Hacker News Reader

Comment by kadoban | Hacker News Reader

Charge at work.

Our main campus has parking for roughly 450 cars. We just added EV charging; two entire parking slots. There's no way our company would outfit every spot with charging in any reasonable future. We already have roughly 35 EVs on the lot.

When a car is parked for 8 hours, even the slowest 3kW charger will charge 70-90 miles of range.

Low-power AC "chargers" are dumb devices, basically just wire. They don't require active cooling, and all of the expensive hardware is in the car. They could be installed on every single parking spot.

Our lot isn't closed, and it's adjacent to a mall. So the only way we'd electrify each spot is with pay outlets (which is what the current 2 are). Otherwise we'd have people leeching off of the company.

You're overthinking this. The solution can be as trivial as putting a padlock on the power outlet. More practically, there are dispensers that read RFID cards, so employee badges can be used to grant access. It can be a raspberry-pi level tech, not a full-blown payment terminal.

You could even just throw up a sign and once in a while tow people who cheat. Not like it's really going to cost a ton anyway.

This is a well-solved problem. My previous employer had all the chargers on the chargepoint network but only available to accounts which verified as employees.

But how many work areas have a charging station available easily?

Not as many as should. The state can probably incentivize creating some more, and job seekers can prioritize it as well. Not to mention workers just asking their employers to do it.

Literally the point of the study

> “We encourage policymakers to consider utility rates that encourage day charging and incentivize investment in charging infrastructure to shift drivers from home to work for charging,” said the study’s co-senior author, Ram Rajagopal

The term "charging station" is hinting at a too big infrastructure. All you need is a power outlet per car. If the car parks for 8 to 9 hours, you don't need a huge amount of power to recharge it.

You need more than just a power outlet per car, with regular 120vac, you pretty much need a breaker and circuit per car, because you shouldn't put two of those on a single circuit, since they'll usually pull up to the 15A rating of the plug, and code restricts you from using more than 20A breaker on a circuit with 15A plugs, so you'll pop the breaker if you've got two 15A loads and they don't communicate to share. It probably makes more sense to get a two or maybe four car charging station per breaker and circuit, and set it for the appropriate amps on the circuit, it can share that appropriately amongst the cars plugged in.

I works out to about 12.5 amps for a normal 15 amp plug. You can't draw the full rated current continuously.

With an MWBC circuit you can however supply two different 15 amp plugs with a single cable 14/3 cable fed off a 15 amp duplex breaker. So it slightly reduces the amount of copper you need to run.

Reply on news.ycombinator.com