Saturday, October 8, 2016

Standard Compact 2S LiPo Battery Charger Circuit

Electronic Kit School. - There are many electronic circuit that designed to result the best LiPo battery charger now. One circuit that can produce supply charger battery is shown look like in Figure 1 below. 

With the main or major component used are LM317 and TL431 IC, this circuit can be used to charge almost all standard 2S LiPo battery packs. The circuit, designed around generally available low-cost components, is very simple, safe, and economical.


Figure 1. Standard Compact 2S LiPo Battery Charger Circuit

Component Parts

  1. LM317 IC
  2. TL431 IC
  3. Capacitors
  4. Resistors
  5. Variable Resistors
  6. Diodes
  7. Transistor
  8. LEDs
  9. PNP Transistor

Circuit like in Figure 1 above show you about the Standard Compact 2S LiPo Battery Charger Circuit using LM317 IC and TL431 IC that give you one reference circuit to build by yourself of battery charger circuit that can be used to charge almost all standard 2S LiPo battery packs

From Electroschematics site that the typical target voltage of a 2S LiPo battery is usually 8.4 V (note that target voltage is not the same as the nominal voltage, which is 7.4 V typical), and LiPo batteries require a special type of charging mode that uses the CC/CV method (constant current/constant voltage) with 1-C charge grade (1 A for a 1,000-mAh battery). However, charging at a lower-than-1-C rate is perfectly safe and will not damage any battery type. The design is optimized for batteries of 1,000 mAh or higher, and the input power source can be any linear/switch-mode power supply capable of catering an output current of minimum 1,500 mA at 18 V. Normally, a LiPo battery connected to this circuit will be charged to 95% of its nominal voltage within 60 minutes and charged up to 100% of its target voltage within two hours thereafter.

Note: Although a balancer is required to maximize energy capability and lifetime of the LiPo battery, most chemistries have shown very little drift and are okay to charge without balancing for several cycles. I will try to publish an add-on LiPo balancer for my LiPo battery charger in the near future.


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