Bumping up alternator voltage..

**H2OPERF** · 12-08-2018, 01:16 PM

I'm going to run a 14v XS battery on my project boat so I was looking for an aftermarket regulator to fit the Nippondenso internally regulated alternator i'm using but the only ones they seem make are for 16v batteries and are set to 19.... kinda high for all the rest of the electronics. Searching the net found you can put a diode or multiple series diodes in the sense wire to the regulator and use the .5v forward voltage drop thru the diodes to make the regulator see less voltage and put out about .5v more for each diode.. Tested the idea and it really works well..

**H2Okie** · 12-09-2018, 08:23 AM

Something to consider . Maybe the voltage regulator you're using has built in protection for this but for the bigger voltage regulators I work with if they lose sensing voltage under load they see this as a "Low voltage" condition and go to maximum output . Diodes can do some weird things like open circuit or explode when they fail which would lead to a loss of sensing voltage to the alternator regulator . I'm sure the current draw for the regulator sensing circuit is low so you could simply substitute a resistor of the proper wattage and ohmic value to drop the sensed battery voltage to the regulator instead of the diode (s) . This is a "Six of one half dozen of another" situation as far as operation goes but the resistor will be more reliable in the long run .
Just something to think about

**H2OPERF** · 12-09-2018, 03:06 PM

I used 6amp diodes and the sense wire only draws less than an 1 amp so hopefully nothing fails but i did disconnect the sense wire when testing it and the voltage went back to the set point at 14.4 volts..