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Guide to Choosing a Battery Charger

Published by Baditude in the blog Baditude's blog. Views: 3897

Choosing the right Li-ion charger for your batteries can be as confusing as choosing the right batteries for your mods. It's my objective to help you become aware of the different features available so that you can make a better, more informed, choice. If you know nothing about chargers, hopefully by the time you read this you will have a good idea of what features you need in a charger.

People often ask, "What's the best charger?" And most people will answer by naming one of the more expensive chargers with all the "bells and whistles". However, that charger may not necessarily be the right or best charger for YOU. For example, you may not need a fancy display screen or a fast charger. A budget charger manufactured by one of the preferred brands may be a better choice for you.

I went all out when I purchased my first Li-Ion charger. I went with the Pila, widely considered to be the best charger four years ago. It was the most expensive charger, only had two bays, and didn't have a LCD screen ... just LED lights. I have no regrets as it performed admirably for nearly two years under heavy use. One of the charging bays eventually stopped working, so I was then in the market for a new charger.

I decided to go with a six-bay Xtar WP6 II charger, as I was using two mods that used the smaller 18350 batteries and was going through 4 - 5 a day. Unfortunately, that model uses a combination of "spacers" and springs to retain the batteries in the charger, and the 18350 batteries kept "popping out". I had to place a heavy textbook on the charger to keep the batteries in the charger. I was not a happy camper.

My third charger, which I happen to still use, is the Nitecore Intellicharger i4. It is a budget charger which suits all of my current needs well.

Its more important that you take from the below video is an efficient way to shop and compare.

Except for a couple of exceptions, I recommend buying an Xtar, Nitecore, or Efest LUC charger. Just like recommended battery brands (Lg, Samsung, Sony), these three manufacturers have earned excellent reputations for producing qualtiy reliable chargers. The best batteries deserve a good charger. Should you buy a cheap generic or offbrand charger, you're probably taking a gamble that the manufacturer did not cut any corners to lower his production costs.

You will need to choose between a single bay, 2-bay, 4-bay, or 6-bay charger. The choice depends upon how many batteries you will need to charge at once. I only see a single bay charger as being useful as an emergency charger for the office or car. Many will get by easily with just a 2-bay charger. If you anticipate going through more than two batteries a day, choose a 4-bay charger. If you anticipate using more than four batteries a day, a 6-bay charger would seem to be ideal.

True independent charging bays will offer faster charge times for each battery being charged simultaneously. The individual charging bays will not be sharing a circuit, which can slow charging times. Independent bays adds more electrical components, and therefore add to the overall cost of the charger. In this case, you get what you are paying for. Not everyone needs a fast charger however. Desirable yes, a necessity no. Chargers without independent bays will still charge batteries in a decent amount of time.

Many companies advertise fully independent charging bays, but it's my guess that the vast majority of multiple bay chargers are not. Once four bays are filled with batteries, two of the four bays will share a circuit. Probably the only chargers which may be truly fully independent are the top of the line expensive chargers.

The budget chargers use LED lights to allow you to monitor the charging progress. The more advanced chargers utilize a Liquid Crystal Display to monitor the charging progress, and also have a digital readout of the battery's voltage. Desireable yes, a necessity, no.

I will say that if you use a mechanical mod, and don't have a voltage tester or multimeter to measure your battery's voltage, using a charger that has a digital readout of the battery voltage is very worthwhile.

All listed chargers here will charge an 18650 battery. However, some may not charge some of the less popular sizes like 14500, 16340, 18350, 18500, or 26650. If you use this size battery, make sure the charger you are considering will accept it.




This is a controversial subject. Those who use them say that the flame retardant bag will contain a fire caused by either the battery or charger. Those who don't use them say they may actually create a problem where none existed.

Charging bags were designed to be used with Li-Po batteries and chargers. Li-Po batteries are used in the remote control car and plane hobby. These batteries are not a safer-chemistry battery, and a "battery incident" with one can be quite spectacular if you are into fireworks and flames.

Li-Po batteries are not charged in the chargers. They are kept separate, connected by battery charger cables. The batteries are placed into the bag, and the charger remains outside of the bag. This is because chargers produce some heat while they charge batteries, and leaving the charger outside of the bag allows the charger to be cooled by natural air circulation.

Li-ion batteries are charged while in the charger, so if using a charging bag both the batteries and charger will be contained inside of the bag. The theory against using a charging bag is that the charger may generate enough heat in the bag to cause a problem, and the heat generated will not be allowed to ventilate inside the bag. I'll leave the decision up to the reader whether to use a charging bag or not.

  • A Standard charger is considered to be a slow / overnight charger. It typically takes up to 12 hours to charge your battery. Slow chargers continue to charge your battery even after it is fully charged. Over time this can shorten the life of your battery. With a slow charger it is important to remove the battery after it is fully charged to maximize the life of your battery.
  • A Rapid charger charges your battery typically in 1 to 3 hours. Once the battery is fully charged it will switch to a trickle charge mode so that it does not overcharge your battery. Most of today's Li-ion chargers are either a rapid charger or smart charger.
  • Smart chargers will typically charge your battery in the same amount of time as a Rapid charger but they will also discharge, analyze, condition, and perform cycle tests on your batteries. In most cases they allegedly will double the life of your batteries. Smart chargers usually have more options in how you charge your batteries, too.
  • Some smart chargers include a wake-up feature, or “boost,” to allow recharging if a Li-ion battery has fallen asleep due to over-discharge. A sleep condition can occur when storing the battery in a discharged state and the self-discharge brings the voltage to the cut-off point. An over-discharge situation can also occur in a mechanical mod. A regular charger treats such a battery as unserviceable and the battery will need to be discarded. Boost applies a small charge current to raise the voltage to between 2.20 and 2.90V/cell and activate the protection circuit, at which point a normal charge commences. Caution applies if Li-ion has dwelled below 1.5V/cell for a week or longer.

Once a battery receives a full charge (4.2 volts), it will naturally start to slowly lose some of that charge, even when not in use. Manufacturers want their customers to be happy with fully charged batteries when they need them, so they design algorhythms which keeps the battery's charge "topped off" while sitting in the charger waiting to be used. Sounds like a great idea, but its not so great for the battery's health.

Trickle charging leaves a battery in a highly excitable and vulnerable state. This is why we tell people to remove their batteries from the charger as soon as they are fully charged, to not leave batteries in a charger overnight while sleeping, and to "rest" batteries before putting them in a mod.

"Rest batteries after charging--
One commonly-reported factor in almost all the incidents we hear of where batteries failed violently while in use is that they were taken directly off the charger and then used immediately, at which point they failed.

Because of this, we think it may be a good idea to rest batteries after charging them. This advice will not be found in the usual 'reference bibles' on batteries, but we see more and different reports than others. Therefore we now advise:

Do not use batteries directly after charging them. Use a battery or batteries you previously charged, and that have rested for several hours. This is especially important if using a stacked pair for higher voltage, as statistically the risk is far higher."

The benefit to resting is increased battery lifespan & minimize the chance of venting.

E-Cigarette Explosions: Comprehensive List
There have been 50 major incidents this year alone and that's just the ones which make the news. They also go on to say...
"It is interesting to note that the nature of e-cigarette explosions has changed over the years. The FEMA document cited above suggests that approximately 80 percent of e-cigarette explosions happen during charging.

How Chargers Charge Your Batteries

Lithium-ion batteries are charged to 4.2v per cell, higher voltages could increase capacity, but reduce service life. And lower ones can increase battery charge cycles at the cost of less run time.

A Charge cycle involves two main stages; constant current or CC, and voltage source or CV, but some chargers skip or add more stages.

Charging process:
Stage 1 – Automatic analyzing battery status
Stage 2 – Quick charge
Stage 3 – Slow charge
Stage 4 – Standby mode, trickle charge​
  • Most batteries are considered overdischarged or dead when their cell voltage is under 2.8-3v, but even in this situation, some cells can be charged again and be reused. To save them, an "aconditioning" stage is done before charging; in this stage, the battery is charged with a 0.1C current limit until it reaches 3v
  • CC stage. This is the stage all the chargers use, and the only one for most fast chargers. During the constant current stage, the battery is basically connected to a current-limited power supply, usually limited to 0.5-0.7 times the nominal battery capacity (that's from 0.5 to 0.7C) it lasts until the cell voltage reaches 4.2v. At the end of this stage, the battery charge is around 70-80%.
  • CV stage or saturation charge. When the battery reaches 4.2v per cell, the charger acts as a voltage limited power supply, The battery voltage remains at 4.2v while the charge current drops gradually. When the charge current is between 3 and 10% of the labeled capacity, the battery is considered fully charged.
  • Topping charge, or "trickle charge". Depending on the charger and the self-discharge of the battery, a topping charge may be implemented. Typically, the charge kicks in when the open terminal voltage drops to 4.05V/cell and turns off when it reaches 4.20V/cell again.
Usually, only stages 2 and 3 are used, and a full charge can take from 2 to 4 hours depending on the charge rate.

Li-ion batteries do not need to be fully charged, nor is it desirable to do so. In fact, it is better not to fully charge, because high voltages stresses the battery. Choosing a lower voltage threshold, or eliminating the saturation charge altogether, prolongs battery life but this reduces the runtime. Since the consumer market promotes maximum runtime, nearly all chargers go for maximum capacity rather than extended service life.​

Here are some charging tips from Battery Mooch:

  • After charging, let your battery cool to room temperature before using it.
  • Don't charge a battery that is below 0°C/32°F. It causes metal to be plated inside the battery eventually leading to an internal short circuit and possibly bursting of the battery.
  • Where possible, setting your charger to 4.1V will reduce stress on the battery and extend its life. But you will lose 10%-15% of the capacity of the battery.
  • Make sure the charger you use turns off once the charge is complete. Check the instructions for the charger you want to use.
  • Never use a trickle charger with Li-Ion batteries! The continuous holding of the battery at the trickle charge voltage damages it.
  • Don't overcharge them. To get the longest running possible time from a battery some chargers go up to as high as 4.27V. While this does result in a bit more vaping time before needing to recharge, it damages the battery. Most of the batteries we use are rated at up to 4.25V but even this is quite high. It's not dangerous until we're approaching 5V but battery damage starts occurring way below this.
  • Without a separate meter monitoring the battery's highest voltage before the charger stops it's hard to know what our batteries are actually being charged to. Our best option is to have our batteries spend as little time as possible fully charged and charge them just before using them. This usually isn't very convenient but it does extend battery life.
  • Charging at a slower rate is better, to a point. Most of our 18650 batteries have a "standard" charge rate of 1.0A-1.5A and a "rapid" charge rate of up to 4A. Charging at 0.5A might help extend the life of your batteries a bit but if the batteries are not getting warm at 1.0A then that's a good compromise between battery life and convenience. Going down to 0.375A or 0.25A won't help much versus charging at 0.5A.
  • Charge 18350's at 0.5A until you know that they aren't getting more than a bit warm.
  • Charge 26650's at 1.0A until you know that they aren't getting more than a bit warm. The better 26650's can be charged at up 2.0A without adversely affecting battery life.
Battery Charger Review Websites:

Originally, my intent was to show pics, prices, and features for each individual charger. However, upon doing some additional research I found that there are way too many quality chargers on the market from the recommended manufacturers to make this task feasable. Just set your priorities on the features you most need and set your budget, and then do your homework to find which chargers meet your requirements and price range. If you're not sure about a particular feature or have questions, contact the vendor for an explanation. I always use RTD Vapor when I need either batteries or a new charger.
Recommended vendors:

Prices and pics are courtesy of RTD Vapor:

Pila IBC Charger - $47.95

At one time widely considered to be the top charger on the market. However, this model has not had any upgrades in the last few years to allow it to remain competitive with the other high end chargers that have display screens. A fast "smart" charger with two independent charging bays. Pila includes spacers for charging 18350 and 16340 size batteries. If you have weak or disabled hands, this is probably the best choice for you, as the spacers used make inserting/removing batteries easier than the sometimes stiff spring-loaded sliding bars seen in most battery chargers.​

OPUS BT-C3100 V2.2 ($48.99)

● LED back light displays charging / discharging / quick test / circuit more clearly in the dark
● New refresh mode can show you batteries capacity
● The charging current can be selected to be 200mA, 300mA, 500mA, 700mA or 1000mA ( 1500mA and 2000mA can only be applied when only slot 1 or 4 is selected ). Default discharging current is 500mA
● It provides four independent charging slots for rechargeable batteries. The charger can charge batteries of different types and sizes and with different capacities at the same time
● The charger integrates the minus delta voltage ( - ΔV ) for NiCd or NiMh battery charging termination, and for Li-ion batteries charging to 4.2V with pre-selected constant current. ( 3.7 Li-FeO4 and 4.35 type high voltage batteries charging mode can be selected through switch on board )
● The charger also includes overheat detection to protect rechargeable batteries and charger itself from overheating
● New added quick test mode to test the battery impedance
● Four Working Modes available at user's choice: Charge, Discharge, Test, Quick Test and Refresh
● Easy to read LCD with back light Showing Battery Voltage, Charge / Discharge Current, Charging Time, Battery Capacity etc.
● Designed for AA ( LR6 ) and AAA ( LR3 )NiCd, NiMH or 3.7V Li-ion/IMR rechargeable batteries in size type of 10440, 14500, 16340 ,17500, 17670, 18350, 18490/18500, 18650​

Xtar VP1 ($24.90)

1.Two independent charging channels for 10440/16340/14500/14650/17670/18350/18500/18650/18700 Li-ion battery
2.Algorithm (CC.CV) charging system
3.Optional and adjustable charge current: 250mA,500mA,1A
4.VP1 with switchable LCD indicator to display the real-time charging voltage and battery status
5.Activation function for over discharging battery. VP1 can recover over discharged batteries
6.Soft start function avoids damage from a large current surge
7.Automatically restart charging when batteries voltage(full charged batteries not taken out from the charger channel) is below 3.9V (batteries may self discharge)
8.Reverse-polarity protection circuit board​

Xtar VP2 ($34.89)

●Three charging current options (0.25A/0.5A/1.0A)

●Three charging voltage options (3.2V/3.6V/3.8V)

●for 10440/14500/14650/16340/17670/18350/18500/18650/18700/22650/25500/26650 3.0/3.2V, 3.6V/3.7V, 3.8V Li-ion batteries

●Low-Voltage, over-load and over-heat protection, power indication, stop supplying when low power

●LED status indications

●Real-time status display

●Adopts PWM technology to control the high efficiency DC-DC circuit, lower the voltage and reduce energy loss

●Three-stage charging and 0V battery activation

●USB Output (5.0V/1.0A)​

Xtar VP4 ($34.99)

Xtar VP4 ($34.99) is an intelligent four channel, completely independent lithium ion LCD battery charger. Charging current can be adjusted automatically according to different channel, the user can also manually choose the current by the current switch button. The 120°angle high definition VA real time display, precision of battery cutting-off voltage, battery power indicators and optional currents, etc., whenever you know the battery charging status. If you want to buy a charger which is multislot, multi charger currents and can see charger status, VP4 charger will be your best option!​

* 10440/16340/14500/14650/17670/18350/18500/18650/18700
or two pcs 22650/ 25500/26650 lithium batteries
* Each channel is independent
* Three-stage charge algorithm(TC-CC-CV)
* Three charge current options (0.25 A, 0.5 A, and 1.0 A)
* Soft-start function, to avoid damage from large charge current while charging
* Automatically cut off when the battery is charged fully
* Precision cut-off voltage at 4.2V
* Compatible with small capacity battery
* Over heat protection
* LCD displays each battery real time status
* Use high power intelligent step-down DC - DC circuit,
greatly reduce the energy loss

Xtar VC2 ($19.95)
The Xtar VC2 charger is the World's first lithium-ion battery charger that features an innovative tachometer-style LCD display screen. This charger will tell you the real power of your battery. The VC2 will display the batteries mAh capacity assuming it is completely drained before charging. Like all of our chargers, it can intelligently identify input power and automatically adjust the the most suitable charge current (0.15A~0.5). It is compatible with both IMR lithium batteries and small capacity batteries. Both channels are independent and it can also tell you if you have bad batteries. And like all XTAR chargers, the VC2 features overcharge protection, over-discharge, short-circuit, and reverse polarity protection. Adopted from the VP2 charger, the VC2 can revive overly discharged batteries as well.

What's Included:
- VC2 charger
- MicroUSB cable
- Microfiber carrying pouch
- User manual
- Warranty card
Applies to: 10440/14500/14650/16340/17500/17670/18350/18500/18650/18700/22650/25500/26650 3.6/3.7V batteries​

- Compatible with IMR lithium battery
- Each channel is independent
- Three-stage charge algorithm(TC-CC-CV)
- Soft-start function, to avoid damage from large charge current while charging.
- Automatically cut off when the battery is charged fully
- Precision cut-off voltage at 4.2V
- Compatible with small capacity battery
- Over heat protection
- LCD displays each battery real time statues
- Use high power intelligent step-down DC - DC circuit, greatly reduce the energy loss;
- Built-in reverse-polarity and short-circuit protection circuit
- Use fireproof material for the shell
- 0V activation function can wake up the over-discharged/sleeping batteries
- 120°angle high definition VA screen to display the charging current ,voltage and power indicator, you can see the charging status from any angle of view.
- Certified by CE, RoHS​

Xtar WP6 II ($33.90)


* Six independent charging channel for 10440/ 14500/ 14650/ 15270/ 16340/ 17670/18350/18500/18650/18700 battery.

* Algorithm charging system (CC/CV)

* 6 spacers included​

Efest LUC V4 ($23.99)

  1. Four independent charging channels
  2. Compatible with most 3.7V Li-ion or LiMn batteries like 10440, 14500, 14650, 18500, 17670, 18650, 18700, 26500, 26650
  3. Large LCD display

Efest LUC Multifunction Charger ($19.99)


1. HD mini LCD screen to display precise voltage and battery capacity level.
2. Each charging channel has independent display of charging status.
3. Switch for adjusting discharge current to charge different size battery.
4. Compatible batteries: 10440, 16340, 18350, 18500, 18650, 26650​

NITECORE Digicharger D4 ($28.95)

NITECORE Digicharger D2 ($19.79)

NITECORE Intellicharger i2 ($12.99)

NITECORE Intellicharger i4 ($19.79)

The above are just a few of the quality chargers available


What everyone should know about Battery Chargers, Battery University
Mooch's Blog
Li-Ion Battery Charging
FDA identifies 92 events of overheating/fires/explosions from 2009 to 2015
Liz W, Hitmetwice, Bonskibon and 3 others like this.
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