Hi - forgive me I'm a mechnical guy with limited electrical knowledge.: )

I noticed cell phone batteries have small circuit boards at the end of the
pack. What is the purpose of the board?

I am being tasked with a project using arrays of larger lithium cells - I
think there are 12 per pack. Each array comes with a circuit board at the
end as well. I noticed on the circuit board there looks to be a small
buzzer or something? Am I correct in seeing that?

If I wish to disassemble the packs to make larger arrays - could I have a
circuit board built to handle the larger array? Or is it more advantageous
to have a bunch of smaller arrays/packs than one large one?

Lastly, are battery packs assembled in series or parrallel and what is the
thining behind one over the other?

Any help appreciated -

"Tank 'm o'Niel" <tanky@tanktank.com> wrote in message
news:479c9ee1$0$30022$4c368faf@roadrunner.com...
> Hi - forgive me I'm a mechnical guy with limited electrical knowledge.: )
>
> I noticed cell phone batteries have small circuit boards at the end of the
> pack. What is the purpose of the board?
>
> I am being tasked with a project using arrays of larger lithium cells - I
> think there are 12 per pack. Each array comes with a circuit board at the
> end as well. I noticed on the circuit board there looks to be a small
> buzzer or something? Am I correct in seeing that?
>
> If I wish to disassemble the packs to make larger arrays - could I have a
> circuit board built to handle the larger array? Or is it more
> advantageous to have a bunch of smaller arrays/packs than one large one?
>
> Lastly, are battery packs assembled in series or parrallel and what is the
> thining behind one over the other?
>
> Any help appreciated -
>
Li-Ion packs have a charge regulator / protection circuit built in.
If you don't know about this cell chemistry I suggest that you educate
yourself before messing with them.

Tom

On Sun, 27 Jan 2008 10:10:13 -0500 in sci.electronics.basics, "Tank
'm o'Niel" <tanky@tanktank.com> wrote,
>I noticed cell phone batteries have small circuit boards at the end of the
>pack. What is the purpose of the board?

Charging of lithium batteries must be very precisely controlled, or
they can turn into huge fireballs. Check out news stories on
flaming Sony laptops, etc.

On Sun, 27 Jan 2008 10:10:13 -0500, "Tank 'm o'Niel"
<tanky@tanktank.com> wrote:

>Hi - forgive me I'm a mechnical guy with limited electrical knowledge.: )
>
>I noticed cell phone batteries have small circuit boards at the end of the
>pack. What is the purpose of the board?
>
>I am being tasked with a project using arrays of larger lithium cells - I
>think there are 12 per pack. Each array comes with a circuit board at the
>end as well. I noticed on the circuit board there looks to be a small
>buzzer or something? Am I correct in seeing that?

I understand that lithium batteries can be extremely hazardous if
mistreated. That PC board is probably a charge controller/battery
monitor to prevent mistreatment.
>
>If I wish to disassemble the packs to make larger arrays - could I have a
>circuit board built to handle the larger array? Or is it more advantageous
>to have a bunch of smaller arrays/packs than one large one?
>
>Lastly, are battery packs assembled in series or parrallel and what is the
>thining behind one over the other?

I respectfully suggest that if you have to ask this question, you
should not be considering re-configuring lithium battery packs.

Connecting batteries (or battery packs) in series increases the
available voltage, while connecting them in parallel increases
capacity, but leaves the voltage the same as for a single battery.

>
>Any help appreciated -
>

--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

"Tank 'm o'Niel" <tanky@tanktank.com> wrote in message
news:479c9ee1$0$30022$4c368faf@roadrunner.com...
> Hi - forgive me I'm a mechnical guy with limited electrical knowledge.: )
>
> I noticed cell phone batteries have small circuit boards at the end of the
> pack. What is the purpose of the board?
>
> I am being tasked with a project using arrays of larger lithium cells - I
> think there are 12 per pack. Each array comes with a circuit board at the
> end as well. I noticed on the circuit board there looks to be a small
> buzzer or something? Am I correct in seeing that?
>
> If I wish to disassemble the packs to make larger arrays - could I have a
> circuit board built to handle the larger array? Or is it more
> advantageous to have a bunch of smaller arrays/packs than one large one?
>
> Lastly, are battery packs assembled in series or parrallel and what is the
> thining behind one over the other?
>
> Any help appreciated -
>

Lithium fires are pretty impressive and surprisingly easy to start by
overcharging cells.

PS - Don't ever throw water on a lithium fire!!!