When you search for reliable solar solutions in Bangladesh, the phrase “smart solar and power” immediately signals a trusted partner for high‑performance panels like the Longi 355 (লংই ৩৫৫). This guide walks you through everything you need to know about this 355 W mono PERC panel, from technical specifications to practical installation advice, so you can make an informed decision for your solar project.
Why choose smart solar and power Longi 355 for your solar system?
The Longi LR4-60HPB is a high‑efficiency panel that delivers up to 19.5% conversion efficiency, thanks to its low‑lid mono PERC cells and half‑cut technology. Its positive power tolerance of 0~+5 W guarantees that every panel meets or exceeds its rated output, a critical factor for distributed projects across the country. With a 25‑year warranty, the panel promises long‑term reliability even under Bangladesh’s hot and humid climate.
Key technical specifications
- Maximum Power: 355 W
- Maximum Power Voltage (Vmp): 34.6 V
- Maximum Power Current (Imp): 10.27 A
- Open‑Circuit Voltage (Voc): 40.6 V
- Short‑Circuit Current (Isc): 11.25 A
- Cell Type: mono PERC
- Operating Temperature Range: –40 °C to 85 °C
- Maximum System Voltage: DC 1000 V (IEC/UL)
- Dimensions (L×W×D): 1722 mm × 1134 mm × 30 mm
- Weight: 20.8 kg
How the Longi 355 fits into different solar system designs
Bangladesh’s solar market includes on‑grid, off‑grid, and hybrid configurations. The Longi 355’s voltage range and high current output make it versatile for all three:
- On‑grid systems: Pair the panel with a string inverter that operates near the 34.6 V Vmp for optimal efficiency.
- Off‑grid setups: Combine multiple panels in parallel to meet the higher current demand of battery chargers.
- Hybrid solutions: Use the panel in a mixed string that feeds both the grid‑tied inverter and a battery management system, enabling seamless transition during power outages.
Because the panel tolerates up to 1000 V system voltage, you can connect many modules in series, reducing wiring losses and simplifying installation on large rooftops.
Choosing the right number of Longi 355 panels for your home
Start by estimating your daily electricity consumption in kilowatt‑hours (kWh). A typical Bangladeshi household uses around 150–250 kWh per month. To cover 80 % of that demand, you would need roughly 5–7 kW of solar capacity. Dividing the required capacity by the 355 W rating gives you 14–20 panels. Adjust the count based on roof space, shading, and orientation.
Factors that influence panel layout
- Roof orientation: South‑facing roofs receive the most sunlight throughout the year.
- Shading: Even partial shading can reduce output; use micro‑inverters or power optimizers if shading is unavoidable.
- Structural capacity: Verify that the roof can support the 20.8 kg weight per panel.
Installation best practices with smart solar and power
Professional installation ensures safety, performance, and warranty compliance. Here is a step‑by‑step overview that smart solar and power (স্মার্ট সোলার অ্যান্ড পাওয়ার) follows for every project:
- Site survey: Our engineers assess roof dimensions, structural integrity, and shading patterns.
- Design and permitting: We create a detailed layout, calculate string configurations, and obtain any required local approvals.
- Mounting system selection: Depending on roof type, we install either fixed‑tilt aluminum frames or adjustable mounts for optimal tilt angle.
- Electrical wiring: Panels are wired in series/parallel according to the design, using MC4 connectors and UV‑resistant cables.
- Inverter integration: The string inverter is connected to the DC combiner box, and the AC output is linked to the household distribution board.
- Testing and commissioning: We verify voltage, current, and insulation resistance, then register the system with the Bangladesh Power Development Board for net‑metering, if applicable.
For more details on how we can help, get a free expert consultation from smart solar and power.
Maintenance tips to keep your Longi 355 performing at peak
Solar panels are low‑maintenance, but regular checks extend their lifespan and maintain efficiency:
- Cleaning: Dust and bird droppings can reduce output by up to 5 %. Clean the surface with a soft brush and distilled water every 3–6 months.
- Inspection: Look for cracked glass, loose mounting bolts, or corrosion on connectors during bi‑annual visits.
- Performance monitoring: Use the inverter’s monitoring portal to track daily production. A sudden drop may indicate shading or a faulty panel.
- Warranty claims: Document any performance issues and contact smart solar and power for warranty service within the 25‑year period.
Common mistakes to avoid when installing Longi 355 panels
Even experienced DIY enthusiasts can stumble over a few pitfalls:
- Incorrect string sizing: Exceeding the inverter’s maximum voltage reduces efficiency and may void the warranty.
- Improper grounding: Neglecting grounding can lead to safety hazards during lightning strikes.
- Using low‑quality connectors: Cheap MC4 clones increase resistance and heat, shortening panel life.
- Ignoring thermal expansion: Panels expand under heat; allow for expansion gaps in the mounting design.
Why smart solar and power (স্মার্ট সোলার অ্যান্ড পাওয়ার) is the trusted provider in Bangladesh
Our company combines local market knowledge with international standards. We offer:
- Free expert consultation: Our engineers assess your energy needs and propose the optimal system size.
- Professional installation: Certified technicians follow IEC guidelines for safety and performance.
- After‑sales support: Routine maintenance visits, warranty handling, and system upgrades are part of our service package.
- Local sourcing: We partner with Longi to ensure authentic panels and genuine warranties.
Ready to start your solar journey? explore our solar products and discover how the Longi 355 can fit into your energy plan.
Future‑proofing your solar investment
Bangladesh is moving toward higher renewable‑energy targets, and many households plan to add battery storage or expand their rooftop capacity. The Longi 355’s high voltage rating and modular design make it easy to scale. Pair the panels with a lithium‑ion battery system and a hybrid inverter to store excess daylight energy for nighttime use, reducing reliance on the grid.
By choosing a panel with a robust 25‑year warranty and proven performance, you protect your investment against future policy changes and technological shifts. The combination of smart solar and power’s expertise and Longi’s engineering excellence ensures that your system remains efficient for decades.
Key takeaways
- The Longi 355 delivers 355 W of power with 19.5 % efficiency, ideal for Bangladeshi rooftops.
- Its mono PERC and half‑cut design provide higher output under high temperatures.
- Installation by smart solar and power guarantees compliance with local regulations and optimal system design.
- Regular cleaning, inspection, and performance monitoring keep the system at peak efficiency.
- Future expansion with batteries or additional panels is straightforward thanks to the panel’s high voltage rating.
Embrace clean, renewable energy today with the Longi 355 and the trusted expertise of smart solar and power (স্মার্ট সোলার অ্যান্ড পাওয়ার). Your roof can become a reliable source of green electricity for years to come.
Related reading: স্মার্ট সোলার অ্যান্ড পাওয়ার হাইব্রিড ইনভার্টার গাইড – Rahimafrooz Hybrid 4KW
Frequently Asked Questions
What is the expected lifespan of the Longi 355 panel?
The Longi 355 comes with a 25‑year performance warranty, meaning it should retain at least 80 % of its rated output for that period under normal operating conditions.
Can the Longi 355 be used in off‑grid battery systems?
Yes, the panel’s high current rating and 1000 V system voltage make it suitable for off‑grid setups when paired with an appropriate charge controller and lithium‑ion battery bank.
How does the half‑cut cell technology benefit performance in hot climates?
Half‑cut cells reduce resistive losses and lower the temperature coefficient, allowing the panel to maintain higher efficiency during Bangladesh’s hot summer months.
Do I need a professional installer for the Longi 355?
Professional installation ensures correct wiring, grounding, and compliance with local regulations, which protects the warranty and maximizes system performance.
What maintenance is required to keep the Longi 355 operating efficiently?
Regular cleaning to remove dust, periodic visual inspections for damage, and monitoring output through the inverter’s portal are sufficient to keep the panel performing well.