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What is the maximum charge rate l could get on a 250e?

At home on a 7.2 kWh Rolec?

On a public changing station?

On this off market USA device which would invalidate the Mercedes guarantee ?


Are there limits Mercedes have set?

My 7.2 kWh is changing at around 16 amps so I think I’m getting 242v at 15.8 amps so 242 x 15.8 = 3.8 kWh :whistle: and not the 7.2 kWh
 

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the B has three 16A charger modules, however in europe they are each wired across one of the three phases.

That means on a typical single phase home charger, or a 7kw public charge point it only charges at 16A or ~3.7 kw as you've discovered. If you find a three phase public charge point (usually advertised as a 22kw post) it will run at 3x16A, or ~11kw.

In the USA, all three chargers reside on a single phase and it will do i believe upto 40A on that single phase. As such, in the US you can buy higher power 40 or 50A home charge units. However if you connect that USA charge unit to the car in the UK, it will still only charge at 16A due to the way the cars configured here.

Oddly teslas using the same charge module seem to have the ability to automatically run in either mode in europe, and can do both higher power single phase and three phase. I guess theres some additional part of the charger thats missing in the Merc which allows it to automatically switch between the modes.

There is a hack you can do however. If you connect your Rolecs single phase output to two of the phases on the car, it will charge at 32A. This requires a custom cable, is very much non-standard and would be dangerous to connect a cable configured in this way to another EV, but it will allow you to charge your car at 32A.


The only other option for higher speed charging on the B is the Jdemo unit from Quick Charge Power. This is an aftermarket addon which adds a Chademo port for rapid charging. This isnt something you'd use at home however, but would allow you to put about 80% charge into the car in about 30minutes from a Rapid public charger.
 

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The first generation Tesla onboard charger was 40 amps (North America only 9.6kW = 40A * 240V)

The 2nd generation Tesla onboard charger has 16 amps in 3 power modules, so potentially 3 * 16 = 48 amps in North America, but they have restricted it to 40 amps.

In Europe, it's wired for three phase 16 amps = 11kW
 

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The first generation Tesla onboard charger was 40 amps (North America only 9.6kW = 40A * 240V)

The 2nd generation Tesla onboard charger has 16 amps in 3 power modules, so potentially 3 * 16 = 48 amps in North America, but they have restricted it to 40 amps.

In Europe, it's wired for three phase 16 amps = 11kW
Understand this is US 240 volts which is two 120 vac lines using a NEMA 14-50 or 14-50R plug which has 50A available to each 120 vac line plus a neutral and a ground. The EV controls this to 40 Amp charging rate.
 
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