Connecting 12V DC Motor to Two 9V Batteries

AI Thread Summary
Connecting a 12V DC motor to two 9V batteries in series, resulting in 18V, is generally not recommended. The motor, rated for 3V to 12V and designed for applications like air blowers, could run excessively fast at 22,500 RPM, leading to potential overheating and damage. Power consumption increases significantly with RPM, risking the motor's integrity if the load isn't reduced. A better approach is to use a voltage regulator or PWM control to maintain the motor at 12V. Using a single 9V battery may be more suitable given the motor's specifications.
cyril joel
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Hello i am abeginer i have to connect a 12v dc motor can i connect it to two 9v batteries in series meabs a total output of 18V.
 
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cyril joel said:
Hello i am abeginer i have to connect a 12v dc motor can i connect it to two 9v batteries in series meabs a total output of 18V.
Welcome to the PF.

In general, the answer would be no. But in some cases it might be okay. Do you have the specification sheet for the 12V DC motor?

Also, you can buy modules to convert your 18V supply down to the 12V needed for the motor. What current is the motor rated for? What is the application? :smile:
 
berkeman said:
Welcome to the PF.

In general, the answer would be no. But in some cases it might be okay. Do you have the specification sheet for the 12V DC motor?

Also, you can buy modules to convert your 18V supply down to the 12V needed for the motor. What current is the motor rated for? What is the application? :smile:
The motor is rated 3v to 12 v 15000 RPM and medium size the application is an air blower
 
The motor would try to run 50% faster on 18V than 12V. So it might try and go 22,500rpm

The power absorbed by a propeller is proportional to rpm cubed (http://www.eaa62.org/technotes/prop.htm) so unless you reduce the size of the load (fan) you might be asking the motor to deliver more than three times it's rated power...

(22500)3/(15000)3 = 3.4
 
If it's an intermittent duty cycle, it might work, but any extended run it'll probably suffer from overheating... Depending on the control system you have for it, you could run a PWM (Pulse width modulation) at about 66%, and it would give you an average of 12V.

If you're thinking of the typical 9V battery in most multimeters and electronics, etc, I think battery life would be very short too.
 
cyril joel said:
i have to connect a 12v dc motor can i connect it to two 9v batteries in series

cyril joel said:
The motor is rated 3v to 12 v 15000 RPM and medium size the application is an air blower

So your really hooking up a 3-12v motor? Why not just use one 9v battery?
 

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