Best 21700 Battery Chargers: (Recommended Options)

Published on: May 29, 2022
Written by Liam Jaxon / Fact-checked by David Rowan

21700 battery chargers, if you have batteries then it is necessary to make it charged as long as you are using the device. In general, 21700 battery chargers are configured to support Lithium-ion chemistries and sometimes 4.2V to 3.6V 21700 model batteries which are available in both protected and unprotected batteries.

Moreover, the batteries are advanced with higher output rather than any 18650 batteries. Sounds great, right? Some of the 21700 batteries capture the upgraded version from the overwhelming battery slots to let batteries get charged at low consumption of power sources. 

best 21700 battery chargers

Either charging speed or the battery slots, whatever you think is the nicest you should grab at first seen and for your concern, we have picked some of the high quality 21700 battery chargers with verified as if our tested info to not let your bucks be wasted. Here is a 5 minutes review you can dive into. 

What Is a 21700 Battery Charger? 

The reasoning behind working as a 21700 named charger for the battery is the superior dimension. As we are explaining, let’s break down the entire name and why the name is. From descendant level, 0 represents the type or shape of the battery that is on the user or the user is going to install it in the device, then 70 indicates the length in millimeters, and the first 2 digits 21 means to measure its diameter in millimeters (mm).

The overall experience and even the specifications indicate that this battery charger is a cylindrical type charger, not only pushing very important benefits while installing but also after the user as well. During the usage, it offers an almost high energy ratio which comprises the level of intending higher capacity. 

Compared to bank marine battery chargers, such a battery is a wise decision if prospective users have a plan to apply and use battery chargers for their Samsung, Orbtronic, and other modeled mobile phones for longer. A protected designed charging bay is quite different not only in terms of length but also in terms of button top. However, another model was designed and named as an unprotected bare flat top cell and it does not contain any backward compatibility. 


As we have mentioned earlier that the most common type of 21700 battery charger is available in 2 different models, one has a protected cell in configuration and the other one is an unprotected bare top cell configured manual charger. 

Protected:  This is an advanced-designed battery charger that has ultra protection and compatible power to restore the button-top battery. However, a protected 21700 battery charger is backward compatible. Unless it is 1mm smaller in size than the unprotected model, a powerful and even the most powerful electronic gadget may include such a small spot. 

Unprotected:  Rather than a 21700 3.7V battery charger, an unprotected battery charger is a lower 3000 mAh battery compatible charger for fast charging. As we can understand it is dropped to a cheaper version named 18650 battery chargers, yet very powerful and larger than any old versions. It opens the flexibility to being installed in different modeled phones and devices at present. Regardless, you can give a trial of each one and 

21700 Battery Charger: Specifications and Features

Prospective users and pro persons find the quality easily of a battery charger, in fact, it remains no damage and stocks higher energy, later on, every time usage. But for that quality maintaining purchase, users should follow a single strategy.

Labeled with “NEW” or with a Sharpe A, B, C and more letters may be used over the body to ensure the outperformance level with voltage and discharge rates. However, this is a technique to utilize on gauging temperature. It is simple, charge and get the result, then compare properly. Let’s break down by which a 21700 battery charger is made of, what are the features and why should you use it. 

Chemistry:  from numerous chemical combinations, users must focus on the chemical combinations that have protected cells. Therefore, if the chemistry reported gets changed, then nothing will happen, not even a single short circuit will occur. However, the purchase sometimes relies solely on the device type that you are using and going to install the battery and charge it later. 

Features: A protected mode battery charger prefers up to 3.6V charging capacity, in particular, 4.2V to 3.6V. Whether the battery is made of big Lithium-ion or AAA, even sometimes supportive to AA to let the user workout on torchlights eventually. Sometimes it differs by brand, for instance, some manufacturers manufacture 4 bays, whether some 3 or less than that. 

USB chargers are the greatest and advanced useful chargers we have ever seen. Recently such 21700 modeled battery chargers can manage to recharge 2 fat batteries at the same time, for instance, D cell batteries, along with 32650 batteries which are a bit advanced rather than 21700 batteries. Not only in measurement but also in supporting issues and charging capabilities. 

Charge current ranges between 0.5A to 2A. Gives enough support to power bank features, LCD display, yet not good to go with longer 21700 battery versions. If you are on-demand for refresh function and capacity check, nothing beats a 21700 battery charger compatibility as long as we have mentioned before that the backward compatibility you can enjoy too. 

View Editor’s Recommended 21700 Battery Chargers

Probably you have an emergency or for regular night purposes as if you face a common load-shedding problem in your living area, you have bought a 21700 battery integrated torchlight which is super comfy. However, to recharge that full bright flashlight, altogether with extra purchased batteries, you need a superior battery charger which may have in-built 4 or more houses to charge at the same time. 

With no ado, we have just practiced and given trials within this month, and guess what for our prospective users? We found super 21700 battery chargers with longer usage assurance that may save your time and worthy bucks right now. 

1. Cosoos Universal 4-Bay Charger

Technical Specifications 

Battery Slots 4
Type Multiple levels of protection
Screen Display LCD
Dimension 5.87 x 2.95 x 1.59 inches
Weight 1 pound 
USB compatibility AC/DC charging cable 

Editor’s Note 

The fast-charging capacity provides a universal battery charger with 4 cells at the same time. You may be confused that how the charging ports are capable of charging 4 different batteries of different types, especially the D-cell types within moments, how could we choose it to be the latest and finest one? 

Well, this was also our overwhelming test, yet we won and more than that Cosoos won mostly, however, other bulk models like 10440 14500 16340 18650 21700 26650 Ni-MH / NiCd: AA, AAA, and C are compatible to get charged with it.

Anyways, back to the point. Can it charge Lithium-ion batteries? Yes, of course, the specialty remains in that. You can easily charge your torchlight batteries, even without any concern, why?

Well, the protection level can maximize the protection and prevent unnecessary accidents. Multi-levels of protection means short-circuit protection over regular current flow protection, in fact, additional reverse polarity protection and over-voltage protection. 

Rather than other models’ integrated displays, this has an in-built no foggy LCD display to let users watch the accuracy or battery has been fully charged or not with other options. The bundle includes a rigid battery cell case, though it is a plastic-made one. 

We prefer most, even you can say it just made our day and that is the AC/DC charging support. Also, from our test, 3W (Ni-MH/Ni-Cd Batteries) and 8.4W (Li-ion Batteries) rated output power. If you purchase it from your local area, then an outlet you can get free of cost. 

What We Liked 

  • Multiple batteries charging capacity;
  • Fast charging;
  • Outlet free;
  • AC/DC charging cable;
  • LCD display;
  • Four cells for charging. 


  • Found nothing. 

2. Edisonbright are-A2 Smart 21700 Battery Charger 

Technical Specifications 

Battery Slots 2
Type Protected 
Screen Display LCD
Dimension 5.87 x 2.95 x 1.59 inches
Weight 1 pound 
USB compatibility AC only 

Editor’s Note

We put the most familiar EdisonBright manufactured 21700 battery in our second list position. The greatest compatibility with the bulkiest batteries just amazed us and guess what? Worked well with 5000mAh batteries without any unnecessary injuries as if it has multiple protection levels. 

We have a specified test, like the PD36r manual indicates 21700 battery integration, yet gave a trial with ROFIS and it works well. With just under 3V, it takes almost 8 hrs to fully charge. As long as it is a button top, then why not? 

However, we may not prefer this model battery charger for 18650 batteries. You may ask why not whether it is pursuing other bulky and hard metallic made batteries including Lithium-ion. This is hard to find the exact match, also no assurance over the protection.

As we have experienced, the model reserves capacity for AC-type current to flow only, while the previous model offers both AC and DC. Compared to the previous 21700 battery charger, this one has similar input and output power.

We have identified that the charger can handle the Streamlight SL-B26 which works with a 18560 battery. Here you can use a small trick as well as a 2-handed task, the anode side of the sliding connector is a bit stiff and you need to slide it with a small tap inside on the springs.  

What We Liked 

  • Adopts advanced microprocessor;
  • Compatible with bulky batteries;
  • Fast charging;
  • 3V compatible;
  • Similar input-output.  


  • AC only. 

3. XTAR X2 2 Bay 21700 Battery Charger 

Technical Specifications 

Battery Slots 2
Type Unprotected 
Screen Display LCD
Dimension 5.47 x 2.95 x 1.5 inches
Weight 1.3 pound
USB compatibility AC/DC
Compatible batteries 14500-26650 Li-ion batteries

Editor’s Note 

A relatively new machine empowering source in the market, right? Yes, fortunately, it starts off pretty well. However, the manufacturer has closed the package with the necessary spare parts and spacers. The tiny displays show the charge current, voltage and even chemistry of the battery. Since the display is available in LCD format, it shows each meter accurately. 

Even you will be impressed if you have the charger with charging capacity at 1A only, sounds great, right? Though the charger gets hot it has its own machinery to discharge the heat and make it cool automatically. In any case, it has more than 4.35V charging capacity of any necessary small regular purchasing accessories. 

Though it is a 2 bay charger, in fact, a common issue that makes it stand out of the crowd and that is the high model battery charging capacity. Since the cells are unprotected and it is nothing suitable for LifePO4 batteries and that made our mind place it into the 3rd listing. But we suggest prospective users try it for regular purposes. 

What We Liked 

  • Handle long batteries;
  • 0.5A-2A charge current;
  • Small display for each slot
  • AA, AAA, NiMH, NiCd, Li-ion 4.2V(3.6V) and Li-ion 4.35V (3.8V)
  • Lightweight. 


  • A bit risky for LiFePO4 (3.2V) batteries;
  • Unprotected. 


4. XTAR VC4S 4 Slot Universal Battery Charger 

Technical Specifications 

Battery Slots 4
Type Protected except for 20700/21700 batteries
Screen Display LCD
Input Port Micro USB Port
Weight 1 pound 
Power input QC3.0(5V⎓3A/ 9V⎓2A )
Constant Current0.5A * 4 / 1A * 2

Editor’s Note 

What is in our 4th listing? Well, it is our favorite and well-known charger version for 21700 battery models. Whatever you can think of, is inside for recharging your gadgets carefully. Though a single drawback just made our mind stressful and that is like the previous model, unprotected open cells to charge your 21700 or more powerful batteries together.

However, we never felt like this can serve a lot more than we are expecting. In addition, the sigma rule has been made invalid and got the texture to discharge, test, check and plot. 

In short, it is a charger-analyzer. Why? The best reason to call this thing is the charging capacity of all the chemistries. So, any guess of skipping the charger from your bucket list?

We don’t even think so, including the high dimension to give the space enough to charge the needed batteries for your common gadgets which you can utilize properly. How about the constant current reservation? Well, more than .5A and less than 2A or equal to 2A. 

No guess that a manual can gradually be important to users for giving a try. Well, prospective users must check it out with the bare parts given in the toolbox. 

What We Liked 

  • AA, AAA, NiMH, NiCd, LiFePO4 (3.2V), Li-ion 4.2V(3.6V) and Li-ion 4.35V (3.8V);
  • Maximum control over every detail;
  • 0.5A-2A charge current;
  • Large display;
  • Bluetooth compatible; 
  • PC connector. 


  • Can only handle flat top 21700 batteries. 

5. EdisonBright Fenix are-D1 USB Powered 21700 Battery Charger

Technical Specifications 

Battery Slots Single 
Type Protected 
Screen Display LCD 
Dimension 7.09 x 5.2 x 2.17 inches
Weight 1.12 pound 
USB compatibility Micro USB 
USB Output 5V/2A
Constant Current0.5A/1.0A/2.0A 0.5A/1.0A
Operating temperature-20°C to 50°C

Editor’s Note 

Again our choice turned out to be good to share with EdisonBright, however, the single battery charging cell just turned our mood off. It is mandatory that every charger may have multiple charging cells in itself whether protected or unprotected, yet this one made, the manufacturer left no stone unturned to make a quality battery charger for 26650, 21700, 18650, 16340, 14500, 10440 AA AAA C battery types

Can you use the discharge function? Well, the function works like a power bank, yet with the charged battery installed, it can recharge your phone with a cord. 21700 fits very well even for the ones that have their own USB charger and overload protection systems built into the battery. 

What We Liked 

  • Set and forget;
  • Lithium-Ion battery charger only;
  • USB in;
  • Not expensive;
  • Better power supply.  


  • The display is not good;
  • Single cell charger. 

6. Sofirn Universal Fast Recharging Charger

Technical Specifications 

Battery Slots 4
Type Protected 
Screen Display LCD 
Dimension 8.03 x 7.36 x 2.52 inches
Weight 1.57 pounds 
USB output 12V/5A

Editor’s Note 

Though it is a renowned, obviously a new player in this 21700 battery charger market. Yes, fortunately, we have experienced a better USB output compatible charger that has 4 cells and each cell contains at least 5A recharging battery within a couple of hours.

It is common sense that a battery charger may not be capable of charging altogether 4 cells with higher amperage at a time. Therefore, the model is not losing, either it is performing or letting users know the repairable lithium batteries over-discharge is lower than 2.5v or even 0 voltage.

In any case, it comes with a better appearance rather than another 4-cell charger for 21700 batteries, XTAR VC4S. Another pinpointed feature is the easiest automatic discharge mode which can detect each battery capacity in each slot. However, it may discharge at least 1A current at the same time in both first and 4th slots. 

There is a ringtone reminder and whenever the battery becomes charged, it starts on absolute ringing. This makes the utilization much more convenient to get access to the charger and battery both. 

What We Liked

  • 4 cells;
  • High USB power output;
  • Micro-USB charger;
  • Lightweight;
  • High charging capacity;
  • Better discharge function. 


  • Hefty-priced than previous models. 

7. XTAR X4 Extended Version Protected 21700 Battery Charger

Technical Specifications 

Battery Slots 
Type Unprotected 
Screen Display LCD
Dimension 8.9 x 5.59 x 1.89 inches
Constant current 0.5A*2, 1A*2 and 2A*1
USB output DC 5V 1A
Operating temperature 0-40℃

Editor’s Note 

Last but not least 21700 battery charger in our listing. Well, this one just somehow dragged us our crew members because of its high density yet less charging capacity all of a sudden. Though the manufacturer has mentioned that the battery charger can optimize 4 batteries at a single moment, not more than 2A per cell.

However, we loved the operating temperature which has crossed the preference over the 1st model Cosoos, about more than 40℃ we have experienced. In fact, its discharging rate and constant current assure at least 0.5A for 2 cells, 1A for another 2, as it indicates no bursting moment. 

the micro-USB input-output port allows 2 18650 and 2500mAh batteries to get fully charged as an empowering tool for your GPS, mobile phone, flashlight and other outdoor devices to help you on tour and traveling in the dark. 

Apart from all those bad and good features, its additional parts are amazing which are free from XTAR manufacturers, for instance, 1pc X4 Charger, 1pc Power Cord and 1pc User Manual.  

What We Liked 

  • 4 bays charger;
  • Fast charger;
  • Auto selected current;
  • Better appearance;
  • Better discharge rate. 


  • Poor display;
  • Hefty-priced. 


Are you missing something before purchasing a 21700 battery charger? Well, reading through the answers to this FAQs section, you may find the extras. 

How Do You Charge a 21700 Battery?

Most of the prospective users ask are all 21700 battery chargers good or not? We answer it which relies on both manufacturer and users maintenance priority. The best thing you can do is to bring the genuine USB-C port charging cable which comes in the battery charger toolbox with the manual. Also, USB power source, for instance, laptop or solar panel, and the rest is all gadgets magic to make it fully charged.  

How Long Does It Take to Charge 21700 Batteries?

As long as we have tested each of the selected 21700 battery chargers, all about 300 to 500 times recharging capacity each charger contains in itself. But later, a possibility of depletion may occur with zero operating efficiency. Each protected battery charger for 21700 models takes or more than that model’s accepted take at least 4-5 hours altogether, yet an unprotected battery charger has a flat top which indicates charging time more than that. 

What Is the Best Vape Battery Charger?

The best vape battery charger should have 3 certain qualities, first is size, second is speed and third is charging accuracy. Good vape batteries may not cause your battery to face uneven charging, overheating and overcharging. Therefore, without the collaboration with 3 qualities, charging capacity dramatically can decrease. 

What AMP Should I Charge My 21700 Battery at?

Either you are querying for the amps should you charge your vape at or for the amp should be charged your 21700 battery chargers at 1 amp and not more than that. Why? Most of the 21700 battery chargers and vapes chargers contain 5A and 1amp charging capacity so as not to face overcharging or burst out to damage your battery. 

How to Choose 21700 Battery Chargers


Size and safety are the foremost selective factors for a 21700 battery charger if you need a quality maintaining one. Why? Well, safety can be ensured by the battery size you are going to charge as if the chances of bursting out the charger and battery become lesser than you can think. In any way, the size of the pin and charging point may decrease the level of getting hot on the battery. 

For example, Cosoos 4 bay charger is a nice one and we even found it as the finest one for charging a different range of batteries. Overcharge protection, short-circuit protection and reverse polarity protection depend solely on the battery charger.  


Not all but almost all battery chargers have been manufactured to speed up the battery charger to charge the batteries within moments without losing a general huge amount of power source like electricity. Fortunately, we have selected such batteries solely for the 21700 model batteries, not only that consume less electricity but are also capable of charging more than 3A of each cell battery. 


This factor indicates how long and accurately a charger lets charging the battery into its full limit. In general, a single battery charger limits up to higher amperage to charge within moments, yet a 4 or 3 bay charger takes a rather long time to charge each cell battery. Moreover, a battery with higher voltage is a second concern, as well as the operating temperature and USB output you must check before purchasing one at a time. 

Wrap Up 

Battery standard maintenance is the most vital role for users who are on definite utilization of common gadgets which are run with batteries. In fact, most of the batteries deserve quite good and quality battery chargers, for instance, EdisonBright 21700 battery chargers that ensure zero short-circuit and overall protection. 

However, we are concerned for our regular readers and the main reason we have pinpointed 21700 battery chargers with an inquiry section.  

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About This Writer

liam jaxon author pic

Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

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