My 8KW Sunsynk seems to clip power at 19.4A on both MPPT's, is this normal as I had the firmware upgraded but seems to do the same?

 

Firmware Version:

SW Ver. M 6.0.2.7 / S 1.7.2.4 / C E.4.3.9

Is the only option to go for a bigger inverter like the 12KW or 16Kw to make more power?

I don't think it's a firmware issue. You just seem to be hitting up against the power limit of the MPPT's, which is 10400W. I guess this is one of the downsides when you're over-panelling an inverter, the 14720W of panels are likely to be clipping down to 19A to stay within the 10400W DC input limit.

If you want to test that theory, try to disconnect one of your MPPT's at night (edit: [not mid-day, taking correction by @Sidewinder]), and see how the remaining MPPT behaves at mid-day. My guess is, that MPPT will be producing closer to 7360W of power by itself with half of your panels connected to it, and probably at around 336V, at 22A of current.

I make full allowance for the possibility that I could be wrong.

If I'm right, your options would be to either upgrade to a more powerful inverter like the Sunsynk 12kW 1P inverter with 15600W max DC input power, which would make full use of your 14270W of panels (as long as your batteries are busy charging). Or a 2nd 8kW inverter in parallel, alternatively the 16kW Sunsynk, so you can use the full 14270W output for AC as well. Otherwise, you could consider adding a micro-inverter or string inverter to AUX of the existing 8kW Sunsynk inverter, and transfer around 8-10 panels from the existing strings to it.

That's if you find that you're not getting enough power to charge all your batteries and run your loads, but considering that your batteries seem to be charged by around 2pm, it might not be really necessary to do anything, just run in load priority, and you might be fine as-is.

Edited November 2, 20241 yr by GreenFields

Thanks for the feedback and it makes sense will try to disconnect one of the mppt connectors tomorrow and test otherwise as you suggested leave it unless I need more power.

@fstofberg

Just make sure you disconnect before the sun comes up, and the reverse after the sun has set. No need to "test disconnect under (full/partial) load" if it is not an emergency!

According to Solar Assistant you are getting a combined +- 12 kW solar production from your 8.8 kW machine. That is very good and nothing to worry about, as @GreenFields has stated the supposed solar max is 10.4 kW. Excess going to batteries, and max AC going to load of +- 8.9 kW (discounting any pass through from Eskom).

If you want higher production or load try a 16 kW unit. (Built like a tank)

Welcome to the forum, and a nice setup you have.  Many people would like to borrow it.😂

Yes mine clips on my parallel string at 19.6A

The strange thing is that the latest 8kW manual says it will clip at 26A.

I asked sunsynk about this and they never came back to me. It's either only for the latest 8kW inverters or it's a typo

@Chris_S that is what I'm seeing on my inverters, I upgraded to the latest firmware, but it never goes above 19.5A per MPPT, I have 2 of the 8KW units the old unit showed 22A per MPPT and the new one shows 26A per MPPT but they both stop at 19.5A.

As @TimCam suggested my next step is going to be the 16KW as I don't have space to mount both 8KW units next to each other.

The 8kW is a solid inverter, but the 16kW machine is just in another class. Get one and you'll see the difference in build quality.

23 hours ago, fstofberg said:

@Chris_S that is what I'm seeing on my inverters, I upgraded to the latest firmware, but it never goes above 19.5A per MPPT, I have 2 of the 8KW units the old unit showed 22A per MPPT and the new one shows 26A per MPPT but they both stop at 19.5A.

As @TimCam suggested my next step is going to be the 16KW as I don't have space to mount both 8KW units next to each other.

On older FW mine would clip at 21A but there was a big problem. If there were intermittent fast moving clouds and the current very quickly hit the 21A it would sometimes cause a DC over current error and the inverter would shutdown and restart. 

Since upgrading the FW and it clips at 19.5A I do not have that problem anymore.