Called out to battery problems in Stone on a recently purchased narrowboat. Lucas A127 55amp alternator output poor and doing very little at tickover. Adverc ok. Tidy but badly installed system by well known and reputable boatyard (not in Stone) : cable sizes poor and Adverc battery sense fitted to common post of 1-2-both switch however long cable run (6mm cable/yellow crimps to domestic batteries) after the switch. Alternator pulley large. Fit a 90 amp marine alternator modified for Adverc. New long span laser cut curved adjusting arm, longer bolts, shims and 60mm custom XPA pulley. Gates Quadpower belt. All cable sizes including earth increased to 35mm and re-routed to shorter runs. Transformed alternator performance quickly jumping to 14.4V at low engine speeds.
The ST drives alternator at 1/2 speed off cam shaft alternator output is often poor at lower engine speeds. ST’s can often be improved relatively easily as the cam pulley is normally a reasonable size. I’ve fitted this alternator to 5 ST’s now with great results.