Mastervolt Masterlink BTM-III 12/24v DC 
A Mastervolt battery monitoring panel brings an end to nasty surprises, like a sudden shortage of battery power.
The Masterlink BTM-III battery monitor provides an accurate indication of the current, amperage, remaining time and remaining capacity of battery bank 1, and the current and estimated capacity of battery banks 2 and 3. The built-in microprocessor calculates the remaining capacity and stores historic data.
The Masterlink BTM-3 includes ten languages: English, French, German, Spanish, Italian, Dutch, Norwegian, Danish, Swedish and Finnish.
WARNING: This product can expose you to chemicals including di(2-ethylhexyl)phthalate (dehp) which is known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.
Owner's Manual (pdf)