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Free shipping on all order above $49.99 to most countries.
Most flashlights can directly get 5 years warranty; battery and accessories get 1 year warranty.
Any questions, please email to info@sperasflashlight.com
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Whether you need high-volume charging for multiple devices or precise battery capacity testing, SPERAS has a smart charger engineered for your specific needs.
| Feature | ZT20 (Diagnostic Focus) | 🔥 D4S (Volume Focus) |
|---|---|---|
| Charging Slots | 2 Independent Slots | 4 Independent Slots |
| Max Charging Current | 2A * 1 slot / 1A * 2 slots | 2A * 1 slot / 1A * 2 slots / 0.5A * 4 slots |
| Special Feature | Battery Capacity Testing (mAh) | Auto-Select Best Charging Current |
| Best For | Testing & restoring old batteries | Charging many batteries quickly |
Maximize your battery life effortlessly. The D4S automatically selects the optimal charging current (0.5A, 1.0A, or up to 2.0A maximum) based on battery status. It features automatic termination upon completion, alongside advanced safety protocols like reverse polarity protection, short circuit defense, and a function dedicated to restoring and activating over-discharged Li-ion batteries safely.
The primary difference is volume vs. diagnostics. The D4S has 4 independent slots, allowing you to charge up to 4 batteries at once, making it ideal for users with lots of gear. The ZT20 has 2 slots but includes a dedicated capacity testing feature (measuring exact mAh), making it better for diagnosing and testing older batteries.
Absolutely. Because each of the 4 slots is controlled independently by the smart microcomputer, you can safely mix battery chemistries (like a Li-ion 18650 and a Ni-MH AA) and sizes simultaneously. The charger will automatically detect what is inserted and apply the correct voltage.
To maximize the lifespan of your batteries, the D4S analyzes the internal resistance and state of the battery inserted. It will then automatically choose the safest and fastest charging current: 0.5A for smaller/fuller batteries, 1.0A for standard charging, or up to 2.0A for rapid charging a single high-capacity cell.
| Model | SPERAS D4S |
|---|---|
| Output Current | 2A*1 1A*2 0. 5A*4 |
| Charging Type | Micro USB USB-C Lightning |
| Channel Qty | 4 Slots |
| Battery Type | Li-on battery IRM batter E.g: 21700 18650 etc |
| Indication Type | LED Indication |
| Application | USB Fast Charger Suitbale for 21700, 18650, 16340, 21700, Ni-MH, Ni-cd battery etc. |

