The price of the Amazon unit is attractive. But, if I want to monitor the voltage/current of both the battery bank and the solar panel. So, I'd need two of these units to do that. Which means two holes, two runs of wire, two shunts, etc. Still, the price of TWO is way less than most battery monitors. You have to ask yourself why?
I went with a single unit (Xantrex Link 20) for my TC which will monitor both the battery bank and the solar panel. They are no longer made so the unit I will get for my new R-Pod will be a
Victron BMV-702 Battery Monitor