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Graydon avatar image
Graydon asked

Feature Request: Multiplus Time of Day programming

I am working through a way to program my Multiplus to only enable AC Input based on time-of-day. I have a PV system, Cerbo GX, Multiplus 3000 and LiFePo batteries

We, in Canada, and I think more and more places in the world vary the price of electricity based on the time of day it is used. Morning and evening rush hours are most expensive, followed by mid-day, and nights & weekends are the cheapest. In Ottawa where I live, the costs at peak times are 21.7¢/KWH peak, 15.0¢/KWH mid-peak and 10.5¢/KWH nights and weekends. This is significant and very costly to run appliances during peak and mid peak times, 7 am to 7 pm, over twice the costs of running appliances at night.

I have my Multiplus connected to my AC mains through a high current wifi switch (iDevices product) that can be programmed to turn on and off per conditions. I have mine set to turn on at midnight, and off at 6 am, the lowest cost time of day for energy, and enough time to charge up my batteries. The rest of the time, 6 am to midnight the batteries and Multiplus Inverter are running my appliances. Thus saving 6 hours of peak time, and 6 hours of mid-peak time, and 7 hours of off-peak time. And, depending on the amount of sun during the day, the batteries may or may not need a full 5 hours of charging from the Multiplus AC Charger.

I would suggest, and like to see, an additional option added to the AC Conditional controls for time of day/day of week. Being able to turn on or off the AC Charger and Power switching based on what day and time it is. I think this would be an extremely valuable tool for most home owners, and expand your potential market greatly, when people see how a small solar powered system can save significant dollars by selective use of the AC power system.

I found this in the community forums that I 'think' will allow me to program the Multiplus to turn on and off based on the time from the Cerbo...I am still working to get it actually working though

https://www.victronenergy.com/live/drafts:acin_ignore_timer_using_ccgx_gen_start_stop_example



MultiPlus Quattro Inverter Charger
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richoff avatar image richoff commented ·
Have you found any answers to this yet? I'm in Ontario with the same situation.
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2 Answers
shaneyake avatar image
shaneyake answered ·

These feature mostly exists already.

In the ESS menu if you go down to the bottom you will see and option for scheduled charging.
You then put in the time for the cheapest electricity and the SOC you would like to be at by the end of that periode. ESS will keep grid usage at 0W during normally hours and charge during that period.

https://www.victronenergy.com/media/pg/Energy_Storage_System/en/configuration.html#UUID-eea56ee5-efe2-0fce-ab6f-ba51656dfb45

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gherlt avatar image
gherlt answered ·

I have been thinking about this als for a few months now, and thinking about economics, easy end user implementation, battery life, flexibility.

In my summer house I do have some batteries, but when my wife cooks diner much of the battery energy is gone ;-) . In the morning comes the medium rate and then right after that the morning high rate period, all that before the photovoltaic modules kick in at a reasonable level for the house hold base load (300W+).

When I spend battery energy in the night (when cost is lowest), economically that makes no sense, as in the morning no energy is left in batteries and have to pay high cost for the first things we do in the morning.
So,my manual solution is that just before midnight (bedtime and start of lowest rate) I switch off the Quattro if battery level is below 80% (= required level with which I reach the morning's start time of "minimal solar power generation" comfortably on "batteriy only").
In the morning, first thing (unless forecast is rain), I switch on the Quattro and then sail on battery through the high-cost hours of the morning.


I would therefor suggest the definition of three scenarios (they all already exist in Victron), which would somehow coincide with the three electricity tariffs:

1- Lowest rate scenario, option of charging batteries
policy: grid preference/consume grid electricity, mantain battery energy
OPTIONAL: charge batteries if below xx% minimum

This is the night tariff if you do not have enough battery to come through the night.
consume grid electricity until end of this period.

OPTIONAL: charge batteries IF below xx% (e.g. 60%).

OPTION ACTIVATED

The xx% percentage varies between seasons, in winter it is higher because sun comes out later (if any) and a bit of high demand in the first morning hours, in summer less so (sun comes out earlier).

Result: If you have enough battery to reach to sunrise, great, do not use this
If the day before you had bad weather (or nights are long=winter), you will use battery and then grid. If battery if below of minimum target, it will be charged.

OPTION DEACTIVATED

This is your case in "good climate/summer": if you do not have enough battery to come through the night, but do not want to accumulate into batteries, because sun comes up very early or powerful, or you do not have a peak consumption in the morning.

Wish list:
Take into account weather forecast (bad weather -> xx% higher), weekends (get up later, xx% lower), a bit of AI would be great !!


2- Medium rate scenario: solar & battery energy preference IF batteries > yy %
That would use solar and battery power, if the battery is at least at yy% (e.g. 50 %).
If not enough energy, use grid if battery below yy%

Intended to use solar/battery mainly, but having a minimum reserve if there is a "high rate" afterwards. You enter high rate times with at least that level of battery.

3- High rate scenario: solar & battery energy use preference down to battery battery minimum (zz%)

Use all energy from solar and battery while there is one.
If battery falls below minimum, grid will be used (no much of a choise here, bar defining zz% minimum)

*******************

In all cases, if solar production is higher than consumption, battery is charged until full.

Now that we have three scenarios, we would just need to define a weekly calender for defining the aplication to each hour of the week.
The end user could define one scenario as base scenario - which would be active all time except for definition of a change or if there are conflicting defintions.
I personally would use high rate a base scenario, define "medium rate scenario" as the "every night" scenario. In case of high demand first hour in the morning (with high rates) of week days, for the night I would choose "lowest rate scenario" with battery charging to 70%.

In any case, I would say that with these scenarios and a weekly timetable would give the flexibility to adjust to all needs and possible configurations of any grid connected end user.

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shaneyake avatar image shaneyake commented ·

You can already do High vs low. You don't need to manually turn off your inverters.

In the ESS Menu setup, under scheduled charging, you can set the SOC you would like to be at and when it should be in this mode, it has weekdays vs weekends. Other than weather is would take care of what you are trying to do.

For more advanced control you can install the large version of the firmware on a Cerbo.
https://www.victronenergy.com/live/venus-os:large

Then using NodeRed, you can take into account weather and even limit the discharge rate during cooking hours. Everything you want is possible, will just take some time to set up.

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gherlt avatar image gherlt shaneyake commented ·

Thank you, but as I suggest the SOC is different for the three rates. For now in ESS you have only one desired SOC level, and yes, a weekly schedule for this SOC level.
All states/functionsI mention are already possible ("Keep batteries charged", "minimum SOC", etcetc). Using Nodered and other 3rd party hardware is not my idea of "integrated", especially considering that all is already there...

So, what I am proposing - as is Graydon - is one place where I define three (or more) states and apply those on a weekly schedule. I am not proposing new functionaliy, I am proposing a new interface.


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