They don't come with Powerex (rather, LSD Imedion 2400's I believe?), but your use sounds heavy if you're draining them 4 times a day. I think you need to invest in the power adapter and get infinite power. I know it sounds like a sales pitch, but adjustable power from just about 0 vapor up to "combustion-in-5-seconds" high if you want/like a fast draw. It IS $60 so it's an investment for sure, but IMO it's already paid itself off for me since I got it ~1.5 months ago.
You're doing a full cycle on the batteries from charged to near-dead I assume, I remember reading a long time ago most batteries are rated for 500 cycles before they start to degrade, so at 4x a day, that 500 charges is achieved in 125 days, if not less... see where I'm going with this?
I also think maybe you need a different vaporizer, although that's almost the equivalent of heresy around these parts
are stealth and portability major factors? Have you considered a desktop vaporizer like the Extreme Q or an Underdog? Possibly even a Pax?