Solar power systems are becoming a popular DIY and prototyping project in India—but there’s a key issue many beginners overlook: reverse current flow. This happens when current flows back into the solar panel from the battery or load, especially at night. It not only wastes energy but can also damage your panel over time.

⚡ The Problem: Reverse Current Drain

Without reverse current protection, your battery might discharge through the panel when there’s no sunlight. This can significantly reduce battery life and efficiency, making your system unreliable.

💡 The Solution: Use a Blocking Diode or MOSFET

The simplest fix is to use a Schottky diode in series with the solar panel. Schottky diodes have low forward voltage drop and prevent reverse flow. For higher efficiency, use a P-channel MOSFET configured as an ideal diode to reduce losses further.

🧰 Practical Example: DIY Solar Charger

If you’ve built a 12V solar charger with a small battery bank, you might notice voltage drops at night. Adding a 15A Schottky diode like the 1N5822 ensures current only flows into the battery and not back out.

🔢 Sample Calculation: Power Loss on Diode

If your panel outputs 2A and your diode has a forward voltage of 0.4V:

P=V×I=0.4V×2A=0.8W

Switching to a low-RDS(on) MOSFET can cut this power loss drastically.

🛒 Product Suggestion: Schottky Diodes & MOSFETs

👉 Shop for Schottky Diodes and MOSFETs

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