Last Updated on June 25, 2018 by

My favorite chargers for recharging all my 18650 cells has always been Nitecore Chargers. I own the Nitecore D4 and the Nitecore i4, which I purchased back in 2015. But now there is a new Nitecore i4, and I’ve been testing it, and comparing it to the previous model for 6 weeks. I’m finally able to reveal my thoughts and impressions on this upgraded, improved Nitecore i4.

Note* Although the Nitecore i4 is the charger of choice for ALL rechargeable batteries, I’m going to focus on the features that Vapers depend on. I understand that we all use our chargers for more than just the 18650 batteries we have, so I’ll include the litany of battery types the Nitecore i4 can charge at the end of this review

The Nitecore i4 is a 4-cell charger, but that is the least of it. There are many battery chargers on the market, and they all charge various battery types. The thing with Nitecore chargers is that Nitecore knows, they understand, that there is the right way to recharge a battery, and a “bad” way to recharge a battery, and while I still trust my older Nitecore i4, this new one blows the doors off it. And, how many Chargers do you know of that carry a full 12-month warranty?

Nitecore i4 New Features for 2017

Twice the charge speed of the previous Nitecore i4

Smart Current Distribution

Compatible with More Battery Voltages

Optimized for IMR batteries

Auto Current Selection

Auto Detection of Non-Rechargeable Lithium Batteries

The Nitecore i4 and Vapers

Naturally, Vapers are not the only people that need battery chargers, but Nitecore knows that of all the various batteries that are rechargeable, the “Vape Battery” (18650, 18500, 18350, 26650) are a big part of their client base. Designing a new and improved i4, the engineers at Nitecore had Vapers in the forefront of their ideas for upgrades and improvements.

Being in the vape industry myself, as someone that is exposed to at least a hundred new mods each year, I can’t but wonder how many box mods the average vaping enthusiast owns, and how often the enthusiasts upgrade or replace their mods. I’m told the average number is 3 mods per Vaper, and in 2017 at least half of them will own a dual 18650 box mod, while larger and larger numbers of Vapers will own mods that require three and four 18650 cells. Any way you slice it, that’s a lot of batteries to care for, and keep charged.

Despite the cost of the average 18650 battery ($12), most Vapers have extra 18650 cells (or 26650) to do a quick exchange when the batteries are depleted. And, perhaps I should keep this to myself, but most of the Vapers I know, including myself, allow our batteries to stay in the charger long after they’ve been fully charged. I certainly don’t advocate this practice, but when my batteries are being charged with a Nitecore charger, I don’t really worry about it. I’ll touch on this again later in this review.

Charge Time and the New Nitecore i4

For me, the biggest improvement of the new Nitecore i4 is the 100% acceleration of the charging time. My older i4 has a maximum output of 750mA, the new i4 is a full 1500mA. That means that batteries charge up twice as fast as the older model. This is a huge deal for Vapers that have a lot of batteries in play.

The second most important improvement is current distribution. How this works is pretty straightforward; when you place 4 cells in the Nitecore i4, each cell is identified and calculations are made to optimize the charge, but more than that, when a battery is fully charged the Nitecore i4 diverts the current from that ‘slot’ and sends it to other slots. As each one becomes fully charged, the maximum current continues to be distributed to the remaining cells, speeding up the charge time even more. This is a major deal, and when combined with the increase in current to 1500mA, that’s all I needed to hear before buying one for each member of the staff.

A SlideShow For Your Enjoyment

Charging 3.7V and 4.2V Batteries

Another cool improvement with the new Nitecore i4 is how users can now mix and match their 3.7v batteries and 4.2v batteries. Using the “V” button on the charger the user can set the charging voltage in each slot, independently. Being able to set the voltage to 3.7v or 4.2 for our cells means extending the life of that battery, which have notoriously short lifespans anyway.

Totally Depleted? No Worries

How many times have you read that you never allow your 18650 cells to deplete completely? Doing so will likely kill the battery, but now Nitecore has developed a method for bringing these 0v batteries back to life.

Nitecore calls this new feature IMR Battery Recovery.

IMR means “Lithium Manganese Rechargeable”. So, in a perfect world we would all say LMR batteries, but the urban legend tells us that someone, somewhere, typed a small-case “L”, which looks like “l”, which looks almost exactly like “I” in most fonts, so IMR sort of stuck, and became the de facto abbreviation for Lithium Manganese Rechargeable batteries.

Because of the nature of the chemistry in Lithium Manganese batteries, once they drain completely they become useless, unable to be charged again successfully. If you’ve been a Vaper for a while no doubt you’ve allowed a battery to drain out and when you placed it in a battery charger it just sat there. You probably thought that 3-month-old battery died an early death, and with just about every charger, you’d be right. But not anymore.

Most of the time (not 100% of the time) a completely depleted cell can now be returned to life with the Nitecore i4. I can’t explain the engineering behind it, but if you have a 0v battery and insert it into a slot of the Nitecore i4, you can hold down the V and C button together to kick start, or reformat, the IMR battery and restore it to life.

Nitecore i4 Quick Charge Option

While the new Nitecore i4 intelligently selects the best charge current based on the battery capacity, especially in 18650 and 26650 cells, you can press and hold that C Button to kick it up to the maximum 1500mA for a fast charge. This feature saves us valuable down time when we need fully charged batteries like yesterday.

Optimized for IMR Cells

As I mentioned above, the Nitecore i4 has been optimized for batteries that Vapers use most often. IMR batteries can be overcharged by shoddy battery chargers because of the chemistry of the battery. The new Nitecore i4 monitors the charging process and will safely make sure that our IMR cells do not overcharge.

The Nitecore i4 also has a timeout feature that will allow a battery to charge for up to 20 hours. Once that 20 hours expires the charger stops charging that slot, and displays a full charge status. Without it, those of us that leave our batteries in our chargers could experience a possible explosion, especially if the battery we’re charging is of low quality, like the tens of thousands of counterfeit batteries.

Reverse Polarity Protection

The most popular 18650 cell is the Flat Top battery. In fact, the only mods I know of that use the Button Top battery was ProVape. Modern flat top batteries can easily be inserted into a battery charger if the user isn’t paying attention. Prior to the Nitecore i4 Lisa would often insert her batteries the wrong way. She would come back in a couple of hours only to discover that the battery didn’t charge. That is unfortunate for Lisa, and for the battery.

The problem is that most battery chargers won’t alert the user to the improper insertion. The Nitecore i4 does, and it does so immediately. All the LED lights above the battery slot light up and blink when the battery was inserted upside down. This won’t prevent every incident, sometimes people are in such a hurry the battery will go in the wrong way and the user walks away without even looking. But, at least now if the user hangs around for even a second, the chances of noticing the blinking lights are greater. Lisa loves this feature by the way, and has caught herself 4 times since she began using her i4.

Bottom Line

I’ve trusted Nitecore since the first time I purchased one. They are known for quality, safety, and superb charging. It is the only battery charger I use. That’s not to say that every other charger out there is garbage, I’m just saying that the Nitecore is the one I trust most.

As far as I’m concerned, replacing all the chargers in the office has already paid for itself by keeping the dozens of 18650 cells we have in constant use around here, and the dozen or so 18650’s we’ve kept in a draw that have depleted down to zero volts and were considered done. We’ve been able to bring 8 of them back to life, the other 4 were more than 2 years old and just couldn’t be restored.

The Nitecore 3100mAh 35A 3.7 IMR Cell

Shortly after installing the Nitecore i4 chargers in our charging stations I was told of an upcoming 18650 cell by Nitecore, a 3100mAh, 35A, 3.7V cell that would be ideal for all the dual, triple, and quadruple box mods in play at Spinfuel VAPE HQ.

I contacted the US distributor and placed an order for 50 of these new cells, along with 50 of their 2500mAh cells. A couple of days after they arrived and was distributed to the staff, and charged of course, we gathered up all the other 18650’s that were purchased 10 months ago, and disposed of them.

Today, all the cells in use here are either the Nitecore 3100mAh 35A cells, or the Sony VTC5+, or the LG H2 cells. The 3100mAh 35A Nitecore cells are used more often than any of the others.

You can trust Nitecore to deliver a safe, fast, and efficient charge to all your rechargeable batteries, but for Vapers, Nitecore is definitely the right choice. (not to mention their new battery!)

John Manzione