Quote:
Originally posted by Jim Meyer
Everyone seems to be concerned with water being a safety issue with our robots. We only have 12 volt batteries.
In an episode of Junkyard Wars, teams had to build machines to pull divers around under water. One team used an electric motor and a 12 volt car battery to power their machine. The team said that 12 volts really isn't dangerous when submerged under water. They proved this when everything worked and they won. (I think)
I don't understand the details but I do know that in most cases 12 Volts and water mix just fine. This is why you can touch both terminals on a battery and not be shocked.
Can someone more knowledgable on this shed some light on the subject?
I still don't think they will have water, but I think for reasons other than safety.
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I can't give the most detailed response but here goes anyway. Water is actually much more of a insulator than it is a conductor. The danger of water comes from the fact that it's a liquid and has a large surface area. Given that we use a relatively low voltage equipment (12V), the amperage over a distance of water is very low. To give an idea, I found information that stated there was approximately 2 Megaohms of resistance across a coffee cup of distilled water (only numbers on resistance of water I could find). Given Ohm's law (V=IR rearranged to I=V/R) we'd get .000006 amps or .006 milliamps. That shouldn't be a high enough current to trigger a damaging short.
I would, however, be much more concerned with the control system. Digital electronics are a bit more sensitive to short circuits than regular electronics are. They also aren't designed to handle the type of surges that can be caused by a short.
I hope I've gotten the physics right here. Someone please correct me if I'm wrong.
Matt