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NEG21C.20Q-745 vs NEG18R.28-515 3 of 19 identical Swap Change panels

Trina Solar TSM-NEG21C.20Q-745 vs Trina Solar TSM-NEG18R.28-515

Trina Solar TSM-NEG21C.20Q-745
TSM-NEG21C.20Q-745
745 Wp 24.00 % TOPCon Bifacial
Open panel page Datasheet PDF
VS
Trina Solar TSM-NEG18R.28-515
TSM-NEG18R.28-515
515 Wp 23.20 % TOPCon
Open panel page Datasheet PDF
The verdict

NEG21C.20Q-745 leads on the differences that matter

The largest is module efficiency: 0.80 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-745 NEG18R.28-515 Difference
Module efficiency 24.00 % 23.20 % 0.80 pp more efficient
Rated power 745 Wp 515 Wp 230 W more power
Temperature coefficient -0.260 %/°C -0.290 %/°C 0.030 %/°C better in heat
Weight 38.3 kg 23.5 kg 14.8 kg lighter
Power density 239.8 Wp/m² 231.6 Wp/m² 8.2 Wp/m² higher
Product warranty 12 yrs 15 yrs 3 yrs longer
Weight per kWp 51.4 kg/kWp 45.6 kg/kWp 5.8 kg/kWp lighter
Open-circuit voltage 50.30 V 40.90 V 9.40 V apart
Short-circuit current 18.73 A 15.96 A 2.77 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 42.30 V 33.90 V 8.40 V apart
Current at max power 17.62 A 15.20 A 2.42 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-745
25,191 kWh
NEG18R.28-515
17,279 kWh
Lifetime gap
7,912 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario NEG21C.20Q-745 NEG18R.28-515
Standard test conditions 25 °C 100.0% of rated power 745 W 515 W
Cool, bright day 40 °C 95.7% of rated power 716 W 493 W
Typical summer roof 55 °C 91.3% of rated power 687 W 470 W
Hot roof 70 °C 87.0% of rated power 658 W 448 W
03

Full specification

Parameter NEG21C.20Q-745 NEG18R.28-515 Difference
Power and efficiency
Rated power 745 Wp 515 Wp +230 W for NEG21C.20Q-745
Module efficiency 24.00 % 23.20 % +0.80 pp for NEG21C.20Q-745
Power density 239.8 Wp/m² 231.6 Wp/m² +8.2 Wp/m² for NEG21C.20Q-745
Open-circuit voltage 50.30 V 40.90 V 9.40 V apart
Voltage at max power 42.30 V 33.90 V 8.40 V apart
Short-circuit current 18.73 A 15.96 A 2.77 A apart
Current at max power 17.62 A 15.20 A 2.42 A apart
Temperature
Temperature coefficient -0.260 %/°C -0.290 %/°C +0.030 %/°C for NEG21C.20Q-745
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.28-515
Weight per kWp 51.4 kg/kWp 45.6 kg/kWp -5.8 kg/kWp for NEG18R.28-515
Warranty and degradation
Product warranty 12 yrs 15 yrs +3 yrs for NEG18R.28-515
Performance warranty 30 yrs 30 yrs Same
Annual degradation 0.35 %/yr 0.40 %/yr -0.05 %/yr for NEG21C.20Q-745
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
#303 vs #1,306
NEG21C.20Q-745 leads by 1,003 places
Power density
#339 vs #1,473
NEG21C.20Q-745 leads by 1,134 places
Heat behaviour
#511 vs #2,165
NEG21C.20Q-745 leads by 1,654 places
Weight
#4,803 vs #789
NEG18R.28-515 leads by 4,014 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#150 vs #5,086
NEG21C.20Q-745 leads by 4,936 places
05

More useful comparisons

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

Written summary

07

Questions about this pairing

Which panel is better: Trina Solar TSM-NEG21C.20Q-745 or Trina Solar TSM-NEG18R.28-515?
According to our database: Trina Solar TSM-NEG21C.20Q-745 has higher module efficiency (24.00% vs 23.20%); Trina Solar TSM-NEG21C.20Q-745 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-745 and Trina Solar TSM-NEG18R.28-515?
Trina Solar TSM-NEG21C.20Q-745 has a module efficiency of 24.00%, while Trina Solar TSM-NEG18R.28-515 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-745 use vs Trina Solar TSM-NEG18R.28-515?
Trina Solar TSM-NEG21C.20Q-745 uses TOPCon cells; Trina Solar TSM-NEG18R.28-515 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-745 and Trina Solar TSM-NEG18R.28-515?
Trina Solar TSM-NEG21C.20Q-745 has a 30 years power warranty; Trina Solar TSM-NEG18R.28-515 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-745 and Trina Solar TSM-NEG18R.28-515 bifacial panels?
Trina Solar TSM-NEG21C.20Q-745 is bifacial (captures light from both faces); Trina Solar TSM-NEG18R.28-515 is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath.

Shop prices: See 248 Trina Solar offers

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.