Here you could see three important parts about the Li-ion battery charger:
- What is a Li-ion battery charger for an electric bike or electric scooter?
- How to choose the lithium battery charger for your electric bike or electric scooter?
- How does the Li-ion battery charger work?
1. What is a Li-ion battery charger for an electric bike or electric scooter？
Given most electric bikes or electric scooters are powered by Li-ion battery, here are talking about the Li-ion battery charger only.
A Li-ion battery charger is a device that connects the lithium battery to the general power source, helps to transform the energy in the lithium battery cells by forcing the electric current through it. Generally, the charger is composed of a housing, input and output plug, rectifier circuit, power conversion circuit, charging monitoring circuit, charging protection circuit, etc.
2. How to choose the Li-ion battery charger for your electric bike or electric scooter?
Mostly, the lithium battery charger comes together with the battery when you ordering a battery.
But sometimes you need a new or extra charger, the following factors could be considered to choose the right charger which will make your battery function as safely and efficiently as possible.
(1) Charger input
Sincere home electricity varies from country to country, such as 120V in the USA, 220V in China, EU, GB, etc. So when you pick up a lithium battery charger, you should ensure its input voltage is supported by your home electricity.
(2) Charger output
First, let’s see about the output voltage, it should be compatible with your battery.
For a 10s Li-ion battery (with 10 cells in series, we call it a 36V battery generally), the charger output should be 4.2*10= 42.0 V.
For a 13s Li-ion battery, the charger output should be 4.2*13= 54.6 V.
For a 14s Li-ion battery, the charger output should be 4.2*14= 58.8 V charger.
For a 20s Li-ion battery, the charger output should be 4.2*20= 84 V charger.
And so on.
A basic charger usually charges at around 2 amps. But it takes too much time with a 2amps charger especially for the larger lithium battery such as 30Ah or bigger. So there is a wide range of chargers with different charge rates on the market now- from 2 to 20 amps or higher. The higher the charger output current, the faster to get the battery full. But the higher current may harm your battery or even make a burning. So what output current of the charger could be chosen?
Generally, we suggest that the charger with an output current of 0.5C-1C.
The “C” rate is the rate of charge (or discharge) as compared to the capacity of the battery.
C-Rate © = Charge or Discharge Current (A) / Rated Capacity of Battery
For a 10 Ah battery pack, 0.5 C would be 5 A, 1C would be 10A.
if you use 3.5 Ah cells, and you have 4 in parallel (3.5Ah*4= 14Ah), the output current of the charger has better to be less more than 7 A. Even 7 A is a pretty high charging rate for lithium batteries. The lower current you charge at, the happier your batteries will be and the longer they will last.
Most common Li-ion battery chargers for electric bicycles or scooters are found in the 2 A to 5 A range. These are all reasonable current levels for most batteries. But if you have a very small battery, such as a 5 Ah battery pack, a 5 A charger would be 1 C, which would be the limit of most cells. So always remember to keep that in mind when choosing your charging current.
(3) Plug and charging connector