Electronic – Powering a small DC motor off of 18650s

dcmotorrelay

I'm trying to power a 12v 5rpm DC motor using a 2ch relay board and some 18650s. I am also using a MT3608 boost converter and a TP4056 to make the whole thing rechargeable. I'm having trouble that when the direction of the motor is changed too quickly it causes the whole circuit to shutdown until I reconnect power. I believe it is something being triggered on the charging board, because when that is removed there is no issues. My questions is there a way I can circumvent this problem. I would imagine there is a much more efficient way to do this (and if there is please let me know), but this was just a small project I was working on with stuff I had laying around. Any help would be greatly appreciated!

Best Answer

i belive that you are using something like this diagram in your wiring , reverse motor

since you`re using 2 channel relays ,you have 4 states for the relays,

1- ch1 on ch 2 on => this will connect both terminals of motor to the dc which will result in hard breaking,

2- ch1 on ch2 off => this will run the motor clockwise/clock side based on your connection

3- ch1 is off ch2 is on => this will reverse the motor direction,

4- ch1 is off ch2 is off => this will turn off motor but it will not break, its like Neutral [N] gear in the car,

  • to move from state 2 to state 3 you should go through either state 1 or 4 , as flipping the status of relays is not instant, a voltage (Ve) will be genetrated in motor also due to mechanical movement, this will be addup voltage to the source (Vs) and so on it will be Vs+Ve and a spike will activate the protection in the MT3608 converter.
  • if your replaced the relays with a transistors (4 of them, 2 n type,2 p-type) you should make sure to let time gap between on and of state for each side so that the transistor leaking current get dumped, else as @transistor said , it will short the system,
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