I have a Voltage Meter I would like to incorporate in my build however I would like it to be turned on by a separate switch. Also since its cheap it requires a 30V max power supply. I’ll be powering it with an ubec. Its just confusing because it has 3 wires which means it has to use a common ground and I don’t know which ground to give it. The specific voltage meter I’m talking about is here: http://www.ebay.com/itm/36-Red-LED-Panel-Meter-Digital-Voltmeter-DC-0-100V-Motor-Motorcycle-EA77-/331868974262 The spst switch is on the red wire. I made a diagram: Which choice should I do?
I think you put Red +Black on your (up to 30v power supply),… then put blue wire on the Pos side of skateboard’s battery pack
Both the battery ground and the bec ground go to black. bec positive goes to red which is 30v or less and then battery positive goes to blue. IMO
Also I have this one and its awesome. You can take the shroud off for a slimmer voltmeter. http://www.ebay.com/itm/282156101427?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
The way I describe how to wire it is the way it is listed in the info section of that Ebay listing.
Wiring: Red: power supply + Black: power supply -, measure - Blue: measure +
I read that too, but I also read somewhere that you shouldn’t mix different grounds.
who said that and what was there reasoning? This is a common ground, shouldnt hurt anything. I think not mixing grounds only applies if its a signal wire and ground Because you want a closed loop.