On Tue, Oct 22, 2013 at 04:41:09PM +0000, Lindy Mayfield wrote: > Yes, that's exactly what I was asking. My "future" battery is the same s= ize, just the chemical reaction inside is a bit more efficient.=20 >=20 > So, it would work just fine. It'd be dangerous has heck without extra pr= otection, but would work. =20 Not exactly. Because the voltage is so low, you'd have to deliver a lot more current in order to deliver the same power. So you'd have to change all the house wiring to accomodate the change in voltage. Consider a typical 240V x 12A circuit. The available power is 2880 VA. According to this ampacity chart: http://www.cerrowire.com/ampacity-charts 14 or 12 gauge copper wire will carry the current with no problem. But if you switched to 9 V then the current becomes 2880 VA / 9V =3D 320A. Take a look at some 4/0 gauge wire here: http://www.ipscustom.com/wr/4_0_19_strand_copper_wire.html It's nearly a 1/2 inch across. It can only carry up to 260 A of current and that's allowing the wire to heat to 90 degrees C. You'd need that type of wire for every outlet and every device you connected to. There's a reason that cross country power lines are 25 kV. It keeps the current reasonable, and the wires not too thick while delivering a lot of power in the process. BAJ >=20 > And this brings me to a better understanding: Current is used only when = needed. And according to Ohm's law I can vary the voltage at the expense o= f current. >=20 > And I'll take a stab at answering my next question. Given that my batter= can supply so much energy, would it matter what voltage it is? If it were= 1 volt and I needed 9 for my alarm clock, I could step it up to 9. If it = were 1000 volts then I could step it down. Would it matter?` >=20 > Actually, I don't know. >=20 > -----Original Message----- > From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf = Of Justin Richards > Sent: Tuesday, October 22, 2013 4:44 PM > To: Microcontroller discussion list - Public. > Subject: Re: [OT] Thought experiment: Understanding volts vs amps >=20 > Not sure exactly what you are asking so I will say some stuff. >=20 > If you are asking if a hypothetical 9V battery that was capable of poweri= ng a house could also be used to power a 9v device like a small 9V radio or= 9V remote control then the answer is yes. You would not be able to fit su= ch a battery inside the 9V radio or 9V remote but you could run wires to th= is hypothetical battery. >=20 > Also if you were to run a house off a hypothetical 9V battery the cables = would need to be much heavier (thicker) as the current would be quite high. > As the current increase the cable size needs to increase. Additionally = to run a house off this battery it would need to be connected to an inverte= r to convert the 9V DC to AC and what ever level of voltage you area uses. > For me it is 240 V. >=20 > With regards to Volts and Amps. >=20 > Power outlets in my house provide 240 volts and are rated at 10amps but a= ny device that I plug in will only draw the current it needs. Many people = confuse this point. So all the devices must be able to be driven by the 24= 0volts. I could connect a light globe (240 watt ) for example that would d= raw only 1 amp while running or a heater rated at 2400 watts that would dra= w 10 amps. >=20 > Please feel free to rephrase your questions if I have failed to answer th= em. >=20 > Regards justin >=20 >=20 > On 22 October 2013 21:13, John Gardner wrote: >=20 > > For some values of "neighborhood", a 'hood-day's worth of > > > > kW-Hrs in 9V battery form factor would make a nice warhead. > > > > "Energy Density" is a term encountered in connection with > > > > batteries, variously denominated in watt-hours per unit mass, > > > > or SI equivalent. > > -- > > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive=20 > > View/change your membership options at=20 > > http://mailman.mit.edu/mailman/listinfo/piclist > > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/cha= nge your membership options at http://mailman.mit.edu/mailman/listinfo/picl= ist >=20 >=20 >=20 > --=20 > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 Byron A. Jeff Chair: Department of Computer Science and Information Technology College of Information and Mathematical Sciences Clayton State University http://faculty.clayton.edu/bjeff --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .