3 ms·

By the way, are super capacitors still a promising technology? What's the hold up on getting those commercialized?

jonmrodriguez 14y ago
(1) Supercapacitors are commercialized, see: http://www.mouser.com/Power/Supercapacitors/_/N-6uivw http://www.mouser.com/Power/Supercapacitors/_/N-6uivw (2) Today's supercapacitors have very poor energy density even compared to batteries. What they do have is good power density, meaning they can deliver their limited energy very fast. (3) Boosting the energy density of supercapacitors will happen but requires many years of great strides in nanotech. Research like this, involving 3D nanostructures with enormous surface area: http://phys.org/news/2012-10-sponge-like-graphene-supercapacitor-electrodes.html http://phys.org/news/2012-10-sponge-like-graphene-supercapac...
- tocomment 14y ago
  Hmm, I'm trying to compare these to batteries. Does anyone know how to convert farads to watt hours?
  - irrelative 14y ago
    Energy stored in a capacitor is equal to: 1/2 * c * v^2 Where c is the capacitance in farads, and v is the voltage. That will produce a value of joules. Note that the capacitor is rated for a given voltage, so that goes in as v. Converting watt hours to joules goes like this: A watt is one joule per second, so a watt hour is 3600 joules.
  - tocomment 14y ago
    By that formula, I only get ~12 joules for a 1 farad capacitor at 5 volts. That seems low. Are you sure it's correct?
    - zokier 14y ago
      WolframAlpha confirms: http://wolfr.am/VWAp9B http://wolfr.am/VWAp9B
    - zalzane 14y ago
      that's correct. welcome to capacitors.
Aardwolf 14y ago
Here is my favorite movie about ultracapacitors: http://www.youtube.com/watch?v=EoWMF3VkI6U http://www.youtube.com/watch?v=EoWMF3VkI6U Very good explanation on the general math and physics of capacitors, current, heat and energy storage, plus awesome demonstrations at the same time :)

(1) Supercapacitors are commercialized, see: http://www.mouser.com/Power/Supercapacitors/_/N-6uivw http://www.mouser.com/Power/Supercapacitors/_/N-6uivw (2) Today's supercapacitors have very poor energy density even compared to batteries. What they do have is good power density, meaning they can deliver their limited energy very fast. (3) Boosting the energy density of supercapacitors will happen but requires many years of great strides in nanotech. Research like this, involving 3D nanostructures with enormous surface area: http://phys.org/news/2012-10-sponge-like-graphene-supercapacitor-electrodes.html http://phys.org/news/2012-10-sponge-like-graphene-supercapac...

tocomment 14y ago
Hmm, I'm trying to compare these to batteries. Does anyone know how to convert farads to watt hours?
- irrelative 14y ago
  Energy stored in a capacitor is equal to: 1/2 * c * v^2 Where c is the capacitance in farads, and v is the voltage. That will produce a value of joules. Note that the capacitor is rated for a given voltage, so that goes in as v. Converting watt hours to joules goes like this: A watt is one joule per second, so a watt hour is 3600 joules.
- tocomment 14y ago
  By that formula, I only get ~12 joules for a 1 farad capacitor at 5 volts. That seems low. Are you sure it's correct?
  - zokier 14y ago
    WolframAlpha confirms: http://wolfr.am/VWAp9B http://wolfr.am/VWAp9B
  - zalzane 14y ago
    that's correct. welcome to capacitors.

Aardwolf 14y ago

Here is my favorite movie about ultracapacitors: http://www.youtube.com/watch?v=EoWMF3VkI6U http://www.youtube.com/watch?v=EoWMF3VkI6U Very good explanation on the general math and physics of capacitors, current, heat and energy storage, plus awesome demonstrations at the same time :)