Geyser timer solution for solar

[SauRoNZA]

There is a lot going on here.

So the inverter I have is a pretty basic inverter. Navasolar PV1800 PRO 5.2KW 48V Offgrid Solar Inverter

It doesn't have any of the fancy features.

So my thinkingh was just get a decent geyser timer that I set for 9am to 2pm or so. If there is good sunlight then geyser heating will be free. If not then running my inverter in SUB mode means it will just feed of the grid its not like I will lose anything because its already running on grid anyways.

I just don't want it to drain the battery if a power outage strike that time. Then I will only have solar + bat and if light is low the battery will be drained quickly. It won't matter if the sun comes back because the battery will charge but what if it rains.

Now I have a battery that is empty. Grid that is off due to power outage but hot water at least. I'd rather have backup battery power than hot water.


How are you guys running the geyser setup on solar?

Off grid inverter and only 5.2kW. So there’s no AC pass through?

I wouldn’t even attempt to run the geyser through that.

 

[wingnut771]

Off grid inverter and only 5.2kW. So there’s no AC pass through?

I wouldn’t even attempt to run the geyser through that.

Can be done.

 

[cavedog]

Off grid inverter and only 5.2kW. So there’s no AC pass through?

I wouldn’t even attempt to run the geyser through that.

Can be done.

So this is the setup I will have right now.

I'm going to add a 2nd inverter in parallel to bring the capacity up to 10.4kw with another 8 panels.

I'm not sure what size my geyser element is now but what is the standard size for a 150l? Is it 3KW?

 

[wingnut771]

So this is the setup I will have right now.

I'm going to add a 2nd inverter in parallel to bring the capacity up to 10.4kw with another 8 panels.

I'm not sure what size my geyser element is now but what is the standard size for a 150l? Is it 3KW?

Not sure you can add parallel inverters with nava.

I think its 3kW, you can drop it to 2kW if you have other loads.

 

[cavedog]

Not sure you can add parallel inverters with nava.

I think its 3kW, you can drop it to 2kW if you have other loads.

The booklet says 3 units. It has the parallel switches at the bottom and cables and installation guide.

 

[SauRoNZA]

Can be done.

Oh I didn’t mean to imply that it can’t be done, its just right on the edge.

 

[cavedog]

Oh I didn’t mean to imply that it can’t be done, its just right on the edge.

I was thinking the same. Maybe I should just wait until I get the second inverter installed. I will speak to the guys tomorrow when they come and install to confirm.

 

[wingnut771]

I was thinking the same. Maybe I should just wait until I get the second inverter installed. I will speak to the guys tomorrow when they come and install to confirm.

Change to a 2kW element now for a few bucks then at least you can boil the kettle when the geyser is on.

 

[LazyLion]

My geyser is on a timer... and it only runs two hours in the early morning, and two hours in the early evening (drawing from Municipal power). Those four hours are enough to keep the water hot in the 200l geyser all the time.

 

[cavedog]

Change to a 2kW element now for a few bucks then at least you can boil the kettle when the geyser is on.

I think I will do this. It says it has a max of 10KW surge supply, but I don't know what exactly the cut-off for over draw is. Probably like 1min or less so i would just need to watch my consumption to not trip the thing all the time.

 

[Speedster]

My geyser is on a timer... and it only runs two hours in the early morning, and two hours in the early evening (drawing from Municipal power). Those four hours are enough to keep the water hot in the 200l geyser all the time.

The vdefining ariable in residential water heating is the number of occupants (and their water usage). 4 hours a day (12kwh) is enough for you. It could be overkill for someone staying alone, and insufficient for a family of 5 who like to bath. The other factor is the ambient water temp - you need about 3.5kWh more when heating 200l from 10degrees (cold winter day) than from 25degrees (hot summer day).

 

[wingnut771]

I think I will do this. It says it has a max of 10KW surge supply, but I don't know what exactly the cut-off for over draw is. Probably like 1min or less so i would just need to watch my consumption to not trip the thing all the time.

Those surge stats are for like 30 seconds or something, it takes care of spikes when pumps and compressors turn on.

 

[denmendez65]

Off grid inverter and only 5.2kW. So there’s no AC pass through?

I wouldn’t even attempt to run the geyser through that.

AC pass through is for overloading the inverter. How is this relevant here?

 

[Speedster]

AC pass through is for overloading the inverter. How is this relevant here?

5kw inverter. 3kw geyser element. You don't see the problem?

 

[denmendez65]

5kw inverter. 3kw geyser element. You don't see the problem?

Is it really off grid inverter though? All these sellers label these things differently. Mine is labeled offgrid but it’s actually a hybrid

 

[denmendez65]

5kw inverter. 3kw geyser element. You don't see the problem?

Also I wouldn’t worry. 1.5kW element and throw a 16A breaker on the non essential load. Get it to supply the kitchen also on non essential. Can run the geyser and another kitchen appliance simultaneously.

There’s a couple of options available for that. I use a timer to kill the kitchen for the period when the geyser is running off the inverter. So it never overloads and no one can make the mistake. I do run it for an hour at most of the inverter though.

With some creativity it can be made to work.

 

[denmendez65]

Is it really off grid inverter though? All these sellers label these things differently. Mine is labeled offgrid but it’s actually a hybrid

The inverter is a hybrid. Not offgrid. So will definitely have pass through. They are all the same these Voltronic clones. Mine has similar specs to the Navasolar one but it’s a MUST inverter. Just a smaller size.

 

[SauRoNZA]

AC pass through is for overloading the inverter. How is this relevant here?

AC pass through isn’t really overloading but just going because solar capacity aka using the AC “in line” on a hybrid inverter.

The power doesn’t run “through” the inverter as such.

 

[denmendez65]

AC pass through isn’t really overloading but just going because solar capacity aka using the AC “in line” on a hybrid inverter.

The power doesn’t run “through” the inverter as such.

Maybe passthrough has different meanings for different inverters. For mine its when the inverter gets overloaded it transfers to the grid automatically and lets the grid supply the load. Thats how I understood the terminology.

Since I have no grid connection to the inverter all that happens is the inverter kills the non essential output to reduce its load. I dont know what happens if the inverter is overloaded on the essential output, never happened before. I suspect it will just switch off.

My kitchen is on non-essential, geyser on essential. Geyser is on essential as it only runs for 30 minutes a day. Currently its set to 1 hour as there is 4 people in the house for the next 2 weeks. Weekend had 7 people (5 adults and 2 kids) so it was set for 2 hours. 1 hour heating in the morning at 7am. And another hour around 1pm. Worked decently well considering I have a small system and used no grid.

 

[SauRoNZA]

Maybe passthrough has different meanings for different inverters. For mine its when the inverter gets overloaded it transfers to the grid automatically and lets the grid supply the load. Thats how I understood the terminology.

It’s not “overloaded” as such, it’s there by design hence the feature.

It’s more like it’s offloading the load to AC.

Overload implies something has gone wrong, which this isn’t.

Since I have no grid connection to the inverter all that happens is the inverter kills the non essential output to reduce its load. I dont know what happens if the inverter is overloaded on the essential output, never happened before. I suspect it will just switch off.

My kitchen is on non-essential, geyser on essential. Geyser is on essential as it only runs for 30 minutes a day. Currently its set to 1 hour as there is 4 people in the house for the next 2 weeks. Weekend had 7 people (5 adults and 2 kids) so it was set for 2 hours. 1 hour heating in the morning at 7am. And another hour around 1pm. Worked decently well considering I have a small system and used no grid.

Yes if there is no grid it’s just going to overload and die.

Same still happens to me when load shedding and there isn’t enough solar or battery capacity to deal with the load, which is why all things geyser etc turn themselves off.