Adjusting Alternator Voltage

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Originally Posted By: George7941
it shows that the setpoint voltage can be changed by cutting the web between the twin terminals. Anyone know how that works?


I can only assume if your batteries are located far from the alternator, by the time voltage gets to them it has dropped a fair bit. Maybe cutting the tie bar ups the setting another +.5 volts or so?
 
That is what it looks like but I cannot find any info online. The only way to find out for sure, I suppose, is for me to cut the web out and see how much the voltage changes. This is a one wire alternator setup with just the B+ connection, no sense or excite or ignition voltage connection
 
If this desired voltage modification is intended to better recharge distant depleted batteries over a thick copper circuit, be aware you should not Idle parked to recharge for more than 10 minutes or so as the alternator can easily heat upto the 220F danger zone.

I can spin a dial and choose any voltage I want, and if maxing out the alternator at idle its stator will raise above 170F in 5 minutes and is still heating quickly. Sub 25MPH driving does not do much either in regards to keeping stator temperature down, but 65MPH freeway driving it will not rise above 132F when maxed out, or nearly so.

I had to trick my engine computer with a 50 watt 10 ohm resistor into thinking it was still connected to the alternator, and I use a Transpo540HD external regulator. It has a potentiometer for voltage adjustment. I snipped the pot's legs and added wires and a larger 10 turn potentiometer so I can easily change the voltage while underway.

About 2/3 more amperage will flow into a battery at 14.7v compared to 13.6v, so it is a very worthwhile modification when one is regularly deeply cycling batteries and wanting to take advantage of a rather large amperage potential charging source.

I've put a digital ammeter on my dash, next to the voltmeters and find it enjoyable to watch amp flow into the battery change with different electrical pressure( voltage) reaching battery terminals.

The battery(s) dictates how many amps it accepts at the voltage reaching the terminals, so in the case of recharging deep cycle batteries an alternator with external regulation is much more desirable than one meant to simply replenish what a starter battery requires, as most vehicles will quickly lower voltage to the Mid 13's so as to not induce overcharging or excessive water usage. Vehicle Voltage regulation was never designed for fastest recharging of depleted batteries, and 80% charged to 100% charged, basically takes no less than 3.5 hours, and this is at ideal voltages reaching battery terminals.
 
Originally Posted By: wrcsixeight
.... I can easily change the voltage while underway.

About 2/3 more amperage will flow into a battery at 14.7v compared to 13.6v, so it is a very worthwhile modification when one is regularly deeply cycling batteries and wanting to take advantage of a rather large amperage potential charging source.


Sounds like you either live off-grid, or do a lot of RV'ing
 
I don't know wrcsixeight's back story but he has posted frequently on the subject of battery charging and he, more than any other Bitoger, likes to ensure his batteries are charged as close to 100% as humanly possible. He is very knowledgeable on AGM batteries and optimum charging methods for them.
 
What I did on my 2002 CVPI was put a Schottky diode inline to the Voltage sense pin of the alternator. A Schottky will drop about .3V. Raised hot idle voltage from 14.2 to 14.5.
First I tried it out with a standard 1N4007 diode since I have a ton on hand. Dropped about .6V and hot idled at 14.8.
I decided that was a little much, so I ordered in the Schottky. Ended up exactly where I wanted it.
 
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