Level 1 charging uses a standard household outlet. It adds roughly 3 to 5 miles of range per hour, making it best for plug-in hybrids or emergency top-ups.
Level 2 charging uses a 240-volt connection, similar to a dryer outlet. It can add 20 to 30 miles per hour and is the standard for home and workplace charging.
DC fast charging is the fastest option available at public stations. It can add hundreds of miles of range in under an hour, though the rate slows as the battery fills.