Charging Station NS (fw 2.03) hooked up to a BMW i4. No current limit set in i4 (max 32A AC supported according to the dash). The Charging station is configured for 11kW/16A max, and 6A min current.
When I hook it up to the car with the BMW-provided 32A-rated cable it only charges with 6A or whatever is set to minimum current, it does not go over it.
Solar power is plenty available (15kW right now). When I raise the minimum current to 16A, then it charges with the full 11kW, but I want it to automatically charge at full speed.
What am I missing?
Hello @mlau . Can you please provide some screenshots of the EVCS or VRM dashboard at the moment when you think EVCS should use higher power for charging?
There is something wrong with you power measurements.
Where is the power for the EVCS coming from?
You charge with 11kW but only have 2,5kW coming from PV, almost nothing from the battery and still feeding back 250W into the grid.
You are “missing” around 9kW of power.
No, you don’t understand, there is only one battery: the lynx shunt gives a reading of all battery units combined while the single unit is used to control charge/discharge current. The units are all identical, but, with 15 dbus-serialbattery instances and batteryaggregator the cerbo becomes completely unusable. But this is completely besides my main point. This system has been working fine for all kinds of loads for almost 2 years.
I simply want the evcs to charge at full power, regardless of battery state. during summers I have enough battery to fully charge the vehicle and support all loads in the house; during winters, well, I need to charge from grid anyway.
Here’s the settings, maybe you can point out what I’m doing wrong?
In auto mode it tries to only charge with surplus PV energy.
That means:
Power is fed back into the grid and/or the battery is being charged and the SOC is above the configured values
In your first screenshot you feed 200W into the grid but the battery is also discharged with 200W, that’s why the EVCS doesn’t allow more current.
Is you PV production throttled due to a feed-in limit configured in the GX device?
Does it work better if the house battery is not full and still gets charged during the day?
You definitely have to fix the wrong battery reading for the EVSC.
Is the lynx selected as battery monitor in the GX device settings?
How does the VRM dashboard look? Does it show the correct battery current there?
Hm, is there a description of the charging-current-decision algorithm? Which system parameters it takes into account and their quantifier? Why would the current battery
discharge power reading affect anything? There’s no settable battery power limit that I’m aware of, just the DC charge/discharge current limits. And these are at 300A (i.e. 13kW), set by the battery monitor (i.e. dbus-serialbattery attached to one of the 15 parallel battery units).
There’s no PV limiting, and let me check tomorrow regarding charging both vehicle and battery.
No, the Lynx Shunt is not the active battery monitor; it’s set to the single dbus-serialbattery unit to control charge/discharge current based on unit cell voltages.
I’ll try manual mode.
(ideally, i want an algo like this:
if (grid_available) {
if (battery_soc < 21%) /* some configurable normal low limit */
charge_current = max_from_grid - solar_excess; /* charge ev from grid */
else
charge_current = Take as much as battery and solar can deliver minus the base loads from the house,
avoid drawing power from grid as much as possible while keeping charging power as
high as possible.
(battery discharge current depends on SOC)
} else {
/* no grid connection */
if (battery_soc < 40%) /* some configurable low emergency limit */
charge_current = 0; /* no charging, keep some battery for house, heatpump in winter */
else
charge_current = Take as much as battery and solar can deliver minus the base loads from the house,
as long as battery soc >40%
}
if (charge_current > charge_current_upper_limit_evcs)
charge_current = charge_current_upper_limit_evcs;
if (charge_current > charge_current_upper_limit_vehicle)
charge_current = charge_current_upper_limit_vehicle;
if (charge_current < charge_current_lower_limit_evcs)
charge_current = 0;
The charge/discharge limit from the battery doesn’t matter it’s the energy currently going in/out of the battery (to/from the grid and coming from PV) that the EVCS uses for the automatic mode.
If all your battery packs are connected to the input of the Lynx it sees all the current and it should be selected as battery monitor.
