Best 21700 battery chargers

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

Keep in mind that most 21700 chargers can not handle protected cells. The brand of the cell doesn't matter. You can have Acebeam, Efest, Nitecore, Samsung, LG or any other battery brand, and still use the following chargers. You just have to pick the one that fits you best.

Best single slot chargers

When you are looking for a simple, 1-bay charger.
Great for traveling and to keep as a backup... because you better have a backup charger at all times! 

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. 

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
  • 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

2-Bay multi chemistry charger.

  • AA, AAA, NiMH, NiCd, Li-ion 4.2V(3.6V) and Li-ion 4.35V (3.8V)
  • Can handle 21700 non-protected batteries
  • 0.2A-1.5A auto charge current
  • LCD Display with current, voltage etc.
  • Refresh function, Capacity check.
  • Price range: $25-$35
  • Read full review here 

This one includes a fan, which only turns on while discharging. Auto charge current for older NiMH cells can be a little problematic, meaning it cannot detect the -dV/dt cut off point. LifePO4 is not recommended with this charger. For 3.7V (4.2V)Lithium Ion batteries its doing a good job. 

4-bay 21700 chargers

4-Bay special charger with powerbank feature

  • AA, AAA, NiMH, NiCd,Li-ion 4.2V(3.6V)
  • Can handle the longest batteries
  • 0.1A-3A charge current
  • USB out at 1A ( powerbank 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.

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
  • 0.5A-2A charge current (2x2A, 4x1A, 4x0.5A)
  • Powerbank feature for on the road
  • LCD Display
  • Price range: $25-$35
  • Read full review here 

The Xtar X4 uses a normal DC cable so you don't have to worry about too less power like you will do with USB chargers. But if you'd like, you can use a Micro USB cable as well. In case you go overseas and don't have the correct 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!

4-Bay USB charger for dummies

  • Set and forget
  • Li-ion 4.2V(3.6V) only
  • Can handle 21700 unprotected batteries
  • Lithium Ion battery charger only
  • 0.5A-2A charge current
  • USB in
  • No display
  • Price range: $15-$20
  • Read full review here 

The previous version had a weak power supply, and couldn't handle the max current. The new one (now available) has a better power supply and can deliver more current for better charging. This is a very very simple charger that does the job, and nothing more! Simple charger for $15-$20

The second best 18650 analyzer

  • AA, AAA, NiMH, NiCd, LiFePO4 (3.2V), Li-ion 4.2V(3.6V) and Li-ion 4.35V (3.8V)
  • Can handle long batteries
  • Can charge 4.35 batteries with 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 handle 21700 batteries
  • Can not handle Protected 21700 batteries!
  • 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. 

Best 8 bay 21700 battery charger

8-bay lithium charger

  • AA, AAA, NiMH, NiCd, LiFePO4 (3.2V), Li-ion 4.2V(3.6V) and Li-ion 4.35V (3.8V)
  • Can handle long batteries like 21700 and even the widest D and 32650 batteries 
  • 0.1A-1A charge current
  • Small display for each slot
  • Rate by charger tester HKJ as Very Good 

A relatively new player in the market, but it starts of pretty well. They even include some spare parts and spacers. The small display shows the voltage, charge current and chemistry of the battery. It can charge 8 batteries at 1A.. very impressive. The charger does get hot of course. It can also charge 4.35V batteries and LifePO4 batteries. There aren't many 8 bay chargers on the market, and this is rather an impressive charger.

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