I have 4 in use in the 12 amp setting for 6-7 yrs. I learned the hard way that I needed them .( & expensive way ) I switched from the old 160 power master to the TCP 400's & the ---- hit the fan ! The reason for the 12 amp setting is in the start up mode if you have 3 or more engines on the same block or TCP . American Models takes a lot of current in start up . Absolutely well worth the money !!
Bob G.