EV Charging Stations

EV charging stations are sort of like gas stations. Gas stations have just one size fits all nozzle and different grades of gasoline. EV charging stations have several different plugs (though they are becoming standardized) and charging power levels.

Charge levels determine how fast your EV will charge up to a point since battery packs today can only accept electric charge at a certain rate and usually no faster.

- The size of the EV battery pack
- The power source
- The charger used

Plug in Hybrids, for instance, have small battery packs compared to the Tesla Roadster or the Coda sedan. The Chevy Volt is somewhere in between. Power sources vary from 110 volts to 440 volts or more, and there are many types of chargers on the market. What do they have in common? Charging levels.

EV Charging Levels

In the US, there are currently 3 levels of charging. These levels are roughly equal to those used in Europe as well.

Level One - This is a standard household outlet at about 110-120 volts and 15 amps maximum, generally regarded as a 1500 watt power source. Check the calculator on the next page to see level one charge time estimates. Level 1 chargers may be simple plugged in, one per circuit, no electrician required.

It is estimated by Frost and Sullivan that some 3.5 million Level one chargers will be installed in the U.S. by 2017.

Level Two - Level 2 power comes from a 220/240-volt circuit similar to a household dryer line. However, an EV charger installed on a 220 volt line requires a dedicated new circuit and charger to be installed. This installation needs to be done by an electrician. Check the calculator on the next page to see Level 2 charge time estimates.

Level 3 - Level 3 charging is at 440 volts or more and beyond household circuitry. These are commercial chargers found at public and private charging facilities. A subclass of the Level 3 charger is the Fast Charger, which can be configured to fill an EV battery pack to 80% full in as few as 15 minutes.

New level 3 hot spots are designed to charge most EVs in under an hour. They are rated to deliver a 50-80% partial charge in a matter of 10-15 minutes or so. To put them in perspective, a fast charger runs around $40,000 USD. There are only a few installed in the US so far, though the number of installations is on the rise.

One caution regarding fast chargers: the battery pack of an EV needs to be fully charged and conditioned to maintain long life and power. For example, Nissan mentions that constant Level 3 charging of the Leaf would lower the range while consistent Level 2 charging would maintain maximum capacity.

Wireless Inductive Charging

One of the hassles of EV charging is the power cables. Besides carrying high voltage, the wires get in the way, do not always agree and take up space, and you have to stop and wait for the charge to complete. Enter wireless charging. The technology is called called magnetic resonance coupling. Charging takes place between two copper coils tuned to the same frequency.

Ultimate Future inductive charging would include chargers embedded in pads from parking lots to roadways. This would go a long way towards relieving range anxiety. You could drive as long as there were pads to continue to provide the current. The technology is in the testing phase, working with a 3 kW static charger, then to a 10 kW system. Great idea, hope it works out.

The concept is being examined and tested by the UK sponsored program - Coventry and Birmingham Low Emission Demonstrators (CABLED) consortium testing programme, researchers at MIT, and Stanford University.

Personal Charge Station Installment

Follow the code, permit, and inspection process the same way you would for any construction project. Check with a licensed electrical contractor for a cost estimates and basic circuit requirements as well.

Permits: Check your local codes and CCRs before charge station installation. Get required permits prior to electrical work.

Inspections: You may need an inspection before work starts, as well as one during construction, and a final inspection. Check your local codes.

One of the latest charging stations in the works uses inductive charging. Inductive charging uses the electromagnetic field to transfer energy between two objects. The new chargers will be a loop placed on your garage floor. The EV owner just drives over the loop and switches on the power. It can be operated by phone if needed.

Standardization in Charging

The standard Level 1 and 2 EV plug is the J1772 plug. This 5-pin plug is intelligent for data purposes.

Eight major auto makers have agreed to a single charging standard. Audi, BMW, Chrysler, Daimler, Ford, General Motors, Porsche and Volkswagen are on the same page to support the gear that will provide 15 - 20 minute battery pack charges.

The new system called CCS (combined charge system) allows the EV driver to charge at a Level 1,2,or 3 charge station for fast to slow charging. The CCS is backwards compatible with J1722 and IEC 62196 connectors.