SPERAS D4S LCD Charger 21… — Speras Flashlight

Name: SPERAS D4S LCD Charger 21700 Charger
Brand: Speras Flashlight
Availability: InStock

Top-down view of the SPERAS D4S 4-slot smart battery charger, highlighting the high-definition LCD screen displaying charging status, voltage, and current

D4S vs. ZT20: Which is right for you?

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

Core Professional Features

Independent 4-Slot Control

Charge different battery sizes and chemistries at the exact same time. The D4S accommodates up to 4 batteries simultaneously (including 21700, 26650, 18650, and Ni-MH/Ni-Cd types). Each slot is controlled entirely independently, automatically detecting battery voltage to safely manage the charge.

Side view of the SPERAS D4S plugged in via USB cable, actively charging multiple different battery sizes including 21700 and 18650 Li-ion cells

Auto-Select Current & Intelligent Restoration

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.

Technical Specifications

USB Input: 5V/2A
DC Output: DC 4.2V / 1A * 2 OR 2A * 1 OR 0.5A * 4
Compatible Batteries: 21700, 26650, 18650, 16340, 14500 Li-Ion, Ni-MH/Ni-Cd, etc.
Dimensions: 122mm (L) * 97.6mm (W) * 31.5mm (H)
Weight: 140g (net weight) / 218.3g (gross weight)

📦 What’s in the Box

1 × SPERAS D4S Smart 4-Slot Charger
1 × Charging Cable
1 × Carrying Pouch
1 × User Manual

SPERAS D4S complete retail packaging and included accessories: charging unit, carrying pouch, USB cables, and instruction manual

Frequently Asked Questions

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.

SPERAS D4S LCD Charger 21700 Charger

About SPERAS D4S LCD Charger 21700 Charger

SPERAS D4S Smart LCD 4-Slot Battery Charger