Hi everyone,

I’m seeing a flat plateau in my PV production curve during peak hours (as shown in the chart from 2026-03-10), and I’m trying to understand the root cause.

My system specs:

∙ Inverter: Felicity 5kW with dual MPPT inputs, each rated at 15A max

∙ Array: 7 panels × 580W = 4,060W total

∙ Measured voltage during plateau: ~300V

∙ Measured current: 11.2A – 11.8A

Observations:

∙ Production ramps up normally in the morning, then hits a hard ceiling around 3,500W and stays flat for several hours instead of forming the expected bell curve

∙ pleaee ignore a noticeable dip and spike around 15:25 , it is because the battery almost full+ no load and grid was off ( so can’t export )

My questions:

1. Is this classic inverter clipping caused by the array’s power exceeding the inverter’s rated output?

2. Could the 15A per MPPT limit be the bottleneck here, even though my measured current is only ~11.8A?

Any insights would be appreciated. Thanks!

10 hours ago, esmail-kassir said:

... Production ramps up normally in the morning, then hits a hard ceiling around 3,500W and stays flat for several hours instead of forming the expected bell curve

Solar panels are rated at "Standard Test Conditions" - thus under laboratory conditions (assuming, amongst others, a radiation intensity of 1000W/m2), and without taking system losses into account.

"Real World" maximum output is normally about 75% - 85% of this, due to solar intensity being less (dust or moisture in the air blocking some sunlight, light "striking angle" being less than optimum, system losses, temperature of panels, etc. etc.)

Your 3500W is pretty close to 85% - You should be happy that your system is running in the upper range of achievable performance...

Of course, you would also get the same flat peak if your demand remains constant during this period - PV panels only produce what is demanded by the system, and nothing more...

Edited March 13Mar 13 by HennieL
type correction

Have you got graphs of the PV voltage and current - might reveal a more obvious clipping. But that change in the graph at 12h15 definitely looks like clipping. Below shows my PV current and you can clearly see the clipping - I have 5kw Sunsynks with a max PV current of 13A and panels that can do 13.5A. The mesured clipped current here is 12.8 so slightly below 13A but close enough that I live with it.

The flat plateau you're experiencing on your Felicity 5kW inverter (3,500W sustained during peak hours, despite a 4,060W array and measured current well below the 15A/MPPT limit) is a clear case of inverter imposed power limiting (a form of clipping), but it's happening earlier and more aggressively than on higher quality or more capable hybrids like my Solis 6kW benchmark.

Using the Solis as a reference point helps highlight why the Felicity behaves this way.

Solis 6kW hybrid Flexible and higher headroom.

• In off-grid mode (or hybrid with battery priority and no strict export limit), Solis inverters are designed to split and maximize PV power flow.

  • Up to the full rated AC output ( 6kW) can go to loads.

  • Excess PV can route directly to battery charging at high rates (often 100–190A+ charging current on many models, translating to several kW of additional charging power).

• With my large 40kWh battery bank providing plenty of absorption capacity, the inverter can harvest beyond its AC rating on peak days observed 8.3kW sustained from a 7.3kW array in December. This is because the total "demand" (loads + aggressive battery charging) exceeds incoming PV, so the MPPTs keep pushing optimal power without throttling. Realworld Solis behavior supports oversized arrays and excess to battery routing, minimizing waste unless hitting absolute limits like max charge current, temperature derating, or firmware caps.

This results in little to no hard clipping during good conditions the production curve stays bell shaped or even exceeds nameplate when batteries soak up the surplus. Felicity 5kW Conservative design leads to early hard clipping Budget oriented inverters like many Felicity models (e.g., IVGM series, T-REX variants, or similar Chinese hybrids) often prioritize cost, simplicity, and reliability over maximum harvest. Key differences that explain your 3,500W plateau.

• Lower effective total power handling and conversion limit. Datasheets and user reports for Felicity 5kW hybrids frequently show max charging plus discharging power capped at 4,600–5,000W (e.g., 4,600W in some IVGM listings, or similar in T-REX-5K variants). In practice, real world PV to battery to AC conversion often settles even lower (3,500–4,500W max observed) due to conservative firmware, internal component ratings (e.g., MOSFETs, inductors), heat management, or efficiency derating. Your plateau at 3,500W (300V × 11.5A) exactly matches this internal bottleneck the inverter throttles the MPPT(s) to stay under its safe total power ceiling, even when batteries aren't full and could accept more.

• Limited flexibility in power routing: Unlike Solis, Felicity models don't appear to allow the same high headroom for excess PV to battery charging without hitting the total limit sooner. Many are tuned for stability in budget off-grid setups (common in markets like Africa/Asia), so they err on the side of caution cap total conversion early to avoid overload risks, rather than pushing harder to the battery.

• MPPT current isn't the issue (as you noted, 11–12A is below 15A per MPPT), and your array oversizing is mild (0.8–1.0× effective after the cap). The bottleneck is the inverter's overall power throughput (not current or voltage), which is more restricted than on premium brands.

This conservative approach is common in lower cost inverters: they deliver reliable basic performance but sacrifice peak harvest on the best days to keep manufacturing simple cheap and reduce failure rates under stress. User forums including powerforum.co.za discussions on Felicity setups often report similar early plateaus around 3.5–4.5kW, even with capable batteries and no loads, aligning with your observations.

Bottom line comparison

• Solis Acts like a "smart manager" that squeezes every possible watt to loads + big battery, exceeding rated AC output when conditions allow minimal clipping, bell-curve production, and occasional over-nameplate peaks.

• Felicity Acts like a "cautious guard" that enforces a stricter total power ceiling early hard flat plateau at a sub-rated level ( 3.5kW in your case), even if batteries could take more classic for budget hybrids prioritizing durability over max yield.

If you want Solis like behavior (higher peak harvest, less clipping), the cleanest fix is upgrading the inverter to a more capable model with higher charge rates and flexible routing. In the meantime, on the Felicity maximize loads during peak sun, check for any firmware updates or adjustable max-charge settings (if available), and accept that some potential energy is curtailed on the sunniest days it's by design in this class of inverter.

18 minutes ago, Powerforum Store said:

the inverter can harvest beyond its AC rating on peak days observed 8.3kW sustained from a 7.3kW array in December.

Wow, 8.3kW out of a little 6K Solis. Punching above its weight.

Yes the Solis Hybrids are exceptional inverters also note my array is already over 4 years old JA Solar 365 Watt All Black monofacial panels so the panels are also impressive not showing any marked deterioration whatsoever and I am in a very hot climate. The inverter is absolutely silent no noises from it at all and it never derates or gets very hot even when it's 40 degrees outside and its working hard. If I had bi facials the performance would have been even better.

So yes I am very pleased with the performance I have 2 x 6 KW units in place one has all the solar panels and the other has a 2 KW Wind turbine on one of the MPPT's in constant voltage mode works very well if the wind is good requires voltage adjustment when the wind is low peak input from the turbine recorded was 2.9 KW peak time of the year for my area for wind is Winter so compliments my solar production nicely.

Edited March 13Mar 13 by Powerforum Store

All speculation. First check maybe if you've got a battery charge rate limit set to around 70A. The solar panels will only produce what the battery system demands.

Beyond that, I'm assuming your 7 panels are installed on one MPPT. Could obviously be wrong, I don't know. I'm wondering whether that inverter has set a limit on the power that one MPPT can produce. Considering the low start-up Voltage on your inverter, I'd try to spread the workload and experiment with connecting the panels in strings of 4 and 3 onto each MPPT and see if it makes a difference at mid-day. Three panels are obviously borderline on the low Voltage end, but the point would be to test if you can go above 3500W in total at noon when the Voltage is expected to be sufficient, and then you could consider based on what you see, whether to return to 7 in series, or add one panel to go 4+4.

1 hour ago, GreenFields said:

Three panels are obviously borderline on the low Voltage end

That what I thought when I chose to install all on one MPPT

I assumed that working around the nominal voltage (300 ish) would be better than ( 120) and more efficient

4 hours ago, Powerforum Store said:

The flat plateau you're experiencing on your Felicity 5kW inverter (3,500W sustained during peak hours, despite a 4,060W array and measured current well below the 15A/MPPT limit) is a clear case of inverter imposed power limiting (a form of clipping), but it's happening earlier and more aggressively than on higher quality or more capable hybrids like my Solis 6kW benchmark.

Using the Solis as a reference point helps highlight why the Felicity behaves this way.

Solis 6kW hybrid Flexible and higher headroom.

• In off-grid mode (or hybrid with battery priority and no strict export limit), Solis inverters are designed to split and maximize PV power flow.

  • Up to the full rated AC output ( 6kW) can go to loads.

  • Excess PV can route directly to battery charging at high rates (often 100–190A+ charging current on many models, translating to several kW of additional charging power).

• With my large 40kWh battery bank providing plenty of absorption capacity, the inverter can harvest beyond its AC rating on peak days observed 8.3kW sustained from a 7.3kW array in December. This is because the total "demand" (loads + aggressive battery charging) exceeds incoming PV, so the MPPTs keep pushing optimal power without throttling. Realworld Solis behavior supports oversized arrays and excess to battery routing, minimizing waste unless hitting absolute limits like max charge current, temperature derating, or firmware caps.

This results in little to no hard clipping during good conditions the production curve stays bell shaped or even exceeds nameplate when batteries soak up the surplus. Felicity 5kW Conservative design leads to early hard clipping Budget oriented inverters like many Felicity models (e.g., IVGM series, T-REX variants, or similar Chinese hybrids) often prioritize cost, simplicity, and reliability over maximum harvest. Key differences that explain your 3,500W plateau.

• Lower effective total power handling and conversion limit. Datasheets and user reports for Felicity 5kW hybrids frequently show max charging plus discharging power capped at 4,600–5,000W (e.g., 4,600W in some IVGM listings, or similar in T-REX-5K variants). In practice, real world PV to battery to AC conversion often settles even lower (3,500–4,500W max observed) due to conservative firmware, internal component ratings (e.g., MOSFETs, inductors), heat management, or efficiency derating. Your plateau at 3,500W (300V × 11.5A) exactly matches this internal bottleneck the inverter throttles the MPPT(s) to stay under its safe total power ceiling, even when batteries aren't full and could accept more.

• Limited flexibility in power routing: Unlike Solis, Felicity models don't appear to allow the same high headroom for excess PV to battery charging without hitting the total limit sooner. Many are tuned for stability in budget off-grid setups (common in markets like Africa/Asia), so they err on the side of caution cap total conversion early to avoid overload risks, rather than pushing harder to the battery.

• MPPT current isn't the issue (as you noted, 11–12A is below 15A per MPPT), and your array oversizing is mild (0.8–1.0× effective after the cap). The bottleneck is the inverter's overall power throughput (not current or voltage), which is more restricted than on premium brands.

This conservative approach is common in lower cost inverters: they deliver reliable basic performance but sacrifice peak harvest on the best days to keep manufacturing simple cheap and reduce failure rates under stress. User forums including powerforum.co.za discussions on Felicity setups often report similar early plateaus around 3.5–4.5kW, even with capable batteries and no loads, aligning with your observations.

Bottom line comparison

• Solis Acts like a "smart manager" that squeezes every possible watt to loads + big battery, exceeding rated AC output when conditions allow minimal clipping, bell-curve production, and occasional over-nameplate peaks.

• Felicity Acts like a "cautious guard" that enforces a stricter total power ceiling early hard flat plateau at a sub-rated level ( 3.5kW in your case), even if batteries could take more classic for budget hybrids prioritizing durability over max yield.

If you want Solis like behavior (higher peak harvest, less clipping), the cleanest fix is upgrading the inverter to a more capable model with higher charge rates and flexible routing. In the meantime, on the Felicity maximize loads during peak sun, check for any firmware updates or adjustable max-charge settings (if available), and accept that some potential energy is curtailed on the sunniest days it's by design in this class of inverter.

Can this feature make the 2 MPPTs work together for the same string ( load sharing)

2 hours ago, esmail-kassir said:

Can this feature make the 2 MPPTs work together for the same string ( load sharing)

What I don't see here is actually doing a short circuit test on the panels or even using a 3-4 ohm high wattage resistor at peak production to verify that the panels can indeed supply more current than the clipping value indicated.

We work around the spec volts and currents. I have 1 panel I bought new but the seller indicated it was below spec on voltage and current and gave a discount. This was perhaps applicable on a whole container which I would not know. Mine gives about 80% output but other members on this forum were not so lucky and got real scrap panels and after trying hard they did get a refund.

22 hours ago, esmail-kassir said:

Can this feature make the 2 MPPTs work together for the same string ( load sharing)

Although it does seem like clipping takes place the one suggestion not mentioned is to find out what the maximum current is that those panels can provide. It could be that the MPPT level is reached at the current value when it starts clipping.

Best would be at peak production level to do a short circuit test but only for a few seconds to be able to read the current with a clamp meter.

Then only can one isolate the clipping to be inverter related.

Edited March 14Mar 14 by Scorp007

My 2 cents:

The graph suggests that the PV output is being limited by the inverter’s MPPT or system settings, rather than the solar array reaching its natural maximum. The flat plateau indicates the inverter is capping the power, not that the array cannot produce more.

It would be worth investigating inverter-side limits, such as battery charge current limits or other configuration settings that could be restricting PV production.

For comparison, here is a VRM graph from a system where the array actually reaches its production ceiling. The array consists of 6 × 460 W panels (2760 W theoretical), yet the maximum observed production is around 2000 W, which reflects real-world conditions rather than an inverter-imposed limit.

In this case the shape of the op's curve suggests inverter limitation rather than array limitation.

I think that the answer to this is possibly quite a lot simpler than most of you are looking for

I suspect that the inverter is just getting to hot and is therefore limiting the amount of solar power coming in

I find this quite often in inverters that don't have active cooling or inadequate ventilation

20 hours ago, James 1 said:

I think that the answer to this is possibly quite a lot simpler than most of you are looking for

I suspect that the inverter is just getting to hot and is therefore limiting the amount of solar power coming in

I find this quite often in inverters that don't have active cooling or inadequate ventilation

I agree the inverter is likely derating however, the technology used in cheaper inverters tends to derate much sooner. I've noticed this in inverters I've tested over the years. Active cooling in itself is not always the issue the overall design of the unit determines how soon it derates.

For example, the Solis Hybrid 5 and 6 kW units do not have external active cooling but feature a very large external heatsink and a small internal circulation fan (which does not extract to the atmosphere). I've never seen my inverters derate due to heat, even in very hot summer environments with ambient temps of 40°C and high humidity, where the IGBT cores run only 5–10°C hotter than ambient.

I know many Sunsynk and Deye users report their inverters running hot and add extra active cooling to manage temperatures. Voltronic-based inverters do derate faster despite having active cooling additionally, their MPPTs are not as advanced, and their architecture is vastly different from Sunsynk, Deye, and Solis.

Interesting Fact Like solar panels, inverters also have a Tier rating. Solis is one of the largest inverter manufacturers globally and holds a BNEF Tier 1 rating (confirmed for Q1 2026), shared with brands like Sungrow, Huawei, and GoodWe.

Deye, Sunsynk, and Victron are not BNEF Tier 1 but are still highly regarded premium residential inverters though they lack the same level of bankability as Tier 1 options.

At the bottom end are brands like Voltronic Power, Must Power, Felicity Solar (and thousands of clones using similar tech under different branding) these are budget inverter systems.

Felicity is more known for batteries, while Voltronic is the largest original design manufacturer in this segment.

These focus on cost-effective, high-volume production for DIY and budget-conscious residential markets. Budget options often involve lower quality components, more hardware limits to prevent damage/failure, and less advanced/rudimentary software with more potential bugs all factors that can affect long term reliability and performance.

This is a general observation you generally get what you pay for in inverters, though choices depend on intended purpose.

Many select purely on price and may be disappointed if expectations don't match higher quality products this is across the board with no intent of judgment.

Also to note: Currently, Tier 1 inverters are not much more expensive than budget ones.As an example, Solis S6 6kW Advanced Hybrid models have been listed around R12,650 VAT included Felicity Solar 6kW Hybrids range between R7,650 and R9,900 VAT included the Sunsynk Lynks 6kW 48Vdc Single Phase Hybrid is in a similar category at around R12,765 VAT included. Prices vary by retailer/stock/date this is purely to show how the market gap has closed between tiers in South Africa, not a marketing ploy.

Such a small price difference between Tier 1/premium and budget brands should make the choice straightforward for many.

However, people often opt to save a few Rand and buy the budget inverter instead of a Tier 1 or premium brand this is by no means a judgment, purely an observation considering the small difference in price.

Edited March 16Mar 16 by Powerforum Store

7 hours ago, Powerforum Store said:

I agree the inverter is likely derating however, the technology used in cheaper inverters tends to derate much sooner. I've noticed this in inverters I've tested over the years. Active cooling in itself is not always the issue the overall design of the unit determines how soon it derates.

For example, the Solis Hybrid 5 and 6 kW units do not have external active cooling but feature a very large external heatsink and a small internal circulation fan (which does not extract to the atmosphere). I've never seen my inverters derate due to heat, even in very hot summer environments with ambient temps of 40°C and high humidity, where the IGBT cores run only 5–10°C hotter than ambient.

I know many Sunsynk and Deye users report their inverters running hot and add extra active cooling to manage temperatures. Voltronic-based inverters do derate faster despite having active cooling additionally, their MPPTs are not as advanced, and their architecture is vastly different from Sunsynk, Deye, and Solis.

Interesting Fact Like solar panels, inverters also have a Tier rating. Solis is one of the largest inverter manufacturers globally and holds a BNEF Tier 1 rating (confirmed for Q1 2026), shared with brands like Sungrow, Huawei, and GoodWe.

Deye, Sunsynk, and Victron are not BNEF Tier 1 but are still highly regarded premium residential inverters though they lack the same level of bankability as Tier 1 options.

At the bottom end are brands like Voltronic Power, Must Power, Felicity Solar (and thousands of clones using similar tech under different branding) these are budget inverter systems.

Felicity is more known for batteries, while Voltronic is the largest original design manufacturer in this segment.

These focus on cost-effective, high-volume production for DIY and budget-conscious residential markets. Budget options often involve lower quality components, more hardware limits to prevent damage/failure, and less advanced/rudimentary software with more potential bugs all factors that can affect long term reliability and performance.

This is a general observation you generally get what you pay for in inverters, though choices depend on intended purpose.

Many select purely on price and may be disappointed if expectations don't match higher quality products this is across the board with no intent of judgment.

Also to note: Currently, Tier 1 inverters are not much more expensive than budget ones.As an example, Solis S6 6kW Advanced Hybrid models have been listed around R12,650 VAT included Felicity Solar 6kW Hybrids range between R7,650 and R9,900 VAT included the Sunsynk Lynks 6kW 48Vdc Single Phase Hybrid is in a similar category at around R12,765 VAT included. Prices vary by retailer/stock/date this is purely to show how the market gap has closed between tiers in South Africa, not a marketing ploy.

Such a small price difference between Tier 1/premium and budget brands should make the choice straightforward for many.

However, people often opt to save a few Rand and buy the budget inverter instead of a Tier 1 or premium brand this is by no means a judgment, purely an observation considering the small difference in price.

I have to agree. When purchasing an inverter, one typically makes a decision that one has to live by for 5-10 years. That's a long time to live with something that is sub-optimal, and particularly so for a residential install, where the good daily performance translates into rands either saved or spent on the household budget every month.

This may sound weird, but with the price differences being so marginal, I almost cannot wait for my old faithful Sunsynk to lose the blue smoke so that I can get a Solis. I have been saving towards it from day one (back in 2020). Thanks for your extensive testing, @Powerforum Store and for sharing your real-world experience.