If you have the Fly More Kit, it (may) have come with the little clip-on accessory that turns it into a USB powerbank. You could use it to juice up your phone or other items.A bit of planning.
You can start up with each battery and set for 1 day discharge for example a day or two before leaving town . . . of course this only takes level down to ~ half, but I’ve never been asked what the levels are in mine (4) when travelling.
Another way, many people drain batteries is to have made a little battery draining tool like a light, numerous posts on the forum about that.