Was looking at this website (to complicated for my brain), but has anybody done this or have something similar? I am looking at doing microinverters and was wondering if this would work. So say my household load is 600w and the pv array is producing 1100w, could it be possible to then say okay, rather than bringing down the PV to 600w to match the load, send the excess to the geyser elements, until I need more for the household load?

 

Not 100% sure if this is possible or not with the microinverter setup.

2 hours ago, Greglsh said:

Not 100% sure if this is possible or not with the microinverter setup.

Me neither, but for sure will be possible in the future.

At the moment though I think all 50Hz micro-inverters are all or nothing in terms of production.

60Hz leads the tech charge with micro-inverters.

2 hours ago, Greglsh said:

Was looking at this website (to complicated for my brain), but has anybody done this or have something similar?

I haven't specifically looked at this product offering, but several products like it that make similar claims.

Some types can create issues as they switch with thyristors and only partially use the sine wave. Introducing harmonics that can affect sensitive equipment.

Some are better that utilize any excess of the entire sine wave.

I haven't seen any that come in at a price, that would realistically save the price of a few more panels..

Some people choose to divert power at the DC side, that comes with its own issues. A geyser element being a resistor isn't bothered by DC, but switching DC, (like a thermostat has to do), is a different ball game.

Assuming feeding back into the Grid isn't an option, then I would consider scheduling your geyser "on" times ( and other loads) to correspond with peak PV production times.

So as to minimize the nett power flow from the grid.

This is the cheapest solution that will get you 3/4's of the way there. (Granted it is not an elegant solution).

Supervising the timer with a "state of charge" contact from a BMV say would get you 95% there.

 

 

 

 

So i have been actually working at the same issue.
I got myself a Hoymiles MI-600 and did not opt in for the DTU unit which can be programmed to read a CT clamp and reduce the total production value from the microinverter, giving you essentially a zero export system.
I only installed 160W worth of panels onto it so far (as i picked up two 80W for cheap and decided to join the solar club), and i end up some days exporting around 50-60W when the fridge is idle. Because of the pre-paid meter installed in the place im renting, i am actually paying for the power that is being exported, and the muni meter behind that spins backwards!!!

So just being a DIY doer, i went ahead and built the circuit on openenergymonitor and used the mk2pvrouter version 3 code with a ardiuno and a SSR attached to a 70W Halogen bulb.
Taking daily readings for the last week, it seems im saving about 200-300W on the pre-paid meter by running the light bulb.

I intend going the full distance and building or buying the actual thing and attaching it to the geyser, so that i can max out with 600W and in theory, i would be able to provide around 2kWh worth of power into the geyser.

Feel free to contact me
 

PhatWheZ

Please let me know how you go with this, I think this is a very good road to follow. During the day while I am at work my house load is about 500w ( no Kettle, geyser,iron,dishwasher etc) will have 1.2kw solar(perfect conditions) and I would like to double this, this year. So basically lets say 1.5kw of "wasted" pv which could be used to heat water.

Please keep me in the loop with how you go with this. 

5 hours ago, Greglsh said:

PhatWheZ

Please let me know how you go with this, I think this is a very good road to follow. During the day while I am at work my house load is about 500w ( no Kettle, geyser,iron,dishwasher etc) will have 1.2kw solar(perfect conditions) and I would like to double this, this year. So basically lets say 1.5kw of "wasted" pv which could be used to heat water.

Please keep me in the loop with how you go with this. 

Do you think it will be that much more efficient than just using a timer to get the geyser to heat during the day when there is lots of sunshine? 

I guess it will use all available PV power while the standard geyser heater takes a lot of power for a short time - the panels will only be able to supply some of the demand when it comes on. 

 

That is my plan for now, to get a Geyserwise and only turn the geysers on during solar production. Just thought this might be more efficient, not 100% sure.

Here's an idea:

 

 

On 2019/04/19 at 7:57 AM, Greglsh said:

Please let me know how you go with this, I think this is a very good road to follow. During the day while I am at work my house load is about 500w ( no Kettle, geyser,iron,dishwasher etc) will have 1.2kw solar(perfect conditions) and I would like to double this, this year. So basically lets say 1.5kw of "wasted" pv which could be used to heat water.

The biggest thing to remember if you are going to have this much power available to be "wasted" is that what do you do when your thermostat kicks in and stops you from dumping power into your geyser.
This approach in my research is only feasible where:

1. you are only going to have a few panels to cover your base load during sunlight hour.

2. net metering is applicable in your areas but, why waste your time with this approach then

 

On 2019/04/19 at 1:28 PM, Elbow said:

Do you think it will be that much more efficient than just using a timer to get the geyser to heat during the day when there is lots of sunshine? 

I guess it will use all available PV power while the standard geyser heater takes a lot of power for a short time - the panels will only be able to supply some of the demand when it comes on. 

The efficiency comes from using the power that would otherwise be exported and billed against you, which is my pain point.
I ran a Sonoff POW R1 few a few months, until it gave way to turn the geyser on and off as you mentioned. This gave me some useful telemetry in identifying how long i actually need to run the geyser to be warm enough and at the same time, how much KWh it uses.
Since then, it burnt out and have gone to manually turning on and off which works perfectly fine for my use. I only run the geyser for 2Hrs once a week to burn out potential bacteria.

Another approach could be to, in the morning turn on the geyser before you leave work and let the solar help cover the bill, then when you get home, just turn it off. With the numbers Greglsh is talking about, he would save around 1KWh atleast

18 hours ago, SilverNodashi said:

Here's an idea

I was looking at this idea as well. There is a lot of reasonably priced power diverters on the market in Australia and the UK. Unfortunately none of them works if the inverter is set for zero export 🙁.

10 hours ago, Fuenkli said:

I was looking at this idea as well. There is a lot of reasonably priced power diverters on the market in Australia and the UK. Unfortunately none of them works if the inverter is set for zero export 🙁.

Well that's the thing. What this guy does, doesn't depend on export at all. It will work with a non grid tie inverter as well, but you need to know some coding and electronics to be able to do it. Basically the code will see if there's enough power available and activate a SSR to run the geyser off the excess solar energy.

I purely just timed mine from 14:00 to 16:00 and we schedule our day so that heavy current items like the washing machine or dishwasher is finish by that time. And I don't have a grid-tie inverter.