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NEG18R.20-515 vs NEG21C.20 740 5 of 19 identical Swap Change panels

Trina Solar TSM-NEG18R.20-515 vs Trina Solar TSM-NEG21C.20 740

Trina Solar TSM-NEG18R.20-515
TSM-NEG18R.20-515
515 Wp 23.20 % TOPCon
Open panel page Datasheet PDF
VS
Trina Solar TSM-NEG21C.20 740
TSM-NEG21C.20 740
740 Wp 23.80 % TOPCon Bifacial
Open panel page Datasheet PDF
The verdict

14 differences, and they point both ways

The largest is rated power: 225 W more power. 5 of 19 comparable parameters are identical.

See all 14 differences
How alike are they
5 of 19 comparable
parameters are identical
identical differs
01

What actually differs

14 of 19 parameters
Parameter NEG18R.20-515 NEG21C.20 740 Difference
Rated power 515 Wp 740 Wp 225 W more power
Module efficiency 23.20 % 23.80 % 0.60 pp more efficient
Weight 23.5 kg 38.3 kg 14.8 kg lighter
Weight per kWp 45.6 kg/kWp 51.8 kg/kWp 6.1 kg/kWp lighter
Product warranty 15 yrs 12 yrs 3 yrs longer
Power density 231.6 Wp/m² 238.2 Wp/m² 6.6 Wp/m² higher
Open-circuit voltage 40.90 V 50.30 V 9.40 V apart
Short-circuit current 15.96 A 18.66 A 2.70 A apart
Module area 2.224 m² 3.106 m² 0.883 m² apart
Voltage at max power 33.90 V 42.10 V 8.20 V apart
Current at max power 15.20 A 17.58 A 2.38 A apart
Cell count 108 132 24 cells apart
Bifacial No Yes No vs Yes
Dimensions 1961x1134x30 mm 2384x1303x33 mm 1961x1134x30 mm vs 2384x1303x33 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
Same temp coeff. for both panels (-0.290 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other.
NEG18R.20-515
17,279 kWh
NEG21C.20 740
24,828 kWh
Lifetime gap
7,549 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario NEG18R.20-515 NEG21C.20 740
Standard test conditions 25 °C 100.0% of rated power 515 W 740 W
Cool, bright day 40 °C 95.7% of rated power 493 W 708 W
Typical summer roof 55 °C 91.3% of rated power 470 W 676 W
Hot roof 70 °C 87.0% of rated power 448 W 643 W
03

Full specification

Parameter NEG18R.20-515 NEG21C.20 740 Difference
Power and efficiency
Rated power 515 Wp 740 Wp +225 W for NEG21C.20 740
Module efficiency 23.20 % 23.80 % +0.60 pp for NEG21C.20 740
Power density 231.6 Wp/m² 238.2 Wp/m² +6.6 Wp/m² for NEG21C.20 740
Open-circuit voltage 40.90 V 50.30 V 9.40 V apart
Voltage at max power 33.90 V 42.10 V 8.20 V apart
Short-circuit current 15.96 A 18.66 A 2.70 A apart
Current at max power 15.20 A 17.58 A 2.38 A apart
Temperature
Temperature coefficient -0.290 %/°C -0.290 %/°C Same
Mechanical
Dimensions 1961x1134x30 mm 2384x1303x33 mm 1961x1134x30 mm vs 2384x1303x33 mm
Module area 2.224 m² 3.106 m² 0.883 m² apart
Weight 23.5 kg 38.3 kg -14.8 kg for NEG18R.20-515
Weight per kWp 45.6 kg/kWp 51.8 kg/kWp -6.1 kg/kWp for NEG18R.20-515
Warranty and degradation
Product warranty 15 yrs 12 yrs +3 yrs for NEG18R.20-515
Performance warranty 30 yrs 30 yrs Same
Annual degradation 0.40 %/yr 0.40 %/yr Same
Technology
Cell technology TOPCon TOPCon Same
Cell type Monocrystalline Monocrystalline Same
Cell count 108 132 24 cells apart
Bifacial No Yes No vs Yes
04

Against the whole database

14,005 panels
Efficiency
#1,306 vs #433
NEG21C.20 740 leads by 873 places
Power density
#1,473 vs #431
NEG21C.20 740 leads by 1,042 places
Heat behaviour
#2,165 vs #2,165
Tied - the same position in the database
Weight
#789 vs #5,125
NEG18R.20-515 leads by 4,336 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#5,086 vs #185
NEG21C.20 740 leads by 4,901 places
05

More useful comparisons

Open the full database
Same series, other bin
Trina Solar TSM-NEG18R.20-515 vs Trina Solar TSM-NEG18R.20-520
One difference: module efficiency
Same series, other bin
Trina Solar TSM-NEG21C.20 740 vs Trina Solar TSM-NEG21C.20Q-760
6 differences, the largest is module efficiency
Same series, other bin
Trina Solar TSM-NEG21C.20 740 vs Trina Solar TSM-NEG21C.20Q-755
6 differences, the largest is temperature coefficient
Same series, other bin
Trina Solar TSM-NEG21C.20 740 vs Trina Solar TSM-NEG21C.20Q-750
6 differences, the largest is temperature coefficient
Same series, other bin
Trina Solar TSM-NEG21C.20 740 vs Trina Solar TSM-NEG21C.20Q-745
4 differences, the largest is temperature coefficient
Same series, other bin
Trina Solar TSM-NEG21C.20 740 vs Trina Solar TSM-NEG21C.20-740
The same specification on paper
06

Written summary

07

Questions about this pairing

Which panel is better: Trina Solar TSM-NEG18R.20-515 or Trina Solar TSM-NEG21C.20 740?
According to our database: Trina Solar TSM-NEG21C.20 740 has higher module efficiency (23.80% vs 23.20%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Trina Solar TSM-NEG18R.20-515 and Trina Solar TSM-NEG21C.20 740?
Trina Solar TSM-NEG18R.20-515 has a module efficiency of 23.20%, while Trina Solar TSM-NEG21C.20 740 is 23.80%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Trina Solar TSM-NEG18R.20-515 use vs Trina Solar TSM-NEG21C.20 740?
Trina Solar TSM-NEG18R.20-515 uses TOPCon cells; Trina Solar TSM-NEG21C.20 740 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-NEG18R.20-515 and Trina Solar TSM-NEG21C.20 740?
Trina Solar TSM-NEG18R.20-515 has a 30 years power warranty; Trina Solar TSM-NEG21C.20 740 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-NEG18R.20-515 and Trina Solar TSM-NEG21C.20 740 bifacial panels?
Trina Solar TSM-NEG21C.20 740 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.

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.