SunPower flexible panels in parallel

Hello,
I am installing two sunpower 100w flexible panels on the back of a sailboat, and because of potential shading issues parallel connection would be preferred. Sunpower's installation pdf recommends only serial connection. Can I install a blocking diode to prevent issues with a parallel connection, if so any recommendations on a diode? The panels will be fed into a Victron 75/15 mmpt charge controller. Thanks!
I am installing two sunpower 100w flexible panels on the back of a sailboat, and because of potential shading issues parallel connection would be preferred. Sunpower's installation pdf recommends only serial connection. Can I install a blocking diode to prevent issues with a parallel connection, if so any recommendations on a diode? The panels will be fed into a Victron 75/15 mmpt charge controller. Thanks!
Comments
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
- Nominal power: 100 Watts
- Power tolerance: +6 / -3 Watts
- Vmp: 17.1 Volts
- Voc: 21.4 Volts
- Imp: 5.9 Amps
- Isc: 6.3 Amps
- Module efficiency: 18.8%
- Dimensions: 45.9" x 21.9" x 0.8"
- Weight: 4.4 lbs (2 kg)
I am hoping to install the panels in parallel.|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
Accordingto the manual blocking diodes are required if in parallel with shading issues to prevent bypass diode damage, see DANGER section in attached pdf
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Any recommendations on sizing of bypass diode, or how I might figure it out?
thanks
Seems to me adding a blocking diode, with associated voltage drop, isn't going to help with the potential too-low pv voltage into the mppt controller @mike95490 mentioned. I'm not sure mppt does much for you on a sailboat anyway unless you're at high latitudes in pretty cold weather. If parallel is a problem, how about a pair of cheap pwm controllers?
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
mcgivor- I can understand trying to keep the system simple with two simple Pwm controllers , but I already have one panel in place, with victron controller, and hope to add another.
Max possible amperage is about 12amps, if I look at the specs above. 10 amps is probably max realistically, is that how you got your recommendation?
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Strangely the website shows a marine application, perhaps they are counting on constant orientation changes, who knows, if it were me I would be asking the manufacturer for their suggestions.
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
I am not sure why blocking diodes on paralleled panels---In the olden days, lower Vmp panels and blocking diodes were used instead of of a solar charge controller (blocking reverse current flow/leakage current at night). These panels were known as "self regulating".
A solar cell in shade is just a reverse biased diode and if the reverse voltage gets too high, the diode fails.
MorningStar makes a nice series of PWM charge controllers (various sizes/configurations/options).
https://www.solar-electric.com/search/?q=morningstar+pwm
And there is the Midnite Brat:
https://www.solar-electric.com/midnite-solar-brat-pwm-solar-charge-controller.html
-Bill
If you have "low voltage panels" (Vmp~18-20 volts or less), you don't need the bypass diodes if they are never put in series.
From the "glossy":
https://www.solar-electric.com/lib/wind-sun/sunpower_SPR-E-Flex-100-110_spec_sheet.pdf
Max system voltage is 45 VDC. So, at best, you can put two panels in series... Which would seem to indicate that one shaded panel (no voltage) and one panel under sun, that would not be more than ~22 volts Voc across a single cell...
The installation guide talks about bypass diodes in the junction box:
https://www.solar-electric.com/lib/wind-sun/sunpower_flexible_panel_installation_guide.pdf
• SunPower does not recommend connecting these panels in parallel without proper system and safety protection.
• Connecting panels in parallel will double the current output of the panels. DC Currents may be greater than 12 amps for 100 W, 110 W and 170 W, and greater than 6amps for 50 W, in high illumination conditions (>1000 W/m2).
• If shading occurs without additional electronic components, such as a blocking diode, the by-pass diodes may be damaged leading to further panel damage and unsafe conditions including fire.
• If Paralleled panels are attached to a battery for charging, the high current may cause damage to the battery and subsequent safety issues.
• The charging characteristics of any battery should always be checked for compatibility with the current and voltage output of the panels prior to use.
The connectors used in these panels allows for modules to be connected in series or parallel. However, connecting the panels in this manner can put the by-pass diode in the panel and the battery at risk for damage and could create a safety issue. Please read the DANGER! note below.
Series Connection
Connecting the panels in series increases the voltage of the system, so the two panels produce double the voltage as compared to one panel. This high voltage can cause damage to the battery and could cause a safety issues. Please read the DANGER! note below. To connect panels in series, connect the negative (-) plug of panel #1 to the positive (+) plug of the panel #2. See Figure1 left.
Parallel Connection
Connecting the panels in parallel increases the current of the system, so the two panels produce double the current as compared to one panel. This high current may cause damage to the battery and the by-pass diode in the junction box and cause a safety issue. Please read the DANGER! note below. To connect panels in parallel, connect the positive (+) plug of panel #1 to the positive (+) plug panel #2 Connect the negative (-) plug of panel #1 to the negative (-) plug of panel #2. See Figure 1 Right. In this configuration, cable adapters will be needed.
-Bill