Controlling DC motor with H-Bridge motor driver and a relay

Controlling DC motor with H-Bridge motor driver and a relay

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I am trying to build a smart car.

I have 4 DC motors with tires. They are yellow 3-6V hobby project motors. I have two L298 H-Bridge boards and 1 relay.

I connected two of motors to one H-Bridge and other two to the other H-Bridge. I want to control it with my Raspberry but the power sources should be different because of the motors’ current so I am using 12V battery for the motors. I also want to use one relay to control its power with the Raspberry to switch. My relay is FL-3FF-S-Z 5VDC single relay (10A-250VAC/30VDC, 12A-125VAC/28VDC.)

Can my relay support the current for 4 DC motors?

10A is written on my relay however I dont know if it can reach to 10A with my 12V battery.

When my motors are loaded, how can I calculate the maximum current if it is working with my relays threshold?


relaydc-motorraspberry-pih-bridgeShareEditFollowFlagedited 3 hours agoJRE44.6k88 gold badges7373 silver badges123123 bronze badgesasked 3 hours agohyorman111 bronze badge New contributor

  • That does rather depend on the motor, and all we know about that is. it’s yellow. – Brian Drummond 3 hours ago
  • Here is the motor datasheet. link – hyorman 3 hours ago
  • Added thanks a lot! – hyorman 3 hours ago
  • Add a simple diagram of how you intend to connect these components. Motors are what we call an inductive load, and for short periods of time can output voltage spikes, or experience surges (like on startup) of much more than their running current. – K H 33 mins ago
  • (1) Ah, me yellow duck knows my sister yellow toy motors take 100 ~ 300mA, So the 10A relay will LOL at us 4 little yellow motors. (2) Your model number “FL-3FF-S-Z 5VDC” is for the bare bone blue box like relay switch, not the relay module which is a PCB with the blue relay switch and other components. (3) Your L298N motor driver is good for newbies, (4) You might like to read some of my old answers for relays and motor drivers:
  • (a) L298N etc: electronics.stackexchange.com/questions/510755/… 
  • / to continue, … – tlfong01 8 mins ago    
  • / cont, …
  • (b) Relay modules etc: electronics.stackexchange.com/questions/505318/…,
  • (c) Relay direct PWM driving motors: electronics.stackexchange.com/questions/481578/….
  • Have a great locking down robot car project! 🙂 Cheers. – tlfong01 6 mins ago    

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