Congrats, Mike, on an exceptionally well done installation of a great product. As another member of the boondocking TMers, I certainly empathasize with the criticality of knowing what the batteries' state of charge (and recharge) is. Good to see we have at least two options for these measurements.
So far I'm doing OK by just monitoring voltage...I'm getting enough sunshine and have enough solar power to recharge the house batteries fully by mid day with moderate nightly power use. I watch my system voltage carefully...as soon as I see the effect of the controller cycling the panels in/out of the circuit, I know I'm good to go for that day. On my last trip I had enough spare solar generation to be able keep all my other electronics (laptop, camera, cell phone) recharged despite fairly heavy use of each gadget.
And on a previous trip, during an enroute business related stop (client consulting visit) I had to leave the truck/trailer parked for 8 full hours in a strip mall parking lot with the refer running on DC the entire time.
Fortunately, the entire day was cloudfree with brilliant sunshine. I had about a 2.5 hour drive between leaving the parking lot and arriving home (not enough for much recharge of the batteries) and when I arrived I ascertained my batteries were actually only discharged by about 15 amp-hours (based on the time it took my .9 amp trickle charger to bring them back to a fully charged state). Solar Rules!!!
But on a longer boondocking trip...with persistent cloudiness and/or heavy night usage of the batteries, staying on top of the battery state could be very critical. So I'm now adding a Xantrex to my list of future goodies.
