I recently purchased a 510/510 volt meter from a well known vendor. I tried it on ego/riva 650/900/1100 mAh & a usb 5v pass through. The lights just flash and don't display a voltage. I asked the vendor and their reply was that it won't work on ego or passthrough. I haven't found a disclaimer on that yet. Doesn't sound right to me. Anyone else experience this?