Can super-capacitors replace batteries in high performance and racing applications? XS Power Batteries is banking on it.
Super-capacitors have long been proposed and argued as an alternative to traditional batteries; whereas batteries store their potential energy in chemical form, super-capacitors do so in a stored electric field. Super-capacitors charge faster and they last longer, because they don’t endure any physical wearing-down from charging and discharging as a battery does. With a super-capacitor, it’s feasible to charge a phone in seconds or an electric car in a matter of minutes. The downside, however, is that super-capacitors have to be larger in order to store the same energy as a battery — in the case of a lithium ion battery found in a phone, there is 20 times the energy stored versus a super-capacitor of equal size and weight.
It can act a a battery when there’s not a necessary reserve. – Brady Basner, XS Power Batteries
“We tell people this is not a battery and you have to treat it differently,” says XS’ Brady Basner. “A capacitor bank has a lot of capacitance, but not a lot of capacity. If you tried to hook one to another battery it would try to pull amperage so quickly that it would melt the terminals, melt the wiring, and probably start a fire. We include an incandescent bulb — if you connect it to a battery using that, it pulls down that amp current enough to avoid any terminal overload. You hook it up to a battery, the light will stay lit until it’s fully charged, and the light will go dead. Now you have a fully charged capacitor bank.”
Basner adds that if you use a capacitor in a street car with an alternator, it will crank the car and remain charged and all is normal. The same goes for an alcohol-burning racecar with a magneto. But with something like a dirt track car that lacks an alternator, the car may crank and complete a lap before it would run to zero volts and die. As well, the banks will draw down over time — perhaps 12.5 volts to 4 volts in a couple of days. As such, racers who aren’t operating their vehicle daily would likely need to re-charge the capacitor each weekend, and drag racers who operate their water pump or cooling fan after a run would find it dying out in a matter of minutes. To sum it up, “it can act a a battery when there’s not a necessary reserve,” Basner explains.
The trade-off, however, is that the capacitor bank can charged in about two minutes. And they’re lightweight: the 12-volt, 500-Farad (Farad is a unit of measure of a capacitors’ storage potential) version shown here weighs just nine pounds. A 1,050-Farad model, the largest of the group, is 22 pounds.
XS offers a complete line-up of SuperBank ultracapacitor modules, including 500-, 630, 1,000, and 1,050-Farad capacities.