Balmar Alternator, heavier guage wire?

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MtHawk

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Jan 24, 2006
18
- - Montana
Those of you that have installed high output alternators. Did you run heavier quage wire? Does it go back to the battery select switch? The wire coming off my existing alternator is only about 8 guage wire, and I can't see where it runs to. My electrical diagrams aren't very detailed from engine. Thanks. Bob Hawkins
 
Oct 25, 2006
80
Robinson and Caine Leopard 43 Somewhere hot and sunny
Bob , the heavy guage wire runs to your battery.

There are a lot of things to consider if you are going to install a high output alternator. Can the belt handle the output? 1/2 inch will work with 100 amp, 120 amp is really pushing it. Are you going to use a "smart" controller? It is recommended. If your old alternator put out 40 amps, it had a 4 AWG wire for 5-10 feet of length to the battery. You are saying 8 AWG, so maybe it is under 5 feet. 100-150 amp alternators require 2 AWG for 5-10 feet of length, 4 AWG for less than 5 feet. Balmar does have excellent documentation on installing their equipment.
 

MtHawk

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Jan 24, 2006
18
- - Montana
Thanks for the response

I am installing the 100 amp and I have a 1/2 inch belt. That should work fine. I'm going to install the max charge regulator (mc 612). I thought the heavy guage wire should go back to the Battery selector switch so I could select battery 1 or 2 or both when charging.
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
The Alternator wire

typically goes to the positive terminal on the starter. This is a short run and then uses the starter cable to connect to the batter selector switch. A point however, your starter may not draw 100 amps (and it certainly does not do it for any length of time) so this wire size will need to be increased if this is your wiring layout.
 

RAD

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Jun 3, 2004
2,330
Catalina 30 Bay Shore, N.Y.
With my ACR

one less thing I have to think about cause I have an engine bank and a house bank and no matter if I'm running the engine for 1 hour or 10 hours all batterys get a charge and now one is flipping switch's I wish my Westerbeke had a compression release like some other diesel mfg's cause thats a great feature when the battery is down.
 

MtHawk

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Jan 24, 2006
18
- - Montana
Everyone's blood pressure ok?

Guess I started something. I hope everyone's blood pressure is ok. I like the idea of going back to the starter. I'm going out this morning and tracing down the existing wire. I know it doesn't go to the starter or the battery switch. I'm wondering if it might hook into the DC side of my 110 battery charger somewhere. I'll keep you "posted." Thanks!
 
Oct 25, 2006
80
Robinson and Caine Leopard 43 Somewhere hot and sunny
Blood pressure fine

We just like to banter back and forth. There are many ways to skin a cat.....
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
For the record

I'm not against things that make a boat safer (electric nav lights) or last longer (Dacron sails) but since I already have a battery selector switch why add complexity and another system to fail if you don't NEED to. My boat is already sucking up enough $$$$. I just don't see the "significant advantage" in these two items. But we are off topic The alternator positive wire has to go to some primary wire coming off the battery or to the battery itself. As a general rule you want to keep the number of connections at the batteries limited to keep corrosion down. Take your positive 12 volts off the common terminal on the battery selector switch and don't put the switch in the battery compartment where it will see acid droplets and start corroding
 

MtHawk

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Jan 24, 2006
18
- - Montana
Sneaky little wire

After further examination that sneaky little wire does run from the alternator to the starter. Couldn't see that at first. That is a major break through. Now I can replace that with heavier wire, 4 guage just to make sure. I haven't decided on combiner yet or just going through the battery selector switch. I still have the rest of the alternator and external regulator wires to figure out. Thank you for the help. I was really struggling and thanks to you guys I'm on a roll again. I'm sure I will have some other questions as I go. THANK YOU, THANK YOU, THANK YOU! Bob Hawkins
 
C

ConchyJoePDA

Way to go!

Way cool Bob. Just remember you need to size the length all the way to the battery, not just 2 the starter. Sail on!
 
Feb 15, 2004
735
Hunter 37.5 Balt/Annapolis/New Bern
Fred ... just don't beat a dead horse...

I used that in a meeting last week (because we were doing it something fierce) and got chewed out for being insensitive. Turns out one of the women in the group is a major equestrian...er?
 
Feb 26, 2004
23,336
Catalina 34 224 Maple Bay, BC, Canada
Second thread on this

Bob, glad to hear you're gaining!!! You posted another thread on this same topic, which kinda makes it hard to keep up. There, in Reply #3, I said: "Alternator Output: The boats with only one 1-2-B switches are usually factory wired with the alternator output to the “C” post of the switch. This means that the switch was actually used for two purposes: (1) which battery bank(s) the alternator charge goes to when the engine is running; (2) which bank is chosen for use for DC power. Newer electrical systems route the alternator and charger outputs to a PDP (positive distribution post) and then to the house bank with a Combiner or Echo Charger (relays) to charge the start bank." One of the things that's had people confused since they started wiring boats and batteries, is that damn little jumper from the starter to the alternator (or from the alt to the strtr, doesn't matter). If you think about what I said, above, it makes sense, simply because it's less wiring for the builders to install. The OUTPUT of the batteries goes to the C post and then to the starter to start the engine. Once the engine is running the output of the alternator GOES BACK THROUGH THIS VERY SAME WIRE to the switch and then to the batteries. That's why there is a connection between the two. Newer electrical designs eliminate that connection, run the alt output to the house bank and wire TO the starter FROM the C post of the switch. Many have designed dual or multiple switches. I personally think that's unnecessary. The real issue is how YOU choose to wire and run your boat. Is there a BEST way to work this? Sure, but that's what this discussion is all about - everyone has their own best way. I chose the combiner route (newer ACR technology is the same concept, so is the Echo Charge) and have the alternator output directly to my house bank PDP. Even if the combiner or ACR or EC fails, I still have the wiring between the 1-2-B switch and the batteries which will parallel them. Normally, we start on 1 and switch to 2 for the house bank, I never use both. I like the backup provided by this system. I also agree that if you can't remember to run one bloody switch, maybe you shouldn't be in charge of a boat! :) Again, suggest you read up in addition to this cat-satisfying series of replies.*pop Just coincidently, the November 2006 Mainsheet has an article I wrote about just this topic, C34 tech Notes section.
 
Feb 26, 2004
23,336
Catalina 34 224 Maple Bay, BC, Canada
Just another thought

Bob, while you're doing all this investigation, suggest that you take notes and draw sketches of the wiring. Here's another resource for you: http://www.c34.org/projects/projects-electrical-system-upgrade-2.html
 

MtHawk

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Jan 24, 2006
18
- - Montana
Excellent source for help!

Thanks again everyone for the help. Stu, sorry about the confusion by posting 2 threads. I was sure I had posted in this forum the first time, but I ended on the Catalina forum. I probably justed screwed up. Thanks for the link. Great stuff and exactly where my thinking is right now. I'm in the process of installing external reg (612). Luckily my boat is in my front yard so I can put this advice to immediate use. Going back out to plug away. Thanks again.
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
Don't forget the ground wire

Some alternators (the good ones) have a ground terminal. This wire has to carry the full alternator output as well. Most OME alternators have a case ground that causes the current to flow through the mounting structure then the engine block and finally back to the battery ground on the engine block. These case ground alternators are not high output for obvious reasons. When upgrading to a high output alternator with a negative terminal you will need to add a wire from it to the engine ground or directly to the battery ground terminal.
 

MtHawk

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Jan 24, 2006
18
- - Montana
Thanks, Bill

I have it installed already, and it is the same size as my positive output wire. My Balmar is not case ground so I made sure of this wire and connection. I have connected to a good ground source on engine at same sight where negative battery wire comes in. Thanks
 
Dec 2, 2003
4,245
- - Seabeck WA
OK, just for clarification, and a wager of

(fill in favorite beverage), I'll bet that your alternator ground stud is part of its' case. It would be silly to insulate it from the case. The stud is just for convenience so you'll have an accessible ground lug.
 
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