Hey there DIYers and tech lovers!
If you're like me and always running out of battery — or just love tinkering with electronics — this blog is for you. I recently got curious about upgrading my old power bank and even building one from scratch. So here’s everything I found, tested, and learned — in plain, real-world language.
🙋♂️ My First Question:
"I have a 10,000mAh Portronics power bank (Model 2242). Can I add 2 more 10,000mAh batteries to it? If yes, how?"
Short answer: Yes, you can — but do it the right way and with safety in mind.
🔎 What’s Inside That Power Bank?
If you open up your power bank, you’ll likely find:
- A 3.7V lithium battery (either cylindrical 18650 cells or flat Li-poly cells)
- A Battery Management System (BMS) — this is like the brain that handles charging, safety, and protection.
- A USB boost converter to step the 3.7V up to 5V output for your phone.
🧠 The Plan to Add Two More Batteries
If you want to turn that 10,000mAh into 30,000mAh:
- Use identical batteries (same type, voltage, brand if possible)
- Connect them in parallel, NOT series — this keeps the voltage same, but triples the capacity
- Upgrade your BMS if the original can’t handle the extra power
🛠️ The Connection (Simplified)
+ Battery 1 +
|
+ Battery 2 +
|
+ Battery 3 + → BMS (B+)
|
- Battery 1 -
|
- Battery 2 -
|
- Battery 3 - → BMS (B-)
All positive terminals together, all negative terminals together — clean and simple. Just make sure all batteries are at similar voltage before connecting (around 3.7–4.1V).
🔐 Use the Right BMS
Get a 1S 3.7V BMS rated for 10A or more, with built-in:
- Overcharge protection
- Over-discharge protection
- Short-circuit and thermal protection
You can find these online on sites like Amazon or Robu.in. Just search:
“1S 3.7V 10A BMS for Li-ion”
⚠️ Quick Safety Reminders
- Never mix old and new batteries
- Use only batteries with the same voltage and chemistry
- Always test with a multimeter before and after connecting
- Wrap things up with insulation or heat shrink tubing
💡 Not Confident? Do This Instead:
Buy a higher-capacity power bank (20,000 or 30,000mAh). It's safer and won’t void warranties or risk overheating.
🙋♂️ Second Question:
"I want to build a new 30,000mAh power bank from scratch. How do I do that?"
Short answer: It’s totally doable — and more fun than upgrading an old one.
🧾 What You’ll Need
| Component | Quantity | Why It’s Needed |
|---|---|---|
| 18650 Cells (3000mAh) | 10 | For total 30,000mAh @ 3.7V |
| 1S 3.7V BMS (10A) | 1 | For battery safety & protection |
| Boost Converter Board (5V) | 1 | Converts 3.7V to USB 5V output |
| Charging Module (TP4056) | 1 | To charge the power bank |
| Wires / Nickel Strips | As needed | For safe connections |
| Spot welder / Soldering iron | 1 | For joining battery terminals |
| Case or enclosure | 1 | To hold everything safely |
⚙️ Wiring Breakdown
-
Connect all 10 batteries in parallel
-
- to + and – to –
-
- Connect them to the BMS (input side)
- BMS output → to Boost Converter (for USB charging)
- Add a charging module to accept input (via Micro USB or Type-C)
- Place all parts into a case and test carefully
🧯 Safety Tips Before You Power On
- All batteries should be the same voltage before combining
- Always check for heating or swelling
- Don’t overcharge or draw more than 10A without upgrading the BMS
- Use proper insulation inside your case
🛠️ Want to See This in a PDF with Diagram?
If you want a visual, printable version of this guide — with connection diagrams and component links — just ping me. I’ll send you a custom PDF based on:
- Your battery type (Li-ion or Li-poly)
- Number/type of USB ports you want (USB-A, USB-C)
- Your tools (soldering or spot welding)
🎯 Final Thoughts
Building your own power bank is more than just a money-saving idea — it’s a solid DIY project that teaches you real electronics, power handling, and safety. Just go slow, use quality parts, and test often.