How to select the best lithium battery charger?

More and more people are choosing to use portable lithium-ion batteries and using them for RVing, camping, fishing, etc. With this, there is a growing demand for lithium-ion chargers. So how to choose the right lithium-ion battery charger?

First understand what is a lithium-ion battery?

You want to buy a lithium ion battery charger, then you must know the most basic knowledge about lithium ion batteries. In the simplest terms, a lithium-ion battery charger can be called a device that limits the voltage. It is a device that helps to safely charge the battery. Essentially, the charger utilizes electrical energy and once the current is correct, it collects the voltage in the lithium battery for you to use later.

Thanks to advances in its chemistry, a lithium battery charger can operate at higher voltages than other battery chargers and has a longer life span.

I will give you more details about Li-ion battery chargers one by one.

Basic features of a Li-ion battery charger 

It usually features no trickle, high withstand voltage and floating charge when fully charged.

These charges are based on a constant voltage, which can also be referred to as a constant charge current algorithm.

How does a charger charge a lithium-ion battery?

Let's analyze the charging process of a lithium-ion battery. The charging process can be divided into four different stages: trickle charging, pre-charging, constant current charging and constant voltage charging. The graph below shows the charging curve for an Aolithium 12v100ah 4s lithium lifepo4 battery.

The charging curve of a typical lithium-ion battery.

What points should I pay attention to when choosing a lithium battery charger?

1.Battery chemistry

Chargers are designed according to the chemistry of the battery. To get the accurate charging voltage, you need to use a charger that matches it.

2.Charging Current

You need to pay attention to what is the maximum charging current the charger can deliver and it will stay at that level. As the battery approaches full charge, the charging current will slowly drop. The maximum charge current occurs mainly when charging a battery with a very low remaining charge. If your battery is too large, you don't want to buy a charger with a very low charging current. Batteries take a long time to fully charge. We recommend that the charging current should be kept at 0.5C or less.

3.Battery Management System

If your Li-ion battery has a BMS system, you need to pay attention to the BMS. it can provide you with overcharge protection and overcharge protection. If you have a more advanced BMS system, then things may be different.

4.Charging Voltage

The charging voltage should not exceed what the particular charge can handle. If you are using a 4.2V lithium battery, this means you need a lithium electronic battery charger with an output voltage of 4.2V x the number of cells in the battery (in series). Again, for example, the US version of the charger must be rated at 110Vac instead of 220Vac. Otherwise, the charger can be damaged or explode.


5.Ah ratings of batteries

Each battery has a specified ampere-hour rating. This relates to the battery's charge storage. This should be the same or higher than your battery. The ideal charge time for a battery is 1-2 hours. Please see below for an example calculation of charge time. Please note that this is not as accurate as it could be. The charge current is not always at its maximum. The charge current usually decreases as the battery approaches full charge.

6.Safety Features

The deciding factors to consider when purchasing a feature-rich charger are battery cost and safety. If you have a very expensive battery, consider purchasing a battery charger with features such as overvoltage, overcurrent protection and safety features. This may only be a supplement to the basic features.

7.Is it compatible

This is another important aspect to consider when choosing a battery charger. If it is compatible with the battery, then you need to consider the termination of the charger. You need to consider whether the charger is convenient enough. You need to consider if the charger input port is compatible with your wall outlet, etc. You need to consider whether the battery will fit into the charger slot, etc.

8.Cost

Li-ion Charger Type

1.Aluminum case chargers

They are of better quality compared to plastic. They can withstand high power levels. They have a cooling fan that can even be adjusted most of the time.

2.Plastic chargers

Their main advantage is that they are easily accessible and inexpensive, which means they do not add to your wallet's burden. The disadvantages indicate their low power. They don't carry a fan with them. In any case, they provide a good backup charger.

3.Balance Chargers

They are mainly used in cars and drones (RC world). They do not have a BMS installed, which clearly tells you that there is no protection.

4.Slow chargers

These chargers do not have a full charge detection. It takes about 14 to 16 hours to fully charge an empty battery. After the battery is fully charged, they keep the battery from getting cold or hot (you can touch it). It is not recommended to use a slow charger to charge a high-capacity battery.

5.Ultra-Fast Chargers

Ultra-fast chargers are becoming a more important requirement for electric vehicles. Li-ion battery chargers also use this variation. If the battery is stressed, the charge should also be cut in half.

How to use a Li-ion battery charger to increase the life of the battery?

Lithium batteries do not need to go into float mode, so they do not need to be monitored so closely. You can connect a LiPo battery without worrying about it overheating or overcharging. In fact, most LiPo batteries can remain unconnected and continue to charge for six to twelve months, which makes them more attractive for solar installations.

Since LiFePO4 batteries provide the longest life between 50% and 80% of charge, it is best to avoid creating settings that allow them to go into float mode, as this may shorten the life of the lithium battery.

  • Use the LiFePO4 battery charger when the battery charge drops 10%: the more, the deeper the discharge, the more degradation.
  • Keep the battery range in the middle. Extreme or lower degrees can affect the battery.
  • The lowest level, such as close to 0% or the highest level, such as close to 100%, will reduce the battery capacity.

Finally, you should know how to go about choosing the right lithium-ion charger. And have a good understanding of how to care for lithium-ion batteries.


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