Gateway SA1 Laptop Battery lasts only 20 minutes....

[Paul678]

...it appears to re-charge very quickly, and discharge very quick too.

Windows 7 shows it at 100%, and then after about 15 minutes, it will suddenly show it's at 7%, and will hibernate automatically, unless i use
another power source. When it's at either 7 or 100%, it will estimate
a ridiculous amount of time remaining, like 59 hours!

I tried the old freezer trick for 24 hours.....it didn't appear to work.

This battery is dead, right?

*sigh*

[mockingbird]

Re: Gateway SA1 Laptop Battery lasts only 20 minutes....

If it's the one that came with the laptop, it's got to be at least 5 years old by now.

[Paul678]

Re: Gateway SA1 Laptop Battery lasts only 20 minutes....

If it's the one that came with the laptop, it's got to be at least 5 years old by now.

What is the average usable lifespan of a lithium-ion laptop battery?

[fddizon]

Re: Gateway SA1 Laptop Battery lasts only 20 minutes....

and that means he needs a replacement????

[Pentium4]

Re: Gateway SA1 Laptop Battery lasts only 20 minutes....

I guess it depends on the manufacturer of the battery but I would say if you're going to use it every day then 3 years tops. And I've noticed they last longer the more you actually use the laptop on battery power, having it plugged in all the time is not good for it

[mockingbird]

Re: Gateway SA1 Laptop Battery lasts only 20 minutes....

What is the average usable lifespan of a lithium-ion laptop battery?

Depends on the quality of the cells. I've seen some batteries last for 3+ years, and some that lasted for less than a year.

[Th3_uN1Qu3]

Re: Gateway SA1 Laptop Battery lasts only 20 minutes....

That's a classic symptom of a bad pair of cells. Usually a single pair gets weaker, dragging down the whole battery. That's why the sudden loss of reported capacity remaining, the bad group discharges much faster and quickly drops below the protection threshold. This is because there is no charge balancing between the individual cells or groups of cells, they are both charged and discharged in series.

So yes, the battery is shot. Remember the #1 enemy of batteries is heat, a close second being float charge (being kept at 100% all the time). If you use your computer for extended periods of time on mains power, take the battery out.

[Paul678]

Re: Gateway SA1 Laptop Battery lasts only 20 minutes....

Thanks for the feedback.

This laptop was made 2008, so the batteries are probably
around 4 years old, so based on what you have all said,
it should be over the hill if 3 years is about the limit.

I'm aware of the dangers of handling bare Lithium-ion cells (fire hazard), but has anyone here tried to re-build or replace the bad cells
in a dead battery?

This site says it's difficult to do:

http://batteryuniversity.com/learn/a...laptop_battery

And this site makes it seem easier:

http://www.engadget.com/2005/06/28/h...aptop-battery/


I'll go with Murphy's law: it's probably not easy.....the cells don't look
like they are easy to obtain, and I read manufacturers usually only sell them to certified battery builders due to the dangers of Lithium-ion.

[Th3_uN1Qu3]

Re: Gateway SA1 Laptop Battery lasts only 20 minutes....

The cells are easy to get on ebay, they go for about $20-$25 for 6pcs, which is what your average laptop battery is made of. You want to get the ones with tabs pre-welded onto them, because if you solder to the cells you lose 25-30% capacity right off the bat. They don't like heat.

The tricky bit is that the batteries have a "gas gauge" IC with EEPROM built-in, which records the number of charges and the capacity. Unless you rewrite that, the battery is still going to think it's well used, and not last long. You need specialized software to rewrite that EEPROM (at least without some painstakingly long reverse engineering), and it goes for around $180. Not practical unless you intend to make this a business. I'd just buy a replacement battery and be done with it.

Where are you from? If you're in the US, i recommend lunatech-laptop-batteries on ebay. The replacement battery for my iBook G4 arrived yesterday from them, and it's working great. Didn't cost an arm and a leg either.

[Paul678]

Re: Gateway SA1 Laptop Battery lasts only 20 minutes....

The cells are easy to get on ebay, they go for about $20-$25 for 6pcs, which is what your average laptop battery is made of. You want to get the ones with tabs pre-welded onto them, because if you solder to the cells you lose 25-30% capacity right off the bat. They don't like heat.

The tricky bit is that the batteries have a "gas gauge" IC with EEPROM built-in, which records the number of charges and the capacity. Unless you rewrite that, the battery is still going to think it's well used, and not last long. You need specialized software to rewrite that EEPROM (at least without some painstakingly long reverse engineering), and it goes for around $180. Not practical unless you intend to make this a business. I'd just buy a replacement battery and be done with it.

Where are you from? If you're in the US, i recommend lunatech-laptop-batteries on ebay. The replacement battery for my iBook G4 arrived yesterday from them, and it's working great. Didn't cost an arm and a leg either.

If it's $20-25 for a new set of cells, I might as well buy a new
battery on Ebay....I saw one for $23.

But I'm sure you have to replace all of them, and not just one.

Yeah, I once designed a charging circuit which utilized a "gas gauge"
chip. It was actually a type of coulomb counter.

How much did your battery cost?

[Th3_uN1Qu3]

Re: Gateway SA1 Laptop Battery lasts only 20 minutes....

$16.95, plus an additional $6.95 for postage to Romania. Quite cheap i must say, but the iBook G4 is also a pretty old laptop, so it's likely that sellers just want to unload their stock.

Cell prices can be lower than $20 for 6pcs, but if you get the ones with the pre-welded tabs, that's about where they range, for the name-branded products at least. There are no-name cells for cheaper, but it's a crap shoot with those.

[tom66]

Re: Gateway SA1 Laptop Battery lasts only 20 minutes....

There's no such thing as a float charge for a lipo. Having a laptop at 100% is really very good for the battery; once it's charged, it's never touched. The laptop will usually run off the AC adapter. I'll bet one cell or two pair cell is failed. I tore down a HP battery with similar symptoms (runs down to 75% then laptop dies); one cell group measured ~0.2V, the others all measured healthy 3.9V or so, barely discharged. Laptop probably hits the under-voltage protection with the failed cell.

[Th3_uN1Qu3]

Re: Gateway SA1 Laptop Battery lasts only 20 minutes....

There's no such thing as a float charge for a lipo. Having a laptop at 100% is really very good for the battery; once it's charged, it's never touched.

Then why do so many people find their batteries dead after an year or two, on their office laptops which have spent all their time plugged in?

You forgot that once the battery is charged and then disconnected, it will start losing charge, then the charging circuit decides it needs to start charging again. This is a bit different from lead-acid float charge, which is connected all the time, but it has a similar effect. Also, a lot of laptops run really hot, especially since when plugged in they are set to maximum performance, and there's also the heat from the battery charging process that adds to that, so the battery has more than "float charge" to worry about. My HP DV5 (back when the battery did work), only charged when it was shut down or in sleep mode, because it gets so hot it's dangerous to charge the battery when it's running.

It is recommended to store a Lithium battery at 30-50% charge.

[Paul678]

Re: Gateway SA1 Laptop Battery lasts only 20 minutes....

Then why do so many people find their batteries dead after an year or two, on their office laptops which have spent all their time plugged in?

You forgot that once the battery is charged and then disconnected, it will start losing charge, then the charging circuit decides it needs to start charging again. This is a bit different from lead-acid float charge, which is connected all the time, but it has a similar effect. Also, a lot of laptops run really hot, especially since when plugged in they are set to maximum performance, and there's also the heat from the battery charging process that adds to that, so the battery has more than "float charge" to worry about. My HP DV5 (back when the battery did work), only charged when it was shut down or in sleep mode, because it gets so hot it's dangerous to charge the battery when it's running.

It is recommended to store a Lithium battery at 30-50% charge.

I expect it would be best to take the battery out of the
laptop if stored for a long period of time, because the
"Always On" circuits in the laptop will add to the self-discharge.