Hi

I have a sunsynk 3.6kw inverter, max solar input 7kw. 15 x 385w panels (5.7kw)

My solar input seems to be limited to just under 4kw. The input chart seems to be shaved above that (attached)

Is this a setting somewhere to increase this 4kw solar limit, or am I misunderstanding what is happening?

?

34 minutes ago, tsf said:

Hi

I have a sunsynk 3.6kw inverter, max solar input 7kw. 15 x 385w panels (5.7kw)

My solar input seems to be limited to just under 4kw. The input chart seems to be shaved above that (attached)

Is this a setting somewhere to increase this 4kw solar limit, or am I misunderstanding what is happening?

?

Some mis understanding. This is a 3.6kW inverter and Sunsynk indicate the maximum PV that could be connected is 4.5kW. To have a warranty be honoured I would reduce the panels connected ASAP.

Refer to the specs for the limits.

Please post the sticker on the inverter here.

Edited May 31, 20251 yr by Scorp007

Thanks for the quick reply

I've checked the spec plate on the side of the inverter and it says 7000w max solar input. (Pic attached). The output power is 3.6kw.

It was installed by a well respected national installer, so I'd be surprised if they overloaded it with too many panels.

But again, sorry if I'm not understanding your point correctly. I don't interact with the inverter much so don't really have a deep understanding of the tech.

Hi @tsf

The Max AC power your inverter can produce is 3960W

The Max solar input power the MPPT can handle is 7000w (you have 5.7kw so well below that)

MAX MPPT voltage is 500Vdc - this number is very important, more so than the max wattage.

The only place is can use the 3000W above the 3960w max AC power is into the battery as that is DC power and that is only if you have space available in your battery.

The main reason for over watting your system is to make up for poor solar conditions so you still make good power even when the weather is bad.

Panels are so cheap now adays that it makes sense to add more panels than you need/can use on good solar days.

I don't see anything wrong with the number of panels that you have, the main thing that has to be within limits is the string voltage which maxes at 500Vdc, check your string voltage and just make sure that it is not close to 500V and you are good. The inverter will throttle the production from the panels it cannot use. It is like plugging an appliance into a 15A socket, it doesn't mean that the appliance has to use 15A, just that it has 15A available.

1 hour ago, Sc00bs said:

Hi @tsf

The Max AC power your inverter can produce is 3960W

The Max solar input power the MPPT can handle is 7000w (you have 5.7kw so well below that)

MAX MPPT voltage is 500Vdc - this number is very important, more so than the max wattage.

The only place is can use the 3000W above the 3960w max AC power is into the battery as that is DC power and that is only if you have space available in your battery.

The main reason for over watting your system is to make up for poor solar conditions so you still make good power even when the weather is bad.

Panels are so cheap now adays that it makes sense to add more panels than you need/can use on good solar days.

I don't see anything wrong with the number of panels that you have, the main thing that has to be within limits is the string voltage which maxes at 500Vdc, check your string voltage and just make sure that it is not close to 500V and you are good. The inverter will throttle the production from the panels it cannot use. It is like plugging an appliance into a 15A socket, it doesn't mean that the appliance has to use 15A, just that it has 15A available.

Thanks for the correct details. There seem to be outdated specs floating around. 😊

1 hour ago, Scorp007 said:

Thanks for the correct details. There seem to be outdated specs floating around. 😊

Speaking under correction, but I recall seeing something about a version of this 3.6kW Sunsynk inverter for the UK market that came with the big 7kW MPPT to cater for poorer solar radiation or maybe bigger batteries or something like that.

4 hours ago, tsf said:

Thanks for the quick reply

I've checked the spec plate on the side of the inverter and it says 7000w max solar input. (Pic attached). The output power is 3.6kw.

It was installed by a well respected national installer, so I'd be surprised if they overloaded it with too many panels.

But again, sorry if I'm not understanding your point correctly. I don't interact with the inverter much so don't really have a deep understanding of the tech.

Now that we know 7kW of panels can be used. It is pretty normal this time of the year to see only 70% output from the PV connected. In summer the average can be over 80% but dependent on direction and angle as well as load connected and SOC of the battery. I would thus not be concerned with only seeing 4kW from PV.

13 hours ago, tsf said:

My solar input seems to be limited to just under 4kw. The input chart seems to be shaved above that (attached)

I see from the chart you posted that both your battery charging, and your feedback into the grid, are limited just below 4kW. Your panels won't produce more electricity than what you consume, no matter how many panels you have, or how bright the sun is shining... Took me a while to make this "discovery" when I started 🙂

Given that you have a 3.6kW inverter, you are probably just maxed out, and your clever inverter is limiting the load, and thus also limiting your PV input.

@Scorp007 & @tsf The inverter is a 3960W inverter, it doesn't matter how many panels you have on it it is not capable of generating more than 3960W of AC power.

The only time it would be able to generate/utilise more than 3960W of power would be if it is charging a battery with the extra DC power.

As I said, the reason for allowing more panels is so that you can still make decent power on low solar radiation days.

Keith from Sunsynk has a pretty good video explaining the reasons for over watting your inverter

12 hours ago, HennieL said:

Given that you have a 3.6kW inverter, you are probably just maxed out, and your clever inverter is limiting the load, and thus also limiting your PV input.

Just a simple question. If you have no grid and your big battery bank can supply say 200A but being a 5kW inverter you have set a maximum discharge current of 100A.

What happens on a Deye/Sunsynk if the 5kW limit with connected load exceeds 5kW?

Thanks everyone.

As you say, the panels won't produce more than can be used. I understand that now.

I tested that by only charging my battery to 70% last night. That meant there was still a charging requirement at peak solar time today. The panels were able to generate produced 5kw to meet that need and export the rest.

Edited June 1, 20251 yr by tsf

That's great to hear 👍

Tell me, where are you located? Just being curious, as I see your PV fluctuates quite rapidly throughout the day. Living in Bloemfontein, South Africa, that is quite strange to me -here it's mostly full sunshine, or when it's cloudy (not that often...) it remains constantly cloudy for most of the day...

So, this is a question I have asked many installers. I have a 5Kw Sunsynk which states on the plate a max solar input of 6500W and 13Adc. My argument has been that the input wattage and amps is immaterial, the system can only use up to the specified figures, but amps are drawn, not pushed, so as long as I don't go higher than 480Vdc, according to Keith, I am quite safe and can use 600W panels that can produce 18A if desired. I keep getting told that I'll blow my inverter, I can only install max 460W panels x14. Am I not seeing something?

@tsf ,

I recon, seeing that you are feeding into the grid @ 3286W average, that is the number programmed into you inverter for max wattage during feed-in. You can adjust it.

1) You panels will only generate as much as the load + Feed-in + Battery charge requires. In this case your battery is full, and your load seems low, hence the +- 4k PV limit.

2) However, the spike in load just before 15h00 would have increased the PV production (with a few second lag), which I don't see.

So I would like to think/agree something is amiss, unless you are suffering with the good old winter "low solar PV production blues", like the rest of us.

14 hours ago, dax021 said:

So, this is a question I have asked many installers. I have a 5Kw Sunsynk which states on the plate a max solar input of 6500W and 13Adc. My argument has been that the input wattage and amps is immaterial, the system can only use up to the specified figures, but amps are drawn, not pushed, so as long as I don't go higher than 480Vdc, according to Keith, I am quite safe and can use 600W panels that can produce 18A if desired. I keep getting told that I'll blow my inverter, I can only install max 460W panels x14. Am I not seeing something?

Try not to exceed the Isc (Short-circuit current) rating on the inverter. I think it's 17A for that model, but check the specs to be sure.

On 2025/06/01 at 11:07 AM, Scorp007 said:

Just a simple question. If you have no grid and your big battery bank can supply say 200A but being a 5kW inverter you have set a maximum discharge current of 100A.

What happens on a Deye/Sunsynk if the 5kW limit with connected load exceeds 5kW?

200A @ 50V = 10,000W , your 5kw inverter however can only generate 5kw of AC power, it does not matter how much DC power you give it.

With no grid connected the inverter will trip out if you try to pull more than 5kw from it for an extended period of time.

It can take going slightly over 5kw limit for a short period of time

Even when the inverter is connected to the grid there is a limit to the amount of power that can flow through the inverter i.e. your essential loads - Sunsynk or Backup Loads-Deye

The max pass thru current on a 5kw Deye/Sunsynk is limited to 35A (this is at 230V, not 50V) so a max power of 35A * 230V = 8050W

So even if your 5kw if grid connected, if you pull more than 8kw of power on the essential load side it will also trip the inverter out.

For this reason it is often better to have your heavy loads on the Sunsynk - non-essential, Deye On-Grid Loads side as that power does not pass thru the inverter but can still be powered by the inverter.

It is however important to understand that the On-Grid Loads cannot be powered if their is no grid present i.e. loadshedding.