The SkelStart Engine Start Module by C8 Energy is a supercapacitor designed to start a vehicle engine even when the battery is largely depleted. The module replaces starter batteries and is engineered to have a similar dimensional envelope as a standard commercial vehicle battery. One module can crank a 27-liter engine, and four SkelStarts can crank a large 85-liter engine, the company said, even when the ambient temperature is as low as -40 degrees F or as high as 149 degrees F.