Best 21700 battery chargers
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 73mm long Most protected 21700 batteries with a USB port are 75mm 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
Fenix ARE D1
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
Small charger with normal power plug.
The only programmable 21700 battery charger. Take note that it will only fit unprotected 21700 batteries.
- 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.
Nitecore UMS2
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 using both slots. The only problem I have with mine is that the Voltage is a little above what is shown in the screen. Buy at Amazon.com
Miboxer C4-12
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.
Xtar X4 (extended version)
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 protected batteries! (this is only for the extended version)
- 0.5A-2A charge current (2x2A, 4x1A, 4×0.5A)
- Powerbank feature for on the road
- LCD Display
- Price range: 30-35
- 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!
Vapcell S4
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 batteries 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-ion, and even charges at a maximum of 3A. Recommended!
The best lithium battery charger
But only for unprotected, short 21700’s
- 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 21700s!
- 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
(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 a 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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An amazing high capacity 5000mAh cell from Lishen
This cell easily competes with other 5000mAh cells like the Samsung 50E or Molicel M50A or LG M50A, while offering higher cycle life, lower price, and better availability. Offering 5000mAh and 9.6A our of a 21700 size cell is great. The huge 1000 cycles to 80% capacity cycle life is far better than the others though which will let this cell keep putting out great power for you. These are grade A cells and are suitable for large battery packs. Lishen LR2170SD Data Sheet
Lishen LR2170SD 21700 5000mah Specifications:
- Size: 21700
- Approximate Diameter: 21.7mm /- 0.2mm
- Approximate Length: 70.9mm /- 0.2mm
- Brand: Lishen
- Manufacturer Rated Nominal Capacity: 5000mAh
- Manufacturer Rated Minimum Capacity: 4900mAh
- Manufacturer Rated Max Discharge Current:
- -20-20°C 1.0C (4.8A)
- 20-35°C 2.0C (9.6A)
- 35-45°C 1.5C (4.8A)
Priced per battery, not per pair.
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If your battery is damaged or defective on arrival (will not take its first charge, or has issues with its first cycle), please let us know within 14 days of receiving your order and we’ll make it right. Please read our complete store policy on defective products here for more information and to see if you’re eligible.
Manufacturer ratings: Please see more information regarding manufacturer ratings here.
Battery Warning
All rechargeable batteries have inherent risks under any circumstance. Use caution with working with li-ion batteries (lithium-ion), LiPo (lithium ion polymer), and any rechargeable cells (together rechargeable batteries), as they have dangerous charging characteristics and are known to explode or burn if mishandled. A purchaser and user of rechargeable batteries should educate themselves on rechargeable batteries, especially as to charging, discharging, assembly, and storage. Learn more about proper storage and care for rechargeable batteries here. We are not responsible for any damage caused by the misuse or mishandling of rechargeable batteries.
- Never completely discharge batteries (below 2.5V under load or 3V unloaded)
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- Properly dispose of all battery cells and chargers in accordance with local laws and mandates (if you’re unsure, contact your local municipality)
- If a rechargeable battery overheats, hisses, or bulges, immediately quarantine the battery from any combustible materials. ideally, take the battery outside
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The difference between 21700 and 18650 lithium battery
The Tesla 21700 lithium battery is also one of the cylindrical lithium batteries is same as 18650 lithium battery, now there is only 21700 lithium batteries can meet the battery performance requirements of electric vehicles.
1700 Lithium battery
The energy density of the 21700 lithium battery is much higher than the 18650 battery because of its larger volume, higher space utilization. And it is widely used in consumer electronics, electric vehicles, balance vehicles, solar energy systems, LED street lights, power tools, etc.; Tesla, Samsung, Panasonic, and LG are the leading batteries manufacturers
Advantages of 21700 lithium battery
The capacity of the single 21700 lithium battery is increased by 35%. Taking the 21700 lithium battery produced by Tesla as an example, after switching from the 18650 model to the 21700 model, the battery cell capacity can reach 3 to 4.8 Ah, a significant increase of 35%.
The energy density of the 21700 lithium battery system is increased by about 20%. According to the data disclosed by Tesla, the energy density of the 18650 lithium battery system used in the early days was about 250Wh/kg. Later, the energy density of the 21700 battery system produced by it was about 300Wh/kg. The volumetric energy density of the 21700 lithium battery was higher than the original 18650nearly 20% higher.
The cost of the system is expected to drop by about 9%. From the analysis of battery price information disclosed by Tesla, the power lithium battery system of the 21700 battery is at 170/Wh, and the price of the 18650 battery system is 185/Wh. After using 21700 lithium batteries on Model 3, the cost of the battery system alone can reduce around 9%.
The weight of the system is lighter, about 10%. The overall volume of the new 21700 lithium battery is more significant than that of the 18650 lithium battery. As the monomer capacity increases, the energy density of the monomer is higher, so the number of battery monomers required for the same energy can be reduced by about 1/3.
The battery’s energy density is increased by more than 20%, and the energy density of the 21700 battery is better than that of the 18650 battery. According to the information disclosed by Tesla, under current conditions, the energy density of its 21700 lithium battery system is about 300Wh/kg, which is about 20% higher than the 250Wh/kg of its original 18650 battery system.
The ultimate comparison guide of 21700 battery vs 18650. two Li-ion cylindrical batteries
There’s a huge difference between an average portable battery and the lithium-ion cylindrical battery. It is portable, reusable, and rechargeable, so you never have to worry about running out of energy. Lithium-ion cylindrical batteries are the smallest rechargeable batteries on the market today. So, you can enjoy more mobility without worrying about charging for an extended period of hours. You can also get your favorite device back to normal working condition to keep you going all day long.
The most widely used lithium-ion cylindrical batteries are 21700, 18650, AA, and AAA. In addition, there is Tesla’s recently launched 4680 large cylindrical battery. Among them, 21700 is often compared with 18650. The same is the cylindrical battery launched by Tesla, what are the differences between the two? This article is a detailed comparison guide on 21700 battery vs 18650, which will give you a comprehensive analysis of the differences between 21700 and 18650, aiming to help you understand the comparison of 21700 battery vs 18650 in more depth.
.What kind of battery is 21700?
The 21700 battery is also known as a rechargeable lithium-ion cylindrical cell. 21700 usually refers to a cylindrical battery with an outer diameter of 21mm and a height of 70.0mm. When 21700 battery vs 18650, the former that appeared later is a more advanced battery technology. Because of the sturdy construction and lightweight weight, this battery can last longer than most other batteries.
.What are 21700 batteries used for?
21700 is the most common type of battery used in flashlights and a range of household portable electronic devices. They have also been introduced in some high-lumen flashlight models. 21700 batteries can also be used to run laptops and even some EVs, they can also be used as vape batteries for vaping (smoking) accessories. If you have experience with electronics, you can probably replace packs by hand. But make sure to get the right size if possible and know how to use them properly, otherwise they might explode with incorrect handling.
.Does Tesla use 18650 batteries? How many are 21700 batteries in a Tesla model 3?
Tesla used the18650 lithium cobalt acid battery made by Panasonic for its model S and Model X cars back in 2013. This battery consists of thousands of independent cells, and each cell is slightly bigger than a regular lithium ion AA battery. Tesla currently holds 4,416 (21700) cells in the Model 3/Y Long-Range battery pack. The battery pack is made of 4 modules into bricks of 46 cells each block.
.What is the highest capacity 21700 battery?
The 21700 batteries have between 3000 milliamps and 5100 milliamps, measuring how many hours’ worth of power the cell can generate. The battery voltage in the 21700s ranges from a low of 2.5 volts to a high of 4.2 volts. The 21700 cells have a 3.7V and 4.2V for charging voltage which is the standard for a 21700 battery. It is clear that a 3.7v, 5100mAh 21700 battery stores 3Ah or 5Ah depending on the model. Usually, the max capacity is 15 to 20 watt-hours. For example, a typical air conditioner uses 9000 BTU, about 1100 Wh (watt per hour). So, it would help if you had up to 74 (21700) batteries to run an AC for 1 hour.
.How long does an 18650 battery take to charge?
Typically, the amount of time to fully charge a 18650 lithium-ion battery takes 4. 5 hours. The capacity of an ordinary 18650 lithium battery is about 2500 mAh, while the output voltage of an ordinary 18650 lithium battery charger is 4.2 volts, and the output current is about 500 mAh. In theory, it takes 5 hours to fully charge the battery. Of course this is not absolute. For high-rate lithium batteries, the allowable charging current can also reach more than 1 amp, so the charging time will be reduced accordingly.
.Can you charge 21700 batteries in a 18650 charger?
Based on the battery charging device, it would fit, and size-wise would work as well as the recesses. It has spring-loaded battery holders to accommodate the versatile size of batteries. The 21700 battery cells are 3 millimeters wider and 5 millimeters longer than a 18650 battery. To be safe, use chargers that explicitly say they are compatible with 21700 batteries.
.Does 21700 last longer than 18650?
The battery cells used in 18650 and 21700 are often discussed, as they offer fairly similar performance. The only notable difference is that the size of the battery cells can vary. Other distinctions between the batteries are their capacity.
18650 Li-ion battery cells
21700 Li-ion battery cells
1 single cell: 2.0Ah–3.0Ah (36 Wh–54 Wh)
1 single cell : 3.0Ah–4.0Ah (54 Wh–72Wh)
2 battery packs : 4.0Ah–6.0Ah (72 Wh to 108 Wh)
2 battery packs: 6.0Ah–8.0Ah (108 Wh–144 Wh)
3 battery packs : 9.0Ah (162Wh)
3 battery packs : 9Ah–12Ah (162 Wh–216 Wh)
The 18650 can provide between 2300-3600mAh while the 21700 has a capacity from 3000 to 5100mAh. It shows the 21700 can be more long-lasting in general than the 18650.
.Is a 21700 battery better than 18650? Can I use a 21700 battery instead of 18650?
The higher power of 21700 cells and lower internal resistance means that 18650 cells have a lower polarization. It is a greater divergence between their voltage curves at higher C-rates. The 21700 batteries are a larger and more powerful replacement for 18650 in EV battery packs. The 21700 has twice the capacity at discharge rates up to 3.75C, which is 50% more than the 18650.
.What is the difference between 18650 and 21700 batteries?
The 21700 batteries weigh between 60 to 65 grams, and their energy density is 300 watt-hours. On the other hand, 18650 batteries weigh between 45 to 48 grams per each, and their energy density is less than 21700 batteries. It shows the 21700 battery is more durable and last longer than a conventional 18650 battery. Some of the important characteristics that determine which cell is better than the other such as follow:
Diameter (Mm)
Capacity (mAh)
The energy density (Wh/Kg)