Voltage Regulator Mounting Location

[rmbrown]

I swear, I remember a discussion on this topic, but my searching skills are lacking today.

I'm headed to the boat tomorrow to mount the new external voltage regulator and I'll wondering what the best spot is?

Suggestions?

[Stu Jackson]

Mike,

Do NOT put it in the engine "room."

I put mine under the head sink.

Others have put theirs in the aft cabin.

[MarcZ]

http://c34.org/bbs/index.php/topic,9837.0.html

[rmbrown]

Oh, Lord... And it was my own thread!

[Ron Hill]

Mike : As I said before I put mine under the head sink on the wall side of the engine. I also cut out a "Tupperware" box to protect it as it's near but not directly under my RACOR filter.

A thought again

[rmbrown]

Yep... I remember thinking that tupperware trick was pretty slick!

I ended up installing mine under the companionway ladder so I could see it better, at the risk of it getting dripped on, so I think I'll steal that idea.

My undersink head cabinet is too crowded and I considered the shelf behind but it would be protected but so hard to see.  In any case, it's installed but not quite wired up.  All connected except the bits that go directly to the alternator in the harness or were connected to my old alternator.

[Stu Jackson]

Mike,

Don't know if you've seen this:

Alternator Regulator Wiring Diagrams - all three http://c34.org/bbs/index.php/topic,4548.0.html

[rmbrown]

Thanks, Stu!

[mainesail]

If you are using an external regulator those diagrams will not result in the performance you've paid for.. Correctly wiring the volt sensing circuit is critical to charging performance...

Here are a couple of articles that can help:

Alternators & Voltage Sensing (LINK)

Programming a Balmar Regulator (LINK)


.

[rmbrown]

Mainesail:

Thanks for the links.  I'll read them (or read them again).

Not to worry re voltage sensing... I used your 1A fuse and 18' of #14 wire to run from VR directly to the hot side of my house battery bank... same terminal as used by the alternator positive lead.

[rmbrown]

Re completion of wiring, what I was primarily confused by on my last trip to the boat was the fact that, while I had a direct (#4) hot wire from alternator to battery, I had a much smaller ground wire and it clearly wasn't going back to the battery.  My boat electrician is heading down today to replace the #4 runs with #1 and to run a dedicated ground all the way from bank to alternator.

The only thing that leaves me unsure about is the tach and the use of the white wire in the VR harness, but I still have some research to do.

On the old alternator, I had:
1) The heavy gauge red lead from pos +output to battery +.  This one is being replaced as described above.
2) I assume ground was via the mechanical connection to the block.  This is being replaced as described above.
3) A red wire from SEN to ?  Not sure where this one leads... haven't looked yet, but I assume it's made obsolete by the voltage sensing wire directly to battery positive in new wiring.
4) A red/white wire from AC tap to ?. 
5) A twisted pair (blue and pink) from EXC to ?

It's the three wires described in 4 and 5 that I have to verify are either obsolete or are connected properly in the new setup.

I appreciate all the help!

[rmbrown]

Mainesail: 

I read the Voltage Sensing link and realize now that I only had it half right.  The sensing wire runs all the way to battery + but the ground for the regulator is still running to the alternator ground, so I'm only correcting for half the voltage drop between alternator and bank.  I'll run a new regulator ground straight back to battery - when I am next at the boat, but now it's a question of wire size.  I ran a #14 for the sense wire, but it expects <1 A.  Since the ground will be used both to sense AND to power the regulator, and since the power lead for the regulator sports a 10A fuse, I'm guessing that #14 isn't enough.

Sizing for 3% drop on a 20 foot run at 11 A, on my calculator, gives me #8 ground wire.  That OK as an extension to harness (in which case it would be 54" shorter?  Or should I run it all the way back to the VR?

[mainesail]

Mike,

The black only carries a few amps. The CMI-105-ER will only ever pull a max of about 6A of field anyway.. When driving the alt the neg is carried through the alt's big neg wire and only a little bit of current is carried on the black wire. Generally bumping from 14GA to 12GA is fine but for longer runs 10GA would be an option. Never seen a need for 8GA..

[Stu Jackson]

If you are using an external regulator those diagrams will not result in the performance you've paid for.. Correctly wiring the volt sensing circuit is critical to charging performance...>>>>>>>>>>>>>>>>>>>

Mike & Maine Sail,

I've modified that link to the 101 topic with my three wiring diagrams to include wording to make it clearer that it doesn't show the alternator sense plus and negatives.  I also included MS's last post and links.  My diagrams were drawn to keep track of the individual wires, and the old wiring in the harness and the new regulator wiring.

[mainesail]

This may help:

Full Size Version: http://www.pbase.com/mainecruising/image/168464586/original.jpg