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Odd power issue — Parallax Forums

Odd power issue

alphanerd132alphanerd132 Posts: 9
in Robotics
I am having an extreme issue with power for the BOE bot. I have taken the board and put it in a old RC car body. I am using relays to control the motors for the wheels and for the turning. Each relay is only drawing 0.02 of an amp. We are also running a bit of wire for the front IR object/wall detectors. So when we add it all up, we have at most 3 relays running at once witch would be 0.06 amp. My issue is though, when I run those, the board drops down to around 3 volts, indicating that my power supply is not giving enough amps for what ever I'm running. Again, the BOE board is said to provide 1 amp but yet me drawing .06 amp is too much for it. What could be my issue here? If it would help I could draw up a diagram for the board that I made for the relays but besides that it there is nothing else running on the board.

Comments

  • kwinnkwinn Posts: 8,697
    Not enough info for more than a guess. post a diagram or picture that shows how things are wired up.

    My guess would be that you are powering the board from the same batteries as the motors and they are pulling the voltage down when they are running.
  • alphanerd132alphanerd132 Posts: 9
    kwinn wrote: »
    Not enough info for more than a guess. post a diagram or picture that shows how things are wired up.

    My guess would be that you are powering the board from the same batteries as the motors and they are pulling the voltage down when they are running.

    Okay ill make a diagram. You are half right. We originally had that issue and the amount that the batteries was taking was so much that it could not even trigger the relays. So we now have 1 pack for the board and 1 for the motors. Both running 6V from 4 AAs
  • Hal AlbachHal Albach Posts: 747
    The regulator on my BOE-BOT board is a National Semiconductor LM2940-5 and according to the data sheet input voltage is to be greater than 6.25 Volts and less than 26 Volts. It appears you may be operating very close to the regulator dropout point. You might try adding a 5th AA battery for the board.
  • ercoerco Posts: 20,255
    I was about to rant here about alkaline batteries but instead I started a thread here.

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