I have a Raspberry Venus coupled with 2 MPPTs. This works so far also wonderfully.
But if the battery is switched off by the BMS due to undervoltage (at night and the Venus is also no longer supplied with power), the MPPTs do not start up again in the morning and the battery cannot be charged again. Only when the Venus is running again, the MPPTs also turn on again.... Is there a solution?
MPPT's don't need a venus to start. If the BMS has cut out then the battery can't start the mppt's and the mppt's need to get 6V above the charge voltage with PV before they activate. This may only happen later in the day. Assuming the panels and wiring is all 100%. You haven't provided any other details, so it's all a guess really.
Unlike "dumb" batteries, different models have different recovery procedures that may prevent it activating again. You would be better served to improve the capacity management or sizing of the batteries, so you can discharge low without forcing the BMS into protect.
Wit the Venus software controlling the MPPT, the MPPT will fall back to the OFF mode if it loses communication with the Venus controller, so no a system like this will not do a black start.
As mentioned above, the system should be designed not to use the BMS low voltage cut out - this is a safety feature that is not intended for 'regular' use. The correct solution would be to have a small script in the Venus device that does load shedding at low voltage / SOC that enables the Venus device to stay alive and the battery /BMS to remain on.
the problem is, sometimes the house is for a long time alone, and if something goes wrong, I like to switch off ALL consumers, also the Venus. There is no way to start the MPPTs automatically?
Hi all,
When configured as being controlled by a BMS, and no long receiving BMS control messages, a charger will still charge, but then at the batteries nominal voltage. In your case 48.0V.
And at the same time show Error 67.
For more details, see here: https://www.victronenergy.com/live/mppt-error-codes#err_67_-_bms_connection_lost.
So, I'm not sure why your system won't start by itself, hopefully this helps to find the cause.
