There may be something technically wrong with that description, but that's the general idea.

Anyway, are there any other kinds of electronics that work like this? I assume this method would be useful for cellphones and other electronics that sit on the charger overnight, but is it used there? I don't know! Help me out.

Offline scikopas

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Re: Batteries
« Reply #1 on: October 21, 2013, 08:54:37 AM »
yeah, this is how all Li-Ion batteries should be cycled to maximize the lifespan of the battery.  If you overcharge, there is risk of the battery getting warmer, and then you start to anneal metallic lithium deposits on the annode instead of having dispersed atoms.  If you discharge it too much you start to lose surface area/pathways and form permanent bonds on the cathode and then the Lithium can't leave.

The protection circuit in all Li-Ion batteries does this to a certain extent (the 0 and 100% values are already moved a little bit so that the batteries don't react violently and explode, as Lithium likes to do) but many people install programs that stop their laptops form charging to 100% and give "low battery" alerts near 30% instead.

I use tp_smapi (Linux kernel modules) to force my laptop to charge and discharge itself between 30 and 80% even when i'm sitting at my desk plugged in all day. I haven't found anything to do this or android yet.


Theres some good information about batteries on this website:
http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
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Offline bn

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Re: Batteries
« Reply #2 on: October 21, 2013, 08:16:30 PM »
Li-ion batteries? I didn't know lions ran on batteries. I thought they ran on the savannah.
Titanium Physicists has a pro-bee-analogy agenda. That's certainly no secret.

Offline bobmath

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Re: Batteries
« Reply #3 on: October 22, 2013, 06:06:51 AM »
Bah-dum pish!

Offline Ed Lolington

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Re: Batteries
« Reply #4 on: October 22, 2013, 11:37:04 AM »
yeah, this is how all Li-Ion batteries should be cycled to maximize the lifespan of the battery.  If you overcharge, there is risk of the battery getting warmer, and then you start to anneal metallic lithium deposits on the annode instead of having dispersed atoms.  If you discharge it too much you start to lose surface area/pathways and form permanent bonds on the cathode and then the Lithium can't leave.

The protection circuit in all Li-Ion batteries does this to a certain extent (the 0 and 100% values are already moved a little bit so that the batteries don't react violently and explode, as Lithium likes to do) but many people install programs that stop their laptops form charging to 100% and give "low battery" alerts near 30% instead.

I use tp_smapi (Linux kernel modules) to force my laptop to charge and discharge itself between 30 and 80% even when i'm sitting at my desk plugged in all day. I haven't found anything to do this or android yet.


Theres some good information about batteries on this website:
http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

Thanks for the info!