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Li-ion LifePo4 1S to 4S BMS Charger Tester with Arduino Uno

This is a BMS charger that would be as universal as possible for testing Li-ion or LifePo4 cells.

It can be strange to study a BMS in regard of the overall choice available on the market for quite a very low price.However, the objective of this project is to build a charging and testing device that can be universal, for a different among of cells to charge and for different technologies. The Arduino Uno based device, manage voltage readings, and according to results manages cells’ shunt or a buzzer. A SSD screen displays where we are. A buck DC-DC converter adjust the charging voltage for a constant charging current.

Whatever if you have the habit or if you are starting in the modern batteries world – e-bikes batteries repair, solar powered systems, etc.… - you can notice that it is not easy to manage Li-ion norLifePo4 cells:

· When you repair a battery pack, if it is easy to detect a dead cell, how do you detect a half-dead one?

· When you are building a new battery pack, BMS user manual requests that cells must be assembled once they are equilibrated. How do you perform such an assembling pack?

· With a usual BMS charger, you need a dedicated voltage value’s power supply. It is not so easy to fit with…

This device may help you J

· It can charge simultaneously from 1 to 4 cells

· Cells can be either Lithium-ion technology – for instance 18650 – orLifePo4 cells (you cannot mix)

· Monitoring of any cells voltage, plus overall voltage

· A internal protection against short circuit also limit for a constant current of about 1 A – hardware setup –

· Any power supply DC 17V to 25V@ 1.5A can fit this device. An internal buck DC-DC converter adapt the needed voltage value. A old DC 19V laptop power supply is perfect

· The balancing is performed by shunts between cells

· Under voltage alarm by buzzer

This project describes how to build such a BMS1S…4S charger / tester.”

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