SPERAS D4S LCD Charger 21700 Charger

The 4-Slot Powerhouse

SPERAS D4S Smart LCD 4-Slot Battery Charger

Scale up your charging capabilities. The SPERAS D4S is built for heavy users who demand efficiency. Featuring 4 fully independent charging slots, auto-selected rapid charging up to 2A, and a comprehensive LCD display, it keeps all your Li-ion and Ni-MH batteries primed and ready for action.

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

Core Professional Features

What is the difference between the SPERAS D4S and the ZT20?

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.

Can I charge Li-ion and Ni-MH batteries at the same time?

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.

How does the "Automatic Current Selection" work?

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.