Hi guys. 
 

So I have been in my new place for about 2months now in summer. 
 

I have the below  

1x Axpert King 5kva

12x 325W Panels

4x Gel batteries 200Ah …. Which are almost dead ☠️ 

I still use roughly 8/14kw every evening (guessing geyser) & overall around 25/30kw in a 24hr period.
last 6days has been 24.19Kw average extra used from the grid.  

1. I have noticed that often the panels don’t produce what they could because the load is too low. 
Turning on extra appliances suddenly allows extra solar to be produced. 
 

So my thought is that there is still part of the house that is not on the 5kva. 
Things like geyser and the odd plugs etc. Not sure why it’s so high in the evening.Will investigate  

I know it wouldn’t be significant savings maybe only 2/5kw a day but possibly a start I can keep building on ?

If I could expand with an additional 5kva Axpert in parallel. ( not extra batteries or panels as yet)
Then during the day when the panels are “idiling” they could be used to power the Geyser and help supplement the power it consumes. 
My thought is at worst my Eskom bill would drop off a little. 
 

2. I could expand possibly batteries next moving to maybe 3x 4.8Kva Lithium batteries as a start to run through the evening to lower that grid usage. 
Think that’s 14.4kw of which I could run it down to 11.52

Then expand later as we require more….
 

3. Then expand on panels as we go. 
is that possible. Eg maybe but some extra panels as I go of the same type till I’m at a size required. 
 

4. If my max I can use on the inverter is 4000W. 
Could I put say 6000w worth of panels on. I know at peak it would only produce the 4000w. 
But would that allow more to be produced under poor conditions like clouds or early morning / late afternoons etc. meaning say early morning normally only makes 300w at a guess now it could potentially make 450w. 

3 hours ago, Dry_Reef said:

If I could expand with an additional 5kva Axpert in parallel. ( not extra batteries or panels as yet)
Then during the day when the panels are “idiling” they could be used to power the Geyser and help supplement the power it consumes. 
My thought is at worst my Eskom bill would drop off a little. 

The trouble with off-grid inverters is that you have to choose to put a load before or after the inverter. With on-grid inverters, you can push power to all the loads, even the non-essential ones like the geyser. And the geyser is a heavy load. The problem is what to do on extended cloudy days, especially if the utility supply isn't reliable, or there is frequent load shedding. Then you have to power your geyser mostly from your ailing battery. That won't be popular.

Adding the second inverter doesn't make much sense before you upgrade the battery.

3 hours ago, Dry_Reef said:

4. If my max I can use on the inverter is 4000W. 
Could I put say 6000w worth of panels on.

I would not go beyond about 20% over the nominal rating of the solar charger. In the King 5 kVA, that's 4000 W, so I would not go beyond 4.8 kVA per inverter. Of course, if you do add the second King, then you can gradually add panels to the second inverter. Be aware that the second inverter will add an extra self-consumption load, about an extra 50 W for a 5 kVA model.

Thanks Coulomb. 

Currently if it’s there is a higher load say 2kva and it gets cloudy it is auto compensated for or filled in from the grid. 
same at night it runs off grid until the power actually fails and goes onto battery’s. 
 

Does that mean mine is on grid then and then a 2nd inverter would thus make more sense ?

On the attached you can see how it draws from grid when there isn’t sufficient supply. 

11 hours ago, Dry_Reef said:

Currently if it’s there is a higher load say 2kva and it gets cloudy it is auto compensated for or filled in from the grid. 

Yes. The King is the only 145 V max model that can do that.

11 hours ago, Dry_Reef said:

Does that mean mine is on grid then and then a 2nd inverter would thus make more sense ?

No, you still can't have the Kings supplying power to the geyser when there is excess, unless you put the geyser on the essential loads side, and that means the geyser could turn on its big load when there is no utility.

If that's extremely rare, you could hope you're home and isolate the geyser if and when it happens, hoping that someone is home at the time.

Edit: To do what you want, you need a grid interactive inverter that can export, and a utility that doesn't mind you exporting power if you don't have enough load for the available solar power. That power that is "exported" by the inverter can be used by your geyser before it gets out to the utility.

So one possibility is to add an ordinary grid interactive inverter instead of another King. It could temporarily use a few strings that the Axpert is presently using, before you add more panels. It probably needs at least 4, 5, or 6 panels in series to do anything. So at times when the King is supplementing load power from its AC-in port, some or all of that may come from the grid interactive inverter. The grid-tie inverter won't need a battery either. However, any time that the utility power goes off, you won't be able to use power from the panels connected to that grid-tie inverter.

Edited December 1, 20223 yr by Coulomb