# I Want To "Reduce" Voltage/Current... **URL:** \ **Category:** NYSpeed Automotive\ **Created:** [May 5, 2008, 7:38pm UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954 "2008-05-05T19:38:23Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![1BADGPGT](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/1badgpgt/32/5123_2.png) [@1BADGPGT](https://forums.speedlife.net/u/1BADGPGT)\ **Post date:** [May 5, 2008, 7:38pm UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/1 "2008-05-05T19:38:23Z")
I have a 12V DC motor that I would like to reduce the voltage to. Instead of getting the 12V or 13.7V (when car is running) I want to be able to reduce it to 5-6V. Maybe even make it so I can adjust it with a knob. I’ve thought of using resistors but, the motor pulls too much current and would beat them resisitors up FAST. Lemmie know what you guys think. Thanks. ---
**Author:** ![AShort](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/ashort/32/4947_2.png) [@AShort](https://forums.speedlife.net/u/AShort)\ **Post date:** [May 5, 2008, 7:43pm UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/2 "2008-05-05T19:43:41Z")
make a potentiometer and set it to the current you want? ---
**Author:** ![Fry](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/fry/32/7284_2.png) [@Fry](https://forums.speedlife.net/u/Fry)\ **Post date:** [May 5, 2008, 8:14pm UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/3 "2008-05-05T20:14:07Z")
Need more info. Yes a pot could work, but it will have to be big enough. ---
**Author:** ![Violator](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/violator/32/7278_2.png) [@Violator](https://forums.speedlife.net/u/Violator)\ **Post date:** [May 5, 2008, 8:40pm UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/4 "2008-05-05T20:40:32Z")
find a rheostat. Older model trains used larger ones. What type of current does it pull. What is the load (what are you using it on) Based on that I can give you options ---
**Author:** ![reliant\_turbo](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/reliant_turbo/32/7189_2.png) [@reliant\_turbo](https://forums.speedlife.net/u/reliant_turbo)\ **Post date:** [May 5, 2008, 8:51pm UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/5 "2008-05-05T20:51:41Z")
PWM (pulse width modulated) instead. doesnt reduce the torque but reduces the speed. search for PWM circuit and some sample designs should pop up. whats this for and approx what current. Brian ---
**Author:** ![Cavi\_Mike](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/cavi_mike/32/5217_2.png) [@Cavi\_Mike](https://forums.speedlife.net/u/Cavi_Mike)\ **Post date:** [May 5, 2008, 9:39pm UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/6 "2008-05-05T21:39:36Z")
> [@Fry](#): > > Need more info. +1 ---
**Author:** ![1BADGPGT](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/1badgpgt/32/5123_2.png) [@1BADGPGT](https://forums.speedlife.net/u/1BADGPGT)\ **Post date:** [May 6, 2008, 3:05am UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/7 "2008-05-06T03:05:13Z")
Voltage = 12.4V car not running/13.7V Car is running. Current = 3-5A~? Im not 100% But, it says in the instructions to use a 6amp fuse. I guess I could check that today. Its for the electric water pump for my IC on my car. I bought a pump that flows too fast :oops: My options are to either buy a lower flow motor, or to make an adjustable voltage regulator. I think building the the regulator would be more fun. I have my prototype breadboard sitting here and trying different circuits using transistors, voltage reg, a 10k pot. But, need to figure out a circuit for higher current. THe reason I’d like it adjustable is, I plan on running a big resv. and might end up needing that extra flow. Thanks Guys ---
**Author:** ![97FormulaWS-6](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/97formulaws-6/32/7384_2.png) [@97FormulaWS-6](https://forums.speedlife.net/u/97FormulaWS-6)\ **Post date:** [May 6, 2008, 4:38am UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/8 "2008-05-06T04:38:18Z")
Just need the primary transistor (3906??) to be able to handle the current (Make sure to put a heatsink on it!!!) otherwise it’s the same circuits as the low-power motor speed controllers. ---
**Author:** ![97FormulaWS-6](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/97formulaws-6/32/7384_2.png) [@97FormulaWS-6](https://forums.speedlife.net/u/97FormulaWS-6)\ **Post date:** [May 6, 2008, 4:39am UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/9 "2008-05-06T04:39:32Z")
[http://solorb.com/elect/pwm/pwm1/](http://solorb.com/elect/pwm/pwm1/) even have the transistor for 10A in there; should be more than enough… simple google search; “PWM Motor”; first page that popped up. ---
**Author:** ![Harvey](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/harvey/32/5069_2.png) [@Harvey](https://forums.speedlife.net/u/Harvey)\ **Post date:** [May 6, 2008, 5:09am UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/10 "2008-05-06T05:09:18Z")
What type of pump is it? It’d probably be allot easier to put a bypass valve, or restriction valve (depending on the pump style). You could also just buy an electronic one [http://www.electronickits.com/kit/complete/motor/ck1400.htm](http://www.electronickits.com/kit/complete/motor/ck1400.htm) If you really want to make your own, here is an article that explains how to do it pretty well [http://homepages.which.net/~paul.hills/SpeedControl/SpeedControllersBody.html](http://homepages.which.net/~paul.hills/SpeedControl/SpeedControllersBody.html) ---
**Author:** ![Cavi\_Mike](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/cavi_mike/32/5217_2.png) [@Cavi\_Mike](https://forums.speedlife.net/u/Cavi_Mike)\ **Post date:** [May 6, 2008, 1:37pm UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/11 "2008-05-06T13:37:43Z")
The slower the pump goes, the less the water/methanol etc. will atomize when it comes out of the nozzle. It will probably make things worse. What you need to do is get nozzles with a finer spray pattern. Also, did you get a high-flow pump or a high-pressure pump? You need a high-pressure for this application otherwise a finer spray nozzle will still dribble. ---
**Author:** ![Violator](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/violator/32/7278_2.png) [@Violator](https://forums.speedlife.net/u/Violator)\ **Post date:** [May 6, 2008, 1:45pm UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/12 "2008-05-06T13:45:14Z")
I agree with Brians suggestion. A PWM circuit is the cleanest, and most efficient way to accomplish what you want. Spec it for 50% over running current. Maybe 7amps? Check tho. ---
**Author:** ![Harvey](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/harvey/32/5069_2.png) [@Harvey](https://forums.speedlife.net/u/Harvey)\ **Post date:** [May 7, 2008, 5:05am UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/13 "2008-05-07T05:05:28Z")
> [@Cavi Mike](#): > > The slower the pump goes, the less the water/methanol etc. will atomize when it comes out of the nozzle. It will probably make things worse. What you need to do is get nozzles with a finer spray pattern. Also, did you get a high-flow pump or a high-pressure pump? You need a high-pressure for this application otherwise a finer spray nozzle will still dribble. I think he is running a closed loop water filled intercooler. He’s pumping as does a radiator, not a sprayer. ---
**Author:** ![neonglh](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/neonglh/32/4951_2.png) [@neonglh](https://forums.speedlife.net/u/neonglh)\ **Post date:** [May 7, 2008, 5:40am UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/14 "2008-05-07T05:40:51Z")
> [@eesti](#): > > I think he is running a closed loop water filled intercooler. He’s pumping as does a radiator, not a sprayer. +1. Its just moving fluid in a circle. ---
**Author:** ![1BADGPGT](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/1badgpgt/32/5123_2.png) [@1BADGPGT](https://forums.speedlife.net/u/1BADGPGT)\ **Post date:** [May 9, 2008, 9:15pm UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/15 "2008-05-09T21:15:21Z")
Yup, no spray just water pumping. Since I’ve only ran water through the pump, I might try to be chummy with the people at the place I got the pump, see if they’d let me trplace it with a lower flow. If I had a few more bucks, I’d one of the many OEM pumps for…Cobalt SS, 'stang GT’s, Sy/Ty, ect ---
**Author:** ![Cavi\_Mike](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/cavi_mike/32/5217_2.png) [@Cavi\_Mike](https://forums.speedlife.net/u/Cavi_Mike)\ **Post date:** [May 9, 2008, 9:18pm UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/16 "2008-05-09T21:18:07Z")
Ahh, makes sense. I was just remembering my hard time when I sprayed my intercooler. ---
**Author:** ![1BADGPGT](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/1badgpgt/32/5123_2.png) [@1BADGPGT](https://forums.speedlife.net/u/1BADGPGT)\ **Post date:** [May 10, 2008, 10:51am UTC](https://forums.speedlife.net/t/i-want-to-reduce-voltage-current/47954/17 "2008-05-10T10:51:09Z")
Thanks BTW for the replys and links. 😉