basic schematic for a 12v gradual power up for small dc water pump

Thread Starter

Fstarocka Burns

Joined Aug 11, 2017
hi everyone - new here so howdy!

I have very small electronic knowledge so please forgive me. I have soldered many years and know what current is -

I have a small transfer pump we hook up to a car battery. alot like this unit but without the power button -

Ours just whirs full speed instantly! It just goes on, it pumps ALOT though, only issue is it eats thru impellers! at $15 a pop I know what the issue is, the immediate spin up of the motor (its VERY powerful) is too much for the little soft rubber impeller and it keeps shearing the center piece loose making it just spin and not pump. One poor chap on amazon was on his 5th impeller already!

Anyway - I was wondering if there was a little schematic I could wire up that would make it power up over say 3 seconds - almost like stepping gradually on a sewing machine pedal -

I dont know what these things draw amp wise but i think 14a is about the usual number for these - and could I wire it up in series to the positive lead?
Last edited:

Thread Starter

Fstarocka Burns

Joined Aug 11, 2017
after some searching I found this and ordered it -


That way I can turn the moor up slowly by hand to full power (which is where I would want it all the time) - and its water proof which means less chance of a spark as i use it for gas now and then -


Joined Nov 4, 2013
My concern would be that if something is so poorly made it can't handle the torque of stating up at full power it probably cant handle the associated torque of doing what it supposed to either.


Joined Jul 18, 2013
Does it sheer the vane or the impeller itself?
You could buy one of the PWM controllers that are all over ebay and bring it it slowly manually.