Ev Charging

{
  "asOf": "2026-10-11T14:31:35.383Z",
  "batteryKwh": 60,
  "chargerKw": 7.68,
  "chargerSource": "40 A breaker x 80% continuous = 32 A at 240 V",
  "chargingEfficiency": 0.9,
  "circuitAmps": 32,
  "circuitVolts": 240,
  "cost": 6.4,
  "costPerMile": 0.0508,
  "degraded": false,
  "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
  "endPercent": 80,
  "energyAddedToBatteryKwh": 36,
  "energyFromWallKwh": 40,
  "hours": 5.21,
  "lossKwh": 4,
  "milesAdded": 126,
  "minutes": 313,
  "notChecked": [
    "charge taper: batteries slow down above about 80% and in the cold, so the last percent takes longer than this linear estimate",
    "the car's onboard charger limit (many cars accept only 7 to 11 kW AC regardless of the circuit)",
    "…2 more"
  ],
  "reasons": [
    "Time = energy from the wall / charger power; energy from the wall = energy added / efficiency.",
    "A continuous load (3 hours or more) may use only 80% of a breaker's rating, which is why a 40 A breaker supports 32 A."
  ],
  "source": "computed locally",
  "startPercent": 20,
  "summary": "Charging 20% to 80% of a 60 kWh battery adds 36 kWh (40 kWh from the wall at 90% efficiency); at 7.68 kW (40 A breaker x 80% continuous = 32 A at 240 V) that takes about 5.2 hours. Cost 6.4 at 0.16 pe…",
  "verdict": "COMPUTED"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://home-energy-calc.x402tookit.com/ev-charging?batteryKwh=60&breakerAmps=40&endPercent=80&milesPerKwh=3.5&pricePerKwh=0.16&startPercent=20'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - 'https://home-energy-calc.x402tookit.com/ev-charging?batteryKwh=60&breakerAmps=40&endPercent=80&milesPerKwh=3.5&pricePerKwh=0.16&startPercent=20' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.02 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.02" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.02 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fhome-energy-calc.x402tookit.com%2Fev-charging
const res = await pay("https://home-energy-calc.x402tookit.com/ev-charging?batteryKwh=60&breakerAmps=40&endPercent=80&milesPerKwh=3.5&pricePerKwh=0.16&startPercent=20");
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.02 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.02"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://home-energy-calc.x402tookit.com/ev-charging?batteryKwh=60&breakerAmps=40&endPercent=80&milesPerKwh=3.5&pricePerKwh=0.16&startPercent=20")
    print(res.status_code, res.text)