I learned this subject from Lisle Bruney at Sure Power in the early nineties. I contracted to build a multi-voltage single alternator system for the US Air Force at Edwards Dry Lake.
Twenty eight years ago, boosters did not exist so I had to settle for a bucker. 100 amperes capacity. A 4875 Leece Neville 24 volt alternator, and a DC to DC bucker the size of a 2,000 watt inverter. Because the efficiency of this device was so poor, I had to over-kill on the capacity of the charging system. It indeed had a electromechanical interrupt.
Let's say a person wants to boost voltage electronically from 13.2 volts to 14.3 volts. Because of dropout voltage limitations of voltage management devices, the voltage would first have to be boosted to beyond device dropout limits then bucked with another circuit.
Efficient? Access eBay. Peruse their selection of DC to DC boosters and buckers.
See the large heat sinks? They are there for a reason as are the warnings to use fan cooling enhancements if an amperage threshold has been breached.
Bottom Line? AWFUL efficiency.
AWFUL efficiency times TWO. Booster + Bucker.
Then read the part about quiescent milliamp draw.
Then realize the successful merchandise that uses voltage threshold switching (battery combiners, BIRDS) switch mechanical relays. And the value of the action cannot be tweaked.
Few things in this area are wonders. Most have drawbacks. Pluses and Minuses. They have to be weighed before choosing. The school of hard knocks (user reviews) is one way to display shortcomings of a device.
