A lot of people are now learning how to build simple DIY power banks. But one thing I discovered quickly is this: Lithium batteries are NOT something to handle carelessly. One wrong connection can damage: your phone, the battery, or even cause overheating. Here are important mistakes to avoid 🧵👇 ❌ Avoid using damaged or swollen batteries. If a battery: looks swollen, leaks, overheats easily, or smells strange, DO NOT use it. Especially recycled laptop batteries. Safety first. ❌ Do not connect batteries directly to your phone. This is one of the biggest beginner mistakes. Phones need: stable voltage, controlled current, proper regulation. That’s why the charging module is essential. Never skip it. ❌ Avoid mixing different battery types together. For example: old battery + new battery, different capacities, different brands. That imbalance can reduce performance or create safety issues. Use matching batteries whenever possible. ❌ Don’t reverse the polarity. Battery connections have: ➕ positive ➖ negative Connecting them wrongly can: destroy the module, damage the battery, or create sparks. Always double-check before powering anything. ❌ Avoid cheap fake batteries. Some batteries sold online have fake capacity labels. A battery labeled: “9900mAh” may actually perform far below that. Quality matters more than exaggerated numbers. ❌ Don’t leave exposed wires uncovered. Bare wires can touch accidentally and cause: short circuits, sparks, overheating. Use: electrical tape, heat shrink, or proper casing. ❌ Avoid charging batteries unattended for long periods. Especially during early testing. If something is connected wrongly, heat buildup can happen gradually. Always monitor new DIY setups carefully. ❌ Don’t use metal objects carelessly around batteries. Coins, keys, scissors, or exposed metal can short battery terminals instantly. That can become dangerous very fast. ❌ Avoid poor ventilation. Lithium batteries generate heat during charging. Don’t trap them inside fully sealed spaces without airflow. Heat is one of the biggest enemies of battery lifespan. ❌ Don’t expect one small battery to power everything. One 18650 battery may: ✅ help a phone …but tablets and larger devices usually need: multiple batteries, stronger modules, better capacity. One thing I’m realizing from learning DIY electronics is this: Technology becomes much less mysterious when you understand the basics. But knowledge and caution must go together. Especially with power-related projects. Building things yourself can be satisfying… …but safety should always come before excitement 🔋⚠️ Would you ever try a DIY power bank project?
