Circuit Help

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • PedroDaGr8
    Senior Member
    • Oct 2006
    • 130

    #1

    Circuit Help

    I am unsure where to ask about this, I am looking to design a -12V circuit (or close to it, even -6V would work I guess). Unfortunately I know very little about circuit design. Chemistry I know boat loads, circuits soldering and simple stuff is about it. It needs to handle a decent number of amps. The reason is, I need to speed up the windshield wipers and I read a few places where instead of applying a ground, a -12V was appleid to the ground. Giving it a functional 24V drop. This resulted in a huge increase in speed of the wipers. Ideally, I will only turn it on using a switch, to be used in those extreme times of rain.

    Edit: since it is going to a motor, extreme tightness of voltage is not needed, as right now the motor sees the typical in car fluctuations from the alternator.

    Another option would be to convert 12V to 18V or so. I would try other wiper motors but I can't find any extra info and can't afford to just go willy nilly trying different ones out.
  • PedroDaGr8
    Senior Member
    • Oct 2006
    • 130

    #2
    Re: Circuit Help

    Aww man pls someone help. Or is this harder than I realize.

    Comment

    • Logistics
      Badcaps Veteran
      • Apr 2007
      • 721
      • USA

      #3
      Re: Circuit Help

      Doesn't that mean you need to install a negative 12V regulator into the system? There are positive and negative voltage regulators.
      Presonus Audiobox USB, Schiit Magni 3, Sony MDR-V700

      Comment

      • PedroDaGr8
        Senior Member
        • Oct 2006
        • 130

        #4
        Re: Circuit Help

        Originally posted by Logistics
        Doesn't that mean you need to install a negative 12V regulator into the system? There are positive and negative voltage regulators.
        I guess. I am not exactly sure how to go about this. I am just at a complete loss here.

        Comment

        • 999999999
          Badcaps Veteran
          • Sep 2006
          • 774
          • USA

          #5
          Re: Circuit Help

          A wiper motor is already running hard (hot) from 12V, you can't put 24V through it and expect it to last.

          The motor may not even have separate ground lead, it may be chassis ground meaning you'd need some robust (tolerant of seasonal elements, rain, vibration, torque, etc) isolation in order to take motor ground to some lower non-ground potential. However, it's pretty likely to be getting wet (which may conduct electricity) unless entirely sealed which is a project in itself since this motor drives a moving wiper arm.

          Since you have only 12V DC system, you would want a step up converter. I don't know the current such a motor uses but the converter would probably need be capable of at least a few amps. It also needs to use non-electrolytic caps due to the temp extremes possible. You could use something like a 2:3 ratio transformer rated for a few amps instead but this is lossy, larger, heavier, and probably costs more.

          Frankly I think this is a bad idea, in bad rain the last thing you want to be is a beta-tester for a windshield wiper circuit. If it were only you risking your car it would be one thing but it risks your life and that of others on othe road. If higher voltage were so easy, reliable, and useful, all cars would probably already have this. Having it work ok in a test before out on the road, is no assurance your wiper motor isn't burning out faster from it and would fail when you need it. j I suppose I'm saying even if you knew how to design this yourself, even then it's a big risk.

          Comment

          • gonzo0815
            Badcaps Legend
            • Feb 2006
            • 1600

            #6
            Re: Circuit Help

            A usual wiper motor is sucking about 150w @ rated voltage. So this would be a powerful step up converter.

            Aside from the problems 9999... pointed out, i think it will giving a very bad mix of switching noise problems in any susceptible circuit.
            Apart from that, building devices for automotive use, is not that easy.
            The environment is very very nasty, a half backed circuit would not last very long there.

            If the car is not new, i would suggest to check the ground cables carefully, as this would making a huge different in available voltage at some currents.
            If that is not the problem, i would suggest to get a faster, more powerful DC motor.
            Check some surplus part shops, they are not very expensive there.

            Comment

            • 999999999
              Badcaps Veteran
              • Sep 2006
              • 774
              • USA

              #7
              Re: Circuit Help

              I'm surprised if a wiper motor draws that much current, 150W is a heck of a lot of heat for this few-cubic-inch motor to dissipate. I was suspecting more along the lines of 3A if that.

              OK, I just did a brief Google Groups search and came upon one experimenter that found a Fiat wiper motor draws (@ 12V) 1.2A no-load and 11A stalled. Naturally this is no guarantee all wiper motors have same current, but I also came across brief notes that some cars had 6A or 10A fuses on the wiper motor circuit.

              Comment

              • hardwareguy
                Badcaps Veteran
                • Jun 2006
                • 405
                • USA

                #8
                Re: Circuit Help

                I wouldn't modify the amount of current entering the motor. Not only could the motor fail, but the wiper gearbox could lock up or strip out as well.

                Try some water beading products like RainX and a new set of high quality wiper blades.... it makes a world of difference.

                Comment

                • dood
                  Deputy dood
                  • Mar 2004
                  • 2462
                  • USA

                  #9
                  Re: Circuit Help

                  I use Rain-x washer fluid and high-quality blades. I rarely have to turn my wipers on high. Usually intermittant is good enough, because the water literally leaves the windshield before the wipers have a chance to swipe. The only thing I have to use wipers for is the road spray or small droplets that don't bead enough to roll off the windshield.
                  Ludicrous gibs!

                  Comment

                  Related Topics

                  Collapse

                  • Astonished
                    Fixing the Charge Circuit of the Batteries of the DC Motor
                    by Astonished
                    Hi friends of electronics

                    What you see in the video and pictures attached is the circuit for charging the batteries of a DC motor.

                    The problem is that this circuit cannot charge the batteries (3 1800mAH NiMH batteries) any more. When the circuit was OK, its green LEDs lit up one at a time to show that the batteries have charged more. But now that the circuit is flawed, LEDs light up as you see in the video and at the same time successive beeps are heard.

                    Please help me fix this circuit.

                    (the datasheet of the IC: https://pdf.datasheet.live/28...
                    01-28-2025, 06:24 AM
                  • Nevillet
                    Simple PIR sensor circuit to drive a small motor
                    by Nevillet
                    Hi All,

                    I'd like some help designing a simple circuit for driving a small DC motor.
                    The PIR module is a HC-SR501 which runs on 6V supply and outputs 2.4V when triggered. (Datasheet attached)

                    I'm not totally sure which motor I need yet but lets assume it'll be 12V and draw a maximum of 100mA.

                    Can somebody design me a simple circuit for me using something like a 2N3904?

                    I'm happy to include a relay if that makes sense.

                    Many thanks.


                    https://www.badcaps.net/forum/attachment.php?attachmentid=3...
                    07-09-2023, 10:48 AM
                  • Document Archive
                    Lenovo ThinkPad X1 Extreme Notebook X Specification for Upgrade or Repair
                    by Document Archive
                    This specification for the Lenovo ThinkPad X1 Extreme Notebook can be useful for upgrading or repairing a laptop that is not working. As a community we are working through our specifications to add valuable data like the X1 Extreme boardview and X1 Extreme schematic. Our users have donated over 1 million documents which are being added to the site. This page will be updated soon with additional information. Alternatively you can request additional help from our users directly on the relevant badcaps forum. Please note that we offer no warranties that any specification, datasheet, or download for...
                    09-07-2024, 06:31 AM
                  • Document Archive
                    Lenovo ThinkPad X1 Extreme Notebook X Specification for Upgrade or Repair
                    by Document Archive
                    This specification for the Lenovo ThinkPad X1 Extreme Notebook can be useful for upgrading or repairing a laptop that is not working. As a community we are working through our specifications to add valuable data like the X1 Extreme boardview and X1 Extreme schematic. Our users have donated over 1 million documents which are being added to the site. This page will be updated soon with additional information. Alternatively you can request additional help from our users directly on the relevant badcaps forum. Please note that we offer no warranties that any specification, datasheet, or download for...
                    09-07-2024, 05:00 AM
                  • Document Archive
                    Lenovo ThinkPad X1 Extreme Notebook X Specification for Upgrade or Repair
                    by Document Archive
                    This specification for the Lenovo ThinkPad X1 Extreme Notebook can be useful for upgrading or repairing a laptop that is not working. As a community we are working through our specifications to add valuable data like the X1 Extreme boardview and X1 Extreme schematic. Our users have donated over 1 million documents which are being added to the site. This page will be updated soon with additional information. Alternatively you can request additional help from our users directly on the relevant badcaps forum. Please note that we offer no warranties that any specification, datasheet, or download for...
                    09-07-2024, 05:00 AM
                  • Loading...
                  • No more items.
                  Working...