> On Wed, 23 Nov 2005, Mike Hunter wrote:
>> Hydrides use higher voltage to produce the proper amperage to do the
>> To do so with LA batteries you would need a truck load. All common
>> flashlight batteries produce 1 1/2 volts but the larger sizes produce
>> amps. Ask Mr. Ohms ;)
> I think Mr. Ohms did not give you a complete reply when you asked him.
> Different battery technologies have different voltages per CELL. A
> normal flashlight battery is a single cell that produces 1.5v. NiCd
> battery cells produce a little under 1.5v. Lead acid battery cells
> produce 2v per cell -- a normal 12v battery has 6 cells in series.
> There are 2 other factors that are key to battery usage:
> 1. Internal resistance. This really determines how large a current the
> battery can deliver.
> 2. Capacity: how long can the battery deliver the necessary current?
> Now, to replace a battery with one of a different type, one would have
> to match the voltage and the internal resistance (otherwise it would not
> produce the necessary power) of the original. To build a small 48v LA
> battery is not hard -- it just requires 24 cells, each of which could be
> quite small. The overall size need not be bigger than a standard 12v
> The next question becomes the capacity -- or really, the energy storage
> density. How much energy can you store in a given weight or size?
> Finally, as was mentioned earlier, charging would likely be a problem
> when replacing one type of battery with another: a charging profile that
> works well for one battery technology may kill another quite quickly.
> So, it's not just about what Mr. Ohm says, but also what Mr. Capacity
> says and Mr. charging profile.
> So, the question should be: Will they also design a trailer to carry all
> the LA batteries need to store enough energy?
Exactly. I didn't realize they used a nominal 48V. So to modify what I
said in my previous, you could get the 48 volts still with a pocketful
(6) of 9-volt transistor radio batteries. Like you said - you have to
have the energy/power. That's why I said that voltage is only half the
Since we're being picky, as with all units named after a person, the
convention is to capitalize the 'V' when *abbreviating* "volts", and to
*not* capitalize it when writing it out. For example, you would write
"48 volt battery", or "48V battery". :)
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')