On Thu, Jun 26, 2008 at 09:31:36AM -0400, Tom?s ? h?ilidhe wrote:
> 
> 
> Jinx wrote:
> > Batteries in series add voltage, batteries in parallel add capacity
> 
> OK so let's say a particular AA battery is 500 mAh. Because it's 1.5 V,
> that means it's 750 mWh, which is 208 mJ.

Yes.

> 
> If I have two of these batteries, then surely I have twice the energy?
> i.e. 1500 mWh   or   416 mJ.

Yes.

> 
> And let's say I put two of these in series to form a 3 V battery. Will I
> have a 3 V battery with 1500 mWh?

No. You'd have a 3V battery with 500 mAh 1500 mWh/3V = 500 mAh.

> It seems to me that regardless of whether I put two batteries in series
> or in parallel, the energy will always be the sum of the two batteries'
> energies. Therefore:

Yes. Remember rule #1.

> Two AA batteries in series:  3 V  and  1500 mWh

Yes. But if you're going to use volts then your other measure should be
amp-hrs since the mWh is the product of volts and amp-hrs.

So 

3V and 500 mAh

> 
> Two AA batteries in parallel:  1.5 V and 1500 mWh

And 1.5V and 1000 mAh.

Both give a total capacity of 1500 mWh.

> That right?

Yes.

BAJ
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