How To Charge Multiple 18650 Batteries?

Disclosure: This page contains affiliate links, As an Amazon Associate, I earn from qualifying purchases (at no extra cost to you). Learn More

A very important factor that determines whether batteries can be revived on charging is how correctly you execute the connection. This is because shoddy and wrong connections are not only counter-productive but can even damage the battery beyond any repairs,  in extreme cases.

To this effect, we are strictly advised to ensure that we always get our connections right before turning on any power supply source. Battery cells can be connected either in series or parallel, though the parallel connection is more commonly used.

Parallel connection distinctively means that you are not charging the voltage of the batteries but rather the amp-hour(Ah) limit of the batteries. The Ah limit or the Ah specification is simply the result of a current cell compared to the extent that batteries can create current.

Table Of Contents

What Are Multiple 18650 Batteries?

Multiple 18650 batteries are lithium-ion-based batteries and they got the name from their sizes; which are 18 mm in diameter and 65 mm in height. These batteries are commonly used to power flashlights, power tools, electric vehicles, vaporizers, cameras, laptops, and many other gadgets.

These batteries can have anything between 300 to 500 charging cycles. They are connected end to end according to similar polarities such that positive terminals are connected end to end and the same goes for the negative terminals as well. They are similar to AA or AAA batteries but are contrastingly a little bigger in size and there are both button top and flat top 18650 batteries.

They are equipped with a USB port built into them, using which you can plug these batteries for charging provided you have a compatible charger. The milliamp of 18650 batteries ranges from about 2300 mAh to a maximum of close to 3600 mAh and the higher the mAh, the longer the batteries will last.

Multiple 18650 batteries are renowned to be the best batteries on the market for several reasons, such as their high capacities, the warranty, and guarantee agreements given in their purchase terms, and so on.

They are also known to last for very long indeed, but how long they last depend on the amount of time they are used, how often they are re-charged, and how well they are maintained. For their exceptional capacities, these batteries cost little or nothing, if you take the time to make the comparison.

How To Charge A Multiple 18650 Batteries

To charge multiple 18650 batteries, you may use either a charger plugged into an AC on the wall socket or into a USB port connected to a laptop or desktop computer.

To effect safe and convenient charging of multiple 18650 batteries, you need to connect the positive terminal of the charger to the positive terminal of the first battery in the pack, and this battery’s positive in turn to the positive terminal of the next battery. Proceed to connect all the positive terminals this way until they are all connected. Thereafter, do the same with the negative terminals until all the negative terminals are connected from the charger to the batteries end to end.

In a nutshell, associate positive to positive and negative to negative. It is highly recommended that you use similar batteries with equivalent voltage and never batteries with different ages and varying voltages. Any contrasts or differences in battery voltages may lead to high current streaming between the batteries which can make the charging either ineffective or even destructive, in extreme circumstances.

It should have been amply clear by now to all those who have followed the article so far that, the place of excellent chargers to our gadgetry and satisfaction cannot be taken lightly for multiple and very cogent reasons.

Check Price On Amazon

To this effect, we highly recommend an unbeatable laptop charger marketed worldwide by Amazon, the Mac Book Air Charger, Replacement 45W Magsafe 2 T – Tip Power Adapter Chargee Compatible with Mac Book Air 11 – inch and 13 inches After Mid 2011 (White). Whatever you desire, with regards to the services of a laptop charger and for all purposes, is yours for the taking.


How Long Does It Take To Charge Multiple 18650 Batteries?

To maximize your usage of multiple 18650 batteries, do not allow them to run down completely before you recharge them. Effectively, you should keep them charged over at least 3.5 Volts. All things being equal, it takes an average of about three to six hours to fully charge multiple 18650 batteries depending on its milliamp.

However, this timing depends on the capacity of the charger you are using as well as the depth of draining of the batteries. Additionally, it is known that the milliamp of typical 18650 multiple batteries ranges from 2300 mAh to about 3500 mph and the higher the milliamp, the longer the charging takes.

This implies that a 2600 milliamp multiple 18650 battery will take a shorter time to charge fully than a 3500 milliamp battery,  which is given as 4 hours and five to six hours respectively. (Read Also: How To Charge Multiple Batteries With One Charger)

Are There Other Ways of Charging Multiple 18650 Batteries?

The varied ways through which you can charge these batteries are dependent mainly on whether you charge them in parallel or in series connections. The parallel connection has the singular benefit of allowing you to re-charge multiple cells at once,  unlike when they are connected in series, which limits how many cells you can charge on the go.

Furthermore, you can charge these batteries either using a charger plugged into an AC adaptor in a wall socket or alternatively, by plugging them into the USB port of either a laptop or a desktop computer. The capacities and other specifications of these chargers determine how well and fast the charging is likely to go.

The best adaptor recommended for charging multiple 18650 batteries effectively is a 12.6 Volts adaptor which is readily available on the market and in some renowned stores. It is highly imperative at this juncture to give you a heads-up, so to say, on where to procure equipment that has all the qualities enumerated in the article and more, for your satisfaction and protection from any after-sales regrets.

Check Price On Amazon

To ensure that you get exactly what you seek, we strongly advise that you consider Amazon’s 65 W 45 W C USB Laptop Charger for HP Chromebook 14 13 X 360 G5 14. This durable and highly efficient laptop charger is a must-have for everyone who requires the services it renders.

 What Precautions Are Necessary When Charging Multiple 18650 Batteries?

Though it is possible to charge multiple 18650 batteries via either parallel or series connections, it is still inadvisable to charge them in parallel connections. Preferably, you should charge them individually and where you have many batteries to charge, the series connection is much better, especially with the aid of a switching regulator that will convert the total stack voltage to that which is required for your load.

This recommendation is made because the per-cell protection chips are largely useless for three or more cells in series because they are likely to break down at around 8 Volts reverse voltage.

To operate li-ion batteries in series safely, you require a separate end of discharge switch, because the per-cell protection chips would not be enough.

It is equally advised to avoid an open or shorted cell connected in a series pack, which is liable to cause the pack to generate insufficient voltage and power, which may render the device unimportant. Furthermore, an open or shorted cell in a parallel pack causes the capacity and run-time of the pack to depreciate and eventually render it useless.

How Can You Improve Multiple 18650 Battery Charging?

The best way to charge multiple 18650 batteries is to charge them singly by using any compatible charger that will deliver the appropriate voltage to the cell. However, where you have to charge them in a pack, you may connect them in a series arrangement provided you have the right charger for it, but be sure to use a switching regulator that will convert the total stack voltage to that which may be required for the load you want it to carry.

It should be remembered also that overcharging and discharging of lithium-ion batteries is likely to cause permanent damage to both the positive and negative electrodes.

Similarly, the excessive discharge may lead to the eventual collapse of the negative carbon layer structure, which will, in turn, cause the insertion of lithium ions into the charging procedure that is likely to interfere with the entire process through overcharging.

In essence, when charging multiple 18650 batteries, avoid both overcharging and discharging, by using the right cell arrangement and also using the most compatible charger. Also, when charging batteries multiply in parallel connection, it is important that you use similar battery models with equivalent voltage and never charge batteries of alternate ages.

Trending Searches

This is because due to the sharp contrasts in battery charge levels, a high current is likely to stream between the batteries and damage them. Alternatively, if you must charge such contrasting batteries together at the same time, use an outer gear to limit the current to less than the battery’s most extreme charge current or inter-connect wire ampacity specification.

This way, the batteries are likely to arrive at the ideal or most suitable working voltage particularly when there is connectivity between a few cells in the arrangement, and thus each of the cells will add its voltage potential in order to get the total energy required over the terminals.

Finally, whenever you are charging your batteries in parallel arrangements, attempt to coordinate their capacities to avoid discharging one battery faster than another.

Before you execute any parallel connection of cells, check their individual voltages. Such caution is necessary because the voltage of one cell should approximate to that of another, otherwise, a high quantity of current may flow from the cell with a higher voltage to that with lower voltage, which can either damage the cell or in some rare occasions, cause a fire outbreak.

Are There Any Risks Associated With Multiple 18659 Charging?

Yes, there are, but luckily they are avoidable. Notably, be careful of the batteries you buy because many used batteries are known to be re-packaged and sold off as new with voltage ratings engraved on them which are contrary to their actual capacities.

These counterfeit batteries are prone to violent explosions when they are overheated during charging or discharging. To guard against this, buy only branded batteries and other accessories from reputable suppliers, some of whom have been introduced to you in this article.

While charging these multiple batteries, always use protected cells, if possible, and where that cannot be done, be sure to at least insert some sort of current limiting device, between the charger and each cell such as a fuse or a PTC(self-limiting fuse).

This is because, when you fail to do as suggested, and your cells are connected in parallel, if one cell begins to fail, all the other cells may dump their charge into the failing cell, thereby worsening the whole process. For this reason, a sort of current limiter is highly needed.

When you connect the cells in parallel, make sure that they are already at the same voltage, and if not, reduce the current until they are. Failure to heed this advice may cause the cells to explode violently.

Finally, make sure that you use only compatible chargers or the rate of charging may be too slow for your liking and the charging may not eventually terminate properly. 

How To Charge Multiple 18650 Batteries – Conclusion

Everything to do with car batteries, from their purchases, all mandatory accessories, efficient charging, proper uses, and down to maintenance, has been given the attention we all know they deserve.

It can therefore be rightly claimed that we do not have much, if any reason, to have the common complaints others contend with.

What’s more, all the products recommended herein are among the very best you can get anywhere on Earth, not to mention that these items would be sold to you at prices which are not comparable to any. We have every support to make the best of what we have learned here. Thank you.

Leave a Reply