Bill,
I have not tried that one - although it looks interesting and hard to beat the price.
I have tried this one out with some interesting results:
Zamp Solar BMPRO1 Bluetooth Battery Monitor
It works as a shunt to connect directly to your batteries. Then you put an app on your phone that tells you the amps, volts and percentage of charge in the app.
Pros:
Very easy to hook up - no need to drill holes, etc...
App read out is very cool - you can watch it in your truck while it is running so you can see if it's charging
Cheaper than Trimetric
Transfer it easily to another vehicle
Accuracy is close to Trimetric
Cons:
The bluetooth connection has issues - it does not like to stay connected and resetting it is painful
It's not the Trimetric which has way more information and data
Accuracy is close to Trimetric but does differ some and not 100%
For the price, you are probably better off getting the trimetric
I've had both systems and the Battery Check has some merits, but the bluetooth connection is bad. You often reset it and it's not worth the money as compared to the trimetric. I would consider it if you battery compartment is hard to get to, you don't like the wiring of the Trimetric (which can be a challenge) or you want something easier to monitor your amps, volts and percentage of charge.
If you are interested, here's the amazon
link.