I have 9 x 550w panels North with 9 x 550w panels West. I installed a 3rd string on my no 3 Mppt, 7 x 610w panels East

What find strange is that all three strings produce the same amount of electricity at 07H30 in the morning. I would have expected my East panels to outperform my West panels

Any reasonable explanation for it

Edited February 24Feb 24 by FransSmith
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34 minutes ago, FransSmith said:

I have 9 x 550w panels North with 9 x 550w panels West. I installed a 3rd string on my no 3 Mppt, 7 x 610w panels East

What find strange is that all three strings produce the same amount of electricity at 07H30 in the morning. I would have expected my East panels to outperform my West panels

Any reasonable explanation for it

Early Morning Sun: At 07H30, the sun is low on the horizon, providing weak, indirect sunlight. In this low-light environment, all strings produce low power, and the differences in orientation (e.g., East vs. West) or length are negligible. If it stay the same at 12 something is wrong.

What's the impact of cloud cover? The image seems to suggest heavy cloud, and I can imagine that grey skies could cause some evening out of the production on the strings. That's on top of the fact that the East-facing string (4270W) has lower power connected than the North and West strings (4950W).

@FransSmith Your Sunsynk 8kW single-phase hybrid inverter has 2 MPPT trackers, each with 2 PV input pairs (total 4 MC4 inputs: typically labeled PV1-1/PV1-2 for MPPT1 and PV2-1/PV2-2 for MPPT2). These two inputs per MPPT are internally paralleled.

This allows up to two separate strings (series arrays) to connect directly to each MPPT, where they combine currents at the same voltage (the MPPT finds one optimal operating point for the paralleled strings).In your setup:The "third string" (7 × 610W East panels) is connected to one of the spare input pairs on an existing MPPT (sharing with either North or West's 9 × 550W string via internal paralleling).

This creates a mismatched parallel combination on that MPPT: different panel wattages (550W vs 610W), likely different Imp (current at max power), and crucially, different orientations (East vs North/West).

The MPPT forces both strings to run at the same voltage, so performance averages out. In very low morning irradiance (07:30, mostly diffuse light, low direct beam), mismatch losses are small, and all "strings" show similar output normal and expected, not strange.

East's early advantage (better angle at sunrise) gets diluted by sharing the MPPT with a non-East orientation.

Mixing panels/orientations on one MPPT reduces efficiency:Lower-current string limits the higher one.

Expect more noticeable losses midday/high sun.

Current safety check (important):Max per MPPT: usually 26A operating (some models 22A; confirm your exact model datasheet e.g., SYNK-8K-SG01LP1 often 26A+26A).

Each string ~11–14A Imp (estimate based on typical 550–610W panels).

Paralleled on one MPPT → total could hit/exceed 26A in peak conditions.

Current rises ~0.04–0.05% per °C above 25°C STC, so hot days increase risk of clipping (power limit) or rare overcurrent issues.

Recommendations:In Solar Assistant, check per-MPPT current (A), voltage (V), and power logs look for hitting max limits during peak.

East should pull ahead from 08:00+ as sun rises (direct beam hits it better); review logs then.

For optimization/safety: Ideally avoid mixing mismatched panels/orientations on one MPPT (re-wire if feasible, e.g., dedicate inputs better). If currents stay high, consider accepting minor clipping or consulting installer.

If equality persists later or East lags midday, check for shading, wiring issues, or string config errors.

Those strings aren't producing very much. I get some sunlight and thus some power early in the morning, but things only really start cooking at about 8:00 on a sunny day. That's when I start to see the difference in string performance.

9 hours ago, Powerforum Store said:

...Your Sunsynk 8kW single-phase hybrid inverter has 2 MPPT trackers, each with 2 PV input pairs (total 4 MC4 inputs: typically labeled PV1-1/PV1-2 for MPPT1 and PV2-1/PV2-2 for MPPT2). These two inputs per MPPT are internally paralleled.

This allows up to two separate strings (series arrays) to connect directly to each MPPT, where they combine currents at the same voltage (the MPPT finds one optimal operating point for the paralleled strings).In your setup:The "third string" (7 × 610W East panels) is connected to one of the spare input pairs on an existing MPPT (sharing with either North or West's 9 × 550W string via internal paralleling).

This creates a mismatched parallel combination on that MPPT: different panel wattages (550W vs 610W), likely different Imp (current at max power), and crucially, different orientations (East vs North/West).

The MPPT forces both strings to run at the same voltage, so performance averages out. In very low morning irradiance (07:30, mostly diffuse light, low direct beam), mismatch losses are small, and all "strings" show similar output normal and expected, not strange...

Well made points, and good advice - because an inverter can accept four PV string inputs it does not guarantee that it has four MPPTs - in this case it only has two.

@FransSmith It would be interesting to learn from your experience - please record the amps and volts reported by your two MPPTs (as reported by your inverter) over a full daylight period if possible, and post the results in this thread. Also, please confirm which direction panels are coupled to each MPPT, if possible - this, together with your data, would confirm if the theory is indeed true (as I suspect it would be...).