Tuesday, March 12, 2013

☈ Super Capacitor Vs Car Battery ☈

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.


Normally if we drain our car battery to much and try to start our car it will cause more damage to the car battery and eventualy it will not charge back up to it's maximum again. However this is not true for super capacitors.

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.

What About Using Lithium Batteries Instead?
Reply to a comment:

They only weigh 1.5Kg (3lbs), will stay charged for a year, survive 1000+ discharge cycles and can be fully charged in 1-2 hours. They cost around $300-500.

While it's true that the lithium battery does have some advantages over using supercapacitors. Like it can stay charged for a year, you also need to consider the life of the lithium battery (about 3-5 years max). And today the cost is about the same, today $300 will get you 6x 3000f farad super capacitors that can make you a very strong supercapacitor car battery replacement that in theory should last you over 200 years..

Here's a few things that are good to know. Porsche AG, Stuttgart was the first car maker in the world to offer a starter battery with lithium-ion technology. Weighing less than 13 lb or 6 kg, the new battery is more than 22 lb or 10 kg lighter than the conventional 60 Ah lead battery.

While the most used batteries today are rechargeable Li-ion, Li-Poly and Lithium Iron Phosphate (LiFePO4) batteries. Li-ion and LiPo batteries have a recommended per-cell safety zone between 3V (fully discharged) and 4.2V (fully charged), although they can normally discharge down to about 2.8V without any problems. Discharging below these levels may cause irreversible/irreparable damage.

Therefore, these batteries must have a built-in safety mechanisms, preventing over-discharging. Conversely, overcharging can also be very dangerous.

The Li-Po batteries have a lower number of recharging cycles than LiFePo4 (1000@0.2C rate, IEC Standard). The projected/estimated life of a Lithium-Ion battery is approximately 3 years from production.

The LiFePO4  batteries exhibit slightly different properties. The LiFePO4 is a kind of Li-Ion rechargeable battery intended for high power applications, such as EV cars , eBikes, electric bike, Power Tools and RC hobby.

The LiFePO4 batteries have more constant discharge voltage and are considered to offer better safety than other Lithium-based batteries.

Other advantages of the Lithium-based rechargeable batteries include the ability of a much faster recharge and higher discharge rates than other chemistries mentioned and usually higher number of recharge cycles (>2000@0.2C rate, IEC Standard) , meaning longer life when not fully discharged, but its energy density is lower than normal Li-Ion cell (Li-Co) LiFePO4 life expectancy is approximately 5-7 years.

The supercapacitors on the other hand can do 10 million times of charging/ discharging. The supercapacitor can be charged/discharged more than 20 times a day for 136 years of continuous usage. It is about 1000 - 2000 times of Li-Ion/Ni-MH/ Ni-Cd batteries. And to fully charge a supercapacitor takes seconds instead of hours for a lithium battery.




This can also be read on ☈ Ultra Capacitors VS Car Battery ☈

Read the full specifications to the most common 2600 farad Boostcap BCAP0010 supercapacitor below
☈ BoostCap BCAP0010 2600 farad Specifications ☈

2 comments:

  1. A lithium automotive starting battery is a much better option. They only weigh 1.5Kg (3lbs), will stay charged for a year, survive 1000+ discharge cycles and can be fully charged in 1-2 hours. They cost $300-500.

    ReplyDelete
  2. While it's true that the lithium battery does have some advantages over using supercapacitors. Like it can stay charged for a year, you also need to consider the life of the lithium battery (about 3-5 years max). And today the cost is about the same, today $300 will get you 6x 3000f farad super capacitors that can make you a very strong supercapacitor car battery replacement that in theory should last you over 200 years..

    Here's a few things that are good to know. Porsche AG, Stuttgart was the first car maker in the world to offer a starter battery with lithium-ion technology. Weighing less than 13 lb or 6 kg, the new battery is more than 22 lb or 10 kg lighter than the conventional 60 Ah lead battery.

    While the most used batteries today are rechargeable Li-ion, Li-Poly and Lithium Iron Phosphate (LiFePO4) batteries. Li-ion and LiPo batteries have a recommended per-cell safety zone between 3V (fully discharged) and 4.2V (fully charged), although they can normally discharge down to about 2.8V without any problems. Discharging below these levels may cause irreversible/irreparable damage.

    Therefore, these batteries must have a built-in safety mechanisms, preventing over-discharging. Conversely, overcharging can also be very dangerous.

    The Li-Po batteries have a lower number of recharging cycles than LiFePo4 (1000@0.2C rate, IEC Standard). The projected/estimated life of a Lithium-Ion battery is approximately 3 years from production.

    The LiFePO4 batteries exhibit slightly different properties. The LiFePO4 is a kind of Li-Ion rechargeable battery intended for high power applications, such as EV cars , eBikes, electric bike, Power Tools and RC hobby.

    The LiFePO4 batteries have more constant discharge voltage and are considered to offer better safety than other Lithium-based batteries.

    Other advantages of the Lithium-based rechargeable batteries include the ability of a much faster recharge and higher discharge rates than other chemistries mentioned and usually higher number of recharge cycles (>2000@0.2C rate, IEC Standard) , meaning longer life when not fully discharged, but its energy density is lower than normal Li-Ion cell (Li-Co) LiFePO4 life expectancy is approximately 5-7 years.

    The supercapacitors on the other hand can do 10 million times of charging/ discharging. The supercapacitor can be charged/discharged more than 20 times a day for 136 years of continuous usage. It is about 1000 - 2000 times of Li-Ion/Ni-MH/ Ni-Cd batteries. And to fully charge a supercapacitor takes seconds instead of hours for a lithium battery.

    ReplyDelete