Best 21700 battery chargers

21700 battery charger guide

Below you can find a list of chargers that have been tested thoroughly by BLF and CPF member HKJ. The reviews will be linked in the descriptions.

Keep in mind that most 21700 chargers do not accept protected cells. The brand of the cell doesn't really matter, as long as it's not built for a proprietary charge system like Olight.

You can have Acebeam, Efest, Nitecore, Samsung, LG, Sony, or any other battery brand, and still use the following chargers. You just have to pick the one that meets your requirements, and accepts the length of your batteries.

Note: most of the chargers below accept cells up to about 70mm (which is the length of a normal, flat top, unprotected 21700 battery).
Most protected 21700 batteries are 73+mm long
Most protected 21700 batteries with a USB port are 75+mm long
Please measure your batteries (and be careful not to cause a short) before ordering the charger.

Don't forget to check out our list of the best flashlight batteries

Best single slot chargers

Small USB charger for lithium, NiCd and NiMh batteries!

  • AA, AAA, NiMH, NiCd, Li-ion 4.2V(3.6V) 
  • Can handle 21700 batteries easily
  • Input 5V Micro USB only.. no mains
  • Including a Powerbank feature: 5V 2A
  • 0.5A-2A charge current
  • Reverse polarity protection
  • Price range $15 - $25
  • Read full review here

Besides charging Li-ion batteries like the 18500, 18350, 18650 and of course the 21700, it can also charge rechargeable AA and AAA batteries. There is a small display that can show battery type, charge current, time, and Ah. Keep in mind that it basically charges at about 1.2A and not 2A. At the 2A setting it drops to about 1.2A. It can charge LifePO4 batteries but it doesn't detect this automatically. You have to set the charger to the LifePO4 setting. 

Opus BT C100 front view

Opus BT C100

The only programmable 21700 battery charger.. Take note that it will only fit unprotected 21700 batteries.

Small charger with normal power plug.

  • AA, AAA, NiMH, NiCd, LiFePO4 (3.2V), Li-ion 4.2V(3.6V) and Li-ion 4.35V (3.8V)
  • Can handle some long batteries
  • Display with details and settings to change
  • 0.5A-2A charge current
  • USB Out with 2.4A max
  • Accepts some longer, protected 21700 batteries, but not all!
  • Charge current can be manually set
  • Inclusive Discharge function, Analyzer, IR (impedance) test and Refresh function.
  • Price range: $15-$20
  • Read full review here of the original 1, and for the updated version.

The recommended 1-bay charger if you just want to have more control over the charger/analyzer. You can charge, discharge, test capacity, text impedance, refresh the batteries etc. Even 32650 batteries fit. Highly recommended.

2-bay 21700 chargers

Nitecore UMS2


Nitecore charger

2-Bay multi chemistry charger.

  • AA, AAA, NiMH, NiCd, Li-ion 4.2V(3.6V) and Li-ion 4.35V (3.8V)
  • Can handle long 21700 protected batteries!!! 
  • 0.2A-2A auto charge current
  • Max 3,000mA charge current, that needs to be manually set
  • LCD Display with current, voltage etc.
  • Refresh function, Capacity check.
  • Price range: $25-$30

This is the charger I user personally for all my longer 21700 batteries. It doesn't matter if the battery is protected, or if it has a USB port.. They will all fit in this charger.

It uses the older micro USB protocol, but can still charge up to 3000mA for a single slot, or 2 *2000mA when used both slots. The only problem I have on mine is that the Voltage is a little above what is shown in the screen.

4-bay 21700 chargers

4-Bay special charger with power bank feature

  • AA, AAA, NiMH, NiCd,Li-ion 4.2V(3.6V)
  • Can handle long batteries up to 73mm 
  • 0.1A-3A charge current
  • USB out at 1A ( power bank function)
  • Large LCD Display
  • Price range: $40-$50
  • Read full review here 

This charger is one of the fastest chargers on the market that can charge 26650 batteries at 3A. Keep in mind that some protected 21700 batteries, or ones with a USB port, may not fit. 

Simple 4-Bay 21700 charger.

  • AA, AAA, Li-ion 4.2V(3.6V)
  • Can handle 2 fat batteries like D cells and 32650 batteries
  • Accepts 21700 unprotected batteries
  • Does not work with long 21700 batteries with button tops/protection boards.
  • 0.5A-2A charge current (2x2A, 4x1A, 4x0.5A)
  • Powerbank feature for on the road
  • LCD Display
  • Price range: $25-$35
  • Read the full review here 

The Xtar X4 uses a normal DC cable so you don't have to worry about power as you do with some USB chargers. But you can still use a Micro USB cable for this charger when needed. In case you go overseas and don't have the correct wall plug with you. It also has a stable 1A USB output. So you can charge your phone or tablet on the fly. HKJ tested the charger and rates it as a good charger!

The second best 21700 analyzer

  • AA, AAA, NiMH, NiCd, LiFePO4 (3.2V), Li-ion 4.2V(3.6V) and Li-ion 4.35V (3.8V)
  • Can handle 21700 batteries, but not the longest with USB ports
  • Can charge 4.35 batteries with a hidden switch
  • 0.2A-2A charge current
  • Can handle most cylindrical battery on the planet
  • Large display
  • Price range: $35-$45
  • Read full review here 

The Vapcell S4+ got lots of love in the flashlight community. The charger can handle AA, AAA, Lithium and even charges at maximum 3A. Highly recommended! 

The best lithium battery charger

  • AA, AAA, NiMH, NiCd, LiFePO4 (3.2V), Li-ion 4.2V(3.6V) and Li-ion 4.35V (3.8V)
  • Can only handle flat top 21700 batteries! 
  • Note: Can not handle Protected 21700 batteries, nor button top 21700's!
  • Maximum control over every detail
  • 0.2A-3A charge current
  • Can handle literally every cylindrical battery on the planet
  • Large display
  • Bluetooth compatible
  • PC connector
  • Read full review here 

This charger does everything you can think of. You can charge all kinds of chemistries. You can discharge, test, plot, check,  and do whatever with this charger. This is my go-to charger analyzer! You can set your own programs, own currents, etc.. This is really the most advanced charger in the world. Period. If you want maximum control over your charging? Get this one, and be done with it. You just need a manual to help you along the way. lol. 

Note: although it can accept 21700 batteries. This is only for unprotected, flat tops. 21700 batteries with a button top, or with protection don't fit!

Best 8 bay 21700 battery charger

Xtar VC8 Plus charger

Xtar VC8 Plus

(There are 2 versions, and only the PLUS version accepts 21700 batteries)

8-bay 21700 charger

  • AA, AAA, NiMH, NiCd, LiFePO4 (3.2V), Li-ion 4.2V(3.6V)
  • 2 ports (DC input, or USB-C)
  • Can handle long batteries like 21700
  • 0.25A-3A charge current (Max 8 slots at 1Amp, or 4 slots at 2A)
  • 2 large displays
  • Battery analyzer (capacity test) built in

Xtar is a very well regarded player in the battery charger market. Besides awesome chargers, they also make flashlights with the focus on scuba divers. Anyway, the VC8 Plus can handle 21700 batteries.

They give you the option to order it with the DC plug, or just USB-C. When ordering, make sure you get the Plus version, and not the normal VC8 version. The Plus version is the one with longer bays.

All 8 bays can be used at the same time, and the maximum charge current is 1A per battery when all 8 bays are used. The charge current increases to 2A when only 4 bays are used. The maximum charge current is 3000mA, when 1 bay is used.

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