The world is filled with many different types of batteries that help power electrical and electronic devices such as smartphones, power tools, bluetooth speakers, wireless keyboards, and so much more.
However, there isn’t one specific type of battery that is used for all devices. They come in all sorts of shapes, sizes, voltages, current capacities, and chemical compositions.
Chemical composition is one of the major characteristics that separate batteries, and make one more suitable for an application compared to its peers.
One of the most common chemical compositions in batteries nowadays is Lithium.
But, when it comes to charging Lithium batteries, the process is a bit more complex.
So, can you charge a Lithium battery with a normal charger? No, you cannot charge a Lithium battery with a normal charger. This is because normal chargers have something known as trickle charging. However, you cannot trickle charge Lithium batteries. Once a Lithium battery reaches its nominal voltage, charging needs to be stopped.
While batteries have the same goal (which is to power electrical and electronic devices), how they go about doing so can vary from one battery type to the next.
Also, there are different charging processes depending on the different chemical compositions.
To better understand if we can charge a Lithium battery with a normal charger, it will help to learn a bit more about Lithium batteries and chargers separately.
Deeper look at a lithium battery
Within the world of Lithium batteries, there exist many variations, with the most common of them being the Lithium- Ion variety. So this article shall concentrate on this particular type to see if it is possible to charge it with a normal charger.
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 which include;
- 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)
How do normal chargers charge a battery
Batteries can be classed into two major categories; Primary and Secondary.
Primary batteries are one off and cannot be used once they run out of charge. Whereas, secondary batteries are rechargeable. This means once they lose charge they can be recharged multiple times with the help of a battery charger.
Lithium batteries need a special charger (as we will see later), however most of the other batteries use standard chargers which have a similar structure and working principle.
Charging a battery involves reversing the chemical reactions that take place when the battery is ‘discharging’.
The most basic chargers do this by supplying either a constant voltage or constant current. However, older chargers required you to manually turn them off to stop charging.
The issue with this is that if you forget to stop the charging, the batteries will overcharge. Or, if you stop charging too early they will not be fully charged (undercharged)
When it comes to both the scenarios mentioned above, overcharging is worse than undercharging. This is because when the batteries are fully charged, they have no means of accepting more energy.
However, that extra energy needs to go somewhere. This extra energy is released in the form of heat that builds pressure within the battery, which can lead to the battery rupturing (sometimes in an explosive manner).
A new technique has been developed which is now included in newer chargers to combat this issue. This technique is known as Trickle 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.
This ensures that you do not have to manually monitor the battery to see if it is at the right charge. Trickle charging will maintain the right voltage level.
What type of charger is needed for 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 key differences to other chargers.
The key differences include;
- Higher voltage per cell
- Tighter voltage tolerances
- Absence of trickle or float charging
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.
Can you charge a lithium battery with a normal charger?
As we have just learnt, Lithium batteries are quite unique compared to other batteries. The process involved in charging them is a bit more complicated.
Normal chargers have a feature known as trickle charging that enables them to keep feeding voltage (at a rate equal to the battery’s self-discharge) to maintain the desired voltage, even while the charger is still plugged in.
However, lithium batteries cannot accept charge once they have reached their optimal voltage.
Due to this, you cannot charge a lithium battery with a normal charger.
Lithium batteries have specially designed chargers which stop charging (thanks to an end-of-charge detection circuit), to protect the battery from overcharge.
How to charge a lithium battery with a normal charger?
While charging a lithium battery with a normal charger is not advised, it might be possible if a few criteria are met.
The first criteria is to ensure the ‘normal charger’ is supplying the same voltage as the lithium battery you are charging.
Not higher, and not lower.
Second is overcharging. We know now that overcharging a lithium battery is very bad so just connecting the battery to the charger and walking away is not a good idea.
So, to avoid this you could set a timer to remind you to remove the batteries so that they do not get overcharged.
But, be aware that even doing this poses some risks as each lithium battery itself will have different charging times depending on factors such as manufacturer, temperature, load, etc.
Can you charge a Lithium battery with a normal charger inside a device?
We have been primarily discussing charging loose lithium batteries (batteries that can be removed from an electronic device) with normal chargers.
However, nowadays most devices have their batteries inbuilt and do not need to be removed. For example, devices like smartphones, laptops, bluetooth speakers, and many more.
So, what about this scenario? Can you charge lithium batteries when they are part of a device?
Yes, you can charge a lithium battery with a normal charger when it is embedded in a device. This is because the device itself will include the necessary charging circuitry (end-of-charge detection) to ensure that the lithium battery does not get overcharged.
This is why it is possible when you go on a trip and forget your charger, you can borrow your friend’s and charge your phone without any issues.