Solar immersion optimiser fitted

[torbrowser]

Finally got round to fitting my immersion optimiser
I went for the solarimmersion unit as its a uk company
My set up is Growatt hybrid SPH inverter and battery storage

Now I was expecting this to use excess kWh’s that would otherwise be exported back to the grid once the battery has fully charged, good idea as on bright days I can throw away a fair bit of power.

What is actually happening is every time the sun shines it switches the immersion on and robs the battery of charge



Had the clamp meter out to try and figure out where things are going,


So to overcome this I have set inverter to ‘battery first’ so now all generated power goes into the battery and in theory once full the inverter will try to export the power and the solarimmersion will detect this and divert to hot water tank

Trouble is meanwhile, every time I boil the kettle I’m pulling power from grid not the generated solar power.
So don’t want to run my system in this mode.

Who else has one of these devices fitted, how does yours function ??

 

[torbrowser]

Just to add, reason I don’t want to rob the battery charging to heat the immersion is because it’s cheaper to heat water with gas.
I only want to heat water when the power would otherwise be exported.

 

[johnb2713]

Is the CT definitely the right way round?

Why is your inverter exporting when the battery isnt full?

Can you set the minimum export value of export before the immersion is triggered?

 

[torbrowser]

Hi John, CT clamp correct, tested with PV disconnected and loads pulled.

No idea why inverter started exporting when immersion triggered, can CT clamps affect each other, have spaced them further apart
You can just about see the 2 clamps in the photo above, blue for inverter and black for immersion.

Don’t understand your last question regarding export, the inverter will export, but only when battery full and no demand, except when immersion triggered.

 

[torbrowser]

Can 2 CT clamps affect one another?

 

[binky]

Can 2 CT clamps affect one another?

Shouldn't do.

 

[torbrowser]

Didn’t think so, strange.
What is puzzling me is what the immersion optimiser CT clamp is detecting to make it operate when inverter starts generating ie, sun out, the inverter never exports before battery is full,
Why is it firing up upon solar generation?

I must be missing something obvious here.

 

[binky]

Didn’t think so, strange.
What is puzzling me is what the immersion optimiser CT clamp is detecting to make it operate when inverter starts generating ie, sun out, the inverter never exports before battery is full,
Why is it firing up upon solar generation?

I must be missing something obvious here.

If you have no other loads on, it will send leccy to the immersion. I have an older version, that starts up from 150w of spare leccy, does yours start from the same figure or lower?

 

[ProDave]

Solar dump controllers normally operate by burst firing the immersion, so it's 3kW then 0kW then 3kW etc over a time period typically between 1/2 and 1 second.

What is actually happening is with the immersion on, you are probably importing power, and when the immersion is off exporting power. This is a neat little trick making use of the way electricity meters work that they don't clock up any usage until one "unit" of energy has passed, typically 1 watt hour. So as long as you keep importing them exporting rapidly and the total each way averages at 0 and at no time does it clock up 1 watt hour in either direction, you do not get metered for anything.

I wonder if this rapid import / export is upsetting the inverters sensing? put simply it cannot cope.

Ask the inverter manufacturer if it is compatible with a burst firing solar dump controller?

 

[torbrowser]

That is a good reply, because when operating, the immersion heater LED indicator in the switch flickers,(occasionally) the instructions say this is likely to happen.

But yes, the inverter is 'reporting' export, but strangely couldn't pin it down with my clamp meter.

But i'm still at a loss as why its firing up when there is no export, other than the miniscule amounts the inverter sends and receives on occasion to monitor the supply, and why having set the inverter to prioratise battery for a set time it doesn't try to fire the immersion up then.

You are on to something here.

 

[torbrowser]

Yes i will get onto the manufacturers of both inverter and solar immersion and ask the question.

 

[torbrowser]

If you have no other loads on, it will send leccy to the immersion. I have an older version, that starts up from 150w of spare leccy, does yours start from the same figure or lower?

I don't know what the figure is, it simply says it proportional to the exported loads.
I get what you are saying, the immersion is getting priority over the battery though, and the electricity is better 'spent' on the battery than the immersion. Until such point that i'm throwing electricity away once the battery is full.

 

[torbrowser]

Just to simplify,

PV system imports and exports normally, only exporting when battery full and no loads on.
Fitted the immersion optimiser, it now operates when battery is not full, but only when PV is generating power (don't know how much before it starts to operate) will check again in daylight.
Once it is heating the immersion, the App control shows export of any excess power to grid, there should be none as this should go to the immersion (is this the inverter being confused, as per pro dave)

The big question is why is this immersion optimiser starting at all when battery is not full and there should be zero exported power.
?

 

[binky]

Just to simplify,

PV system imports and exports normally, only exporting when battery full and no loads on.
Fitted the immersion optimiser, it now operates when battery is not full, but only when PV is generating power (don't know how much before it starts to operate) will check again in daylight.
Once it is heating the immersion, the App control shows export of any excess power to grid, there should be none as this should go to the immersion (is this the inverter being confused, as per pro dave)

The big question is why is this immersion optimiser starting at all when battery is not full and there should be zero exported power.
?

Sounds like the immersion is more responsive than the battery, which in turn is confusing the battery algorithms.

You might have been better off with an Eddi which you can control for 2 loads

 

[torbrowser]

Thanks Binky,
So you think the Immersion CT clamp responds quicker than the inverters CT clamp, Immersion pulls load, inverter 'sees' this as just load, and sends power to it accordingly, by passing the battery. - As it is intended to.

Makes sense.

Getting somewhere.

 

[binky]

Thanks Binky,
So you think the Immersion CT clamp responds quicker than the inverters CT clamp, Immersion pulls load, inverter 'sees' this as just load, and sends power to it accordingly, by passing the battery. - As it is intended to.

Makes sense.

Getting somewhere.

Sounds like that to me, I know my immersun is very good at what it does, and it's a simple gadget compared to an inverter, so will respond a lot quicker, it's got far less to do!

 

[torbrowser]

Just had a look at the EDDI controller.
It reads the same as the spiel that came with the one i have fitted from https://solarimmersion.co.uk/
Quite a difference in price though, i wonder why

 

[torbrowser]

Sounds like that to me, I know my immersun is very good at what it does, and it's a simple gadget compared to an inverter, so will respond a lot quicker, it's got far less to do!

The immersun looks and sounds the same as what i have, and assuming you have batteries on your system and the immersun is working fine, what do you think the reason is yours works and mine doesn't?

 

[binky]

The immersun looks and sounds the same as what i have, and assuming you have batteries on your system and the immersun is working fine, what do you think the reason is yours works and mine doesn't?

I don't have batteries, my energy use is too low to justify buying them.

I would have a chat with the immersun technical helpline, it sounds like you need to set it for, say, 200w before it works. That will hopefully allow the batteries to do their thing before it cuts in.

 

[johnb2713]

Just had a look at the EDDI controller.
It reads the same as the spiel that came with the one i have fitted from https://solarimmersion.co.uk/
Quite a difference in price though, i wonder why

EDDI works ! LOL

It sounds from the symptoms that the CT is fitted on the wrong cable, it sounds as if it's on the output of the solar inverter rather than on the incoming supply. I know from your photographs that doesnt appear to be the case.
If you take the CT off the wire does the unit still trigger the immersion?