Wrong Gateway Laptop battery?

I have two original 6MSB Gateway laptop batteries rated at 11.1V 4800mAh.
Although I purchased another on online that is compatible with my laptops,
but it turns out to be a 8MSBG and rated at 14.4V 4800mAh.

Well I plugged it in and it charged okay. I also ran my laptop on battery
and that worked too. Oddly enough, Windows and BattStat claimed that I will
have 4 hours of runtime on that battery. I couldn't believe it. I think the
best I got from my other batteries was like 3 hours. So I ran this one on
battery and I got 3:42 out of it before it hit 3%.

Unbelievable! And why the difference in voltage between the sets of
batteries? Why the longer life? Higher voltage?

BattStat 0.98 reports:

6MSB wear level 36% and I get about 1:42 (two years old)
6MSB wear level 16% and I get about 2:42 (two years old)
8MSBG wear level 10% and I get about 3:42

Btw, 10% wear level is about what I get with a fresh battery. I suppose if
you get one right out of the factory, you might do better. All of the
batteries look the same size, but the 8MSBG feels a little heavier.

--
Bill
Gateway Celeron M 370 (1.5GHZ)
MX6124 (laptop) w/2GB
Windows XP Home SP2 (120GB HD)
Intel(r) 910GML (64MB shared)

"BillW50" <> writes:

>I have two original 6MSB Gateway laptop batteries rated at 11.1V 4800mAh.
>Although I purchased another on online that is compatible with my laptops,
>but it turns out to be a 8MSBG and rated at 14.4V 4800mAh.

The old battery used 3 cells in series (3.7 V each) to get its voltage;
the new one uses 4 cells instead to give the higher voltage. In fact,
it's likely that both batteries use pairs of cells connected in
parallel, with the pairs connected in series, for a total of 6 cells in
the old and 8 cells in the new (thus the first digit of the battery ID
is the number of cells).

Since the new batteries have the same mAh rating, and power is volts
times amp-hours, the new battery stores about 4/3 as much energy as the
older ones. How? It's possible that the older batteries had some empty
space, and the new one fills it with extra cells. Or perhaps the new
battery has denser cells, that store the same amount of energy in a
smaller package, so now there's room for 8 instead of 6 in the same
case.

>Well I plugged it in and it charged okay. I also ran my laptop on battery
>and that worked too. Oddly enough, Windows and BattStat claimed that I will
>have 4 hours of runtime on that battery. I couldn't believe it. I think the
>best I got from my other batteries was like 3 hours. So I ran this one on
>battery and I got 3:42 out of it before it hit 3%.

>Unbelievable! And why the difference in voltage between the sets of
>batteries? Why the longer life? Higher voltage?

All explained by having 8 cells instead of 6, and 4/3 as much energy
stored in the same size package.

Dave

Barry Watzman <> writes:
>Re: "power is volts times amp-hours"

>No, power (watts) is volts times amps. Not amp-hours. Amps and
>amp-hours (or mah, milliamp hours) are not the same thing.

If you want to use engineering terms, I was comparing energy, not power.
Volts times amp-hours gives you total stored energy. But I was writing
informally, and I didn't expect the distinction between power and energy
to mean anything to the person who asked the question.

>Re: "all explained by having 8 cells instead of 6, and 4/3 as much
>energy stored in the same size package"

>While that is basically correct, who said that the two batteries WERE
>the same size? Sometimes, the larger capacity batteries actually are
>physically larger.

The original poster wouldn't be surprised about the longer runtime
if the new battery was physically larger, would he? The fact that he
was surprised suggests that the new battery was the same size.

Dave

"Barry Watzman" <> wrote in message
news:1325d$4884a14d$...
> Likely the first digit is the number of cells; so the two you had were 6
> cell, and the new one is 8 cell.

That makes sense as 14.4 volts is consistent with the voltage from 4 series
connected Li-ion cells (in this case 8 cells in series parallel). 11.1
volts is consistent with 3 Li-ion-polymer cells in series (in this case 6
cells in series parallel). Unles there is evidence that the laptop is
compatible with the higher voltage battery, I would be reluctant to continue
using it. It may run OK for a while but

> The relationship between run time and the ratio of power requirement of
> the laptop to battery capacity is not linear. If you double the capacity
> of the battery, the run time goes up by a lot more than two. The capacity
> of rechargeable batteries is normally calculated using a discharge rate
> that takes 20 hours to discharge the battery (e.g. for a 1,000 mah
> battery, a 50ma (.05 amp) discharge rate should produce a 20-hour life.
> But a 250 ma discharge rate might result in a life of only an hour or
> less, not 4 hours.
>

Unlike lead-acid batteries, lithium-ion batteries do suffer a reduction in
capacity as the discharge current increases. This is generally true up to
and boyond the maximum discharge current of individual cells (which isn't
particularly high).
>

"Barry Watzman" <> wrote in message
news:e5b0c$48868c5a$...
> Re: "power is volts times amp-hours"
>
> No, power (watts) is volts times amps. Not amp-hours. Amps and amp-hours
> (or mah, milliamp hours) are not the same thing.
>

Of course, he really meant 'Energy' which is volts times Ampere-hours.

> Re: "all explained by having 8 cells instead of 6, and 4/3 as much energy
> stored in the same size package"
>
> While that is basically correct, who said that the two batteries WERE the
> same size? Sometimes, the larger capacity batteries actually are
> physically larger.
>

However, improvements in cell technology can negate that somewhat.

>
> Dave Martindale wrote:
>> "BillW50" <> writes:
>>
>>> I have two original 6MSB Gateway laptop batteries rated at 11.1V
>>> 4800mAh.
>>> Although I purchased another on online that is compatible with my
>>> laptops,
>>> but it turns out to be a 8MSBG and rated at 14.4V 4800mAh.
>>
>> The old battery used 3 cells in series (3.7 V each) to get its voltage;
>> the new one uses 4 cells instead to give the higher voltage. In fact,
>> it's likely that both batteries use pairs of cells connected in
>> parallel, with the pairs connected in series, for a total of 6 cells in
>> the old and 8 cells in the new (thus the first digit of the battery ID
>> is the number of cells).
>>
>> Since the new batteries have the same mAh rating, and power is volts
>> times amp-hours, the new battery stores about 4/3 as much energy as the
>> older ones. How? It's possible that the older batteries had some empty
>> space, and the new one fills it with extra cells. Or perhaps the new
>> battery has denser cells, that store the same amount of energy in a
>> smaller package, so now there's room for 8 instead of 6 in the same
>> case.
>>
>>> Well I plugged it in and it charged okay. I also ran my laptop on
>>> battery
>>> and that worked too. Oddly enough, Windows and BattStat claimed that I
>>> will
>>> have 4 hours of runtime on that battery. I couldn't believe it. I think
>>> the
>>> best I got from my other batteries was like 3 hours. So I ran this one
>>> on
>>> battery and I got 3:42 out of it before it hit 3%.
>>
>>> Unbelievable! And why the difference in voltage between the sets of
>>> batteries? Why the longer life? Higher voltage?
>>
>> All explained by having 8 cells instead of 6, and 4/3 as much energy
>> stored in the same size package.
>>
>> Dave
> ** Posted from http://www.teranews.com **

"M.I.5¾" <_SPAM.co.uk> wrote in message
news:488ecb79$...
>
> "Barry Watzman" <> wrote in message
> news:1325d$4884a14d$...
>> Likely the first digit is the number of cells; so the two you had were 6
>> cell, and the new one is 8 cell.
>
> That makes sense as 14.4 volts is consistent with the voltage from 4
> series connected Li-ion cells (in this case 8 cells in series parallel).
> 11.1 volts is consistent with 3 Li-ion-polymer cells in series (in this
> case 6 cells in series parallel). Unles there is evidence that the laptop
> is compatible with the higher voltage battery, I would be reluctant to
> continue using it. It may run OK for a while but
>
>> The relationship between run time and the ratio of power requirement of
>> the laptop to battery capacity is not linear. If you double the capacity
>> of the battery, the run time goes up by a lot more than two. The
>> capacity of rechargeable batteries is normally calculated using a
>> discharge rate that takes 20 hours to discharge the battery (e.g. for a
>> 1,000 mah battery, a 50ma (.05 amp) discharge rate should produce a
>> 20-hour life. But a 250 ma discharge rate might result in a life of only
>> an hour or less, not 4 hours.
>>
>
> Unlike lead-acid batteries, lithium-ion batteries do suffer a reduction in
> capacity as the discharge current increases. This is generally true up to
> and boyond the maximum discharge current of individual cells (which isn't
> particularly high).
>>

Correction: that should have read lithium-ion batteries do *not* suffer a
reduction in capacity as the discharge current increases