Hi all!

I've been lurking here for a while, trying to stay relatively up to date for when I want to take the plunge to solar myself.  That day is now getting closer, and I've been looking at inverters.  The Sunsynk/Deye range appear to come highly recommended, and appeal to me since they will offer the most flexibility in the long run.  I am however confused by a few things, so I'm hoping the kind folks on this forum can please offer some advice?

I need to decide between the 5kW and the 8kW models (though obviously prefer the smaller one).  I also need to decide whether I want to put most of the house on it, or just some basic essential loads, with the rest left as non-essential.  To figure this out, I need to understand how the inverter blends power.

I understand the 5kW has up to 7.7kW of passthrough.  If one has that installed with 5kW of solar, and wire everything on essential, midday sun is shining, and then switch on a 3kW kettle, 3kW Geyser and 500W of other stuff.  What will happen?  Will the inverter push 5kW from solar and supplement the remaining 1.5kW from grid?  (This is how I understand it - so as long as there is grid, you can effectively have over 7kW of loads running, just not all off solar?)

Then, same inverter, middle of the night, with roughly 5kW of battery hooked up to it (0.5C battery).  This can only supply up to 2.5kW before the battery will get upset, so what happens if suddenly 5kW of load is switched on?  Will the inverter use 2.5kW from battery, and pull the rest from Eskom?

And then finally, same scenario as above, but Eskom goes on a loadshedding spree in the middle of the night, and the 2.5kW limit of the battery is exceeded.  I imagine the battery will trip and leave you in darkness - but will the inverter manage this and trip before the battery?

At the start I imagine I'm going to go quite light on batteries, since they add significant cost to a system.  I'd like to have some battery available as a backup for load shedding and potentially cycle it for the early evening loads, but it looks like the best bang for the buck will come from solar during the day, not at night.  But, I don't want to half-bake the wiring and have to rewire house plugs and things at a later stage when I do decide to add more battery and want to move more loads to essential - so I want to get that right from the start.

Our peak load (without geysers and pool pumps) will currently be mostly under 5kW, but I am worried about the day that someone plugs in a toaster without thinking and potentially leaves us in the dark.  If it the inverter will indeed blend grid up to 7kW without keeling over, then I'm feeling reasonably comfortable that we can drive the entire house from it, but leaving geysers and pool pumps on the non-essential side.  (And maybe just having a couple a plugs on the grid side, should one ever need to run high-wattage appliances?)

Thanks!

On 2022/07/16 at 4:14 PM, sgs said:

Hi all!

I've been lurking here for a while, trying to stay relatively up to date for when I want to take the plunge to solar myself.  That day is now getting closer, and I've been looking at inverters.  The Sunsynk/Deye range appear to come highly recommended, and appeal to me since they will offer the most flexibility in the long run.  I am however confused by a few things, so I'm hoping the kind folks on this forum can please offer some advice?

I need to decide between the 5kW and the 8kW models (though obviously prefer the smaller one).  I also need to decide whether I want to put most of the house on it, or just some basic essential loads, with the rest left as non-essential.  To figure this out, I need to understand how the inverter blends power.

I understand the 5kW has up to 7.7kW of passthrough.  If one has that installed with 5kW of solar, and wire everything on essential, midday sun is shining, and then switch on a 3kW kettle, 3kW Geyser and 500W of other stuff.  What will happen?  Will the inverter push 5kW from solar and supplement the remaining 1.5kW from grid?  (This is how I understand it - so as long as there is grid, you can effectively have over 7kW of loads running, just not all off solar?)

Then, same inverter, middle of the night, with roughly 5kW of battery hooked up to it (0.5C battery).  This can only supply up to 2.5kW before the battery will get upset, so what happens if suddenly 5kW of load is switched on?  Will the inverter use 2.5kW from battery, and pull the rest from Eskom?

And then finally, same scenario as above, but Eskom goes on a loadshedding spree in the middle of the night, and the 2.5kW limit of the battery is exceeded.  I imagine the battery will trip and leave you in darkness - but will the inverter manage this and trip before the battery?

At the start I imagine I'm going to go quite light on batteries, since they add significant cost to a system.  I'd like to have some battery available as a backup for load shedding and potentially cycle it for the early evening loads, but it looks like the best bang for the buck will come from solar during the day, not at night.  But, I don't want to half-bake the wiring and have to rewire house plugs and things at a later stage when I do decide to add more battery and want to move more loads to essential - so I want to get that right from the start.

Our peak load (without geysers and pool pumps) will currently be mostly under 5kW, but I am worried about the day that someone plugs in a toaster without thinking and potentially leaves us in the dark.  If it the inverter will indeed blend grid up to 7kW without keeling over, then I'm feeling reasonably comfortable that we can drive the entire house from it, but leaving geysers and pool pumps on the non-essential side.  (And maybe just having a couple a plugs on the grid side, should one ever need to run high-wattage appliances?)

Thanks!

All your assumptions are correct 

Hi @sgs,

Soon after I finished my SS 8kW installation, I did a "stress" test, as my whole house is on essential.

I switched on a few heavy loads, so that load was exceeding PV supply, and it blended/balanced everything from 3 (supply) sources automatically.

At the end it boils down to setup/priority, as each installation may vary, depending on what the user requirement is.

Haven't had the need to "police" usage, or been able to trigger an overload. Hopefully it will give a beep warning, and if not actioned, I suspect it will do a shutdown.

Most systems these day are designed for minimal attention, provided management and comms between inverter and batteries are in place. Unlike the systems from yester year, specially Lead Acid types of Batteries.

I have the 5kw and it blends with no issues quite high... as long as Eskom is around. When there is LOS / outage then you are limited to the 5KW (plus whatever limitations the batteries place on you). Very high level view of the last few months of my load

Thanks all!  This is great! 

I should therefore be able to confidently go with the 5kW model if I leave ovens, pools and geysers off the essential side, and adjust our usage accoring to time-of-day.  Going to the 5kW vs the 8kW is an extra R10k+ that can go into solar panels or battery storage - awesome!

Put the pool on the essential side and just use a timer, pool pump is normally about 1000 watts . My 5kva Sunsynk handles that no problem 

On 2022/07/16 at 4:14 PM, sgs said:

Hi all!

I've been lurking here for a while, trying to stay relatively up to date for when I want to take the plunge to solar myself.  That day is now getting closer, and I've been looking at inverters.  The Sunsynk/Deye range appear to come highly recommended, and appeal to me since they will offer the most flexibility in the long run.  I am however confused by a few things, so I'm hoping the kind folks on this forum can please offer some advice?

I need to decide between the 5kW and the 8kW models (though obviously prefer the smaller one).  I also need to decide whether I want to put most of the house on it, or just some basic essential loads, with the rest left as non-essential.  To figure this out, I need to understand how the inverter blends power.

I understand the 5kW has up to 7.7kW of passthrough.  If one has that installed with 5kW of solar, and wire everything on essential, midday sun is shining, and then switch on a 3kW kettle, 3kW Geyser and 500W of other stuff.  What will happen?  Will the inverter push 5kW from solar and supplement the remaining 1.5kW from grid?  (This is how I understand it - so as long as there is grid, you can effectively have over 7kW of loads running, just not all off solar?)

Then, same inverter, middle of the night, with roughly 5kW of battery hooked up to it (0.5C battery).  This can only supply up to 2.5kW before the battery will get upset, so what happens if suddenly 5kW of load is switched on?  Will the inverter use 2.5kW from battery, and pull the rest from Eskom?

And then finally, same scenario as above, but Eskom goes on a loadshedding spree in the middle of the night, and the 2.5kW limit of the battery is exceeded.  I imagine the battery will trip and leave you in darkness - but will the inverter manage this and trip before the battery?

At the start I imagine I'm going to go quite light on batteries, since they add significant cost to a system.  I'd like to have some battery available as a backup for load shedding and potentially cycle it for the early evening loads, but it looks like the best bang for the buck will come from solar during the day, not at night.  But, I don't want to half-bake the wiring and have to rewire house plugs and things at a later stage when I do decide to add more battery and want to move more loads to essential - so I want to get that right from the start.

Our peak load (without geysers and pool pumps) will currently be mostly under 5kW, but I am worried about the day that someone plugs in a toaster without thinking and potentially leaves us in the dark.  If it the inverter will indeed blend grid up to 7kW without keeling over, then I'm feeling reasonably comfortable that we can drive the entire house from it, but leaving geysers and pool pumps on the non-essential side.  (And maybe just having a couple a plugs on the grid side, should one ever need to run high-wattage appliances?)

Thanks!

Great questions.
 

Guys, sorry for the highjack, but does the Kodak OG 7.2 function in the same way when load exceed 7.2 kW ? (1st question)

 

Thanks

 

Edited July 31, 20223 yr by Wannebe

On 2022/07/31 at 7:52 PM, Wannebe said:

Guys, sorry for the highjack, but does the Kodak OG 7.2 function in the same way when load exceed 7.2 kW ?

On paper, it seems so. You are allowed short term overloads (e.g. for starting motors), but nothing more than a minute or so (depending on how much overload).

Edit:

Quote

(1st question)

Pardon my manners! Welcome to the forum.

Edited August 2, 20223 yr by Coulomb