I was hooking up digital amp meter(0-30 amp DC/Shunt) Also a 0-200 volt digital meter. Both require 5 volt power supply.I have a 5 volt out-put regulator. So hooked up a 9 volt battery through a switch to 5 volt regulator, run shared positve wire and shared ground to both meters. So far so good, both lit up,switch activated both. Then installed 30 amp shunt in-line on positive side of incoming DC from Wind Turbine. Hooked amp meter, one lead to each end of shunt. Hooked Volt meter, positive wire to one end of shunt, negative wire to negative DC wire from turbine. I should back up a step I tried volt meter first, When hooked to battery string it showed 49.6 volts,so I knew that worked. I disconnected leads to battery bank, hooked amp meter leads to shunt, reconnected battery leads and poof! a spark, no amp meter and seconds later no volt meter! What happened? It was disconnected from Wind Turbine at the time so no incoming current, only current it could have read was from the batteries.So if I understand this right it should have showed no amps as no current was flowing. Do I need a diode to just read current going to batteries?..or does it matter?.. Lost again.. This is the wiring diagram I used http://www.lightobject.com/support/PMeter.htm Should the Amp gauge be on On negative side? Should both gauges be on separate 5 volt regulators?..Lots of questions