Battery replacement for Latitude C600

Archived from groups: comp.sys.laptops (More info?)

Jonas Hei wrote:
> The battery (P/N 75UYF) on my Dell Latitude C600 appears to be dead.
>
> I have an old battery (from another dell) which is P/N 3149C - it
> appears to be fine - at least the LEDS on the batter do indicate some
> charging.
>
> The text on back of 75UYF says that it is replaceable by 3149C (and
> others like 1691P, 5081P, 53977).
> However, I still need confirmation because 75UYF and 3149C do seem to
> differ in the following respects (physically they are the same size):
>
> Rating: (for 75UYF) 14.8V 3800mAh, and 14.4V and 3000mAh (for 3149C)
> Charging Current: (for 75UYF) 3.5A, and 3A (for 3149C)
>
> Do these differences mean that I shoudn't be replacing 75UYF with 3149C?
>
> Any ideas, clarifications, and tips are wellcome.
>
> Thanks.

You need to measure the charging current. IF it doesn't exceed 3A, you
should be ok. Most people go from a smaller battery to a bigger one,
so this isn't an issue.

But you got me to thinking...and we all know how dangerous that is...
14.8V is a number typically associated with a lithium-Ion battery.
14.4V is a number typically associated with NiCd or NiMH batteries.
My 1691 and 75yuf are both LiIon 14.8V
Are you sure the 3149 is a lithium? If not, you'd need to worry about
compatibility with different chemistries. Dell wouldn't let you plug
the wrong one in...would they??? Hmmmm. Older laptops made during the
NiMH/LiIon transition accepted both. Of course, I could google that
info, but that's your job. ;-) You'd think the compatibility info on
battery vendor sites would be reliable???
I've found that NOT to be the case with memory vendors.
mike


--
Return address is VALID.
Bunch of stuff For Sale and Wanted at the link below.
Toshiba & Compaq LiIon Batteries, Test Equipment
Yaesu FTV901R Transverter, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

Archived from groups: comp.sys.laptops (More info?)

Jonas Hei wrote:
> On Thu, 03 Jun 2004 02:18:48 -0700, mike <spamme0@juno.com> wrote:
>
>> Jonas Hei wrote:
>>
>>> The battery (P/N 75UYF) on my Dell Latitude C600 appears to be dead.
>>> I have an old battery (from another dell) which is P/N 3149C - it
>>> appears to be fine - at least the LEDS on the batter do indicate
>>> some charging.
>>> The text on back of 75UYF says that it is replaceable by 3149C (and
>>> others like 1691P, 5081P, 53977).
>>> However, I still need confirmation because 75UYF and 3149C do seem
>>> to differ in the following respects (physically they are the same
>>> size):
>>> Rating: (for 75UYF) 14.8V 3800mAh, and 14.4V and 3000mAh (for 3149C)
>>> Charging Current: (for 75UYF) 3.5A, and 3A (for 3149C)
>>> Do these differences mean that I shoudn't be replacing 75UYF with
>>> 3149C?
>>> Any ideas, clarifications, and tips are wellcome.
>>> Thanks.
>>
>>
>> You need to measure the charging current. IF it doesn't exceed 3A,
>> you should be ok. Most people go from a smaller battery to a bigger
>> one,
>> so this isn't an issue.
>
>
> May be my questions are too daft - I apologize.
> But how can I measure the charging current?
>
> As I understand it (please correct me if I am wrong), the charging
> circuitry in my Dell C600 can charge a battery by providing 3.5A
> (because the 75UYF, that it came with, is rated at 3.5A).
> Now if I replace 75UYF with a 3149C (Charging current: 3A) then for
> charging, the 3149C will draw only 3A from the charger in the laptop -
> and I think that is ok. Am I correct?

The correct answer is...it depends on stuff we can't know about.
It's possible/typical that there's a current limit in the charger
that limits how much MAXIMUM current the battery can get. It's
possible/likely that a fully discharged battery will take ALL that
the laptop will let it have. So, there is a risk of overheating the
lower capacity battery. A little heat is bad. A lot of heat in a
lithium can be
catastrophic. There is considerable controversy over how much is too
much. I lean toward the conservative/paranoid side.

>
>>
>> But you got me to thinking...and we all know how dangerous that is...
>> 14.8V is a number typically associated with a lithium-Ion battery.
>> 14.4V is a number typically associated with NiCd or NiMH batteries.
>> My 1691 and 75yuf are both LiIon 14.8V
>> Are you sure the 3149 is a lithium? If not, you'd need to worry about
>> compatibility with different chemistries. Dell wouldn't let you plug
>> the wrong one in...would they??? Hmmmm. Older laptops made during the
>> NiMH/LiIon transition accepted both.
>
>
> The text on battery's back says it is Li-ion.
>
> Of course, I could google that
>
>> info, but that's your job. ;-) You'd think the compatibility info on
>> battery vendor sites would be reliable???
>> I've found that NOT to be the case with memory vendors.
>> mike
>
>
> I did a search on Google - plenty of hits - they all seem to indicate
> that one can replace a 3149C with 75UYF.
> Nobody really says that a 75UYF can be replaced by a 3149C. But may be
> I am being too paranoid. It probably should be replaceable. As you
> said earlier, normally people go from smaller battery to bigger.
> Unfortunately I am being forced to move from a bigger (3800mAh) to a
> smaller on (3000mAh)...
>
> What do you suggest? Should it give 3149C a try?

I just thought of another disturbing possibility.
It's hard to know what they were thinking when they printed 14.4V on the
battery, but here's a possibiltiy. Your battery has 4 cells. Current
technology cells can be charged to an absolute maximum of 4.2V.
So a fully charged battery is actually 16.8V. Previous generation
chemistry could be charged to an absolute maximum of 4.1V. And YES,
that 0.1V can be the difference between a fully charged pack and a
fire. So, .1V x 4 cells = 0.4V, which just happens to be the difference
between 14.4 and 14.8V. So, it would be safe to put a 14.8V battery in
a 14.4V laptop, but NOT SAFE to put the 14.4V into a 14.8V laptop.

We have no actual facts to guide us, but there are enough disturbing
clues that I'd be afraid to use the battery in your new computer.

If you asked 20 people on the web, you'd probably get 20 answers that
it's safe from 20 people who don't have a clue. If you asked
Dell or the battery manufacturer, they'd probably be conservative and
say something like, "use only the battery type supplied with your unit."
They have lawyers; random web inputs don't. Even if you found someone
at tell who really knew what was going on, they'd probably be safe
and not tell you anything you could use to make the decision.

You probably don't know what Lithium battery leakage smells like. It's
hard to describe. Kinda sweet, yet pungent at the same time. Has some
of the smell characteristics of perfume. If you find that smell around
your laptop, you know you've gone too far and it's too late to save the
battery. If it catches fire, you'll know cause there'll be a hole in
the table where your laptop used to be.


mike




--
Return address is VALID.
Bunch of stuff For Sale and Wanted at the link below.
Toshiba & Compaq LiIon Batteries, Test Equipment
Yaesu FTV901R Transverter, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/