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Question about connecting to 12 Volt Battery — Parallax Forums

Question about connecting to 12 Volt Battery

kenwtnkenwtn Posts: 250
edited 2012-05-03 10:58 in BASIC Stamp
Hi All,

I m wanting to build a Mars Rover type robot. I have a small motor cycle battery 12 volts that I want to use for a couple of reasons, 1 for powering everything and the other is give the robot some weight for traction. I also have a 12 volt solar panel I plan on using to keep the battery charged. Anyways to get to my question, what pre-cauntions should I use? I have several Basic Stamps on Homework and other boards and although these boards have 5 volt regulators on them I m a bit worried about connecting to a battery that can put out so many amps.

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2012-05-03 10:27
    The issue isn't the ability of the battery to supply lots of Amps, but the voltage available. 12V lead-acid batteries actually put out roughly 13.8 Volts when they're fully charged. A 5V regulator turns the "excess" voltage into heat. In your case, you might have 13.8V - 5V = 8.8V. Even if the current draw through the regulator is only 250mA, that's 2.2 Watts of heat that the regulator needs to get rid of, particularly without a formal heatsink ... just the board itself and a little area of copper to conduct the heat away. What you should plan to use is some kind of switching pre-regulator like this one, set to maybe 6V output voltage.
  • kenwtnkenwtn Posts: 250
    edited 2012-05-03 10:58
    Mike thank you for that imformation.
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