The world is filled with many variations of battery each having its own unique characteristics. 

One of the most common batteries used nowadays is Lithium-Ion.

Sooner or later, the Lithium-Ion is going to go dead (lose all its charge), and if it is a rechargeable battery, will need to be recharged.

Letting a battery go fully dead is not an ideal situation, so knowing at what voltage a Lithium-Ion battery loses all its charge will help you extend its lifespan.

So, at what voltage is a Lithium-Ion battery considered dead? The voltage at which a Lithium-Ion is dead is around 3.4 volts. This voltage can vary depending on factors such as the temperature and also its manufacturer. Lithium-Ion batteries should not be used when they are dead.  They contain a cutoff circuit to protect them from being used past the voltage at which they have lost all its charge. 

This article shall take a look closer at Lithium-Ion batteries and its discharge profile. 

Deeper look at a Lithium-Ion battery

There are many batteries that exist in the world today, and while they all share one main goal, which is to provide power to electrical and electronic devices, they differ in many different characteristics.

Characteristics such as;

• Chemical composition
• Nominal voltage
• Current capacity 
• Shape
• Size
• Energy Density 
• Specific Energy density

The main characteristic here that plays a major part in determining many of the other factors (such as voltage, current capacity, energy density, etc), is the Chemical Composition.

Batteries produce electrical power from chemical reactions that occur inside the battery. There are a range of chemicals that are used in different batteries which include;

• Nickel-Cadmium (Ni-Cd)
• Zinc-Carbon 
• Lithium-Ion (Li-Ion)
• Lead-Acid 
• Alkaline 

The chemical composition we are most concerned about for this article is Lithium-Ion (Li-On). 

The battery is constructed using cells where lithium-ions move from the negative electrode through an electrolyte towards the positive electrode. 

Lithium-Ion battery nominal voltage 

To better understand at what voltage a Lithium-Ion battery is dead, it will first help to understand the voltage at which it is operational.

The voltage of the battery is one of the most important characteristics when selecting a battery for a particular application. 

All electrical and electronic devices have a specific voltage rating that they require to operate efficiently and effectively. 

So, you will have to select a battery with the exact voltage (or a bit higher), to satisfy the needs of that device. 

The voltage of a battery refers to the amount of electrical potential it is able to hold, and is given in the standard international unit of Voltage (V).

All batteries have a theoretical voltage, however, the actual voltage (nominal voltage) produced will be lower.

This is due to polarisation and resistance losses, and is largely dependent on the current drawn by the load and the internal impedance of the battery. 

The maximum voltage that a lithium-ion battery is capable of producing is 4.2V, however this will soon drop to its nominal voltage of 3.7V. 

Different types of Lithium-Ion battery

Lithium-Ion batteries come in a variety of shapes and sizes to suit the needs of many different applications, from power tools to RC planes. 

Below are the different shapes available for lithium-ion batteries;

• Small cylindrical (single cell with, solid body, with no terminals)
• Large cylindrical (single cell,solid body, with threaded terminals)
• Flat or pouch (soft, flat body)
• Rigid plastic case (large threaded terminals) 

But, do the  different variety of shapes of lithium-ion batteries share the same voltage? 

Yes, while they vary in size, the batteries share the same nominal voltage of 3.7V. 

What about devices that require larger voltages, and use lithium-ion batteries? To generate a larger voltage, lithium-ion batteries can be connected in series. 

Note, this process is a bit more complicated than connecting other batteries in series, as the impedances of lithium-ion batteries need to be matched. 

So, two lithium-ion batteries connected in series (with their impedances matched of course), will now have a nominal voltage of 7.4V.

Adding more batteries will consequently increase the voltage by 3.7V.

Lithium-Ion batteries are available in packs with these higher voltages. 

Voltage at which a Lithium-Ion battery is dead

There are a couple of voltages that we need to be aware of when using a lithium-ion battery (or any other battery for that matter).

The first being the nominal voltage, which we now know is 3.7V for lithium-ion batteries. 

Another voltage that is of utmost importance is the voltage at which the battery is considered dead, when it has lost all its charge.

It is essential to know this voltage as the battery will need to be recharged back to its nominal voltage to be able to effectively power electronics. 

So, what is the voltage at which a lithium-ion battery is considered dead?

The voltage at which a lithium-ion battery is dead is around 3.4V. 

If the battery is still connected and continues to discharge past 3.4V, a cutoff circuitry kicks in around 3V and disconnects the battery for protection purposes. 

What can affect how fast a lithium-ion battery goes dead?

There are a couple of factors that can affect how fast the lithium-ion battery goes dead, with the two major factors being;

• Load
• Temperature

Load

The first obvious factor is the load that is placed on the battery. A great analogy for this is to imagine you are carrying a backpack (which represents the load), and your energy levels represent the battery. 

If you have a lot of items in the backpack, the weight is going to be larger. This means you have to generate more power to carry the load, which is going to cause you to tire faster (lose all your energy).

However, if you only had a few items in the backpack (which meant the weight is far less), you would need to generate less power to carry it. This means you would be able to travel further. 

This concept is similar for batteries. If a greater load is placed on the battery (such as powering a motor), the battery is going to have to generate more power causing it to lose charge faster and go dead.

But, if the battery is connected to a device such as an LED (which consumes far less power than a motor), the battery will last much longer. 

Temperature

The next major factor that influences the performance of a battery is temperature.

Lithium-Ion batteries have a range of ideal temperatures at which they can be charged and discharged at.

The ideal temperature to charge a lithium-ion battery is 32°F (0°C) to 113°F (45°C) and the ideal discharge temperature is –4°F (-20°C) to 140°F (60°C).

However it is not recommended to charge or discharge the lithium-ion batteries at the extreme temperatures (either real cold or hot).

Higher temperatures can have a temporary advantage of greater performance and increased storage capacity, however, the long term side effect is a decreased life cycle.

Every battery has an internal resistance and when they are subject to drastically lower temperatures, the internal resistance increases.

This means that the battery has to do more work to overcome this increase in resistance causing it to lose power and go dead faster. 

What happens when a Lithium-Ion battery is dead

There are two things not to do with a Lithium-Ion battery when it comes to voltage;

• Do not charge them past their maximum safe voltage of 4.2V 
• Do not discharge them below the minimum safe voltage of 3V.

Lucky for you and me, we do not have to worry about constantly monitoring the battery to see if the voltage goes past these two limits.

When it comes to charging, lithium-ion batteries require a special charger to ensure that the maximum voltage is not exceeded.

This means lithium-ion battery chargers do not have trickle charging (which is a common technique used to charge a battery when it has reached full charge). 

Once the lithium-ion battery has reached full capacity, the battery charger stops charging the battery.

For discharging, lithium-ion batteries include a similar protection circuit that is built on the cell (usually at the the top of the battery covered in tape).

This protection circuit will monitor and disconnect the battery once it has gone dead to protect it from damage. . 

Can a lithium-ion battery become dead if it is not used?  

Yes, a lithium-ion battery can go dead if it is not used (even though it is not supplying a load).

All batteries have something that is known as shelf life. 

The shelf life of a battery tells us the time a battery can hold its charge when it is not being used. After that time, the battery will start to lose charge and need to be recharged (if it is a rechargeable battery).

Lithium-Ion batteries have a self-discharge rate of 5% per month at room temperature.

Irreversible capacity loss occurs if the battery is unused for longer than 12 months. 

If the battery is at a voltage of 1.5V or lower, do not try recharging it. Over long periods of time a build of copper shunts can result within the battery which can cause shorts, leading to excessive heating which could result in the worst case scenario of an explosion. 

How to check if a Lithium-Ion battery is dead

The easiest way to check the voltage of a lithium-ion battery to see if it is dead is to use a Multimeter.

A multimeter is an electronic measuring instrument that has a range of functions which include measuring voltage, current, resistance, continuity, diode test, frequency, etc. 

The number of electrical quantities it is capable of measuring solely depends on the complexity of the multimeter. 

However, all standard multimeters will measure the three main quantities which are voltage, current and resistance. 

To measure the voltage of a lithium-ion battery, follow the steps below;

1. Set the multimeter to voltage mode (ensure the voltage of the battery you are measuring is within the range of the multimeters capability) 
2. Connect the positive (red) lead of the multimeter to the positive terminal of the battery
3. Connect the negative (black) lead of the multimeter to the negative terminal of the battery
4. Note the voltage that the multimeter displays

Should you continue to use a Lithium-Ion battery when it is almost dead? 00

If you measure the voltage of a lithium-ion and it happens to be nearing its dead voltage of 3.4V, should you continue to use it?

No, the best option here is to recharge the battery.

Using a battery when it is almost dead can drastically reduce its lifespan.

The post At what voltage is a Lithium-Ion battery dead? appeared first on Electronic Guidebook.

These mobile devices use many different types of rechargeable batteries to keep them energised, but the most common being Lithium-Ion.

Lithium-Ion batteries need to be charged once they have fully discharged. 

But, more often than not, you might need to use the device that has a lithium-ion battery when charging it. 

So, can you charge a Lithium-Ion battery while using it? Yes, you can charge a Lithium Ion battery while using it, however, it’s not the best practice. Doing so will result in a lower rate of charge which means it will take longer to charge the lithium ion battery. 

There are some other issues that arise when trying to charge a lithium battery while using it which shall be discussed further in this article. 

Deeper look at how a battery is charged

Knowing the process of how a battery is charged, will help you better understand why using a Lithium-Ion battery while charging it isn’t very ideal.

There are two main classes of batteries; Primary and Secondary.

Primary batteries are one-off batteries that must be disposed of after they have fully discharged. These types of batteries can only be used once.

Secondary batteries are rechargeable. This means that when they have been fully discharged of all their energy, they can be ‘recharged’ back to their full capacity and used again. 

A Lithium-Ion battery is a type of rechargeable battery. 

They can be recharged multiple times, and their lifespan is largely dependent on their chemical composition.

How a battery charger charges a battery  

But, rechargeable batteries do not just recharge by themselves (which would be neat if they could). However, they require the aid of a battery charger.

Batteries power devices by converting stored chemical energy into electrical power (which is a product of voltage and current). 

The process when a battery releases its energy to power devices is known as discharging. While reversing the discharging process and giving energy back to a dead battery is known as recharging.  

Charging a battery involves a number of steps which include;

• Charging
• Stabilising (optimising the charging rate)
• Terminating (knowing when to stop the charging process)

Charge and Discharge rates of batteries vary from one to the next depending on factors such as their chemical compositions and size (the amount of charge they are able to hold for their given physical size).  

Discharging involves the release of electrons when a chemical reaction occurs in between the two terminals (or electrodes) and electrolyte (the substance that separates the electrodes). 

Once the chemical reaction within the battery is over, the battery is effectively out of charge (flat).

For primary (disposable) batteries this is the end of the road, however, rechargeable batteries can be recharged to be used again.

Battery chargers are used to reverse the chemical reaction process to recharge the battery. While discharging involves energy leaving the battery, charging a battery involves feeding energy back into a battery (using a battery charger) to reset the chemicals to their initial state. 

To feed energy back into a battery, battery chargers supply electric current for a predetermined period of time. 

Reasons not to charge a Lithium-Ion battery while using it

It might seem that a battery charger has a simple task of just feeding current to a Lithium-Ion battery to recharge it.

However, there is a bit more that happens within the battery charger to ensure that the battery is optimally charged while also being protected. 

So it might not be the best idea to charge a Lithium-Ion battery while using it. 

Let’s take a look at why. 

There are a couple of things that happen when you try to charge a Lithium-Ion battery and use it at the same time.

Reason #1 not to charge a Lithium-Ion battery while using it

Firstly when a battery is being charged, it is subjected to a voltage higher than its own. This is why current flows from the battery charger to a battery.

If you try using a Lithium-Ion battery while it is charging (for low currents), you could trigger safety circuits as it may detect the extra current as an overcurrent or short, and stop the charging process. 

For higher currents, the load will draw power from the battery charger which means that the battery isn’t going to get much current and is going to charge at a slower rate taking it a longer time to reach full capacity. 

Reason #2 not to charge a Lithium-Ion battery while using it

The second issue that arises is that every now and then, the battery charger stops charging to monitor the voltage of the Lithium-Ion battery. 

When this happens, the battery will start supplying current to the load which isn’t an ideal situation as the Lithium-Ion battery will then report a different voltage when subjected to a load, as opposed to when not under load circumstances. 

This messes up the charging process.

Can you charge a Lithium battery while using it for consumer electronics? 

The scenarios we have discussed above have mostly been with Lithium-Ion batteries that are detachable from devices (like power tools for example), where the battery charger is a separate entity.

But, many consumer electronic devices (that use Lithium-Ion batteries), have their charging circuits embedded in them.

Devices such as smartphones, smart watches, laptops, and so much more. 

These devices have come a long way, and include sophisticated charging circuits within them. 

Most of the time you would have used one of these devices while you were simultaneously charging it as well.

But, how is this possible?

These devices have been designed with charging circuits that allow one to use it and charge it at the same time. 

Engineers would have realised that sooner or later, the user would need to use their device (especially smartphones) when charging.

Note, while it may be possible, it is still not advisable to do so as you will still be slowing down the rate of charge.

What is the best way to charge a Lithium Ion Battery?

As we have just learnt, charging a battery and while using it is not good practice. Doing so will reduce the rate of charge which means it is going to take longer for the Lithium-Ion battery to reach full charge.

To charge a Lithium-Ion battery more efficiently, follow the three tips below;

1. Do not use the battery while it is charging
2. Do not charge the battery under extreme temperatures (cold or hot). Stay within moderate temperature settings
3. Avoid fully charging the battery (especially with Lithium-Ion batteries). A partial charge will extend its lifespan 

For consumer electronics like smartphones, turn the device off and then charge. This will drastically reduce the charge time. 

The post Can you charge a Lithium-Ion battery while using it? appeared first on Electronic Guidebook.

They provide power to a plethora of portable devices like TV remotes, smartphones, wireless keyboards, smartwatches, clocks, and so much more. 

While having one universal battery available for all applications might save a lot of hassle in choosing the right one, the world of batteries is filled with many different types. 

Batteries can differ in certain characteristics which include; chemical composition, voltage, physical dimension, specific energy, specific power, performance and lifespan. 

Due to this, one type of battery might be more suitable for a particular application compared to another. 

Can you replace NiMH batteries with Lithium?

Yes, you can replace a NiMH battery with a lithium battery. To replace NiMH batteries with lithium, you will need to ensure they are the same size, shape and voltage rating. However, practically it is not a good idea as each battery is designed for different applications. A NiMH battery is more suited for applications requiring high current draw (like power tools) compared to Lithium batteries. 

This article will take a closer look at each battery, as well the key characteristics of batteries and why replacing a NiMH and Lithium battery isn’t really ideal. 

Key characteristics of rechargeable batteries

While some characteristics of a battery might be distinguishable by just looking at them (things like their shape and size), there are other key characteristics which you won’t be able to find out by looks alone. 

These characteristics ultimately determine what type of applications the battery will be used in, as every application has different needs and demands. 

The key characteristics of batteries include; 

• Nominal Voltage
• Specific Energy
• Specific Power 
• Performance 
• Lifespan 

Nominal Voltage

Is the normal voltage that the battery provides. Some batteries might indicate a higher voltage at full charge, however, this voltage drops down to its nominal voltage soon after. 

Specific energy

This is basically the current capacity of a battery which relates to how much current a battery is capable of storing for its given weight. 

If a device needs to operate for long periods of time at a moderate load, batteries with higher specific energy are the ideal choice.

Specific Power

Is the battery’s ability to provide high current. The higher the specific power, the larger the current it can output. 

If a device needs a  high current for a short amount of time, batteries with higher specific power are the ideal choice. The tradeoff is that the specific energy of the battery decreases. 

Performance

A battery is going to be subject to a wide range of temperatures. The performance of a battery gives an indication of how well it will perform to these different temperatures. 

Extreme heat can reduce the lifespan of a battery, while extreme cold can temporarily lower its performance. 

Lifespan

This tells us how long a battery is going to last. Things like temperature, depth of charge and load play huge roles in determining the lifespan. 

As we saw above, heat can drastically reduce the lifespan of a battery. 

Deeper look at NiMH and Lithium batteries

To better understand the question at hand, it will help to learn a bit about both batteries.

NiMH batteries

Let’s start with NiMH batteries. 

The battery is available as disposable (can only be used once), or as a rechargeable (which means they can be used multiple times as long as it is recharged ).

Most of the time (if not all), batteries get their name from what chemical they are composed of. In this instance the chemical composition is Nickel Metal Hydride (where NiMH is just an abbreviation). 

Different types of NiMH Batteries

NiMH batteries are available in various different sizes for different types of devices. While their size varies, the majority of them provide a nominal voltage of 1.2 volts. 

However the size of the battery will affect its current capacity. The smaller the battery, the lower the current capacity, and vice versa. 

Below is a list of the different sizes of NiMH batteries (which are split into two categories; consumer and industrial). They are available with or without tabs.

Consumer;

• AA
• AAA
• C
• D
• 9 volt (rectangular)

Industrial;

• Sub C
• A
• 1/3 AA
• 1/3 AAA
• 2/3 A
• 2/3 AA
• 2/3 AAA
• 4/3 A
• 4/5 A
• 1/2 D

Electronic devices that use NiMH batteries

Due to their ability to deliver high current (specific power), NiMH batteries are used in high drain electronic devices that require this large current to operate.

A digital camera is an example of a device that requires a high current around 1000mA (mainly for the flash). NiMH batteries are able to deliver this current without losing too much of its capacity. 

Other electronic devices that use NiMH batteries include;

• Flashlights 
• Portable Vacuum Cleaner
• Portable power tools (drills, jigsaws, circular saws, sanders, grinders, etc)
• Electric toothbrushes
• Electric razors
• Camcorders

Lithium batteries

Next up are Lithium batteries. 

The most common of lithium batteries used in portable electronic devices is the Lithium Ion. So, going forward this type of Lithium battery will be used. 

Just like the NiMH battery, the lithium ion battery is aptly named due to it using lithium ions. 

During the discharge cycle, the lithium ions move from the negative terminal (cathode), through an electrolyte to the positive terminal (anode).

Different types of Lithium Ion Batteries

Lithium Ion batteries come in a variety of shapes for different applications. 

• Small cylindrical (single cell with, solid body, with no terminals)
• Large cylindrical (single cell,solid body, with threaded terminals)
• Flat or pouch (soft, flat body)
• Rigid plastic case (large threaded terminals) 
• AA
• AAA
• 9V (rectangular) 

Electronic devices that use Lithium batteries

Lithium batteries have a much lower specific power rating compared to NiMH batteries. But, this reduction in specific power results in higher specific energy which means they can provide current for longer periods of time.

This is ideal for devices that do not require high currents, but need to operate for longer periods of time.

Devices such as;

• Smartphones
• Smartwatches 
• Wireless keyboard/mouse
• Wireless speakers
• Wireless earphone/headphones
• Vaping devices 
• Electronic toys 

Can you replace NiMH batteries with Lithium?

Now that we have learnt about some of the crucial characteristics, as well as a little about each battery, we can delve into whether we can replace a NiMH with a Lithium battery.

All batteries have the same task, which is providing power to electrical and electronic devices. But, as we saw there a set of characteristics that ultimately determine the ideal application where a battery will be used.

NiMH have higher specific power, making them ideal for applications that require a large hit of current for short periods of time. 

Lithium batteries on the other hand have higher specific energy, which is perfect for devices that require less current, but need to last for longer. 

At the beginning of the article we saw that you might be able to replace a NiMH with a Lithium battery, however this is not the best idea. 

But why?

This comes down to the specific power and energy of each battery. 

Say you have a portable vacuum cleaner. The vacuum cleaner requires a high current to run the motor to suck dirt on the ground.

A NiMH battery is best suited for a vacuum cleaner as it can provide this high current. 

Now, if we replace this NiMH battery with a Lithium counterpart, the lithium battery is not going to be able to provide the sufficient current to run the motor of the vacuum cleaner.

But, there are many high current devices that use Lithium batteries. How is this possible?

These batteries are designed specifically for certain applications and are not your typical consumer batteries that can be bought off the shelf at your local electronic store. 

They are designed to have high specific energy and power. 

For example, electric cars require high current for the motors, and need to last a long time as well (otherwise you won’t be able to get very far).

What’s the best option if you need to replace the NiMH batteries?

If you need to replace a NiMH battery, your best option is replacing it with another NiMH battery of the same specification (voltage and current capacity).

This way the performance of the device it is being used in will not be affected.

The post Can you replace NiMH batteries with Lithium? appeared first on Electronic Guidebook.

Lithium Batteries are a type of rechargeable battery used in many portable electronics. 

When Lithium batteries lose their charge, they need to be ‘recharged’ using dedicated chargers. However, the sun provides us with free clean energy that can be used to power devices via Solar Panels.

Can you charge a Lithium battery with a solar panel?

Yes, you can charge a Lithium battery with a solar panel, but it is not recommended to connect a solar panel directly to a lithium battery as they can be damaged from overcharge. Also, lithium batteries require a special process of charging which will need to be followed if you are using a solar panel to charge it. 

This article will take a deeper look at Lithium batteries and what is required to charge them using a solar panel. 

Deeper look at a lithium battery and solar panels

To understand the question at hand, it will first help to take a closer look at the lithium battery and the process of charging them (I will keep it brief). 

Rather than going through unwanted information about the battery, I will cover its key characteristics 

Lithium Ion batteries  

While there are many different types of Lithium batteries, the most common of them is the Lithium Ion. So this article shall concentrate on this particular type to see if it is possible to charge it with a solar panel. 

Most (if not all) batteries are given their name because of the type of chemical composition they are made of. In this case, the battery uses lithium ions.

During the discharge cycle, the lithium ions move from the negative terminal (cathode), through an electrolyte to the positive terminal (anode).

Different types of Lithium Ion Batteries

Lithium Ion batteries come in a variety of shapes for different applications. 

• Small cylindrical (single cell with, solid body, with no terminals)
• Large cylindrical (single cell,solid body, with threaded terminals)
• Flat or pouch (soft, flat body)
• Rigid plastic case (large threaded terminals) 

Other key characteristics of Lithium Ion batteries are their Nominal voltage and Current Capacity.

Nominal Voltage: This is the normal voltage that the battery operates at. Some batteries might have a higher voltage at full charge, however, this value will soon drop down to its nominal voltage after a predetermined amount of time. 

All the packages above come with a nominal voltage of 3.7 volts. However, cells can be connected in series to generate larger voltages.

For example, three lithium-ion cells can be connected in series to give a voltage of 11.1 volts, or four cells can be connected to give a voltage of 14.8 and so on. 

Current capacity: Is the amount of current that the battery is capable of storing. It is usually given in Amp-hours (Ah) or Milliamp-Hours (mAh). 

Lithium-Ion batteries come in a range of current capacities ranging from as low as 40 mAh all the way to 2.6 Ah. 

To increase the current capacity further, batteries are connected in parallel. However, this is a bit more of a complicated process as the internal impedance of each battery needs to be matched. 

What is the process involved to charge a Lithium Battery

The Lithium-Ion is a special kind of battery compared to other batteries of different chemistries. This type of battery has strict requirements when it comes to charging it. 

The battery charger is a voltage limiting device with some differences to other chargers. 

The key differences include;

• Higher voltage per cell
• Tighter voltage tolerances
• Absence of trickle or float charging

Trickle charging is when a battery charger is able to charge a fully charged battery at a rate equal to its self-discharge rate, which allows the battery to maintain its full charge level. 

A lithium-ion battery charger does not offer trickle charging because the battery cannot accept overcharge. The battery can become unstable if charged above its nominal voltage which could result in permanent damage. 

Damage can result in the form of an explosion! 

The charger comes with strict settings that adhere to the restrictions that come with charging this type of battery which will include features such as an end-of-charge detection circuit  to monitor when the battery is fully charged. 

What is a solar panel?

Now, let’s take a closer look at the solar panel. 

Solar panels are increasing in popularity, and becoming the go to for providing a means of free, clean renewable energy to homes, business, and much more. 

They work in conjunction with the awesome powers provided by the sun, which is the biggest source of solar energy in our galaxy, the milky way. 

Solar panels are panels that convert light (solar energy) from the sun into electricity which can be used to power electrical and electronic equipment. 

They come in a variety of sizes and power outputs depending on the needs of the application it will be used for. 

Connecting a solar panel directly to a load

So, these awesome panels have the ability to provide power to electrical and electronic devices. But, is it possible to connect them directly to a load?

Connecting a solar panel directly to a load is not the most ideal option as there are a few drawbacks;

• The load will be unable to draw the maximum power at any given instant from the solar panel
• The solar panel could be overloaded due to the demands of the load
• It might be a cloudy day, and the sun might pop in and out which means you won’t have a steady stream of power (so they are weather dependant)

A better option would be to store the energy produced by the solar panel in a rechargeable battery where the load can then draw power from.

How do you charge a battery with a solar panel?

Solar panels are rarely used by themselves to charge a battery. They will be one of a few components used in what is known as a Solar Power System. 

The solar power system can then be used to power electrical and electronic loads. 

Components of a solar power system include;

• Solar Panel(s)
• Charge Controller 
• Rechargeable battery
• Inverter (AC applications) 

Let’s take a look at each component and what job it has in the overall system. 

Solar Panel – has the task of converting sunlight into electricity.

Charge Controller – the current produced by the solar panel is fed into the charge controller. The controller regulates the current produced by the solar panel to protect the batteries from overcharging. 

The controller can detect when the battery is fully charged and can stop, or limit the current (trickle charge) received by the battery. 

They also have the job of protecting the solar panel from reverse current (current being fed back into the solar panel from the batteries) when there is no sunlight. This can also lead to the battery losing unwanted charge. 

Rechargeable battery – rechargeable batteries are where the power generated by the solar panels is stored. They come in a variety of shapes, sizes, chemical compositions, voltages, and current capacities. 

Inverter – The current produced by a solar panel is normally a Direct Current (DC). However, solar panels are used in many settings where Alternating Current (AC) is required. An inverter has the capability of converting this DC current to an AC current. 

Can you charge a Lithium battery with a solar panel?

Yes, you can charge a lithium battery with a solar panel (this is assuming that the solar panel has the right output power requirements to charge the battery). 

However, there are some issues to consider before doing so. 

The first major one being overcharging. We learnt earlier that lithium batteries (especially the Lithium Ion variety) are easily damaged when they are charged above their nominal voltage. 

For this reason, lithium battery chargers do not have trickle charging. The charger is designed specifically to stop charging the battery when it has reached its ideal voltage. 

Connecting a solar panel directly to a lithium battery is not an ideal scenario, as the solar panel has no means of knowing when to stop providing power to the battery.

It will constantly be feeding energy to the battery (as long as there is sunlight) which will lead to overcharging and damage to the battery. 

Other issues include what we discussed earlier in the section about connecting a solar panel directly to a load which include;

• The lithium battery not being able to draw maximum power from the solar panel
• Solar panel being overloaded
• Charging the lithium battery is dependant on the weather (cloudy days are not ideal)

What is needed to charge a Lithium Battery with a solar panel?

While there are some issues when it comes to charging a lithium battery with a solar panel, all is not lost! There is a way to work around these issues.

So what is needed to charge a lithium battery with a solar panel? 

You will need the same components we saw earlier in the section ‘how to charge a battery with a solar panel’. In this instance we have a solar panel, and a rechargeable battery. So all that is required is a charge controller.

The charge controller will take care of the main issue of the lithium battery being overcharged. It will also provide a constant current to charge the battery, and protect the solar panel from any reverse current. 

However, a note has to be made. Since there are many different types of batteries, there will also be many different types of solar charge controllers to meet the individual needs of each type of battery.

So, you will need to buy a solar charge controller designed for lithium batteries so that it will stop charging the battery when the nominal voltage is reached. 

The post Can you charge a lithium battery with a solar panel?
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