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390/MR vs 405/MR 16 of 19 identical Swap Change panels

JA Solar JAM54S30-390/MR vs JA Solar JAM54S30-405/MR

JA Solar JAM54S30-390/MR
JAM54S30-390/MR
390 Wp 20.00 % PERC
Open panel page Datasheet PDF
VS
JA Solar JAM54S30-405/MR
JAM54S30-405/MR
405 Wp 20.70 % PERC
Open panel page Datasheet PDF
The verdict

405/MR leads on the differences that matter

The largest is module efficiency: 0.70 pp more efficient. 16 of 19 comparable parameters are identical.

See all 3 differences
How alike are they
16 of 19 comparable
parameters are identical
identical differs
01

What actually differs

3 of 19 parameters
Parameter 390/MR 405/MR Difference
Module efficiency 20.00 % 20.70 % 0.70 pp more efficient
Power density 199.7 Wp/m² 207.4 Wp/m² 7.7 Wp/m² higher
Rated power 390 Wp 405 Wp 15 W more power
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.
390/MR
12,640 kWh
405/MR
13,126 kWh
Lifetime gap
486 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 390/MR 405/MR
Standard test conditions 25 °C 100.0% of rated power 390 W 405 W
Cool, bright day 40 °C 94.8% of rated power 370 W 384 W
Typical summer roof 55 °C 89.5% of rated power 349 W 362 W
Hot roof 70 °C 84.2% of rated power 329 W 341 W
03

Full specification

Parameter 390/MR 405/MR Difference
Power and efficiency
Rated power 390 Wp 405 Wp +15 W for 405/MR
Module efficiency 20.00 % 20.70 % +0.70 pp for 405/MR
Power density 199.7 Wp/m² 207.4 Wp/m² +7.7 Wp/m² for 405/MR
Open-circuit voltage 36.85 V 37.23 V Effectively the same
Voltage at max power 30.64 V 31.21 V Effectively the same
Short-circuit current 13.61 A 13.87 A Effectively the same
Current at max power 12.73 A 12.98 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 50.0 kg/kWp 48.1 kg/kWp Effectively the same
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

Against the whole database

14,005 panels
Efficiency
#12,214 vs #10,764
405/MR leads by 1,450 places
Power density
#12,255 vs #10,626
405/MR leads by 1,629 places
Heat behaviour
#10,419 vs #10,419
Tied - the same position in the database
Weight
#3,317 vs #2,073
405/MR leads by 1,244 places
Warranty
#9,798 vs #9,798
Tied - the same position in the database
Overall
#12,390 vs #11,881
405/MR leads by 509 places
05

More useful comparisons

Open the full database
Same series, other bin
JA Solar JAM54S30-390/MR vs JA Solar JAM54S30-415/MR
4 differences, the largest is module efficiency
Same series, other bin
JA Solar JAM54S30-390/MR vs JA Solar JAM54S30-410/MR
4 differences, the largest is module efficiency
Same series, other bin
JA Solar JAM54S30-390/MR vs JA Solar JAM54S30-400/MR
3 differences, the largest is module efficiency
Same series, other bin
JA Solar JAM54S30-390/MR vs JA Solar JAM54S30-395/MR
One difference: module efficiency
Same manufacturer
JA Solar JAM54S30-390/MR vs JA Solar JAM66D46-740/LB
16 differences, the largest is module efficiency
Same manufacturer
JA Solar JAM54S30-390/MR vs JA Solar JAM66D46-735/LB
16 differences, the largest is module efficiency
06

Written summary

07

Questions about this pairing

Which panel is better: JA Solar JAM54S30-390/MR or JA Solar JAM54S30-405/MR?
According to our database: JA Solar JAM54S30-405/MR has higher module efficiency (20.70% vs 20.00%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of JA Solar JAM54S30-390/MR and JA Solar JAM54S30-405/MR?
JA Solar JAM54S30-390/MR has a module efficiency of 20.00%, while JA Solar JAM54S30-405/MR is 20.70%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does JA Solar JAM54S30-390/MR use vs JA Solar JAM54S30-405/MR?
JA Solar JAM54S30-390/MR uses PERC cells; JA Solar JAM54S30-405/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 JAM54S30-390/MR and JA Solar JAM54S30-405/MR?
JA Solar JAM54S30-390/MR has a 25 years power warranty; JA Solar JAM54S30-405/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 394 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.