Charging Lithium - why laptop batteries last 1 year

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Charging Lithium - why laptop batteries last 1 year

Cor van de Water
Go to this presentation from TI:
http://focus.ti.com/asia/download/TechDay09cn_Analog_Power_1_Battery_che
mistry_fuel_gauge.pdf
and look at slide 8, then realize that many laptop BMS'es
will charge to 4.3 or even 4.35V per cell to get the pack
"full" in a short time.
No wonder laptop batteries always fail after about 1 year...

Regards,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [hidden email]    Private: http://www.cvandewater.com
Skype: cor_van_de_water     IM: [hidden email]
Tel: +1 408 383 7626        VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

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Re: Charging Lithium - why laptop batteries last 1 year

Evan Tuer
On Sat, Mar 13, 2010 at 1:47 AM, Cor van de Water <[hidden email]> wrote:
> Go to this presentation from TI:
> http://focus.ti.com/asia/download/TechDay09cn_Analog_Power_1_Battery_che
> mistry_fuel_gauge.pdf
> and look at slide 8, then realize that many laptop BMS'es
> will charge to 4.3 or even 4.35V per cell to get the pack
> "full" in a short time.

I don't think that's done to speed up recharging - in fact it will
take longer to get them all up to the higher voltage as the charger
tapers off.

It will, however, ensure that every last drop of energy is squeezed
out of the battery.

A bigger contributer to them dying early in laptops is heat.

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Re: Charging Lithium - why laptop batteries last 1 year

shred
My laptop batteries are going on 5 years now & still work fine.
My cell phone batteries on the other hand seem to be on their way out after 18 months.
BTW I don't use my laptop very often, my cell phone I use every day.
Neal
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Re: Charging Lithium - why laptop batteries last 1 year

Jukka Järvinen-2
Lifetime of the cell phone and laptop batteries greatly depends how
you use them. Most of the time I use my laptop it's actually connected
to the mains and  cells are getting away with nearly no load.

Cellphone is used nearly always with the battery. And charged just
before it goes completely dead.

There are differences too in the BMS systems in both devices. They
contribute to this too.

-akkuJukka


2010/3/14 shred <[hidden email]>:

>
> My laptop batteries are going on 5 years now & still work fine.
> My cell phone batteries on the other hand seem to be on their way out after
> 18 months.
> BTW I don't use my laptop very often, my cell phone I use every day.
> Neal
> --
> View this message in context: http://n4.nabble.com/Charging-Lithium-why-laptop-batteries-last-1-year-tp1591366p1592087.html
> Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.
>
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>



--
http://www.google.com/profiles/jarviju#about

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Re: Charging Lithium - why laptop batteries last 1 year

Lee Hart
In reply to this post by shred
shred wrote:
> My laptop batteries are going on 5 years now & still work fine.
> My cell phone batteries on the other hand seem to be on their way
> out after 18 months. BTW I don't use my laptop very often, my cell
> phone I use every day.

Battery life is a combination of factors. The big ones are number of
depth of discharge, how hard it is charged, the total number of
charge/discharge cycles, and heat.

5 years is a long time for a laptop battery. They typically run hot,
often get deeply discharged, and they supply the cheapest chargers they
can get away with. But if you don't use it much, you've avoided the heat
and it won't have many charge or discharge cycles.

--
Lee A. Hart | Ring the bells that still can ring
814 8th Ave N | Forget the perfect offering
Sartell MN 56377 | There is a crack in everything
leeahart earthlink.net | That's how the light gets in -- Leonard Cohen

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Re: Charging Lithium - why laptop batteries last 1 year

shred
Yes and like Jukka I am plugged in most of the time I'm using it.
When I'm on the road I maybe draw it down 20% DOD on average.
I have an inverter in my car too so if the kids are going to watch a whole movie I'll plug in.
My cell phone on average gets charged once per day and is down about 40% dod at that point.
Neal
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Testing prototype motor.

R. C. Carroll
A major motor manufacturer has asked us to test a new prototype motor - we'll let the list know the results....

>From what we have noticed so far:
1/2 inch terminal connections
split brushes
increased pressure springs
recessed mounts
thermistor
increased cooling fan
increased mounting/lifting points
New end bell with refined mounting holes.

I took some fairly detailed pictures and posted them at:
http://a1.to   Sorry there is no slideshow (yet) but you can download for view on line.

Rich Carroll
Pioneer Conversions


     

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