Figure 1: Schematic diagram shows the parallel installation of a bank of supercapacitors in a vehicle's electrical system.
With the Direct Parallel approach above, the supercap extends battery life and it shares the high current loads of the system. But it offers no protection from house load drain, so a vehicle with the lights turned on after the engine is turned off may still fail to restart.
Under a typical operating conditions, batteries have a lifespan of three to four years. Adding a super cap to the system extends the life of the battery significantly enough where it may seldom have to be replaced and engine-start reliability improves dramatically.
The Supercap Starter approach is designed to guarantee starting by making it less susceptible to house load drains. The supercaps are directly connected to the starter, and lead-acid batteries would only supply the other electricity needs in the car such as radios, lighting and air conditioning. The schematic in Figure 2 below provides a typical configuration for the Supercap Starter approach.
Figure 2: Schematic diagram shows supercapacitor installation in a vehicle's electrical system referred to as Smart Start. This method prevents the supercap from draining due to house loads and maintains engine-start reliability.
Two pictures below demonstrate a supercapacitor design for heavy vehicles. There are three terminals on the device, and one of the positive terminals connects only to the starter. The other positive terminal connects to the battery for recharging. This scenario offers to extend the longest battery life because it does not subject lead-acid cells to the typical 1,000 AMP discharges required for engine starts.
Figure 3: Heavy-duty supercapacitors feature two positive terminals, one for the engine starter and one for the battery. This prevents the battery from the constant wear and tear from typical engine