Trina Solar TSM-NEG18R.20-520 vs Trina Solar TSM-NEG21C.20-735
VS
The verdict
13 differences, and they point both ways
The largest is rated power: 215 W more power. 6 of 19 comparable parameters are identical.
See all 13 differencesHow alike are they
6
of 19 comparable
parameters are identical
parameters are identical
identical
differs
01
13 of 19 parameters
What actually differs
Parameter
NEG18R.20-520
NEG21C.20-735
Difference
Rated power
520 Wp
735 Wp
215 W more power
Weight
23.5 kg
38.3 kg
14.8 kg lighter
Weight per kWp
45.2 kg/kWp
52.1 kg/kWp
6.9 kg/kWp lighter
Product warranty
15 yrs
12 yrs
3 yrs longer
Open-circuit voltage
41.20 V
50.10 V
8.90 V apart
Short-circuit current
15.99 A
18.62 A
2.63 A apart
Module area
2.224 m²
3.106 m²
0.883 m² apart
Module efficiency
23.40 %
23.70 %
0.30 pp more efficient
Voltage at max power
34.10 V
41.90 V
7.80 V apart
Current at max power
15.25 A
17.55 A
2.30 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.20-520
17,447 kWh
NEG21C.20-735
24,661 kWh
Lifetime gap
7,214 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario
NEG18R.20-520
NEG21C.20-735
Standard test conditions
25 °C
100.0% of rated power
520 W
735 W
Cool, bright day
40 °C
95.7% of rated power
497 W
703 W
Typical summer roof
55 °C
91.3% of rated power
475 W
671 W
Hot roof
70 °C
87.0% of rated power
452 W
639 W
03
Full specification
Parameter
NEG18R.20-520
NEG21C.20-735
Difference
Power and efficiency
Rated power
520 Wp
735 Wp
+215 W for NEG21C.20-735
Module efficiency
23.40 %
23.70 %
+0.30 pp for NEG21C.20-735
Power density
233.8 Wp/m²
236.6 Wp/m²
Effectively the same
Open-circuit voltage
41.20 V
50.10 V
8.90 V apart
Voltage at max power
34.10 V
41.90 V
7.80 V apart
Short-circuit current
15.99 A
18.62 A
2.63 A apart
Current at max power
15.25 A
17.55 A
2.30 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.20-520
Weight per kWp
45.2 kg/kWp
52.1 kg/kWp
-6.9 kg/kWp for NEG18R.20-520
Warranty and degradation
Product warranty
15 yrs
12 yrs
+3 yrs for NEG18R.20-520
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
14,005 panels
Against the whole database
Efficiency
#882
vs
#517
NEG21C.20-735 leads by 365 places
Power density
#909
vs
#582
NEG21C.20-735 leads by 327 places
Heat behaviour
#2,165
vs
#2,165
Tied - the same position in the database
Weight
#635
vs
#5,576
NEG18R.20-520 leads by 4,941 places
Warranty
#21
vs
#21
Tied - the same position in the database
Overall
#4,727
vs
#233
NEG21C.20-735 leads by 4,494 places
05
Open the full database
More useful comparisons
Same series, other bin
Trina Solar TSM-NEG18R.20-520 vs Trina Solar TSM-NEG18R.20-515
One difference: module efficiency
Same series, other bin
Trina Solar TSM-NEG21C.20-735 vs Trina Solar TSM-NEG21C.20-740
The same specification on paper
Same series, other bin
Trina Solar TSM-NEG21C.20-735 vs Trina Solar TSM-NEG21C.20-730
One difference: module efficiency
Same series, other bin
Trina Solar TSM-NEG21C.20-735 vs Trina Solar TSM-NEG21C.20-725
3 differences, the largest is module efficiency
Same series, other bin
Trina Solar TSM-NEG21C.20-735 vs Trina Solar TSM-NEG21C.20-720
3 differences, the largest is module efficiency
Same series, other bin
Trina Solar TSM-NEG21C.20-735 vs Trina Solar TSM-NEG21C.20-715
3 differences, the largest is module efficiency
06
Written summary
Checking cache...
07
Questions about this pairing
Which panel is better: Trina Solar TSM-NEG18R.20-520 or Trina Solar TSM-NEG21C.20-735?
According to our database: Trina Solar TSM-NEG21C.20-735 has higher module efficiency (23.70% vs 23.40%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Trina Solar TSM-NEG18R.20-520 and Trina Solar TSM-NEG21C.20-735?
Trina Solar TSM-NEG18R.20-520 has a module efficiency of 23.40%, while Trina Solar TSM-NEG21C.20-735 is 23.70%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Trina Solar TSM-NEG18R.20-520 use vs Trina Solar TSM-NEG21C.20-735?
Trina Solar TSM-NEG18R.20-520 uses TOPCon cells; Trina Solar TSM-NEG21C.20-735 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.20-520 and Trina Solar TSM-NEG21C.20-735?
Trina Solar TSM-NEG18R.20-520 has a 30 years power warranty; Trina Solar TSM-NEG21C.20-735 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.20-520 and Trina Solar TSM-NEG21C.20-735 bifacial panels?
Trina Solar TSM-NEG21C.20-735 is bifacial (captures light from both faces); Trina Solar TSM-NEG18R.20-520 is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath.
Shop prices: See 250 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.