There are two types of NiMH batteries, ‘regular’ and Low Self Discharge (LSD). LSD NiMH batteries have 10-20% less capacity that the highest capacity standard NiMH cells but lose much less of their charge over time. I use LSD NiMH’s because the charger in the KX3 has to be enabled manually and doesn’t continually top up the batteries. For scenarios where I’d really care about the extra capacity, I use an external lithium iron battery pack anyway
The generally recognized ‘best’ LSD NiMH batteries are the Sanyo Eneloop XX batteries (the black ones, not the standard white Eneloops which have less capacity). They do come at a significant cost premium, however, for the 10-15% extra capacity they have over less expensive NiMH LSD cells.
If you do not use the 2 meter module you can do as I have and use the hole
in the case for the 2 meter antenna. I used star washers to bite into the
metal and have a 1/4" or so of a small machine screw sticking out. It does
a great job of grounding the rig.