My bird's just come back from repair with two motors, an ESC, the shell and the GPS replaced. I charged both my batteries last night looking forward to a flight today but she won't initialise. Both batteries show 4 LED's on test but I'm wondering if the juice is flowing into the bird? I haven't used the batteries for about four months but they charged normally and both show a full charge. I've a standard digital voltmeter and have inserted the probes into the battery's sockets but get no volts showing before or after I press the battery switch. Do the two small (communication?) terminals have to be involved in this sort of test? Do I short them or put some sort of load across them in order to get volts out of the main sockets? What's the procedure for testing a battery with a standard digital voltmeter please?