Data Sources and Methodology

This page explains what DCFC Tracker uses as source data, how site records are interpreted, and what the main displayed fields mean.

Data sources

Site inventory. The NREL Alternative Fuels Data Center (AFDC) Station API is the base layer. DCFC Tracker focuses on DC fast charging records and stores snapshots over time for filtering, matching, and historical comparison. A small number of sites not yet published to AFDC are added directly from network sources.

Pricing and site detail. Collected directly from public data published by these networks: Tesla, Electrify America, EVgo, IONNA, ChargePoint, Blink, BP Pulse, Shell Recharge, Rivian, Mercedes-Benz, Red E, Francis Energy, and Walmart. Each network is refreshed on its own schedule, most of them daily or more often. Prices are labeled by source on station pages and reflect the rate published at the last sync, which may differ from the rate charged at the stall.

Enrichment. PlugShare location links are matched with automated best-effort logic. They are intended as a convenience link, not as authoritative validation of a site.

DCFC Tracker is an independent project and is not affiliated with, endorsed by, or operated in partnership with any charging network.

When sites are removed

Site records occasionally stop appearing in the AFDC feed. DCFC Tracker does not treat a single absence as a closure. When a site first goes missing, the date is recorded and nothing changes on the public site. If the site is still absent from the feed after 48 hours, it is marked as delisted and removed from public pages and alert emails. If it returns to the feed later, it is restored automatically and its history picks up where it left off.

A site leaving the AFDC feed does not necessarily mean it has closed or been removed from service. Records are sometimes withdrawn, corrected, or republished for administrative reasons. Delisting on DCFC Tracker reflects the site's status in the source data, not a confirmed physical closure.

Recent changes feed

  • Hardware changes (stalls added or removed, CCS to NACS conversions, connectors added, CHAdeMO removed) are read from changes to a site's AFDC record. The date shown is when the record changed, which can trail the work on site by weeks. Tesla's AFDC records refresh in batches, so Supercharger changes arrive together and are shown as one row.
  • Tesla also publishes each Supercharger's stall count and maximum power. Where Tesla's figures are ahead of the AFDC record (more stalls, or a max power that differs by 10% or more), lists, filters and site pages show Tesla's (site pages mark it "per Tesla"). A rise in either is logged as a change dated when we detect it, usually within a day or two; "Faster charging" means max power rose 10% or more. When the AFDC record later catches up, that update is not shown again.
  • Stall counts are charging ports; connector counts are cables. A site whose CCS count rises while its stall count stays flat has added cables to existing stalls, not new stalls.
  • Price changes follow the peak per-kWh rate shown for the site. Moves that reverse within two days are netted out, and runs of ten or more same-network changes within a few days are grouped.
  • Offline 24h+ lists outages of at least a day, as reported by the network's own data where we sync it, otherwise by AFDC.
  • Removed from listing covers sites absent from the AFDC feed for 48 hours or more, the point where they are delisted here (see above), excluding sites re-listed under a new record nearby. It is not a confirmed closure: about 3 in 4 such sites return, half of all of them within a week, and a site's row leaves the feed when it does. The default Highlights view waits until a site has been missing for 30 days, by which point about 1 in 4 still return.

Definitions used on the site

  • Open date is the date currently provided by the source record. It may change later if AFDC revises the station.
  • First seen is when DCFC Tracker first captured the station in its own dataset.
  • Last confirmed reflects the current source field and may represent a later update rather than a physical site visit.
  • Connector counts and total DC fast stall counts reflect the latest stored station snapshot, not a historical average.
  • Hidden sites are excluded from public pages and alert emails. This applies to sites delisted from the source feed, as described above, and to records that appear invalid or duplicated.

Limitations

  • Some records are corrected after initial publication, which can change open date, power, stall counts, or connector details.
  • Charging network apps and in-vehicle navigation should be treated as the operational source of truth before a trip.