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Goodwe Inverter being more controllable


SteRi

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Hi all

 

I am new here.. I was wondering if my new goodwe 4.6 es could do this scenario.

 

I want to add a heat pump to the pool to utilize the extra wattage my panels can produce.. I have ample amounts of excess power from the solar panels..

 

The scenario would be to run the heat pump from let's say 9 am to 3 pm everyday to heat the pool.. is there a way for the inverter to cut the heat pump if there is no solar power available I.e very cloudy ect. I would hate to use eskom to fill the gap when there is no PV power. I have been told you can do this on a victron as it is more controllable. Would be great if a goodwe could do this..

 

Just interested in hearing your thoughts around this or maybe a different solution

 

Thanks again

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There are various 3rd party solutions for the likes of immersion heaters, but in my opinion they are priced so that their pay back period practically makes them self- excluding.

Regarding your Goodwe, I don't know the inverter capabilities, but if there was capability of controlling an output relay via custom logic, that could work.

But, the solution I'd consider first is inverter agnostic, but it may not work for you. You'd have study your own conditions, again I am not sure what is available to you.

In my own set up, I notice about an 18V swing in my grid voltage between drawing from the grid at night and max solar production during the day. This (in my own scenario), would be sufficient of a difference to control an off the shelf relay that would give me a contact when the sun was shining. Probably a 10V swing would be enough to discriminate.

There are a host of voltage settable relays, with hysteresis settings and built in timers so that the pump motor could enjoy a level of stability without stopping and starting for every cloud.

They certainly exist, but you'd have to do your research.

 

 

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Thank you all for the replies..

 

It does not seem i will win with Goodwe and the Scenario i gave above..

 

I am probably going to have to go the way you went Pietpower and use a smart switch to turn it off and on when i notice it is just a bad solar day.

 

I really hope they add a bit more functionality to this inverter as this small customization does not warrant me to go a full Victron route.

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26 minutes ago, SteRi said:

This would obviously need me to have relay inputs and from what i can tell there are no relay inputs on a Goodwe, Maybe someone with more knowledge can verify this for me.

No, it wouldn't, the opposite in fact, as I said it is an inverter agnostic solution. 

You only need  monitor the grid voltage and need the output of the voltage monitoring relay to switch on the heat pump.

The inverter is not directly involved.

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On 2020/01/13 at 11:32 AM, SteRi said:

Hi all

 

I am new here.. I was wondering if my new goodwe 4.6 es could do this scenario.

 

I want to add a heat pump to the pool to utilize the extra wattage my panels can produce.. I have ample amounts of excess power from the solar panels..

 

The scenario would be to run the heat pump from let's say 9 am to 3 pm everyday to heat the pool.. is there a way for the inverter to cut the heat pump if there is no solar power available I.e very cloudy ect. I would hate to use eskom to fill the gap when there is no PV power. I have been told you can do this on a victron as it is more controllable. Would be great if a goodwe could do this..

 

Just interested in hearing your thoughts around this or maybe a different solution

 

Thanks again

For a shame, 99% of the PV inverters have no way how to tell you that there's some extra wattage available. There's a couple of reasons behind this, the 2 most obvious are:

  • Electrically, you can't measure available power (watts) if there's no load that is actually consuming that power.
  • Lack of dry contact output on the inverter itself and proprietary communication API of the each inverter manufacturer.

Therefore, if you want to intelligently power on/off your heat pump, you have to use something what's called WattRouter or generally "Power Diverting Device":

1) WattRouter

https://solarcontrols.cz/en/wattrouter_mx.html

The device is measuring the export to the AC grid and if there's some excess power going to the grid, then it activates the relay. If there's import from the grid, the device will open the relay. Both threshold values can be adjusted, of course. On top of relays, the WattRouter can control SSRs too, which allows more fine-grain power diverting for immersion heaters etc.

image.png.21c9cc436660f400e8418e38bf4443c1.png

image.png.3cc4bdefa3400ba880fcd7e682ae60fd.png

2) Home brew solution

Since GW4.6ES has batteries, there's a cheap and simple way how you can control the heat pump with an Arduino. It's a home brew solution, so you need to have some skills with the electronics and programming, of course:

  • Grab an Arduino, add 2 resistors as a voltage divider and measure the 48V DC voltage on the battery bank that the GW4.6ES is charging.
  • Add any suitable relay board from ebay
  • Create a code that will close the relay whenever the voltage on a battery reaches "full charge". In most cases it's somewhere around 52-55V for lithium, just check the specsheet for your batteries.
  • Add a condition, that when the battery voltage drops roughly 2V under the "full charge", the relay will open.

If there's enough sun and the battery is full, the above solution will turn-on the heat pump. If there's still enough power to run the heater and keep the battery charged, it will stay ON. If there's not enough sun, then the battery will start to discharge, and the heater will be turned OFF after a minute or two. Of course, the code will need some tuning and a hysteresis in order to avoid excessive cycling of the relay. Works with any inverter that has batteries.

 

3) Other

Some other solutions are to utilize EmonPI from OpenEnergyProject or EDDI from MyEnergi:

https://myenergi.com/product/eddi/
https://guide.openenergymonitor.org/applications/solar-pv/

Both of the above are utilizing AC current transformers for measuring export to the grid. EmonPI would need some additional HW and customization, EDDI is a bit overkill and won't work directly with a heat pump as it's meant for immersion heaters primary.

Good luck!

 

image.png.37a01adc200a476957346afd11cc7667.png

 

image.png.a4c78726d643491a59171dfcc91de65b.png

 

 

Edited by Youda
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21 hours ago, Youda said:

Therefore, if you want to intelligently power on/off your heat pump, you have to use something what's called WattRouter or generally "Power Diverting Device":

I was also looking for a way to accomplish power diverting with my Goodwe ES inverter. Unfortunately all the available power diverters rely on the "grid feed in information" from a CT clamp and do not work if the inverter is set to zero export (most of the GTI's in South Africa are set up like this). I like your home brew solution because it is very cheap and will work well with Lithium batteries. Another solution (much more expensive) is to use a Victron BMV and use the relay to switch the desired loads based on SOC.

Edited by Fuenkli
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