My ums2 keeps going into reboot loop when at times inserting a 18650 battery; tried 2 brands of batteries; multiple usb cables; defective?

Have you tried a more powerful (output) USB adapter? If the issue persists, contact us (the seller) and we will have the issue resolved swiftly.

Will this unit charge a protected 21700 battery? I know it will accept the unprotected battery.

Yes. It can charge both protected and unprotected 21700 battery.

Does this unit have a discharge function?

No, it does not have a discharge function.

Does it test for battery capacity?

No. It does not display the capacity of the battery.

Nitecore UMS2 Dual Slot USB Smart Battery Charger for Li-on/Ni-MH/Ni-Cd/IMR 16340 14500 18650 21700 20700 AA AAA and Other Batteries with Battery Organizer

Nitecore UMS2 Dual Slot USB Smart Battery Charger for Li-on/Ni-MH/Ni-Cd/IMR 16340 14500 18650 21700 20700 AA AAA and Other Batteries with Battery Organizer

Product ID: 740204718

Details

Brand
Nitecore
Colour
Black
Item weight
5.56 Ounces
Output voltage
4.35 Volts
Specification met
CE

⚡4000mA max dual-slot fast charge

📊Real-time LCD battery & charge status

🔋Universal multi-chemistry & size support

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€ 298.47

Duties & taxes included

In stock

Sold byAmazon SpainDelivered byDesertcartCustomer service byDesertcartReturns14 days · 30 with PRO

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Description

🔌 Power up smarter, faster, and safer — never run out of juice again!

SMART SAFE CHARGING 🔒 - Automatically adjusts current and voltage to maximize battery lifespan and prevent overcharge.
TURBOCHARGE YOUR POWER ⚡ - Delivers up to 4000mA total output with QC2.0+ USB for lightning-fast dual battery charging.
STAY INFORMED INSTANTLY 📊 - Bright LCD screen keeps you updated on battery health, charging mode, and progress in real time.
TRAVEL READY ORGANIZATION 🎒 - Includes a sleek LumenTac battery organizer to keep your power essentials neat and accessible on the go.
ALL IN ONE BATTERY COMPATIBILITY 🔋 - Supports Li-ion, Ni-MH, Ni-Cd, IMR, and common sizes from AAA to 21700 — perfect for every device.

The Nitecore UMS2 Dual Slot USB Smart Battery Charger offers ultra-fast charging up to 4000mA total output with QC2.0+ support, a clear LCD display for real-time battery and charging status, and intelligent charging technology that protects and extends battery life. Compatible with a wide range of battery chemistries and sizes, it’s the ultimate all-in-one charger for professionals and travelers alike, complete with a handy battery organizer for on-the-go convenience.

Specifications

ASIN	B07JN49XYM
Amperage	3000 Amps
Brand	Nitecore
Color	Black
Colour	Black
Current Rating	2 Amps
Customer Reviews	4.4 out of 5 stars 783 Reviews
Input Voltage	5 Volts
Input voltage	5 Volts
Item Weight	5.56 Ounces
Item weight	5.56 Ounces
Manufacturer	NITECORE
Mfr Part Number	UMS2+ORG
Model Number	UMS2
Number of Ports	2
Output Voltage	4.35 Volts (DC)
Output voltage	4.35 Volts (DC)
Specification Met	CE
Specification met	CE

Reviews

P**.

Display is not accurate

19.11.2025

C**.

Really Impressive Charger, Big Upgrade from My Old One, Speedy, Easy, and Informative!

15.08.2025

A**Y

Great product!

3.03.2026

W**K

Great Recharger

21.02.2026

D**N

Solid upgrade from the Nitecore I2. Does not have an integral power supply.

23.11.2025

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