The Zoom H6 digital audio recorder is powered from the accessory USB port on the battery, shown above.
It’s a good idea to not allow these batteries to be uncharged for long periods because of their self-discharge property; I mark them each time they’re charged, and aim at less than 6 months before recharging.
And double check to ensure that the terminals of the P-tap connector are properly aligned to the corresponding terminals of the battery plate- if not, there’s risk of short-circuiting the cable (I’ve done it – ONCE).