The dc-dc converter has a maximum throughput of 50 A at 14.5 V. Headlamps and other exterior lighting, HVAC, wipers, and the audio system account for about 40 A, so in "normal" use the supercapacitor system is well within range. However, on a cold day, particularly right after vehicle start, the driver may be using the rear window defogger and perhaps the optional seat heaters. These could push the electrical load over the dc-dc converter's capacity. If so, the smart charging system triggers a relay that bypasses the capacitor system completely, and for that period (likely to be brief) the car's electrical system reverts to conventional alternator-powered operation.