Thank you kindly for the response. I changed my 8kw to a 10kw with 3 x MPPT and installed a string of 7 x 610w East so I have a overdesigned system, but I will benefit greatly in the winter months

On 2026/02/24 at 8:44 AM, FransSmith said:

I changed my 8kw to a 10kw with 3 x MPPT and installed a string of 7 x 610w East

And presumably you kept the 18 x 550w north and west panels...

Nice - that's nearly double my current 8.05kWp. I'm hoping to add a third string of 7 x ~600W panels this winter, taking my total to ~12kWp. Should allow me to go completely off grid.

On 2026/02/24 at 8:44 AM, FransSmith said:

Thank you kindly for the response. I changed my 8kw to a 10kw with 3 x MPPT and installed a string of 7 x 610w East so I have a overdesigned system, but I will benefit greatly in the winter months

Thank you for the feedback and nice upgrade 👌👏
Just for discussion sake and for others reading the thread it’s worth clarifying something about MPPT configuration on the 8kW vs 10kW units.
On the Sunsynk 8kW Hybrid Inverter, you have 2 MPPTs with 2 inputs per tracker. If configured correctly, it could have been arranged as:
MPPT1:
• 9 × 550W North
• 9 × 550W West
MPPT2:
• 7 × 610W East
Since the North and West strings use identical panels and identical string lengths (9 in series), their Vmp is the same. When paralleled on one MPPT, the tracker operates at a common voltage and the string receiving more irradiance simply contributes more current. In this case, there is no voltage mismatch penalty.
The East string (7 × 610W) would remain independently tracked on MPPT2.
So from a pure solar harvesting perspective, the 8kW unit could have achieved essentially the same DC efficiency if wired optimally.
That said, the upgrade to the Sunsynk 10kW Hybrid Inverter does bring advantages:
True independent tracking per orientation
Higher AC output headroom (10kW vs 8kW)
More flexibility for future expansion
Better winter production due to the additional East capacity
Your winter benefit will mainly come from the added 7 × 610W East array and the broader production curve not strictly from having a third MPPT.
Overall, it’s a strong system either way 👍

On 2026/01/08 at 8:22 AM, GordonH said:

Out of curiosity, what does the Victron have extra that could go wrong?

Pros and cons, but Victron is more modular. For example, the MPPT is separate and the inverter is only an inverter. With Sunsynk, my 8 kW inverter contains two MPPTs. Then there's Victron's comms component (Cerbo GX), etc. I'm not arguing either way: pros and cons, as I said. In the end, the Victron and Sunsynk designs are fundamentally different, with Victron being transformer-based, while the Sunsynk relies heavily on high-power switching electronics.

On 2025/11/12 at 10:19 AM, FransSmith said:

I have a 8kw Sunsynk 10kw inverter with 18 550w north and west with 3 x Bslbatt 5 kw batteries

My neighbour around the corner installed 2 x 5kw Victron inverters with 16 panels and 4 x Freedom Won batteries.

At the same time during the day, his solar panels deliver 5 to 6 kw whereby mine only hover at 3 to 3.5kw

I have posted about this before but never actually got an answer. Must I just accept that Victron setup is better than Sunsynk???

I have an 8kw Sunsynk 1ph and I regularly see over 7KW output. I have 20 north facing 410 W panels facing north on 40° sloped roof.

Currently over 5KW even though the sky is overcast.

5 hours ago, PAG said:

18 550w north and west

5 hours ago, PAG said:

20 north facing 410 W

You are not comparing apples to apples by using peak output North compared to 2 orientations North and West. @PAG and @FransSmith Post kwh/day then compare.

@TaliaB

Just want to check my logic on your suggestion of

MPPT1:
• 9 × 550W North
• 9 × 550W West
MPPT2:
• 7 × 610W East

Even though the 2 strings on MPPT1 is pointing in 2 different directions, for most of the day (sun up high) they will each produce close to maximum Imp of 13.15A. Paralleling them will mean they go to 26.3 A total, way above the 22 A a 8kW can handle. So that will only result in a lot of clipping to 22A.

Also, 9 x 550W PV will generate up to 480V DC (in winter, allowed for temps down to -5), way above the efficient MPPT voltage top end of 450V. To me that may be sailing a bit too close to the wind (or sun in this case!).

I have more or less the same scenario, but as my system is old, and when the 8kW came out, it had a 18A limit, so i chose 365W PV, to give me max. 18A. I've upgraded F/W , supposedly to get the 22A limit, but them again, I've never seem close to 18A ever.

Had a quick look at my stats, and see that my PV1 = 8 x 365 x 2 (both north) and PV2 (8 x 365 North + 8 x 365 West), and they are maxing out at the same Amps.

So if I extrapolate my experience of getting 16.4A (actual) vs 18A (theoretical), the 2 x 550W String should max out to about 26.3 * 16.4 / 18 = 24A.....So hopefully the MPPT's can handle that clipping long term.

Maybe one day I will swop out my PV2 with 2 x 8 x 545 PV, but that is a schlep with new COC's, permissions etc,.

Hopefully I'll get incentivised to do this, sooner than later as I see an EV being part of my long term future.

17 hours ago, Sidewinder said:

@TaliaB

Just want to check my logic on your suggestion of

MPPT1:
• 9 × 550W North
• 9 × 550W West
MPPT2:
• 7 × 610W East

Even though the 2 strings on MPPT1 is pointing in 2 different directions, for most of the day (sun up high) they will each produce close to maximum Imp of 13.15A. Paralleling them will mean they go to 26.3 A total, way above the 22 A a 8kW can handle. So that will only result in a lot of clipping to 22A.

Also, 9 x 550W PV will generate up to 480V DC (in winter, allowed for temps down to -5), way above the efficient MPPT voltage top end of 450V. To me that may be sailing a bit too close to the wind (or sun in this case!).

I have more or less the same scenario, but as my system is old, and when the 8kW came out, it had a 18A limit, so i chose 365W PV, to give me max. 18A. I've upgraded F/W , supposedly to get the 22A limit, but them again, I've never seem close to 18A ever.

Had a quick look at my stats, and see that my PV1 = 8 x 365 x 2 (both north) and PV2 (8 x 365 North + 8 x 365 West), and they are maxing out at the same Amps.

So if I extrapolate my experience of getting 16.4A (actual) vs 18A (theoretical), the 2 x 550W String should max out to about 26.3 * 16.4 / 18 = 24A.....So hopefully the MPPT's can handle that clipping long term.

Maybe one day I will swop out my PV2 with 2 x 8 x 545 PV, but that is a schlep with new COC's, permissions etc,.

Hopefully I'll get incentivised to do this, sooner than later as I see an EV being part of my long term future.

@Sidewinder

Sunsynk 8kW 9 + 9 JA 550W panels on a single MPPT (overpaneling strategy, current limits & Voc safety)
I’d like to share my configuration and the reasoning behind it, including MPPT utilisation, overpaneling, and cold-condition voltage safety.
System:
Inverter: Sunsynk 8kW inverter (newer revision, 22A MPPT input, 500V max PV voltage)
Panels: 18 × JA Solar 550W.Total array size: 9.9 kWp.
Configuration
MPPT1:
2 × strings of 9 panels (9S2P)
String 1: North-facing
String 2: West-facing
Dual inputs used (internally paralleled).
Electrical Summary
Per string (9 panels in series):
Vmp ≈ 370V
Voc (STC) ≈ 9 × 49.5V ≈ 445V
Imp ≈ 13A
Combined at MPPT:
~26A theoretical vs 22A MPPT limit( ISC per Mppt 44A)
Cold Temperature Voc Check (Critical Design Step)
Using a typical temperature coefficient for Voc: βVoc ≈ -0.28% / °C Temperature delta:
From 25°C (STC) to -5°C = -30°C
Voltage increase: 0.28% × 30 ≈ 8.4% increase. Adjusted Voc at -5°C:
445V × 1.084 ≈ 482V.
Inverter max PV voltage = 500V
Worst-case string Voc ≈ 482V
Safety margin ≈ 18V (~3.6%) below absolute max within safe limits.
No risk of overvoltage trips under expected conditions.
Design Approach & Justification
1. OEM overpaneling allowance
Sunsynk allows 120–150% DC oversizing
This system = 124%. Within recommended range.
3. Overpaneling improves yield better performance under cloud cover, Morning/afternoon low irradiance and
winter conditions. Higher annual energy yield, not just peak output.
4. Orientation diversity
North midday peak West afternoon peak
Reduces simultaneous current and
smoothes generation curve.
5. NOCT-based realism
Real current per string ≈ 10–11A
Combined ≈ 20–22A aligns closely with MPPT limit in practice.
Trade-offs
Occasional clipping at peak overlap
Single MPPT tracking mixed orientations minor mismatch losses.

@TaliaB ,

Thanks you for the detail explanation and calcs, as this saves me from retyping the numbers that substantially matches your's!

I concur that in moderate low temps (up to 0 deg C), there is still some small margin left to play with and the mentioned config should work as planned (i.e. max overpanneling).

In parts of our country e.g. Sutherland, I would be a little nervous, but maybe that's just me.

What I would like to see is if anybody does experience Amps clipping regularly, what the AC & DC temps do in that case. In my (limited) experimentation, I've experiences lower temps when I work the inverter harder, specially via PV. What I would insist on (for my own installation), is additional cooling fan, if clipping does occur, as my 3 x extra computer fans lowers both AC & DC temps by approx. 10 Deg C.

On 2026/04/18 at 10:08 AM, TaliaB said:

@Sidewinder

Sunsynk 8kW 9 + 9 JA 550W panels on a single MPPT (overpaneling strategy, current limits & Voc safety)
I’d like to share my configuration and the reasoning behind it, including MPPT utilisation, overpaneling, and cold-condition voltage safety.
System:
Inverter: Sunsynk 8kW inverter (newer revision, 22A MPPT input, 500V max PV voltage)
Panels: 18 × JA Solar 550W.Total array size: 9.9 kWp.
Configuration
MPPT1:
2 × strings of 9 panels (9S2P)
String 1: North-facing
String 2: West-facing
Dual inputs used (internally paralleled).
Electrical Summary
Per string (9 panels in series):
Vmp ≈ 370V
Voc (STC) ≈ 9 × 49.5V ≈ 445V
Imp ≈ 13A
Combined at MPPT:
~26A theoretical vs 22A MPPT limit( ISC per Mppt 44A)
Cold Temperature Voc Check (Critical Design Step)
Using a typical temperature coefficient for Voc: βVoc ≈ -0.28% / °C Temperature delta:
From 25°C (STC) to -5°C = -30°C
Voltage increase: 0.28% × 30 ≈ 8.4% increase. Adjusted Voc at -5°C:
445V × 1.084 ≈ 482V.
Inverter max PV voltage = 500V
Worst-case string Voc ≈ 482V
Safety margin ≈ 18V (~3.6%) below absolute max within safe limits.
No risk of overvoltage trips under expected conditions.
Design Approach & Justification
1. OEM overpaneling allowance
Sunsynk allows 120–150% DC oversizing
This system = 124%. Within recommended range.
3. Overpaneling improves yield better performance under cloud cover, Morning/afternoon low irradiance and
winter conditions. Higher annual energy yield, not just peak output.
4. Orientation diversity
North midday peak West afternoon peak
Reduces simultaneous current and
smoothes generation curve.
5. NOCT-based realism
Real current per string ≈ 10–11A
Combined ≈ 20–22A aligns closely with MPPT limit in practice.
Trade-offs
Occasional clipping at peak overlap
Single MPPT tracking mixed orientations minor mismatch losses.

Two things to note:
1. The cloud edge effect can potentially increase the power produced by the panels by up to 25% so I would not move so close to the MPPT maximum voltage which might let the MPPT smoke out.
This is produced by boosting the irradiance when clouds around a clear sun act like a reflector. This effect occurs most likely under cold, bright windy weather.
2. Depending upon your latitude, a west facing array at a nominal 30 degrees slope would cause a significant drop in energy during the winter months.
For example, on the South African highveld, the potential harvested energy of an array facing due north would look like this, per kW of installed panels.

A west facing array would give you something like this due to the winter midday sun being lower in the horizon and at right angles to the panels

The combined effect of the two arrays would be to flatten the curve but still a dip from April to July

9 minutes ago, IanO said:

1. The cloud edge effect can potentially increase the power produced by the panels by up to 25% so I would not move so close to the MPPT maximum voltage which might let the MPPT smoke out.
This is produced by boosting the irradiance when clouds around a clear sun act like a reflector. This effect occurs most likely under cold, bright windy weather.

Power ≠ Voltage cloud edge effect mainly increases irradiance ,current (Imp), not voltage (Voc).
MPPT voltage limit risk is driven by cold temperature, not cloud reflection.
Your real danger condition is:
Low temperature (e.g. <-5°C )
High Voc string design near Mppt max. Cloud edge is not the primary cause of overvoltage damage.
Cold Voc design margins = primary concern.

The real design rule (this is the key point)
If you're designing strings: Voltage safety (critical). Always base on cold Voc worst-case, use panel Voc at STC, apply temperature coefficient calculate at minimum expected temperature (e.g. -5°C in SA highveld)
This is what protects your MPPT.