I am trying to help my dad with a project of his where were trying to build a lighthouse powered by solar panel in which it spins a motor at night and charges battery during the day. This is a DC application. We have the front end, being charging the battery all figured out. However, the backend, being controlling motor and having motor only turn at night, is the hard part. We have a controller for controlling the speed of the motor working with no issues. It is the last part that we need help with, which is the photocell sensor light switch. We figured that we need to place the photocell between the battery and the speed controller. The photo sensor switch says it works for AC and DC application and says AC/DC on the device we received. The directions that came with it state this for working with DC application, "black line connect to input power (-) negative. White line connect to input power (+) positive and load device (+) positive. Red line connect to load device (-) negative." So I believe line is meaning wire and load device will be the speed controller with power being my battery. I have tried it using the directions and doesn't work. I looked on comments on the amazon page where we brought the products (got 2 of them) and the comment said that black wire is hot wire with red wire goes to load and then white wire is ground. That didn't work either. I have waited at least a minute with light shining directly at the sensor and it doesn't turn off the motor to simulate day. Here is a link to my diagram with both directions based and amazon comment based that I tried: https://i.sstatic.net/abZwW.jpg

Here is a link to the sensor on amazon: https://www.amazon.com/gp/product/B01M1O3C1V/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Here is a link to the speed controller on amazon: https://www.amazon.com/gp/product/B00F839VNQ/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

here is a link to the motor: https://www.amazon.com/gp/product/B07FKKWSFJ/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1

The battery is a car battery rated for 12 volts and 23 amp max. The speed controller is rated for 6v-90v at a max of 15 amp. The sensor is rated for 12 volts at 10 amp max. We need the speed controller to slow the speed of the motor as it is way to fast for those of you wondering. The motor is rated for 12 volts at 150 watts max. I do not know if I have fried the sensor or not, but I do not think so because I do not smell any smoke or anything and it is NOT black to indicate frying it. I do have the second one I can use, but I prefer not to use it until I know for sure what I did wrong in case my current one is damaged, if it is.

So my question is what is wrong with my diagram or why isn't it working? Thanks in advance.

  • \$\begingroup\$ The solar panel produces power when there is sunshine, so use that to hold a relay open and once the panel is not producing much it will then allow the motor to work. Seem to have read / answered this before, so check around for it. \$\endgroup\$
    – Solar Mike
    Commented May 24, 2020 at 6:14
  • \$\begingroup\$ Does this answer your question? How to Wire DC Motor to Solar Panel and Battery to Only turn on at Night? \$\endgroup\$
    – Solar Mike
    Commented May 24, 2020 at 6:15
  • \$\begingroup\$ That is my own post. XD. That did not work but I solved that problem with my controller as you see above amazon link for that. It actually works very well. However, that link above tries to solve the problem of controlling the motor, not activating it only at night issue that I have now. So no that does not solve my issue Solar Mike. \$\endgroup\$
    – Sean.D
    Commented May 24, 2020 at 13:40

1 Answer 1


Your diagram is wrong.
Based on the labels on the photo-switch in this image.

  • Connect battery negative, controller P- and photoswitch white wire together

  • Connect Battery positive to photoswitch black wire

  • Connect photoswitch red wire to controller P+

If that does not work the photoswitch may be dead.

enter image description here

  • \$\begingroup\$ What is "+ve" mean? Otherwise I understand what your saying. \$\endgroup\$
    – Sean.D
    Commented May 24, 2020 at 13:42
  • \$\begingroup\$ I created the Diagram that I think you mean here: imgur.com/a/fVljxl6 Is this what you meant? I just want to make sure before wiring it. \$\endgroup\$
    – Sean.D
    Commented May 24, 2020 at 14:28
  • \$\begingroup\$ I went ahead and took a chance and thank you Russel as your suggestion worked! Turns on only when I cover up the sensor and turns off when there is light to the sensor, exactly what we want. I understand what I did wrong as my previous wiring diagram was essentially bypassing the sensor, not what we wanted. Thank you again. \$\endgroup\$
    – Sean.D
    Commented May 25, 2020 at 0:18
  • 1
    \$\begingroup\$ Battery +ve = Battery + = Battery positive. Yes. DFiagram is correct. \$\endgroup\$
    – Russell McMahon
    Commented May 25, 2020 at 2:44
  • 1
    \$\begingroup\$ Understood. Well anyways, your suggestion worked. Thanks again. I gave you the green checkmark and an upvote. \$\endgroup\$
    – Sean.D
    Commented May 25, 2020 at 2:50

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