In winter, on a dark day, my 65 solar panels produce a total of about 5Kwh per day (from about 10am to 4pm). So during 18 hours there is no output from the panels.
But the 3 Multiplusses consume 54 watts per hour (so for 18 hours total approx. 1 Kwh).
Is it wise to turn off the Multiplusses at night? Or is this unwise because of the life span of the Multiplusses?
You mean after the batteries are drained? Otherwise it would not make sense i suppose. If you have loads connected to AC-out like a UPS function this is not an option as you would cut all power there. If you have a grid tied ESS system and only use AC-in, i suppose it would save a little power, see if it outweighs the cost savings though. I have no answer on the lifespan.
Thank you for your response.
At this time nothing is connected to the AC-out.
The intention is to make emergency power points in the house soon. When the grid fails at night, these can easily be activated by turning on the Multiplusses. The advantage of this setup (that the power to the house does not run through the AC-out) is that power will remain in the house if the Victron system fails (I presume the AC-out will also fail then?).
The battery is 70% charged, but not yet used, because in the Netherlands we still receive full compensation for power that is fed back into the grid. However, this is expected to expire in some time. Then it will make sense to start using the battery at night and it will not be an option to turn off the Multiplus.
There is another reason to turn off the Multiplus at night: even without solar power, the battery continues to charge and discharge continuously. This ranges from a few watts to about 500 watts ore more. I have read that this is the normal behavior of ESS. But the chargers and inverters are in continuous operation as a result. Inverting the power, again takes power.
Right now, I leave the Multiplusses on, but switch on the External Control option on the ESS at night (there is no external control). This breaks the communication between MPPT, Multiplusses and BMS, and the inverter and charger of the Multiplusses turn off.
I suspect it is better not to turn off the Multiplus completely at night, because of possible wear and tear on the relays (sparking).
AES is - as far as I know - only an option for a standalone situation and not for on-grid.
Ah i understand now with the current full compensation. I would not bother turning the system off if you are running Victron MPPTs.
Look at it this way: with your amount of panels, you will get 100kwh excess in one day mid summer, that compensation alone will keep your multiplusses running cost zero trough winter, sort of.
If you would have a coupled Fronius AC inverter. You could turn the Victron system off for now, but its not the case as i understand.
To complete the story: There are 4 Victron MPPTs and 1 Fronius 3-phase inverter (in the shed). In order not to complicate things, the Fronius is not connected to the AC out (so does not work in case of grid failure).
The installation is designed to have as much yield as possible in winter and with the premise that soon there will probably be (almost) no more compensation for the surplus of solar energy in summer (the grid operators want to get rid of compensation as soon as possible).
A yield of 100 Kwh per day in summer is perhaps not feasible, I think, because there are 35 panels facing north (installation has only been running for a few weeks).
We have diffuse light 80% of the time in the Netherlands. Then it doesn't matter whether the panels are facing south or north. That is also what I see on a cloudy day.
Some would suggest against switching the multis on and off every day but personally, I would suggest taking full advantage of the ESS. That is, when your batteries are charged the system can export the excess power and you can be compensated for that. Meanwhile, while you have your own power (from batteries or solar) you are not consuming from the grid and the batteries actually extend the hours your solar works for you. This is good for your pocket and the evironment.
