How EV Grids plans your route — methodology

You type origin and destination (and optional via points or round-trip). A vehicle preset fills connector types, rated range, and a typical highway Wh/km. You can override start SOC, reserve SOC, search threshold, charge-to percentage, trip mode, overnight bias, prefer-lower-cost, and a max ₹/kWh cap.

These are planning inputs, not live telemetry. Distances in the API are kilometres. The km/mi toggle only changes display.

EV Grids geocodes the places, then requests a driving route from Google Directions (or OpenRouteService when configured). The returned polyline is the path used for distance, charger discovery, and SOC walk-through — not a straight line between cities.

Long routes may be split into chunks so Places lookups stay within time and cost limits. Identical city pairs may reuse a cached polyline for up to 30 days. Cache is a speed tool, not a live CCTV of the road.

Named corridor pages (for example Hyderabad → Goa) are editorial overlays on the same planner. They pre-fill cities and sensible defaults. The planner itself works for any same-country pair the maps API can route — including places that do not have a corridor article.

International routing is supported as a product feature. Search indexing of those pages is separate: empty or thin international corridors stay noindex until they have useful unique content and charger data.

We sample points along the driving path and query cached charger data plus live Places / OpenChargeMap where needed. Stations far from the polyline are dropped even if they look close as the crow flies — a 150 kW site 18 km into a city is usually a worse highway stop than a 60 kW plaza gun a few hundred metres off the NH.

The vehicle preset’s inlet (typically CCS2 on recent Indian highway EVs, plus Type 2 where the preset includes it) excludes slow AC-only sites when you plan for highway DC. Minimum kW from the preset also filters out trickle chargers that cannot serve a long-distance stop.

We do not invent connector counts. If maps data is thin, the stop card will show what we have — not a fabricated gun list.

Usable range is energy, not brochure kilometres. The planner walks the polyline using your Wh/km. A default real-world range factor of about 0.85 versus rated range is applied in configuration when you have not set a custom efficiency — a highway planning margin, not a promise of your dashboard.

Search threshold (default 30% SOC) is when we look for DC. Reserve (default 20%) is the arrival floor we try not to cross. Keep threshold above reserve. Raise both in heat, monsoon, and ghats.

Candidate chargers are scored with the live ranking weights in the API: detour 0.30, power 0.25 (higher in Fastest mode), ratings 0.20, operational status 0.10, amenities 0.10, reliability prior 0.05. Prefer lower-cost or Cheapest mode adds estimated ₹/kWh at weight 0.12. Overnight can add lodging-nearby at 0.10. A reported-busy penalty of 0.12 applies when we have that signal.

The top reachable site at a trigger becomes the primary. Nearby alternatives become backups. Estimated ₹/kWh is indicative when inferred from operator name; it is not live tariff unless the listing actually has a price.

Swapping a backup re-checks later legs so stop 2 cannot strand stop 3. If a cheaper but farther gun breaks the chain, the UI can offer a fix. The itinerary then shows arrival SOC, energy to add, and an indicative session cost.

When you accept the list, selected chargers become Google Maps waypoints. EV Grids does not navigate, book a stall, or start a session.

Take Hyderabad to Bangalore: 570 km on NH44/NH48, planned in a preset with roughly 45 kWh usable and a typical highway figure of 165 Wh/km, starting at 90% and holding a 20% reserve.

Step 1–3, route and corridor. Google Directions returns the driving polyline. Distance comes from that polyline, not from a straight line between the two cities, and every later step is measured along it.

Step 4–6, discovery and filtering. Points are sampled along the route and charger listings near those points are collected. The preset's CCS2 inlet removes AC-only sites, and the minimum power filter removes hardware that cannot serve a highway stop.

Step 7–9, the energy walk. 570 km at 165 Wh/km is about 94 kWh of road energy — more than twice the usable pack, so at least two DC sessions are needed. Starting at 90% and refusing to drop below 20% leaves roughly 70% of 45 kWh, about 31 kWh, or on the order of 190 km before the first stop. The search threshold of 30% means the planner starts looking before that limit rather than at it.

Step 10–13, scoring. Candidates near the first trigger are scored: detour at 0.30 dominates, so a site a few hundred metres off the highway outranks a more powerful one several kilometres inside a town. Power at 0.25, ratings at 0.20, operational status and amenities at 0.10 each, and a reliability prior at 0.05 order the rest. The top reachable site becomes the primary; nearby alternatives become its backups.

Step 14–15, validation and itinerary. The walk continues from the departure state of charge at stop one to find stop two. If you swap in a backup that sits farther along, the later legs are re-checked so the second stop cannot leave the third unreachable. The result is a stop list with arrival percentages and indicative costs, which then opens in Google Maps as waypoints.

What this example is not: a promise. The chargers it picks may be queued, the tariff may have changed, and your consumption is probably not exactly 165 Wh/km. That is why the reserve exists and why every stop carries a backup.

Charger status, queue length, pricing, and access can change hourly. Outages and road closures happen. Always verify a backup stop and your car’s SOC display before you rely on a plan.

EV Grids is independent — not Google, Tata Power, Jio-BP, or an automaker. Vehicle names are presets. See Terms and Contact for support.