When to Use 4500 mAh  Lithium Ion Battery Manufacturer？

Battery research is focusing on lithium chemistries so much that one could imagine that the battery future lies solely in lithium. There are good reasons to be optimistic as lithium-ion is, in many ways, superior to other chemistries. Applications are growing and are encroaching into markets that previously were solidly held by lead acid, such as standby and load leveling. Many satellites are also powered by Li-ion.

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Lithium-ion has not yet fully matured and is still improving. Notable advancements have been made in longevity and safety while the capacity is increasing incrementally. Today, Li-ion meets the expectations of most consumer devices but applications for the EV need further development before this power source will become the accepted norm. BU-104c: The Octagon Battery – What makes a Battery a Battery, describes the stringent requirements a battery must meet.

As battery care-giver, you have choices in how to prolong battery life. Each battery system has unique needs in terms of charging speed, depth of discharge, loading and exposure to adverse temperature. Check what causes capacity loss, how does rising internal resistance affect performance, what does elevated self-discharge do and how low can a battery be discharged? You may also be interested in the fundamentals of battery testing.

• BU-415: How to Charge and When to Charge?
• BU-706: Summary of Do’s and Don’ts

What Causes Lithium-ion to Age?

The lithium-ion battery works on ion movement between the positive and negative electrodes. In theory such a mechanism should work forever, but cycling, elevated temperature and aging decrease the performance over time. Manufacturers take a conservative approach and specify the life of Li-ion in most consumer products as being between 300 and 500 discharge/charge cycles.

In , small wearable batteries deliver about 300 cycles whereas modern smartphones have a cycle life requirement is 800 cycles and more. The largest advancements are made in EV batteries with talk about the one-million-mile battery representing 5,000 cycles.

Evaluating battery life on counting cycles is not conclusive because a discharge may vary in depth and there are no clearly defined standards of what constitutes a cycle(See BU-501: Basics About Discharging). In lieu of cycle count, some device manufacturers suggest battery replacement on a date stamp, but this method does not take usage into account. A battery may fail within the allotted time due to heavy use or unfavorable temperature conditions; however, most packs last considerably longer than what the stamp indicates.

The performance of a battery is measured in capacity, a leading health indicator. Internal resistance and self-discharge also play roles, but these are less significant in predicting the end of battery life with modern Li-ion.

Figure 1 illustrates the capacity drop of 11 Li-polymer batteries that have been cycled at a Cadex laboratory. The 1,500mAh pouch cells for mobile phones were first charged at a current of 1,500mA (1C) to 4.20V/cell and then allowed to saturate to 0.05C (75mA) as part of the full charge saturation. The batteries were then discharged at 1,500mA to 3.0V/cell, and the cycle was repeated. The expected capacity loss of Li-ion batteries was uniform over the delivered 250 cycles and the batteries performed as expected.

Eleven new Li-ion were tested on a Cadex C battery analyzer. All packs started at a capacity of 88–94% and decreased to 73–84% after 250 full discharge cycles. The mAh pouch packs are used in mobile phones.

Although a battery should deliver 100 percent capacity during the first year of service, it is common to see lower than specified capacities, and shelf life may contribute to this loss. In addition, manufacturers tend to overrate their batteries, knowing that very few users will do spot-checks and complain if low. Not having to match single cells in mobile phones and tablets, as is required in multi-cell packs, opens the floodgates for a much broader performance acceptance. Cells with lower capacities may slip through cracks without the consumer knowing.

Similar to a mechanical device that wears out faster with heavy use, the depth of discharge (DoD) determines the cycle count of the battery. The smaller the discharge (low DoD), the longer the battery will last. If at all possible, avoid full discharges and charge the battery more often between uses. Partial discharge on Li-ion is fine. There is no memory and the battery does not need periodic full discharge cycles to prolong life. The exception may be a periodic calibration of the fuel gauge on a smart battery or intelligent device(See BU-603: How to Calibrate a “Smart” Battery)

The following tables indicate stress related capacity losses on cobalt-based lithium-ion. The voltages of lithium iron phosphate and lithium titanate are lower and do not apply to the voltage references given.

Note: Tables 2, 3 and 4 indicate general aging trends of common cobalt-based Li-ion batteries on depth-of-discharge, temperature and charge levels, Table 6 further looks at capacity loss when operating within given and discharge bandwidths. The tables do not address ultra-fast charging and high load discharges that will shorten battery life. No all batteries behave the same.

Table 2 estimates the number of discharge/charge cycles Li-ion can deliver at various DoD levels before the battery capacity drops to 70 percent. DoD constitutes a full charge followed by a discharge to the indicated state-of-charge (SoC) level in the table.

Depth of Discharge Discharge cycles NMC LiPO4 100% DoD ~300 ~600 80% DoD ~400 ~900 60% DoD ~600 ~1,500 40% DoD ~1,000 ~3,000 20% DoD ~2,000 ~9,000 10% DoD ~6,000 ~15,000

* 100% DoD is a full cycle; 10% is very brief. Cycling in mid-state-of-charge would have best longevity.

Lithium-ion suffers from stress when exposed to heat, so does keeping a cell at a high charge voltage. A battery dwelling above 30°C (86°F) is considered elevated temperature and for most Li-ion a voltage above 4.10V/cell is deemed as high voltage. Exposing the battery to high temperature and dwelling in a full state-of-charge for an extended time can be more stressful than cycling. Table 3 demonstrates capacity loss as a function of temperature and SoC.

Temperature 40% Charge 100% Charge 0°C 98% (after 1 year) 94% (after 1 year) 25°C 96% (after 1 year) 80% (after 1 year) 40°C 85% (after 1 year) 65% (after 1 year) 60°C 75% (after 1 year) 60% (after 3 months)

Most Li-ions charge to 4.20V/cell, and every reduction in peak charge voltage of 0.10V/cell is said to double the cycle life. For example, a lithium-ion cell charged to 4.20V/cell typically delivers 300–500 cycles. If charged to only 4.10V/cell, the life can be prolonged to 600–1,000 cycles; 4.0V/cell should deliver 1,200–2,000 and 3.90V/cell should provide 2,400–4,000 cycles.

On the negative side, a lower peak charge voltage reduces the capacity the battery stores. As a simple guideline, every 70mV reduction in charge voltage lowers the overall capacity by 10 percent. Applying the peak charge voltage on a subsequent charge will restore the full capacity.

In terms of longevity, the optimal charge voltage is 3.92V/cell. Battery experts believe that this threshold eliminates all voltage-related stresses; going lower may not gain further benefits but induce other symptoms(See BU-808b: What causes Li-ion to die?) Table 4 summarizes the capacity as a function of charge levels. (All values are estimated; Energy Cells with higher voltage thresholds may deviate.)

Charge Level* (V/cell) Discharge Cycles Available Stored Energy ** [4.30] [150–250] [110–115%] 4.25 200–350 105–110% 4.20 300–500 100% 4.13 400–700 90% 4.06 600–1,000 81% 4.00 850–1,500 73% 3.92 1,200–2,000 65% 3.85 2,400–4,000 60%

Every 0.10V drop below 4.20V/cell doubles the cycle but holds less capacity. Raising the voltage above 4.20V/cell would shorten the life. The readings reflect regular Li-ion charging to 4.20V/cell.

Guideline: Every 70mV drop in charge voltage lowers the usable capacity by about 10%.
Note: Partial charging negates the benefit of Li-ion in terms of high specific energy.

* Similar life cycles apply for batteries with different voltage levels on full charge.
** Based on a new battery with 100% capacity when charged to the full voltage.

Experiment: Chalmers University of Technology, Sweden, reports that using a reduced charge level of 50% SOC increases the lifetime expectancy of the vehicle Li-ion battery by 44–130%.

Most chargers for mobile phones, laptops, tablets and digital cameras charge Li-ion to 4.20V/cell. This allows maximum capacity, because the consumer wants nothing less than optimal runtime. Industry, on the other hand, is more concerned about longevity and may choose lower voltage thresholds. Satellites and electric vehicles are such examples.

For safety reasons, many lithium-ions cannot exceed 4.20V/cell. (Some NMC are the exception.) While a higher voltage boosts capacity, exceeding the voltage shortens service life and compromises safety. Figure 5 demonstrates cycle count as a function of charge voltage. At 4.35V, the cycle count of a regular Li-ion is cut in half.

Besides selecting the best-suited voltage thresholds for a given application, a regular Li-ion should not remain at the high-voltage ceiling of 4.20V/cell for an extended time. The Li-ion charger turns off the charge current and the battery voltage reverts to a more natural level. This is like relaxing the muscles after a strenuous exercise(See BU-409: Charging Lithium-ion)

Figure 6 illustrates dynamic stress tests (DST) reflecting capacity loss when cycling Li-ion at various charge and discharge bandwidths. The largest capacity loss occurs when discharging a fully charged Li-ion to 25 percent SoC (black); the loss would be higher if fully discharged. Cycling between 85 and 25 percent (green) provides a longer service life than charging to 100 percent and discharging to 50 percent (dark blue). The smallest capacity loss is attained by charging Li-ion to 75 percent and discharging to 65 percent. This, however, does not fully utilize the battery. High voltages and exposure to elevated temperature is said to degrade the battery quicker than cycling under normal condition. (Nissan Leaf case)

• Case 1: 75–65% SoC offers longest cycle life but delivers only 90,000 energy units (EU). Utilizes 10% of battery.
• Case 2: 75–25% SoC has 3,000 cycles (to 90% capacity) and delivers 150,000 EU. Utilizes 50% of battery. (EV battery, new.)
• Case 3: 85–25% SoC has 2,000 cycles. Delivers 120,000 EU. Uses 60% of battery.
• Case 4: 100–25% SoC; long runtime with 75% use of battery. Has short life. (Mobile , drone, etc.)

* Discrepancies exist between Table 2 and Figure 6 on cycle count. No clear explanations are available other than assuming differences in battery quality and test methods. Variances between low-cost consumer and durable industrial grades may also play a role. Capacity retention will decline more rapidly at elevated temperatures than at 20ºC.

Only a full cycle provides the specified energy of a battery. With a modern Energy Cell, this is about 250Wh/kg, but the cycle life will be compromised. All being linear, the life-prolonging mid-range of 85-25 percent reduces the energy to 60 percent and this equates to moderating the specific energy density from 250Wh/kg to 150Wh/kg. Mobile phones are consumer goods that utilize the full energy of a battery. Industrial devices, such as the EV, typically limit the charge to 85% and discharge to 25%, or 60 percent energy usability, to prolong battery life(See Why Mobile Batteries do not last as long as an EV Battery)

Increasing the cycle depth also raises the internal resistance of the Li-ion cell. Figure 7 illustrates a sharp rise at a cycle depth of 61 percent measured with the DC resistance method(See also BU-802a: How does Rising Internal Resistance affect Performance?) The resistance increase is permanent.

Note: DC method delivers different internal resistance readings than with the AC method (green frame). For best results, use the DC method to calculate loading.

Figure 8 extrapolates the data from Figure 6 to expand the predicted cycle life of Li-ion by using an extrapolation program that assumes linear decay of battery capacity with progressive cycling. If this were true, then a Li-ion battery cycled within 75%–25% SoC (blue) would fade to 74% capacity after 14,000 cycles. If this battery were charged to 85% with same depth-of-discharge (green), the capacity would drop to 64% at 14,000 cycles, and with a 100% charge with same DoD (black), the capacity would drop to 48%. For unknown reasons, real-life expectancy tends to be lower than in simulated modeling(See BU-208: Cycling Performance)

Li-ion batteries are charged to three different SoC levels and the cycle life modelled. Limiting the charge range prolongs battery life but decreases energy delivered. This reflects in increased weight and higher initial cost.

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Battery manufacturers often specify the cycle life of a battery with an 80 DoD. This is practical because batteries should retain some reserve before charge under normal use(See BU-501: Basics about Discharging, “What Constitutes a Discharge Cycle”) The cycle count on DST (dynamic stress test) differs with battery type, charge time, loading protocol and operating temperature. Lab tests often get numbers that are not attainable in the field.

What Can the User Do?

Environmental conditions, not cycling alone, govern the longevity of lithium-ion batteries. The worst situation is keeping a fully charged battery at elevated temperatures. Battery packs do not die suddenly, but the runtime gradually shortens as the capacity fades.

Lower charge voltages prolong battery life and electric vehicles and satellites take advantage of this. Similar provisions could also be made for consumer devices, but these are seldom offered; planned obsolescence takes care of this.

A laptop battery could be prolonged by lowering the charge voltage when connected to the AC grid. To make this feature user-friendly, a device should feature a “Long Life” mode that keeps the battery at 4.05V/cell and offers a SoC of about 80 percent. One hour before traveling, the user requests the “Full Capacity” mode to bring the charge to 4.20V/cell.

The question is asked, “Should I disconnect my laptop from the power grid when not in use?” Under normal circumstances this should not be necessary because charging stops when the Li-ion battery is full. A topping charge is only applied when the battery voltage drops to a certain level. Most users do not remove the AC power, and this practice is safe.

Modern laptops run cooler than older models and reported fires are fewer. Always keep the airflow unobstructed when running electric devices with air-cooling on a bed or pillow. A cool laptop extends battery life and safeguards the internal components. Energy Cells, which most consumer products have, should be charged at 1C or less. Avoid so-called ultra-fast chargers that claim to fully charge Li-ion in less than one hour.

References

In this highly technologically sophisticated world, you might be hearing or seeing the word mAH or milliampere per hour when you are shopping for a new gadget or watching reviews, or unboxing videos of a newly released device. But have you ever wondered—what is mAh for batteries? Why do they matter? Or what is its importance to you as a consumer? Well, the information might not seem relevant to you, but knowing them can give you a good sense of the value you are getting when you are buying an electronic or handheld device.

In this blog, I will discuss the basic information you need to know about the subject matter of mAh. And then, I will help you with how the amount or level of mAh affects the quality and longevity of your battery. So without any further ado, let’s get right into today’s discussion.

What is mAh?

As we move towards an increasingly digital and connected world, the role of batteries in powering our devices has become more important than ever. The capacity of a battery to hold a charge and provide power for an extended period of time is measured in milliampere-hours (mAh). But what exactly does this measurement mean?

In simple terms, mAh refers to the amount of energy a battery can store and release to power a device. The higher the mAh rating, the more energy the battery can hold and the longer it can power your device before needing to be recharged. Therefore, mAh is an important factor to consider when purchasing a battery for your devices.

mAh vs AH: What’s the Difference?

When it comes to batteries, there are two common units used to express the capacity of the battery. These are mAh and Ah. Both mAh and AH are units of measuring energy, but they differ in their magnitude of measurement.

mAh, or milliampere-hour, is a more commonly used term in the world of batteries, particularly in smartphones, tablets, and other portable electronics. It is a metric that measures battery capacity, which is the amount of charge that a battery can hold. As the name implies, milliampere-hour means one-thousandth of an ampere-hour, so 1 mAh is equivalent to 0.001 AH.

On the other hand, AH, or ampere-hour, is the standard unit for measuring the amount of electric charge that flows in one hour. An ampere is a unit of electric current that represents the rate of flow of electrical charge. Thus, an ampere-hour equals the flow of a charging current of one ampere for one hour.

To put it simply, mAh and AH represent the same concept, but they differ in magnitude. While AH is used for larger applications like vehicles or solar panels, mAh is generally used for measuring the battery capacity of smaller devices.

How Is mAh Calculated?

In simple terms, the formula is mAh = x Wh/V. That is to ssy, to calculate the milliampere-hours (mAh) of a battery, we need to multiply its watt-hours (Wh) by and then divide the result by its voltage (V).  For example, if you have a battery with a rating of 2Wh under 5V. The power capability computation is—

mAh = x 2Wh / 5V

mAh = / 5V

mAh = 400

Impact of mAh on Battery Life

It's undeniable that battery life is one of the critical parts of our device experience, which can impact our productivity. Therefore, understanding the impact of the milliamp-hour (mAh) rating on battery life is essential.

How mAh Affects Charging Time?

mAh (milliampere-hours) is a measure of battery capacity, which represents the amount of electric charge that a battery can store. The higher the mAh rating of a battery, the more charge it can hold, and thus, the longer it can power a device.

The relationship between mAh and charging time is simple. The higher the mAh rating, the longer it will take to charge a device fully because it has a larger capacity to store electric energy. On the other hand, a lower mAh rating means the device's battery has less capacity to store electric energy and can be charged relatively faster.

However, charging time isn't just dependent on mAh alone. Other factors such as the charging method, cable quality, and device usage during charging also play a role. For instance, using a fast charging adapter for a device with a low mAh rating could lead to the battery overheating and reduce its lifespan.

How Much mAh is Good for a Battery?

A good mAh for a battery depends on the battery and electronics they are embedded into. For example, a power bank is considered to have a good battery capacity if it has 12,000 mAh. On the other hand, smartphones with excellent battery power life are above 4,500 mAh, tablets have batteries have a average capacity about 8,000 mAh, which also goes for laptops.

Does Higher mAh Mean Longer Battery Life?

Yes. A device with a higher milliampere per hour rating means longer battery life. For example, a smartphone with mAh will only last you about 3 to 5 hours if you use them for an extensive amount of time playing games or watching videos. But a smartphone with a battery rating of mAh or higher can give you power consumption of over 5 hours of engaging in games or watching movies, for example. However, you also have to bear in mind the higher the battery rating means the longer it charges as well.

But if you need your device to last longer than it should, you can get a power bank or power station battery pack like our Anker 760 Expansion Battery, equipped with our innovative InfiniPower™ technology and LiFePO4 batteries for unmatched endurance and reliability. It features premium electronic components with a lifespan of up to 50,000 hours, ensuring you get the most out of your investment. The battery's secure 3-point protective clasp protects against leakage current during charging, providing peace of mind. Built with durability in mind, the Anker 760 Expansion Battery features a drop-proof unibody design and impact-resistant structural composition to withstand the rigours of everyday use. An ultra-smart temperature control system monitors various temperature levels up to 100 times per second to optimize performance and safety.

We stand behind our product with an impressive 5-year full-device warranty, twice the industry average. With the Anker 760 Portable Power Station Expansion Battery and its unparalleled longevity, you can power your devices with confidence for a decade.

Wrap Up

To wrap things up, the milliampere per hour of the device does not affect battery life directly. But knowing what is mAh for batteries is important to give you a good sense of why they matter to you in shopping for a new electronic that will make your life more comfortable and convenient.

Frequently Asked Questions About What is mAh for Batteries

The following are additional concerns many people have about what is mAh for batteries and their importance to you—

Is Higher mAh better?

A higher mAh battery means more capability in storing and producing power that can last for several hours or even days or so. However, a higher battery rating also means longer battery recharge.

What Does a mAh battery mean?

A mAh battery refers to the capacity of the battery to hold a certain amount of energy. Specifically, the "mAh" stands for milliampere-hour, which is the measurement unit for the energy capacity of batteries. A battery with a capacity of mAh is capable of delivering a continuous current of 1A for 5 hours, or 0.5A for 10 hours, or 5A for 1 hour, and so on.

Which is Better mAh or mAh?

mAh battery capacity is better than mAh battery capacity in regards to storing and producing electric current. However, the disadvantage of a mAh battery is that it takes longer to recharge than a mAh battery.

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