Keenstone 18650 Battery Charger, Smart Universal Charger LCD Display for Rechargeable Batteries

The Keenstone 4-Bay Universal Battery Charger is a dedicated charging station built to handle mixed sets of rechargeable cells. It solves the hassle of keeping multiple single-format chargers around by supporting standard household Ni-MH and Ni-Cd sizes alongside numerous lithium-based cylindrical batteries like 18650, 14500, and 26650 cells.

Each of the four charging slots operates independently. By pressing the corresponding A, B, C, or D button, you can cycle through real-time feedback on the LCD screen, tracking the exact voltage, active current, and charging time for any single cell. The unit also lets you toggle between 500mA and 1000mA charge currents to match lower-capacity cells or speed up charging on larger batteries.

For safe operation, the internal circuitry provides protection against overcharge, over-discharge, short circuits, and reverse polarity. It also complies with a long list of regulatory standards, including UL, CE, FCC, RoHS, PSE, and TUV GS certifications.

On the downside, the charger offers only two fixed current rates (500mA and 1000mA), giving you less fine-tuning compared to chargers with continuous or micro-step current selection. The data also does not specify external power brick details or whether it can run from USB power sources.

Verdict: This charger is a solid, practical choice for anyone regularly using mixed cylindrical rechargeable batteries who wants clear, slot-by-slot tracking on an integrated LCD screen.

A great fit if you:

• Use a mix of household rechargeable sizes like AA, AAA, and specialty 18650 or 26650 lithium cells
• Want individual digital readouts for voltage, current, and charge time for each bay
• Need built-in safeguards against reverse polarity, short circuits, and overcharging

Consider something else if you:

• Require custom current settings outside of the 500mA and 1000mA options
• Need a charger with USB output ports to power external devices

What types of batteries does this charger support?
It supports Li-ion, LiFePO4, IMR, INR, and ICR chemistries in sizes including 25500, 22650, 18650, 18490, 18500, 18350, 16340 (RCR123A), 14500, and 10440, as well as Ni-MH and Ni-Cd batteries in A, AA, AAA, AAAA, and SC sizes.

What information appears on the LCD screen?
By pressing the A, B, C, or D slot buttons, the screen displays the voltage (V), charging current (mA), and elapsed time (h) for each battery independently.

What safety protections are built into the charger?
The unit includes intelligent circuits that protect against overcharging, over-discharging, short circuits, and reverse polarity.