>> Or rather, that's what the books I've read claim, anyway...
> 
> I bet they are "for teh n00bz" -level books :).

Well, it does say "ages 5 and above"...

>> Yeah. That's because there's a limit to how much current the battery can
>> supply.
> 
> And that's because of the internal resistance. If there were no such
> thing, what would limit the current?

I'm sure there's a logic there somewhere - it just doesn't make any 
sense to *me*. ;-)

>> Indeed, I'm told the only reason cars use lead acid batteries (which are
>> very heavy yet don't actually hold that much charge) is so that they can
>> briefly deliver the astronomical current required to turn the starter
>> motor. 
> 
> Actually cars use lead acid batteries because they still are just the
> best way to deliver that current reliably. NiCD -batteries can't stand
> uneven charging, NiMH -batteries can't deliver enough current IIRC,
> Litium batteries (both LiPo and Li-ion) can't stand water-freezing
> temperatures. It all actually makes sense :).

...as I said, you need the wattage to turn the starter motor. ;-) If you 
only needed electricity for the sparks and lights and stuff, you 
wouldn't need nearly as much power. (Freezing would still be an issue 
tho...)

>> From the sources I've read, if it weren't for that, you'd only
>> need a battery a fraction of the size to run the spark plugs, headlights
>> and other electrical bits.
> 
> Actually you wouldn't need a battery to run those things, you'd just
> need a battery/capacitor to regulate the current coming from the alternator.

Not if you expect the headlights to work while the engine isn't running. ;-)

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