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Comment by spacebanana7 | Hacker News Reader

One thing I'm really scared of is EV charger software being modified by users, hackers or bugs to pull max power at times that don't suit the grid.

In the UK, for example 10 million EVs all pulling 7kw would overwhelm the roughly 70GW potential of the grid. Even a million EVs charging at an inconvenient time could add a 7GW draw which is enough cause a problem.

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Incoming voltage monitoring is a requirement for EV chargers in the UK. The sudden huge demand would result in a voltage drop, the chargers would then detect the under-voltage condition and they'd stop charging.

Would the voltage drop before the fuse blew in local transforms?

Modern grids have batteries to manage instantaneous spikes of demand so there’d be a race.

It will first damage the batteries very fast, second, most users don't want to mess with that, they want to plug and play. So, on both counts your fears are misplaced.

In the event of an internet outage, wall box chargers are legally required to default on. In practice most chargers interpret this as taking the full 7kw - whether this is a bug or misreading of the intent of the law doesn't really matter from the perspective of the grid.

Large ISP outages that affect millions of people are not uncommon on a decade by decade basis, and I suspect an uncomfortable number of UK EV chargers are in some way linked to eu-west-2.

[1] https://www.legislation.gov.uk/uksi/2021/1467/regulation/7/m...

It sounds like a genuine attack vector to me. If someone hacked say teslas firmware supply chain and made all chargers pull max power at the same time, it could be a national infrastructure crippling attack.

Where would they dump the power? You need a load of some sort. 7kW requires a voltage drop between a hot and a neutral. If it's a 1V drop then you're going to get a hot load of amps.

Into what it was designed for, maybe.... a car?!

Im thinking in an attack situation hackers might plan for say a 3am mass dump and pull on the grid by all cars that are charging overnight. This would definitely be possible by altering firmware, and would be bad enough to blow some local substations for sure.

I may be misunderstanding your concern but the idea would be for Tesla to dump the energy into car batteries or powerwall storage.

I've never seen a charger in the US that doesnt operate 24/7 regardless of grid load, is this different in other countries?

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