The Mastervolt Alpha Pro III is a three-stage alternator regulator for 12V and 24V systems, with up to 20A of field current.
Twenty amps of field current is what allows it to drive a large alternator properly. Field current is what the regulator uses to control output, and a regulator with insufficient field capability cannot bring a high-output alternator to its full rating however well it is programmed.
It supports a wide range of chemistries including lithium-ion. That matters on a conversion, since a standard internal regulator charges lithium to a lead-acid profile and either undercharges the bank or pushes it past where it should stop.
Three-stage regulation turns a standard alternator into a more effective charging source. A stock alternator holds one voltage regardless of state of charge, which fills a bank to perhaps 80 percent and then stops making progress. Explore more alternator parts and accessories.
- 20A of field current drives a large alternator
- Too little field cannot reach the full rating
- Supports lithium as well as lead-acid
- A stock alternator stops progressing near 80 percent
