Replace Battery with SuperCapacitor

Project Description

Unlike ordinary capacitors, batteries store energy in a chemical reaction. And because of this the ions are actually inserted into the atomic structure of an electrode. Unlike in an capacitor, the ions simply “cling”. This is important because storing energy without chemical reactions allows super capacitors to charge up and discharge much, much faster than batteries.

And because capacitors does not suffer the wear caused by chemical reactions, they also last a lot longer.


For example a capacitor the size of a D-cell battery, has a capacitance of about 20 microfarads. But if we take a similarly sized supercapacitor, it has a capacitance of 300 Farads. What this means is at the same voltage, the supercapacitor could in theory store up to 15 million times more energy. 

However a typical 20-microfarad capacitor would be able to handle as much as 300 volts, while an ultracap would be rated at only 2.7 volts. At a higher voltage, the electrolyte inside the supercapacitor starts to break down. So in reality an super capacitor have the ability to store about 1,500 times the energy of a similar sized capacitor. This would be something you would need to take into consideration in you’re attempts on storing energy in a capaciator.

Supercapacitors are very effective at accepting or delivering a sudden surge of energy, and that makes them a good alternative for a regular 12v car battery.

With electric cars for example super capacitors provide the power or “boost” needed for acceleration, while a battery provides range and recharges the supercapacitor between surges. They normally also go by the name “Boost Capacitors” or “Boostcap” simply because that’s their normal usage in industry. The Maxwell product line even have the name BOOSTCAP® ultracapacitors, and these are the ones you would normally find if you are searching for big capacitors.

While some electric vehicles are using super capacitors for acceleration. The devices also appear in hundreds of other applications, from cell phone base stations to alarm clocks to audio systems.

If you like to use supercapacitors instead of you’re car battery they could provide power during stops (running lights, radio, air conditioner, etc.).” They would also provide power for the restart, and then be “recharged during the next interval of travel.”

Building you’re own DIY car battery replacement with supercapacitors for automotive applications

So where can I really buy a +12 volt capacitor to replace a car battery?

Actually this is what you would need to do. Get 6 ultracapacitors connected together (normally they have about 2.5 Volts each)

What you would need are, 6 supercapacitors (normally they have about 2.5 Volts each)

So 2.5 Volts x 6 = 15 Volts fully charged. You could do with only 5 super capacitors giving you 12.5 Volts but it’s not recommended, you need the extra volts to be there. Besides you’re alternator will put out more than 12.5 volts when it’s charging anyways. Most cars have some electronics that drain you’re battery like the car alarm. So if you leave you’re car standing for a week the supercapacitors might have drained to much and you will not be able to crank over the engine.

With 14-15 Volts you wont be having any problem starting you’re car even if you leave it for 4-5 days. However any drain can be stopped with a simple solar panel to recharge the supercapacitors, so if that is done you always should always have them fully charged and ready to start you’re car.

Another interesting thing replacing you’re car battery with super capacitors are the weight. A normal lead acid car battery have a weight around 30 pounds. However installing supercapacitors in it’s place you will actually save around 25 pounds in weight.

What all this boils down to is you will save weight = better gas milage
The ultracapacitor will charge up very quick and not load the engine as much = better gas milage
They will also probably last the entire life of the car = save you maintinance and money.
They will also prevent voltage drop when restarting the engine that could be causing aftermarket electronics to shut off like the stereo.


Project Progress


Project Timing

  • Start
    Jul 21 2017
  • End
    Jul 31 2017

07/21/2017 07/31/2017


Overall Project Completion

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