Working principles of Deye 5kw inverter

[neko_kun]

I've done as much research as I can and just want to make sure that my understanding of how it works is correct:

5kw Deye inverter + 4 x 545 watt solar panels + 1 x 5kwh battery was installed in December 2023, another 6 x 545 watt panels will be installed in the first week of January 2024 and then another 2 x 5kwh batteries later in 2024. Property has 1 house and 1 flat where grandma lives. House and flat has separate geysers. House geyser has 3.2kw element and then the flat has 2.2kw element. At the moment everything runs of the UPS-load side of the inverter. My plan is to split the geyser in the flat to the smart output port on the inverter in January when they install the additional panels

Scenario 1) Normal day with lots of sun. Settings on smart port would be to turn on the flat geyser whenever there is 3kw incoming solar and battery is at least 80% charged, except when the house geyser is running(each geyser has separate timer so will just ensure that the timers do not turn on at the same time)

Scenario 2) Rainy day when solar input does not reach 3kw and geyser does not turn on at all. Get home at 6pm and Grandma says there is no hot water. In this scenario I could just set the minimum solar input to 0 on the smart meter settings screen, this should then basically allow me to then manually turn on the geyser?

I want to make sure that I can still manually turn on the geyser in a case like scenario 2. It's also not a case of split everything and see if it works as I would have to hire an electrician to install a new cable from the geyser to the inverter that is situated in the main house and then if it doesn't work I'll have to pay him again to change everything back to the way it is now.

Then just one more feature I want to make sure about. In the manual it says maximum AC output 25amps which is 5.5kw then there is another line that says maximum AC pass through of 35amps which is 7.7kw. Internet says this means that I can run a 7.7kw load on the inverter while there is AC grid power without any of the overload safety systems engaging and turning off the inverter?

 

[Killerwatt]

Just my 2c here. Have a sunsynk and also initially wanted to put the geyser on the smart load. But soon we realised that you always want hot water, rain or shine. So geyser ended up downsizing the element from 4kw to 2kw and runs for around mid day on a timer with another slot in the early morning to bump up temps. Grid will supply the balance on a rainy day.

Coupled to this is a timer setting to top up the battery in the evening. On a rainy day the grid will get the SOC to a level that gets us through the night. If there was enough sun then no power is pulled from the grid.

Honestly best use of smart load seems to be for non essential loads, especially if you have additional solar. The problem with the smart load solely for a geyser is the inability to set a timer. You can get around it with an ATS but it wasnt worth the hassel for me.

Yes you can pull 35amps through the inverter this is the limit of the internal switches.

 

[Pr0d1gy2020]

Agree with Killerwatt, best to run timers on both geysers so they only come on during the day and when sun is up and you can set timer to switch between geysers in 30 min/1 hour intervals, and downsize elements, so that you can run other appliances without overload.

 

[neko_kun]

Thanks for the input guys. Yeah if manually turning on the geyser becomes the issue then it won't be worth while for me either

I doubt an overload would happen very easily but it could happen. i have changed everything on the property to gas that I could except the geysers. I could always upgrade the inverter later down the line but when i placed the order the price difference between buying the 5kw vs the 8 or 10kw was better spent on solar panels

I was also considering changing the house's element to a smaller one because the current one is a massive™ load

 

[SnowmanZA]

For the geysers, I can recommend this:

Solar Geyser System | Apex

Our Apex Solar Geyser System solution has been certified against two international standards, received a regulatory compliance certificate from the national regulator, and been approved by ICASA radio spectrum compliance.

www.apexsolar.tech

 

[Billionairebum]

For the geysers, I can recommend this:

Solar Geyser System | Apex

Our Apex Solar Geyser System solution has been certified against two international standards, received a regulatory compliance certificate from the national regulator, and been approved by ICASA radio spectrum compliance.

www.apexsolar.tech

My brief understanding of this is that is could connect directly to solar panels and it has a temperature probe into the element?

 

[phenix456]

I've done as much research as I can and just want to make sure that my understanding of how it works is correct:

5kw Deye inverter + 4 x 545 watt solar panels + 1 x 5kwh battery was installed in December 2023, another 6 x 545 watt panels will be installed in the first week of January 2024 and then another 2 x 5kwh batteries later in 2024. Property has 1 house and 1 flat where grandma lives. House and flat has separate geysers. House geyser has 3.2kw element and then the flat has 2.2kw element. At the moment everything runs of the UPS-load side of the inverter. My plan is to split the geyser in the flat to the smart output port on the inverter in January when they install the additional panels

Scenario 1) Normal day with lots of sun. Settings on smart port would be to turn on the flat geyser whenever there is 3kw incoming solar and battery is at least 80% charged, except when the house geyser is running(each geyser has separate timer so will just ensure that the timers do not turn on at the same time)

Scenario 2) Rainy day when solar input does not reach 3kw and geyser does not turn on at all. Get home at 6pm and Grandma says there is no hot water. In this scenario I could just set the minimum solar input to 0 on the smart meter settings screen, this should then basically allow me to then manually turn on the geyser?

I want to make sure that I can still manually turn on the geyser in a case like scenario 2. It's also not a case of split everything and see if it works as I would have to hire an electrician to install a new cable from the geyser to the inverter that is situated in the main house and then if it doesn't work I'll have to pay him again to change everything back to the way it is now.

Then just one more feature I want to make sure about. In the manual it says maximum AC output 25amps which is 5.5kw then there is another line that says maximum AC pass through of 35amps which is 7.7kw. Internet says this means that I can run a 7.7kw load on the inverter while there is AC grid power without any of the overload safety systems engaging and turning off the inverter?

Use the "Zero export to CT" mode and connect your geysers directly to the utility. When there's excess solar, the additional household loads will benefit from it (including the geyser), when there's not, grid power will be used.

If you connect the geysers to the backup load, it'll work pretty similarly except you'll be limited to the 5kW total provision of the inverter and you run the risk of depleting your battery storage if the geyser is used during load shedding (for example).

 

[SnowmanZA]

My brief understanding of this is that is could connect directly to solar panels and it has a temperature probe into the element?

Yes, it has a special fitting to attach a temperature probe to your thermostat. This lets it monitor your geyser temperature directly. You connect a few solar panels to it and it will use the PV to heat your water with your standard AC element. It has a few settings that you can adjust regarding the temperatures and when it is allowed to use AC to heat your element. If the water isn't very hot and you need hot water soon, you can also tell it to boost quickly from AC etc. It's quite nice.

 

[Divan85]

Use the "Zero export to CT" mode and connect your geysers directly to the utility. When there's excess solar, the additional household loads will benefit from it (including the geyser), when there's not, grid power will be used.

If you connect the geysers to the backup load, it'll work pretty similarly except you'll be limited to the 5kW total provision of the inverter and you run the risk of depleting your battery storage if the geyser is used during load shedding (for example).

What @phenix456 said above is the correct way to do it IMHO. It is also the way I did my installation. My geyser and stove is still on utility whereas all the plugs and lights are on the inverter. I set my geyser timer to run during peak sun-hours (13H00-14H00) everyday, that way the excess solar is used to power the geyser.

To put it in perspective, the day before xmas we spent almost all day in the kitchen with the oven running non-stop for almost 10hrs, coupled with the hour the geyser ran and we still only used about 3kWh (units) of utility power, the rest was powered by the solar even though it is not on the output of the inverter.

 

[Pansyfaust]

We have it setup so that everything is on the inverter, but we have installed a sonoff "loadshedder" relay switch which is a smart dumb switch. Essentially, when there is loadshedding, the relay switches on, which then causes the geyser (and pool pump) in our case to turn off. This prevents the geyser from using any backup power we might have on rainy days with loadshedding or when we do a geyser warm up in the morning before the sun is fully out.

We have an 8KW sunsyk, so it is a bit easier to manage loads, but I would definitely get some smart switches for the geysers if you plan to run both off a 5KW inverter.

 

[Stangrhys1102]

I have a 5kw Deye (6kw of solar + 1 battery) with two geysers. One geyser is off the inverter along with the oven, and the other geyser is on the inverter. To be honest, I think having both geysers on the inverter would be optimal if all your geysers were smart. When there is loadshedding, it's quite inconvenient not being able to heat both of the geysers when there is loads of solar. I have reduced the element in each geyser to a 2kw element, so there is often enough solar to heat both concurrently. I make sure that dishwasher and washing machine has already run by the time the first geyser comes on at 9:30. Doing this, I manage to buy less than 100kwh per month while using about 800kwh in the home. I pretty much only buy 3 or 4kwh between 6pm and 10pm at which point i move to battery for the night. It's really important that you are able to remotely switch on geysers and pumps according to available solar. This way you can shift as much load as possible to sunny hours.

 

[Killerwatt]

I have a 5kw Deye (6kw of solar + 1 battery) with two geysers. One geyser is off the inverter along with the oven, and the other geyser is on the inverter. To be honest, I think having both geysers on the inverter would be optimal if all your geysers were smart. When there is loadshedding, it's quite inconvenient not being able to heat both of the geysers when there is loads of solar. I have reduced the element in each geyser to a 2kw element, so there is often enough solar to heat both concurrently. I make sure that dishwasher and washing machine has already run by the time the first geyser comes on at 9:30. Doing this, I manage to buy less than 100kwh per month while using about 800kwh in the home. I pretty much only buy 3 or 4kwh between 6pm and 10pm at which point i move to battery for the night. It's really important that you are able to remotely switch on geysers and pumps according to available solar. This way you can shift as much load as possible to sunny hours.

With that much solar it does make sense but only if your battery has as much power as the pv array. The mppts on these inverters are not the fastest so power draw on transients comes from the battery.

Setting up aux load to be on when grid is availible will work allong with the timers. You would just need to manually manage your useage power as you are.

 

[ettiene]

Non-essentials only helpfull if there is less stages of loadshedding. Otherwise it's a waste, half the day your panels does nothing at stage 6. Kinda defeats the purpose of having solar...

Yes, it has a special fitting to attach a temperature probe to your thermostat. This lets it monitor your geyser temperature directly. You connect a few solar panels to it and it will use the PV to heat your water with your standard AC element. It has a few settings that you can adjust regarding the temperatures and when it is allowed to use AC to heat your element. If the water isn't very hot and you need hot water soon, you can also tell it to boost quickly from AC etc. It's quite nice.

This is also a waste, when your geyser is hot these panels can be used to charge battery if they where on the inverter. Instead with this thingamajig they useless for the rest of the day.


With panels so cheap you need to max out what your inverter can handle, not for sunny days but rather for the bad days.

Heat water storage is by far the cheapest way to store energy. To maximise on this set geyser on max temp, 70c and also have a look in adding a pre heat geyser infront of the current ones when you have excess solar.