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NEG21C.20Q-750 vs NEG18R.20-515 3 of 19 identical Swap Change panels

Trina Solar TSM-NEG21C.20Q-750 vs Trina Solar TSM-NEG18R.20-515

Trina Solar TSM-NEG21C.20Q-750
TSM-NEG21C.20Q-750
750 Wp 24.10 % TOPCon Bifacial
Open panel page Datasheet PDF
VS
Trina Solar TSM-NEG18R.20-515
TSM-NEG18R.20-515
515 Wp 23.20 % TOPCon
Open panel page Datasheet PDF
The verdict

NEG21C.20Q-750 leads on the differences that matter

The largest is module efficiency: 0.90 pp more efficient. 3 of 19 comparable parameters are identical.

See all 16 differences
How alike are they
3 of 19 comparable
parameters are identical
identical differs
01

What actually differs

16 of 19 parameters
Parameter NEG21C.20Q-750 NEG18R.20-515 Difference
Module efficiency 24.10 % 23.20 % 0.90 pp more efficient
Rated power 750 Wp 515 Wp 235 W more power
Temperature coefficient -0.260 %/°C -0.290 %/°C 0.030 %/°C better in heat
Power density 241.4 Wp/m² 231.6 Wp/m² 9.9 Wp/m² higher
Weight 38.3 kg 23.5 kg 14.8 kg lighter
Product warranty 12 yrs 15 yrs 3 yrs longer
Weight per kWp 51.1 kg/kWp 45.6 kg/kWp 5.4 kg/kWp lighter
Open-circuit voltage 50.50 V 40.90 V 9.60 V apart
Short-circuit current 18.77 A 15.96 A 2.81 A apart
Module area 3.106 m² 2.224 m² 0.883 m² apart
Annual degradation 0.35 %/yr 0.40 %/yr 0.05 %/yr slower
Voltage at max power 42.50 V 33.90 V 8.60 V apart
Current at max power 17.66 A 15.20 A 2.46 A apart
Cell count 264 108 156 cells apart
Bifacial Yes No Yes vs No
Dimensions 2384x1303x33 mm 1961x1134x30 mm 2384x1303x33 mm vs 1961x1134x30 mm
02

What it means on a roof

Thirty years of production
Each panel's own declared degradation curve, at 1,200 kWh/kWp a year
NEG21C.20Q-750
25,360 kWh
NEG18R.20-515
17,279 kWh
Lifetime gap
8,081 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario NEG21C.20Q-750 NEG18R.20-515
Standard test conditions 25 °C 100.0% of rated power 750 W 515 W
Cool, bright day 40 °C 95.7% of rated power 721 W 493 W
Typical summer roof 55 °C 91.3% of rated power 692 W 470 W
Hot roof 70 °C 87.0% of rated power 662 W 448 W
03

Full specification

Parameter NEG21C.20Q-750 NEG18R.20-515 Difference
Power and efficiency
Rated power 750 Wp 515 Wp +235 W for NEG21C.20Q-750
Module efficiency 24.10 % 23.20 % +0.90 pp for NEG21C.20Q-750
Power density 241.4 Wp/m² 231.6 Wp/m² +9.9 Wp/m² for NEG21C.20Q-750
Open-circuit voltage 50.50 V 40.90 V 9.60 V apart
Voltage at max power 42.50 V 33.90 V 8.60 V apart
Short-circuit current 18.77 A 15.96 A 2.81 A apart
Current at max power 17.66 A 15.20 A 2.46 A apart
Temperature
Temperature coefficient -0.260 %/°C -0.290 %/°C +0.030 %/°C for NEG21C.20Q-750
Mechanical
Dimensions 2384x1303x33 mm 1961x1134x30 mm 2384x1303x33 mm vs 1961x1134x30 mm
Module area 3.106 m² 2.224 m² 0.883 m² apart
Weight 38.3 kg 23.5 kg -14.8 kg for NEG18R.20-515
Weight per kWp 51.1 kg/kWp 45.6 kg/kWp -5.4 kg/kWp for NEG18R.20-515
Warranty and degradation
Product warranty 12 yrs 15 yrs +3 yrs for NEG18R.20-515
Performance warranty 30 yrs 30 yrs Same
Annual degradation 0.35 %/yr 0.40 %/yr -0.05 %/yr for NEG21C.20Q-750
Technology
Cell technology TOPCon TOPCon Same
Cell type Monocrystalline Monocrystalline Same
Cell count 264 108 156 cells apart
Bifacial Yes No Yes vs No
04

Against the whole database

14,005 panels
Efficiency
#219 vs #1,306
NEG21C.20Q-750 leads by 1,087 places
Power density
#219 vs #1,473
NEG21C.20Q-750 leads by 1,254 places
Heat behaviour
#511 vs #2,165
NEG21C.20Q-750 leads by 1,654 places
Weight
#4,401 vs #789
NEG18R.20-515 leads by 3,612 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#123 vs #5,086
NEG21C.20Q-750 leads by 4,963 places
05

More useful comparisons

Open the full database
Same series, other bin
Trina Solar TSM-NEG21C.20Q-750 vs Trina Solar TSM-NEG21C.20Q-760
3 differences, the largest is module efficiency
Same series, other bin
Trina Solar TSM-NEG21C.20Q-750 vs Trina Solar TSM-NEG21C.20Q-755
One difference: module efficiency
Same series, other bin
Trina Solar TSM-NEG21C.20Q-750 vs Trina Solar TSM-NEG21C.20Q-745
The same specification on paper
Same series, other bin
Trina Solar TSM-NEG21C.20Q-750 vs Trina Solar TSM-NEG21C.20Q-740
3 differences, the largest is module efficiency
Same series, other bin
Trina Solar TSM-NEG21C.20Q-750 vs Trina Solar TSM-NEG21C.20Q-735
3 differences, the largest is module efficiency
Same series, other bin
Trina Solar TSM-NEG21C.20Q-750 vs Trina Solar TSM-NEG19RC.20Q
8 differences, the largest is module efficiency
06

Written summary

07

Questions about this pairing

Which panel is better: Trina Solar TSM-NEG21C.20Q-750 or Trina Solar TSM-NEG18R.20-515?
According to our database: Trina Solar TSM-NEG21C.20Q-750 has higher module efficiency (24.10% vs 23.20%); Trina Solar TSM-NEG21C.20Q-750 tolerates heat better (temp coeff -0.260%/°C vs -0.290%/°C). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Trina Solar TSM-NEG21C.20Q-750 and Trina Solar TSM-NEG18R.20-515?
Trina Solar TSM-NEG21C.20Q-750 has a module efficiency of 24.10%, while Trina Solar TSM-NEG18R.20-515 is 23.20%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Trina Solar TSM-NEG21C.20Q-750 use vs Trina Solar TSM-NEG18R.20-515?
Trina Solar TSM-NEG21C.20Q-750 uses TOPCon cells; Trina Solar TSM-NEG18R.20-515 uses TOPCon. Modern n-type technologies (TOPCon, HJT, BC) typically deliver higher efficiency and lower degradation compared to older PERC (p-type) cells.
What is the warranty on Trina Solar TSM-NEG21C.20Q-750 and Trina Solar TSM-NEG18R.20-515?
Trina Solar TSM-NEG21C.20Q-750 has a 30 years power warranty; Trina Solar TSM-NEG18R.20-515 has a 30 years power warranty. The power warranty guarantees a minimum percentage of rated output at the end of the warranty period (typically 80-87%). Product (materials) warranties are usually shorter.
Are Trina Solar TSM-NEG21C.20Q-750 and Trina Solar TSM-NEG18R.20-515 bifacial panels?
Trina Solar TSM-NEG21C.20Q-750 is bifacial (captures light from both faces); Trina Solar TSM-NEG18R.20-515 is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath.

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Every figure here is from the manufacturers' own datasheets - a dash means the value is not published, never an estimate. The thirty-year projection and the temperature scenarios are calculations from those figures, and each states its assumption above.