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NEG18R.28-475 vs NEG21C.20Q-745 4 of 19 identical Swap Change panels

Trina Solar TSM-NEG18R.28-475 vs Trina Solar TSM-NEG21C.20Q-745

Trina Solar TSM-NEG18R.28-475
TSM-NEG18R.28-475
475 Wp 21.40 % TOPCon
Open panel page Datasheet PDF
VS
Trina Solar TSM-NEG21C.20Q-745
TSM-NEG21C.20Q-745
745 Wp 24.00 % TOPCon Bifacial
Open panel page Datasheet PDF
The verdict

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

The largest is module efficiency: 2.60 pp more efficient. 4 of 19 comparable parameters are identical.

See all 15 differences
How alike are they
4 of 19 comparable
parameters are identical
identical differs
01

What actually differs

15 of 19 parameters
Parameter NEG18R.28-475 NEG21C.20Q-745 Difference
Module efficiency 21.40 % 24.00 % 2.60 pp more efficient
Rated power 475 Wp 745 Wp 270 W more power
Power density 213.6 Wp/m² 239.8 Wp/m² 26.2 Wp/m² higher
Temperature coefficient -0.290 %/°C -0.260 %/°C 0.030 %/°C better in heat
Weight 23.5 kg 38.3 kg 14.8 kg lighter
Product warranty 15 yrs 12 yrs 3 yrs longer
Open-circuit voltage 39.00 V 50.30 V 11.30 V apart
Short-circuit current 15.68 A 18.73 A 3.05 A apart
Module area 2.224 m² 3.106 m² 0.883 m² apart
Annual degradation 0.40 %/yr 0.35 %/yr 0.05 %/yr slower
Voltage at max power 32.30 V 42.30 V 10.00 V apart
Current at max power 14.72 A 17.62 A 2.90 A apart
Cell count 108 264 156 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
NEG18R.28-475
15,937 kWh
NEG21C.20Q-745
25,191 kWh
Lifetime gap
9,254 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario NEG18R.28-475 NEG21C.20Q-745
Standard test conditions 25 °C 100.0% of rated power 475 W 745 W
Cool, bright day 40 °C 95.7% of rated power 454 W 716 W
Typical summer roof 55 °C 91.3% of rated power 434 W 687 W
Hot roof 70 °C 87.0% of rated power 413 W 658 W
03

Full specification

Parameter NEG18R.28-475 NEG21C.20Q-745 Difference
Power and efficiency
Rated power 475 Wp 745 Wp +270 W for NEG21C.20Q-745
Module efficiency 21.40 % 24.00 % +2.60 pp for NEG21C.20Q-745
Power density 213.6 Wp/m² 239.8 Wp/m² +26.2 Wp/m² for NEG21C.20Q-745
Open-circuit voltage 39.00 V 50.30 V 11.30 V apart
Voltage at max power 32.30 V 42.30 V 10.00 V apart
Short-circuit current 15.68 A 18.73 A 3.05 A apart
Current at max power 14.72 A 17.62 A 2.90 A apart
Temperature
Temperature coefficient -0.290 %/°C -0.260 %/°C +0.030 %/°C for NEG21C.20Q-745
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.28-475
Weight per kWp 49.5 kg/kWp 51.4 kg/kWp Effectively the same
Warranty and degradation
Product warranty 15 yrs 12 yrs +3 yrs for NEG18R.28-475
Performance warranty 30 yrs 30 yrs Same
Annual degradation 0.40 %/yr 0.35 %/yr -0.05 %/yr for NEG21C.20Q-745
Technology
Cell technology TOPCon TOPCon Same
Cell type Monocrystalline Monocrystalline Same
Cell count 108 264 156 cells apart
Bifacial No Yes No vs Yes
04

Against the whole database

14,129 panels
Efficiency
#8,388 vs #329
NEG21C.20Q-745 leads by 8,059 places
Power density
#8,476 vs #366
NEG21C.20Q-745 leads by 8,110 places
Heat behaviour
#2,220 vs #515
NEG21C.20Q-745 leads by 1,705 places
Weight
#3,013 vs #4,829
NEG18R.28-475 leads by 1,816 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#8,934 vs #150
NEG21C.20Q-745 leads by 8,784 places
05

More useful comparisons

Open the full database
Same series, other bin
Trina Solar TSM-NEG18R.28-475 vs Trina Solar TSM-NEG18R.28-480
One difference: module efficiency
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
06

Written summary

07

Questions about this pairing

Which panel is better: Trina Solar TSM-NEG18R.28-475 or Trina Solar TSM-NEG21C.20Q-745?
According to our database: Trina Solar TSM-NEG21C.20Q-745 has higher module efficiency (24.00% vs 21.40%); 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-NEG18R.28-475 and Trina Solar TSM-NEG21C.20Q-745?
Trina Solar TSM-NEG18R.28-475 has a module efficiency of 21.40%, while Trina Solar TSM-NEG21C.20Q-745 is 24.00%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Trina Solar TSM-NEG18R.28-475 use vs Trina Solar TSM-NEG21C.20Q-745?
Trina Solar TSM-NEG18R.28-475 uses TOPCon cells; Trina Solar TSM-NEG21C.20Q-745 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.28-475 and Trina Solar TSM-NEG21C.20Q-745?
Trina Solar TSM-NEG18R.28-475 has a 30 years power warranty; Trina Solar TSM-NEG21C.20Q-745 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.28-475 and Trina Solar TSM-NEG21C.20Q-745 bifacial panels?
Trina Solar TSM-NEG21C.20Q-745 is bifacial (captures light from both faces); Trina Solar TSM-NEG18R.28-475 is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath.

Shop prices: See 194 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.