21V 2A Li-Ion Battery Charger for 4-Series 18650 Packs | Qme
21V 2A Li-Ion Battery Charger for 4-Series 18650 Packs | Qme
21V 2A Smart Lithium Battery Charger — 4-Series 18650 Li-Ion Compatible
Keep your 18V lithium battery packs fully charged and performing at their best with this compact, intelligent 21V 2A charger. Designed for 4-series 18650 Li-ion battery packs, it delivers reliable, controlled charging with multiple built-in protection circuits — so you can charge with confidence every time.
Key Features
- Output Voltage: 21V DC — optimized for 4-series 18650 lithium battery packs (nominal 18V)
- Charging Current Options: 0.5A and 1A selectable output for flexible, battery-friendly charging
- DC Connector: 5.5mm x 2.1mm barrel plug for broad compatibility
- Compact Form Factor: 94 x 47 x 33 mm — easy to store and transport
- 2 Color Options: Choose the style that suits your setup
- Input Over-Current Protection: When input current exceeds 2A, a built-in fuse automatically cuts off power to prevent internal circuit abnormalities and reduce fire risk
- Output Current Protection: Charging current is regulated within a safe range to preserve battery health and maximize battery lifespan
- Short-Circuit & Over-Voltage Protection: Multiple safety layers guard against common electrical faults
- LED Charging Indicator: Clear visual status so you always know when charging is complete
- Clip Included: Convenient clip for easy handling and placement during charging
Who Is This Charger For?
Whether you use 18650 lithium cells in power tools, DIY battery packs, portable lighting, or other 4-series Li-ion applications, this charger provides a safe and consistent top-up every time. The compact dimensions make it ideal for workshop benches, storage drawers, or on-the-go use.
Safety & Standards
For guidance on safe lithium battery charging and handling, visit the U.S. Consumer Product Safety Commission — Lithium-Ion Battery Safety resource for best practices.
Specifications
- Output Voltage: 21V DC
- Input: Standard AC (compatible with included plug type)
- Charging Current: 0.5A / 1A
- Compatible Battery: 4-Series 18650 Li-ion (18V nominal)
- Connector: 5.5mm x 2.1mm DC barrel plug
- Dimensions: 94 x 47 x 33 mm
- Color Options: 2 available
- Brand: Qme
Frequently Asked Questions
Q: What type of batteries is this 21V lithium charger compatible with?
A: This charger is designed for 4-series 18650 Li-ion battery packs with a nominal voltage of 18V and a full-charge voltage of 21V. It uses a standard 5.5mm x 2.1mm DC barrel connector, making it compatible with a wide range of DIY and commercial battery pack configurations.
Q: What safety protections does this lithium battery charger include?
A: The charger features input over-current protection (fuse cut-off above 2A), output current regulation to protect battery health, and short-circuit/over-voltage protection. These multiple safety layers help prevent electrical faults and extend the life of your battery pack.
Q: What is the difference between the 0.5A and 1A charging settings?
A: The 0.5A setting provides a slower, gentler charge — ideal for conditioning or maintaining batteries. The 1A setting charges faster and is suited for everyday top-ups. Both settings stay within safe parameters to protect battery longevity.
Q: How do I know when charging is complete?
A: The charger features a built-in LED indicator that changes status when the battery is fully charged, giving you a clear and easy visual confirmation without having to monitor voltage levels manually.