[ltp] Battery croaked

[Micha]

On Wed, 21 May 2008 12:55:20 +0600
"Dmitry E. Mikhailov" <sexandvodka@gmail.com> wrote:

> > Do you have any idea about the differences between *original* and
> > *second-choice* batteries (as I see in ebay) ? I never test
> > second-choice battery.
> First of all, new original battery should look exactly like your current 
> original battery. No scratches on the plastic. No badly glued labels. But 
> counterfeit batteries are like counterfeit money. Sometimes it's hard to say 
> if it's a fake. You can try to distinguish it by price. Usually an original 
> laptop battery costs about $100 or more. If they sell it for $30, don't 
> expect it to be that good.
> 
> 
> > How many time a battery can be warranted :
> > I establish more than 2 years for an original battery ?
> The Li-ion battery generally loses 50% every two years. But if you own a 
> thinkpad, you can deal with it. Li-ion batteries don't like to be fully 
> discharged and to be fully charged. Under these circumstances they degrade 
> faster. On thinkpads an embedded controller can control the charge, not just 
> simply push the battery to it's 100%. I have a two-year-old X41 and I got 
> that:
> 

They also don't like too much heat, which is the only way to avoid is to remove
the battery when connected to the mains. I heard some people advocate that but
it's too much of a hustle for me.


> root@ibm scriptlets.d]# cd /sys/devices/platform/smapi/BAT0
> [root@ibm BAT0]# cat last_full_capacity
> 24020
> [root@ibm BAT0]# cat design_capacity
> 27360
> 
> I lost 12% of the capacity in two years. That's because of:
> 
> [root@ibm BAT0]# cat start_charge_thresh
> 40
> [root@ibm BAT0]# cat stop_charge_thresh
> 70
> 
> So the battery is being charged only if it's at 40% or less, and the charge 
> stops at 70%. 
> 
> > But I ignore the age a second-choice battery can last.
> Less than original. Much less. As for (my) cell phones, el-cheapo batteries 
> die in about 6-8 months. Too bad, but I don't have any way to get an original 
> one.
> 

there is some luck involved here also. A couple of years ago I bought a new
battery over ebay for my previous laptop (a sony erricson at the time - don't
touch them even if your life depends on it, the customer service would be
better if it didn't exist at all).

Anyway, that laptop is still with my sister, the battery had more capacity then
the original (also according to acpi) and also lasted more than the original
which backs that claim. Could be that they just sent be a good one by mistake
though ;-)

> > These second choice battery are sold with a right capacity.
> > Is it the real capacity or not ? What is this capacity 6 month after ?
> Can't say much for laptop batteries, but AFAIK it's just the same stuff as 
> cellphone batteries. So:
> The original battery for my SonyEricsson P900 smartphone is 1260mAH
> The spares were rated the same. But after they die, I remove the plastic 
> shielding to get to the cell itself. Then google for the code printed on a 
> cell. I got 3 batteries. They are 850mAH, 900mAH and an unidentified one. So 
> they are initially worse than an original battery. The production quality 
> make them degrade faster so the capacity drops further. As I can say, you get 
> the half of the rated non-original battery capaticy. I wish I could by an 
> original, but can't find one.
> 

There are two issues that can arise with replacement batteries.
1. Fake capacity
2. Old batteries/cells (they sat on a shelf for too long and degraded)

The three things you can do to guess at the quality, is
1. Check the price (if it's too low it's probably a fake)
2. Check the reviews, laptops unlike cell phones and cameras have a shorter
running time so it's easier to see if the batteries are up to spec and at least
under linux you can see the reported capacity.
3. Check the reported spec. Batteries have a maximum spec per volume. Original
manufacturers, selling the batteries for such a price, don't have a reason to
squeeze in less juice than possible (battery life time is one of the things
laptops are rated on), so they probably push the capacity at least almost to
the limit. If the stated spec of the ebay battery is higher than the original
battery (~5% may still be ok), then it's probably a fake capacity.

The only way to really know what they sold you is to take apart the battery and
check the numbers on the cells for the real spec, but then the battery is
useless ...

> And yes, most of the batteries (even genuine one) are made in asia but there 
> are so much differences between Japan and China :-)