Electric Vehicle Batteries
Electric vehicle battery chargers come in a variety of brands and characteristics. Zivan, Manzanita Micro, Elcon, Quick Charge, Rossco, Brusa, Delta-Q, Kelly, Lester and Soneil are the top 10 EV chargers in 2011 according to EVAlbum.com. These chargers vary from 1 KW to 7.5 KW maximum charge rate. Some use algorithm charge curves, others use constant voltage, constant current. Some are programmable by the end user through a CAN port, some have dials for maximum voltage and amperage, some are preset to specified battery pack voltage, amp-hour and chemistry. Prices range from $400 to $4500.
A 10 amp-hour battery could take 15 hours to reach a fully charged state from a fully discharged condition with a 1 amp charger as it would require roughly 1.5 times the battery’s capacity. Public EV charging stations provide 6 kW (host power of 208 to 240 VAC off a 40 amp circuit). 6 kW will recharge an EV roughly 6 times faster than 1 kW overnight charging. Rapid charging results in even faster recharge times and is limited only by available AC power and the type of charging system.
Onboard EV chargers (change AC power to DC power to recharge the EV’s pack)
- Isolated: they make no physical connection between the A/C electrical mains and the batteries being charged. These typically employ some form of Inductive charging. Some isolated chargers may be used in parallel. This allows for an increased charge current and reduced charging times. The battery has a maximum current rating that cannot be exceeded
- Non-isolated: the battery charger has a direct electrical connection to the A/C outlet’s wiring. Non-isolated chargers cannot be used in parallel.
- Power Factor Correction (PFC) chargers can more closely approach the maximum current the plug can deliver, shortening charging time.
There is a list of public EV charging stations in the U.S.A. and worldwide. Project Better Place is deploying a network of charging stations and subsidizing vehicle battery costs through leases and credits.
Non-contact Magnetic Charging
Researchers at the Korea Advanced Institute of Science and Technology (KAIST) have developed an electric transport system (called Online Electric Vehicle, OLEV) where the vehicles get their power needs from cables underneath the surface of the road via non-contact magnetic charging, (where a power source is placed underneath the road surface and power is wirelessly picked up on the vehicle itself. As a possible solution to traffic congestion and to improve overall efficiency by minimizing air resistance and so reduce energy consumption, the test vehicles followed the power track in a convoy formation.