Hi,
From what I understand, the M3 (at least as delivered in Europe) has three onboard AC chargers, each connected between neutral (N) and a respective AC phase (L1, L2 and L3). Each charger supports up to 16 amps, resulting in a total power of 11 kW if drawing 16 amps on all three phases.
Does anyone know if it would be safe/possible to, deliberately, add/remove phases over time. For example, can I start the charging period by supplying only L2, then change to L1 + L3, then to L2 + L3, then L1 + L2 + L3, and so on? Or would the car go crazy or even be damaged by such deliberate play with the phases? Time between changes would be on the order of minutes, or similar (i.e. not multiple times per second).
The reason for asking is that as the protocol used to communicate between the car and wall connector only provides a single "maximally allowed current draw" to be communicated to the car (via the control port), the current will always try to draw a same amount of current on all phases.
This is fine, except when e.g. one phase is heavily loaded while there is lots of margin left on the other two phases. When load balancing/current limiting, the most heavily loaded phase will decide the maximally allowed current for all three phases. For example, if the main brakers support 16 amps on each phase, and phase 1 (L1) is currently loaded with 10 amps, the car will have to charge by drawing at most 6 amps from each phase, even if the other phases (L2 and L3) are currently not that loaded and has lots of current margin left.
It would thus be nice if one could, instead, decide to drop the heavily loaded phase and continue charging on the remaining phases only. The maximally allowed charging current communicated via the control port could then be increased, and the overall charging power made larger (at least in some situations, if e.g., using the above example, L2 and L3 are each currently loaded with less than 7 amps).
Any comments?
From what I understand, the M3 (at least as delivered in Europe) has three onboard AC chargers, each connected between neutral (N) and a respective AC phase (L1, L2 and L3). Each charger supports up to 16 amps, resulting in a total power of 11 kW if drawing 16 amps on all three phases.
Does anyone know if it would be safe/possible to, deliberately, add/remove phases over time. For example, can I start the charging period by supplying only L2, then change to L1 + L3, then to L2 + L3, then L1 + L2 + L3, and so on? Or would the car go crazy or even be damaged by such deliberate play with the phases? Time between changes would be on the order of minutes, or similar (i.e. not multiple times per second).
The reason for asking is that as the protocol used to communicate between the car and wall connector only provides a single "maximally allowed current draw" to be communicated to the car (via the control port), the current will always try to draw a same amount of current on all phases.
This is fine, except when e.g. one phase is heavily loaded while there is lots of margin left on the other two phases. When load balancing/current limiting, the most heavily loaded phase will decide the maximally allowed current for all three phases. For example, if the main brakers support 16 amps on each phase, and phase 1 (L1) is currently loaded with 10 amps, the car will have to charge by drawing at most 6 amps from each phase, even if the other phases (L2 and L3) are currently not that loaded and has lots of current margin left.
It would thus be nice if one could, instead, decide to drop the heavily loaded phase and continue charging on the remaining phases only. The maximally allowed charging current communicated via the control port could then be increased, and the overall charging power made larger (at least in some situations, if e.g., using the above example, L2 and L3 are each currently loaded with less than 7 amps).
Any comments?
