EV Charging Fundamentals: Right-Speeding and the Dwell-Time Table

Right-Speeding. Match charging speed to dwell time◆. That is the whole principle, and nearly every expensive mistake in parking-facility charging comes from ignoring it.

A vehicle parked for eight hours needs roughly 6 kW to leave with a full battery: ordinary Level 2◆ service. Direct-current fast charging◆ delivers that same energy in under forty-five minutes, which is precisely what an all-day parker does not need, at a price the owner should not pay. A DCFC installation typically costs ten to twenty times its Level 2 equivalent once equipment, switchgear, and utility service are counted, and it drags demand charges◆ into an electric bill that Level 2 rarely touches. Installing fast charging where vehicles dwell all day is not future-proofing. It is buying a race car to sit in traffic.

The discipline runs the other direction too. Where dwell is genuinely short (a retail garage with forty-minute turnover, a curbside pickup zone), Level 2 delivers so little range per session that it functions as decoration. Short dwell either justifies DC service or justifies no charging at all, and the honest analysis frequently lands on the second answer.

MARGIN NOTE The full dwell-time matrix (facility type by charging level, with the supporting load calculations) is maintained in the Council's Right-Speeding EV Charging white paper. The Book states the principle; the paper carries the machinery. One click, always current.

Right-speeding◆ is therefore not an equipment question but a diligence sequence: establish dwell time from your own transaction data, size the charging level to it, and treat any proposal that starts with the hardware rather than the dwell profile as the sales document it is. Owners who follow the sequence buy less equipment, serve more vehicles, and keep their electrical capacity, the scarcest resource in the building, for the decades of demand growth ahead of them.

Equipment Selection. Equipment selection is a solved problem once dwell time is known. The table below is the solution; the unsolved problems (networking, service, warranty, parts) are everything that happens after the purchase order, and they occupy the rest of Part B.

Count ports, not stations, and make every vendor do the same. A "station" can carry one connector or four, and the industry's own datasets confuse the two at roughly a three-to-one ratio, an error that silently triples or thirds a capacity plan depending on which direction it runs. Every quantity in the procurement, from the demand analysis to the maintenance contract's uptime definition, should be denominated in ports◆.

Two selection notes that outlast any model year. First, buy the connector◆ landscape as it is: NACS has become the de facto light-duty standard, and equipment that cannot serve it, natively or by adapter strategy, is aging on the loading dock. Second, load management belongs in the specification from the first port: an ALMS◆ lets a fixed electrical service feed more ports by sharing capacity intelligently, which is usually the difference between the phased build-out of section 7.11 and a service upgrade the project cannot afford.