How EV Grids works

EV Grids exists for a narrow job: decide where to charge on a highway trip in India (and on same-country trips elsewhere), then hand navigation to Google Maps. It is not a sat-nav, not a charging-network app, and not a live traffic overlay. That split is deliberate. Maps already does turn-by-turn well. What EV drivers still need is a stop list that matches their car, their battery buffer, and the actual road — not a pin dumped in the nearest city centre.

Where it works

Any same-country trip that Google Directions can route, up to roughly 2,800 km per leg — origin and destination must be in the same country, so Delhi to Mumbai or Berlin to Munich are fine while Delhi to Dubai is not. Charging cost is shown in the local currency, and operator tariff estimates are matched per market rather than converted from rupees.

Two things do vary by region. Charger coverage depends on what the underlying map data and our cache hold, which is currently strongest in India. And the written material — corridor guides, monsoon and ghat advice, network notes — is India-first. The planner itself does not change.

What you enter

Origin and destination can be city names. A vehicle preset (Tata Nexon EV, Mahindra BE 6, Hyundai Ioniq 5, and dozens more) fills connector types, a typical highway Wh/km, and a rated range. You can override Wh/km, start SOC, reserve SOC, search threshold, trip mode (balanced / fastest / fewer stops / cheapest), and a max ₹/kWh cap. Overnight mode biases toward lodging-adjacent sites when you will sleep on the road.

Distances in the product are stored in kilometres. If you prefer miles, the km/mi toggle only changes what you see — corridor guides, sitemaps, and structured data stay in km so listings stay consistent.

Step 1 — driving path, not a straight line

The API asks Google Directions for the driving polyline between your origin and destination (and optional via points). Chargers are discovered near that path, not as a radius around the start city. A 150 kW charger 18 km into a city is usually a worse stop than a 60 kW plaza gun 400 m off the highway. Ranking uses detour along the route, not crow-flies distance.

How rated range and Wh/km fit together

Two numbers do different jobs, and it is worth being precise because they are easy to confuse. Wh/km × distance is the energy the route needs, and that is what drives SOC along the polyline. Separately, pack energy is implied from the preset's rated range against a reference vehicle (60 kWh ≈ 400 km rated) when the preset does not carry its own kWh figure.

The 0.85 factor is a margin applied to rated range to get usable highway range — it does not change your Wh/km. With adjust for conditions enabled, the terrain and weather factor multiplies on top of it (for example 0.85 × 0.88 ≈ 0.75 of rated range). If you enter your own Wh/km from a real trip, the energy side of the calculation uses your figure.

Step 2 — when to look for a charger

Usable range is not brochure range. The planner converts your pack into energy using Wh/km, then walks the route. When estimated SOC would fall through your search threshold (default 30%), it searches for DC stops before you would hit the reserve floor (default 20%). That gap — threshold minus reserve — is the planning margin for traffic, AC, and a missed exit. Read the full range and SOC guide if those three numbers still feel abstract.

Step 3 — how a stop is scored

Each candidate charger gets a score from the weights below. These are the values the API uses, not an illustration:

• Detour 0.30 — Extra kilometres off the driving path. The heaviest single factor, which is why a nearby 60 kW plaza gun can outrank a distant 150 kW site.
• Charging power 0.25 (increased in Fastest trip mode) — Listed kW ceiling for the station, normalised across a 50–350 kW range.
• Ratings 0.20 — Star rating from the underlying map listing, damped by how many reviews exist. These are third-party map ratings, not EV Grids reviews.
• Operational status 0.10 — Listings marked closed or non-operational are pushed down.
• Amenities 0.10 — Food, restrooms, and lodging signals attached to the listing.
• Reliability prior 0.05 — A confidence prior derived from rating volume. It is a prior, not a live view of whether a gun works.
• Estimated ₹/kWh 0.12 (only with Prefer lower-cost or Cheapest mode) — Indicative tariff, sometimes inferred from the operator name when the listing has no price.
• Lodging nearby 0.10 (only in overnight mode) — Biases toward sites next to accommodation for multi-day drives.
• Reported-busy penalty −0.12 (only when a busy signal exists) — Subtracted when the listing reports all connectors in use.

Cost-aware ranking pairs with trip cost; sourcing and accuracy limits are on charger data & accuracy.

The top site becomes the primary recommendation. Nearby alternatives become backups. If you swap a backup in, the planner re-checks later legs so stop 2 cannot strand stop 3. That chain check is why “Fix trip” appears when a cheaper but farther gun breaks reachability.

Step 4 — cost, SOC chart, and Maps

Each stop shows estimated arrival SOC, energy to add, and an indicative session cost. The SOC chart is a planning sketch, not a second instrument cluster. When you are happy with primary + backup picks, open Google Maps: selected chargers become waypoints. Return-trip URLs are available when you planned a round trip.

Repeat searches for the same corridor are cached on the API so the second plan is faster. Live gun counts and tariffs still change — treat the itinerary as a plan, not a reservation.

What EV Grids does not do

We do not book a stall, start a charge session, or pay the operator. We do not claim a charger will be free when you arrive. We do not replace your car’s remaining-range display. We do not affiliate with automakers or networks; vehicle names are presets, and network names describe public sites. Corrections go through contact.

Where to go next

New to highway DC? Start with the EV charging guide. For a specific road, use a corridor page such as Hyderabad → Goa or Bangalore → Chennai, then Plan now. Longer how-tos live in trip guides.