JA Solar JAM54S30-420/MR vs JA Solar JAM54S31-400/MR
VS
The verdict
JAM54S30-420/MR leads on the differences that matter
The largest is module efficiency: 1.00 pp more efficient. 15 of 19 comparable parameters are identical.
See all 4 differencesHow alike are they
15
of 19 comparable
parameters are identical
parameters are identical
identical
differs
01
4 of 19 parameters
What actually differs
Parameter
JAM54S30-420/MR
JAM54S31-400/MR
Difference
Module efficiency
21.50 %
20.50 %
1.00 pp more efficient
Power density
215.1 Wp/m²
204.8 Wp/m²
10.2 Wp/m² higher
Rated power
420 Wp
400 Wp
20 W more power
Weight per kWp
46.4 kg/kWp
48.8 kg/kWp
2.3 kg/kWp lighter
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 (-0.350 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other.
JAM54S30-420/MR
13,612 kWh
JAM54S31-400/MR
12,964 kWh
Lifetime gap
648 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario
JAM54S30-420/MR
JAM54S31-400/MR
Standard test conditions
25 °C
100.0% of rated power
420 W
400 W
Cool, bright day
40 °C
94.8% of rated power
398 W
379 W
Typical summer roof
55 °C
89.5% of rated power
376 W
358 W
Hot roof
70 °C
84.2% of rated power
354 W
337 W
03
Full specification
Parameter
JAM54S30-420/MR
JAM54S31-400/MR
Difference
Power and efficiency
Rated power
420 Wp
400 Wp
+20 W for JAM54S30-420/MR
Module efficiency
21.50 %
20.50 %
+1.00 pp for JAM54S30-420/MR
Power density
215.1 Wp/m²
204.8 Wp/m²
+10.2 Wp/m² for JAM54S30-420/MR
Open-circuit voltage
37.58 V
37.07 V
Effectively the same
Voltage at max power
31.80 V
31.01 V
Effectively the same
Short-circuit current
14.10 A
13.79 A
Effectively the same
Current at max power
13.21 A
12.90 A
Effectively the same
Temperature
Temperature coefficient
-0.350 %/°C
-0.350 %/°C
Same
Mechanical
Dimensions
1722x1134x30 mm
1722x1134x30 mm
Same
Module area
1.953 m²
1.953 m²
Same
Weight
19.5 kg
19.5 kg
Same
Weight per kWp
46.4 kg/kWp
48.8 kg/kWp
-2.3 kg/kWp for JAM54S30-420/MR
Warranty and degradation
Product warranty
12 yrs
12 yrs
Same
Performance warranty
25 yrs
25 yrs
Same
Annual degradation
0.55 %/yr
0.55 %/yr
Same
Technology
Cell technology
PERC
PERC
Same
Cell type
Monocrystalline
Monocrystalline
Same
Cell count
108
108
Same
Bifacial
No
No
Same
04
14,005 panels
Against the whole database
Efficiency
#7,958
vs
#11,308
JAM54S30-420/MR leads by 3,350 places
Power density
#7,882
vs
#11,370
JAM54S30-420/MR leads by 3,488 places
Heat behaviour
#10,419
vs
#10,419
Tied - the same position in the database
Weight
#1,155
vs
#2,441
JAM54S30-420/MR leads by 1,286 places
Warranty
#9,798
vs
#9,798
Tied - the same position in the database
Overall
#11,103
vs
#12,072
JAM54S30-420/MR leads by 969 places
05
Open the full database
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Same series, other bin
JA Solar JAM54S30-420/MR vs JA Solar JAM54S30-400/MR
4 differences, the largest is module efficiency
06
Written summary
Checking cache...
07
Questions about this pairing
Which panel is better: JA Solar JAM54S30-420/MR or JA Solar JAM54S31-400/MR?
According to our database: JA Solar JAM54S30-420/MR has higher module efficiency (21.50% vs 20.50%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of JA Solar JAM54S30-420/MR and JA Solar JAM54S31-400/MR?
JA Solar JAM54S30-420/MR has a module efficiency of 21.50%, while JA Solar JAM54S31-400/MR is 20.50%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does JA Solar JAM54S30-420/MR use vs JA Solar JAM54S31-400/MR?
JA Solar JAM54S30-420/MR uses PERC cells; JA Solar JAM54S31-400/MR uses PERC. 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 JA Solar JAM54S30-420/MR and JA Solar JAM54S31-400/MR?
JA Solar JAM54S30-420/MR has a 25 years power warranty; JA Solar JAM54S31-400/MR has a 25 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.
Shop prices: See 389 JA 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.

