My portable HF kit is coming together rather nicely. To go along with the KX3, I've got a 31' Jackite pole for antenna support. I have a 88' doublet fed with 300 Ohm twinlead and a 20m dipole fed with 450 Ohm window line. I tossed a short piece of RG-8x into the bag for use with my binding post-to-BNC adapter just in case I have issues with using the twinlead or window line.
I'm powering everything from a pair of 3200 MAh LifePO4 batteries connected in series to get 13V. The LifePO4 batteries are rather light for the power they provide and can take a charge rather quickly.
For several years I've been running the full KX-Line; KX3, PX3, and KXPA100. I carry the LNR EndFedz with a couple of different length elements to aid in ease of use along with a lightweight dipole. To complement the 33ft fiberglass pole, I picked up two 20ft fiberglass poles for the ends of the dipole. Everything is powered by a Bioenno 20Ah LifePO4 battery. I have a MPPT charge controller specific for the LifePO4 battery and solar panels.