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tpwchr avatar image

How to deviate the solar exceedance in an off-grid?

I would like to know how to manage the excess PV production once the batteries are full and all electric needs are supplied. I want to send that exceedance to a water heater for an off-grid. Thanks

offgridvictron
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4 Answers
Vance Mitchell avatar image
Vance Mitchell answered ·

Could you give us some more information about your system? There’s a few ways to achieve what you are after depending on what you currently have.


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I'm currently designing an offgrid installation of 6300Wp, 4x 2,4kWh Pylontech, MPII, 2x MPPT 250/100 and Cerbo GX. Thank you Vance.

One way to achieve what you want is to use assistants in Ve.configure to turn AC2 on when certain conditions are met (such as SOC above 95%, off if below 90%). That is depending on inverter load and using an AC water heater.

You could also use the cerbo to control a battery protect (or relay of some sort) to power a DC heater.(personally I would add a BMV and have it control a relay, but I’m sure it can be done from the cerbo)

With a system that size I would discuss with your Victron dealer/supplier as there might be better or simpler options.

EDIT: This is my case: https://www.victronenergy.com/live/actor_offgrid


I found this product https://runhutech.en.made-in-china.com/product/SFWEedbKyYcD/China-Hwc01-Ce-Certification-Solar-Water-Heater-Intelligent-Controller-Electric.html that uses the clamp to check the excess energy. I guess this would not be possible for an off grid


"The Solar Immersion Controller works by using a clamp which scans your renewable generation and detects any excess energy that would be sent to the grid"

I’m not familiar with that product or system so can’t help with that sorry.

jomugu avatar image
jomugu answered ·

@tpwchr, @Alexandra,

Hi all,

I'm using diy energy excess usage system for a Fronius Primo 3.1 / Multiplus 24/3000 /4500Wp Canadian Solar / 24 V 445 Topzs TAB battery bank off-gryd system.

I can detect when the Fronius is throttled, which means energy excess, and use that excess, calculated by radiation measuring, in six different presets loads. I can switch on and off those loads (1 or 0). Also, I have developed a seventh load with 0-10 V signal control.

This method can be scalable to any size. Also, I'm working now to adapt it to DC-coupling, but AC-coupling give you some extra benefits.

The loads that I'm using right now for energy excess are two AC units, one water heater (1200Wp) and a water treatment plan.

As I manage the loads via IFTTT, adding the new ones doesn't require any wiring, just some programming.

A challenge for me is the water heater to be used with a power regulator. I tried with a phase angle regulator, and the result is that the Multiplus wave is disturbing a lot. I'll read a little more about ACThor, but we must take into account that this is off-grid, no grid powerful signal to help.

Contact me if interested.

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Janek Plathe avatar image
Janek Plathe answered ·

Hi,

I have an island system and use dumbloads, I will install the MyPV system in November. As I have AC and DC coupled PV I have two options for controlling the unit in my island setup.

A: frequency shifting: the AC connected Fronius PV inverter output is reduced if neccesarry by increasing the the frequency from in example 50 to 52. telling the Fronius to reduce the output as the produced energy is not needed.
the ACThor is adjusted exactly opposite. He will increase its energy output I.e to the the heating coil if the frequency rises.


B: My other way I.e to control the charging speed for an EV is via an Lux Sensor.
the Lux value equipped with an correction Factor equals pretty close the possible maximum energy output of the entire system - even if reduced because the consumption is low and battery is full.


Possible maximum energy out - current consumption = energy left for the Wallbox.


greetings

Janek

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Hi all,

I'm using diy energy excess usage system for a Fronius Primo 3.1 / Multiplus 24/3000 /4500Wp Canadian Solar / 24 V 445 Topzs TAB battery bank off-gryd system.

I can detect when the Fronius is throttled, which means energy excess, and use that excess, calculated by radiation measuring, in six different presets loads. I can switch on and off those loads (1 or 0). Also, I have developed a seventh load with 0-10 V signal control.

This method can be scalable to any size. Also, I'm working now to adapt it to DC-coupling, but AC-coupling give you some extra benefits.

The loads that I'm using right now for energy excess are two AC units, one water heater (1200Wp) and a water treatment plan.

As I manage the loads via IFTTT, adding the new ones doesn't require any wiring, just some programming.

A challenge for me is the water heater to be used with a power regulator. I tried with a phase angle regulator, and the result is that the Multiplus wave is disturbing a lot. I'll read a little more about ACThor, but we must take into account that this is off-grid, no grid powerful signal to help.

Contact me if interested.

Have you checked carlotron? https://carlotronsolar.com/descripcion/ it's exactly what offgridders need, i might buy it in the future if I buy ceramic heater accumulators for next winter.

tpwchr avatar image
tpwchr answered ·

So nobody uses the excess of power in offgrid ? Strange that Victron hasn't provided a way of using this extra power into something else I guess.

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I ask Victron for years to help me to integrate Victron into automation but none helps.

Fronius has his own module for Fibaro and for Homey....

So I work hard an in final I integrated Victron into Home Center 2 from Fibaro, and I have all Victron values in app.

In this way I create some rules based on few parameters, if battery is 98 %, if consumption of home is under 2000w, if lux meter is over 200lux, then turn on the AC and heat/cool the home.

In my case I have 3 Ac that turn on automatically based on certain values, and also turn off based on few rules :))


In this way I use all my excess of energy to heat the home.

Of course, you can use a module that turn on the boiler, or to charge the car....or whatever.


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