How to Charge a Lithium Polymer (LiPo) Battery
A LiPo charger is circuit board which provides a stable charging current to a battery which shuts off once it's fully charged and often has LED indicators for power and charge status. There many types of chargers designed for Lithium batteries but there are two main types. There are chargers which will only charge the battery and require it to be removed from its current system and connected to the charger. The other type of charger allows the battery to be charged while also still providing power to your project.
Knowing The Battery
Before choosing your charger it's important to know what charging current your battery requires. For most batteries the charging rate should not exceed 1C which can be calculated as 1 x Battery Capacity.
Charging Rate = 1 x C (Battery Capacity)
So for a 800mAh battery the charge current should not exceed 800mA. You'll need to remember this value as different chargers have different standard charge rates, most can be changed but additional parts and soldering is often required to do that.
These chargers are very simple and easy to use/setup. There is usually a 2-pin JST connector for connecting the battery and a USB connector to provide power to the charger. Most models will also have a LED indicators for power and charge status. We stock a number of different versions which use different USB connections, USB-C, Mini-USB and Micro-USB.
Passthrough chargers allow you to charge the connected battery while still providing power to your system. These boards will switch from battery power to the the USB input when it is connected. They usually also have a USB-A output and/or 5V/3V pins for connecting to your project. Like the standalone chargers these boards usually also have LED indicators for power, charge status and battery level.
There are a number of different options when it comes to passthrough chargers. Some are designed for specific uses such as the Sunny Buddy or the Solar Lithium/Ion Charger which are meant for use with solar pannels. Others are more standard and have a USB or powered output pins and boost the voltage up to 5V like the PowerBoost range of boards.