What D-Tap dummy battery I can use with the zv-e10?

[MPR-Nordic]

I want to use a d-tap dummy battery with my v-mount (delivers 14 or 8 v via d-tap). If a np-fw50 delivers 7.4v, do I need a dummy battery that can take 11-17v and step down to 8? Or do I need exact 7.4? Or I need to be looking at completely other figures?

Thanks, Mane