LeafCharge

Why it exists

The Leaf will not tell you what it is doing. Plugged in in the garage, the dashboard is dark; to find out how full the battery is you have to unlock the car, get in, push Start, and read the dash. Every single time. That was the itch, and it is a small one, which is exactly why it went unscratched for years.

The better reason arrived more slowly. Charging fast is a choice, and it is usually the wrong one. Lithium cells dislike heat and fast charging makes heat, and over a few thousand cycles that difference shows up as capacity you no longer have. Fifteen amps over eight hours puts the same energy into the pack as forty amps over three, with less wear on it. If the car is going to sit there all night anyway, there is nothing to be gained by hurrying.

So LeafCharge works backwards from the moment you actually need the car. Tell it you are leaving at seven and it picks the slowest rate, and the delay to go with it, that still gets you there. Then, while the session runs, it estimates the charge percentage as it climbs, so you can check from the couch instead of the driveway.

None of the maths is Leaf-specific — it works for any EV on any home setup, and at public chargers too. It just got named after the car that annoyed us into building it.