10 Questions You Should to Know about High power INR18650 batteries

One of the most revealing attributes of a Li-ion battery’s health is its internal resistance. IR plays a vital role to make the best performance of your Li-ion batteries. Many users try to test the batteries’ IR via using smart chargers by themselves. In this article, we have collected ten frequently asked questions about the internal resistance of the lithium ion batteries. 

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Q: How does internal resistance affect batteries’ performance?

A: Ohm’s Law states that V=IR . A battery with low internal resistance delivers high current on demand. High resistance causes the battery to heat up and the voltage to drop. The equipment cuts off, leaving energy behind. A battery’s State of Health (SoH) is 100% when new, and decreases from there, with its internal resistance increasing and capacity decreasing.

Q: What is the normal internal resistance of an battery?

A: It will depend on your batteries’ different conditions and usages, also on how you measure the IR. You may test some of your new cells measuring around 50-80 milliohms. And there is reference list online about cells’ IR and ranking:

Milli-Ohm

Battery Voltage

Ranking

75-150mOhm

3.6V

Excellent

150-250mOhm

3.6V

Good

250-350mOhm

3.6V

Marginal

350-500mOhm

3.6V

Poor

Above 500mOhm

3.6V

Fail

Q: How to measure the batteries’ internal resistance?

A: The main reasons we want to test for a battery’s internal resistance is to understand its condition, as a higher than normal reading will indicate that the battery is near the end of its working life. And there are different ways to check the IR of a battery, and it’s by looking at the Direct Current (DC) and Alternating Current (AC):

*Direct Current – measures the voltage drop at a given current, looks only at pure resistance.

*Alternating Current – takes reactance into account and provides the impedance, which may be different from the DC reading but both are correct.

Q: I have a battery charger that can measure batteries’ internal resistance, while I notice that the resistance levels changes sometime I test it. Is this normal? How do I determine how much resistance is good or bad?

A: The resistance levels will change depending on a lot of factors, such as temperature, the contact between the battery and positive, negative plates of the charger. Please try looking up the manufacturers datasheet to check whether it is within margins. If it’s with the range, the battery should be good.

Q: Why is charging current determined by internal resistance? Does IR affect charging time?

A: The internal resistance basically tells how is the battery health so based on that the charger can select the appropriate charging current to make the best out of the battery. The lower the internal resistance, the faster for the battery to charge. For example, the batteries tend to lose capacity as they age, also the internal resistance increasing, then it may need more time for charging.

Q: I got a battery fully charged on the VC4SL, then tried on mode IR, but the charger didn’t test the battery’ internal resistance. Why does a fully charged battery not work for an IR check? How about the procedures of the charger testing IR?

A: The VC4SL charger adopts the direct current load method to test battery internal resistance. It means to apply a little bit larger current to the battery for a short period of time. Based on the voltage’s change of the battery, also together with the applied current, it can calculate the DC internal resistance of the battery. If the battery gets fully charged, in case of over-charging, the charger won’t test internal resistance in order to protect the battery.

Q: Will low charging current affect IR testing function on xtar chargers?

A: When the adapter input current is lower than 700mA via the charger, which is insufficient for internal resistance testing, the charger doesn’t test IR either. 

Q: For testing a same one battery’s IR on my xtar VC8, why do I sometimes get the different IR numbers on the charger?

A: For some chargers testing the batteries’ IR, it needs to put the batteries into the slots first. So it’s important to make sure whether the contact between the battery and the positive, negative plates is well. If there is poor contact, it may have a big deviation for the IR testing. 

In addition, some chargers adopt current load method to test the IR. When the battery voltage is particularly low, due to the large variation of the battery voltage, the measured IR will also be relatively high. The suitable testing voltage range is 3.6 V-3.8V for IR testing. If the battery voltage is higher than 4.16V, in order to prevent overcharging, the IR test will be interrupted, which may also cause the deviation of the displayed IR value.

Q: The VP4 plus tests the resistance results that are pretty consistent with a real cell IR tester. Is it because it uses separate probes for measuring IR? Then, it’s better than the typical in slot measurement on some chargers?

A: Yes, the VP4 plus probes are four terminal, and the 4 terminal connection means that it will automatic compensate for any wire resistance and connection resistance at the charger. It can precisely measure the batteries’ IR as a multi meter. For some chargers with the spring loaded holders’ design, which it self causes variable contact/resistance.

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Q: For DIYing Li-ion battery packs, such as e-bikes battery pack, why it’s necessary to test cells’ IR and assemble identical IR cells into series?

A: You know the lower the resistance, the less voltage drop the cell will experience under load. This leads to less heat build up, which provides for a longer total cell life and, therefore, a longer battery pack life. If one of the cell has a much higher IR than the other cells, it will experience more voltage drop than the other cells. This causes energy to flow from the good cells into the bad one, which only exacerbates the issue. And remember, as a cell’s temperature increases, so does its resistance. This creates a potentially hazardous positive feedback loop that will make your battery pack fail a whole lot sooner than it otherwise would have. So, when you are learning how to make a Li-ion battery pack by yourself, the IR testing is one of the important steps.

We get a lot of questions about the difference between rechargeable batteries and common one-time use batteries like AA & AAA batteries. Between different brands, strengths and confusing names, it can be easy to get lost when trying to research different types of rechargeable batteries and how to best care for them. We put together a complete list of our most frequently asked questions about batteries to help you understand how to get the very most out of your Fenix light and battery life.

What is an Battery?

An battery is a lithium-ion battery. The name derives from the battery’s specific measurements: 18mm x 65mm. For scale, that’s larger than an AA battery. The battery has a voltage of 3.6v and has between mAh and mAh (mili-amp-hours). (Osborne, ) These batteries are used in flashlights, laptops, electronics and even some electric cars because of their reliability, long run-times, and ability to be recharged hundreds of times over. batteries are what would be considered a “high drain battery.” This means that the battery is designed to generate high output voltage and current to meet the power demands of the portable device in which it is being used. Hence why these powerful little batteries are utilized in more complex, power-hungry electronics that require a constant, high level of power for operation. It also has a high depth of discharge, meaning that the battery can be drained all the way down to 0% and still have the capacity to fully recharge the battery. However, this is not recommended practice, as overtime this will cause long term damage to the battery and affect its overall performance. Learn more about caring for and enhancing the life of your later in the article.

History of the Battery

The lithium-ion battery was first invented in the ’s by an Exxon researcher named Michael Stanley Whittingham. His pioneering work to create the first version of the lithium ion battery then set in motion decades more research to finetune the battery to be as efficient and safe as possible. Then in , a team of researchers and scientists named John Goodenough, Rachid Yazami, and Akira Yoshino worked together to develop and bring to market the lithium ion cell. The very first lithium ion battery cells were mass produced and sold by Sony. (Neverman et al., ) Since then, tweaks and enhancements have been made to extend the output and lifespan of the battery. Each of these changes resulted in a more efficient battery and in turn, a higher demand for their use and applications in the market. Today, lithium-ion batteries dominate the battery industry and have become ubiquitous in many household products we use everyday. There’s a very good chance you own many products powered by batteries, whether you realize it or not. As of , lithium-ion batteries account for 66% of all portable rechargeable battery sales. (Osborne, )

How a Battery Works

There are two types of batteries: protected and unprotected. As a rule of thumb, we always recommend using protected batteries. protected batteries have an electric circuit embedded within its packaging. This circuit protects the battery from “over charges” and “over discharges.” Both are situations you want to avoid. When a battery over charges, it can overheat, burst or catch fire.

It doesn’t take much imagination to understand how this malfunction can cause some serious problems for both the user and the manufacturer of the batteries. In fact, In , Samsung released its newest smartphone, the Galaxy Note 7. It didn’t take long for reports to begin coming that the phones were exploding while charging. There had been a flaw in the design of the ’s lithium ion battery that caused it to short circuit and catch fire.

Two separate recalls were put in place by the The U.S. Consumer Product Safety Commission, covering 1.9 million phones in the United States. Globally, to date, 96 percent of the 3 million phones that were sold have been returned. The debacle cost Samsung a pretty penny and a damaged reputation because of the number of fires and injuries the phones caused. It should be noted that the batteries within these phones were not specifically , they were a larger, different type of mAh lithium ion battery.

But for how widely used these batteries are, it seems like it is one of those easily overlooked technologies that we take for granted. From the moment we wake up to the moment we go to bed, there’s a very good chance we used some kind of battery. We don’t really realize how much they really do for us throughout our daily lives. Perhaps it’s because lithium-ion batteries are rarely seen on their own, instead they’re always encased inside the object they are charging. Not a lot of people take the time to consider how their electric toothbrush works, let alone how the batteries powering the toothbrush work.

There is actually a lot going on inside the battery’s tiny, colorful packaging. While the battery is being charged, the positive electrode lithium-cobalt oxide gives up some of it’s lithium ions which travel through the electrolyte to the negatively charged graphite electrode on the opposite side of the battery. The ions remain there until the battery is in use, during which the lithium ions travel back to the positive electrode, producing energy and powering the battery as it does so. In both the charging and discharging instances, electrons are flowing in the opposite direction of the ions around the outer circuit of the battery. (Osborne, ) The flow of ions through the electrolyte and electrons through the outer circuit are an interconnected process. One does not and can not happen without the other. Thus, should the battery completely discharge and the ions stop moving through the electrolyte, the electrons can’t make their way through the outer circuit and power is lost.

In the same way, should you turn off the object your battery is powering, the electrons will stop flowing through the circuit and so too will the ions. In essence, the battery stops discharging at a high rate. It should be noted that the battery will still continue to discharge at a very slow rate, regardless of whether the appliance is connected. Hence why you should always check the power level of your batteries every month or two in appliances that get more infrequent use.

What makes lithium-ions different from more simplistic batteries is their electronic controllers. These can be found only in the aforementioned “protected” batteries. Electronic controllers are built-in systems that regulate how the battery charges and discharges. It’s meant to prevent any overcharging or overheating that can, in some cases like the Galaxy Note 7 incident, cause lithium-ion batteries to explode. Using an unprotected lithium-ion battery can be tricky business to the uninitiated battery user. They are designed much more simply, meaning there is less of a chance for something to malfunction and are a bit smaller than protected batteries so they can fit into tighter spaces. However, the lack of protection opens the door to higher risks of overheating and explosion. Using unprotected batteries will, in general, yield the same performance but require more vigilance when it comes to charging and discharging.

Average Cost of a Battery

The cost of a battery can range widely depending on the brand, package size and whether it is a protected or unprotected battery. For example, the Fenix battery can range in price from $9.95 to $22.95 (these batteries are cheaper than most other brands when factoring in discounts), depending on the particular battery variation you are interested in. These batteries have a USB charging port right on the side of the battery itself, making recharging simple. They are at a bit higher price point than others because they are built with safety as a top priority, boasting three sets of overheating protection to prevent short circuiting so you can get up to 500 charge cycles out of a single battery without cause to worry about explosion or over discharging. Some unprotected batteries on the market can be found at cheaper prices, but as with anything you buy online, it’s important to factor in more to your purchase decision than just the price.

Pro Tip: As a general rule, if it seems too good to be true, it probably is. We suggest always buying any kind of technology, especially potentially dangerous ones like lithium-ion batteries, from a trusted source or name brand manufacturer.

Buying improperly manufactured or poorly made chemically-based products can yield unpleasant results, causing injury and destroying the appliance you were meaning to power. Before purchasing batteries online, it might be a good idea to check reviews from past customers or online tech forums to make sure you’re making a safe choice that also fits your power needs.

Different Types & Uses of Batteries

There are as many brands of batteries as there are uses. batteries are some of the most versatile on the market. They can be used to power just about anything, from electric cars to digital cameras.

As stated before, it is important to do your research beforehand when it comes to purchasing such potentially dangerous, though extremely useful products. Electric cars, such as the Tesla Model X and Model S , is what is known as a BEV, aka: battery electric vehicle.

These cars are powered by a hoard of lithium ion cells all working together. The Model S is powered by a battery pack that contains over 7,104 cells capable of storing up to 85 kWh of energy. Recently, Tesla engineers have redesigned a new battery pack for their electric cars to hold 516 cells in each module for a total of 8,256 cells capable of storing a little more than 100 kWh of energy. This makes it possible for these electric cars to have a max range of over 300 miles on a single charge. It is a marvel to see how far scientists and engineers have come to in such a relatively short time. Everyday new improvements and enhancements are pushing the bounds of what this technology can do, how we think about electricity, and what role it will play in our everyday lives in the future.

How to Charge Battery

Depending on the brand of battery, you might need to charge your batteries as they were designed. But, for the most part, you don’t really need a specific type of charger or special cord to recharge your batteries – as long as it’s rated safe to charge lithium ion batteries. If you use a charger that is not meant for lithium ion battery types, it could result in, at best, permanent damage to your batteries and at worst, they could explode. Some batteries, such as the Fenix battery detailed above, actually are charged directly using simply a USB cord.

To get the very most out of your battery’s life span, we suggest making sure that your batteries are never fully discharged or drop too low in power if you can help it. Totally discharging the battery makes the ion transfer process much harder when it comes time to recharge the battery, thus limiting the capacity of the battery as a whole. The same is true for overcharging your batteries. Intaking too much power at once can put stress on the cells and cause damage in the long run. Instead, experts suggest “partial” charges to extend the overall lifespan of your batteries. While this does mean you might have to charge your batteries more often, it will save you time and money in the long run by helping you get the very most out of your existing batteries, saving you from the need to buy more.

How Long Do Batteries Last?

Most batteries have a life cycle of around 300-500 charge cycles. For example, Fenix batteries are rated for 500 cycles. This means that the battery will be able to fully charge to at least 80% of its initial capacity. Once it reaches that threshold, the battery’s “life cycle” is considered over. Though you can still probably get plenty more charges out of the battery, it’s capacity will slowly diminish further with time.

Most of us have all experienced this first hand when buying a new smartphone. Time and use will slowly diminish the battery’s life capacity, even with careful charging considerations. Extreme hot or cold temperatures can affect your battery life, as well.

Pro Tip: Make sure to never charge your batteries in below freezing temperatures! This can cause significant degradation and damage. For example, don’t leave your batteries to charge in a freezing garage in the winter.

How Long Does It Take to Charge a Battery?

The average battery takes about 4 hours total to charge. Of course, this can vary a bit based on the health of your battery and the type of charger you are using. To check the health of your battery, try to take note of how long it takes the battery to charge up, whether it is accumulating more heat than usual while it charges, if it is not producing as much power as it once did, or holding a charge as well. These are all indicators that your battery is reaching its end of life.

Battery Storage Best Practices

batteries need to be stored in a dry, room temperature space. Avoid any situations that might subject your batteries to either extreme cold or heat. Between the range of -20 to +50°C (-4°F to + 122°F) is sufficient but the most optimal storage temperature is somewhere around 77°F or 25°C. If you are planning on storing your batteries over a long period of time, it is actually better to have them charged at around 50% rather than 100%. This will help extend the lifespan of your batteries over time. Make sure to remove the batteries from it’s application before long term storage. For example, if you use your rechargeable batteries in a flashlight, take them out to be stored separately.

Pro Tip: Never store batteries in a pocket or bag that also includes any metal items such as keys, pins, or coins. This might cause accidental discharge. (battery & Instructables, )

How to Discard Batteries Safely

Once your battery has reached the end of its life span, it is important to dispose of them responsibly. Never simply through these batteries into the trash! Though lithium ion batteries do not contain as many of the dangerous chemicals as other batteries, they still are considered hazardous waste and can cause fires or leak harmful chemicals into the earth. Many electronic or home improvement stores will have battery drop off zones or hazardous waste collection bins where you can get rid of your dead batteries without potentially causing environmental damage. Stores or collection centers will then send these batteries to recycling centers where they can harvest the metals inside to be reused. This is the most environmentally-friendly and economical way to dispose of old, damaged, or leaking batteries.

Rechargeable Batteries, Accessories and Flashlights

If you are in the market for a new rechargeable battery, flashlight or accessory. Fenix Lighting has been a trusted leader in rechargeable lighting solutions for decades. We offer state-of-the-art lithium-ion battery technology. Our rechargeable batteries and lighting solutions provide some of the very best in efficiency, performance, and lifespan in the industry. With thousands of satisfied customers and counting, our customers and fans come back to us again and again because they know when they buy Fenix, they are getting reliable, quality products backed by a full guarantee. Give our lineup a look or feel free to contact our friendly customer service line for recommendations or advice.

Source Cited:

Osborne, O. (, September 09). Where did the Lithium Ion battery come from? – UK. Retrieved January 25, , from https://.uk/where-did-the-lithium-ion-battery-come-from/

Neverman, A., Says, G., Grammyprepper, Says, A., Says, D., Smith, D., . . . Alonso, R. (, October 28). Everything You Need to Know About the Battery. Retrieved January 25, , from https://commonsensehome.com/-battery/#:~:text=%20protected%20batteries%20have%20an,over%20current%20and%20short%20circuit

Understanding Tesla’s lithium ion batteries. (n.d.). Retrieved January 25, , from https://evannex.com/blogs/news/understanding-teslas-lithium-ion-batteries

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