Balmar alt/reg issue - Incorrect Field Voltage

[smac999]

Wiring to starter is Standard practice. Why run a large cable from alternator to switch (2awg +). When you already have a large cable running to switch near by that isn't being used with engine running.

you need to measure all the points with the engine running. Voltage at alt post, voltage at both sides of shunt, voltage at starter post, voltage at battery switch, voltage at both batteries. follow the power and sense wire for the reg (if If has a sesnse some just use the power wire). Compare it to vaule on reg screen

Use the same ground for all measurements. Ie start battery ground. Then retake all measurements with the alt ground post, or engine block.

Then you can isolate if problem is in pos or neg cable sections

If should be easy to find the section loosing voktage. Abd fibd the problem. if you are losing voltage slowly at each point the. You'll have to re do everything with bigger / better wire


Do the test with bAtteries drained some. If they are full and alt isn't putting out any current you won't see any drops or problems.


If you left the factory orange cabling (probably a 10 awg?). This is Likly a main factor. a 100a alternator connected to starter post should be a 4awg or 2 awg. And bigger if run to batteries instead. Ground wire if there is one should be sane size to engine neg.

[DeepFrz]

You can do it that way of course. What you need to do then is ensure that your sense wire is connected to the start battery and that you have a charge solenoid/relay connecting your start battery and the house bank.

Best practice now is that you run the alternator directly to the house battery bank through a fuse at the battery end. You need to ensure that the cabling is of sufficient size for both positive and negative cables. Don't forget that you probably replaced a much smaller alternator, in terms of current, with a much more powerful alternator. Then you need an echo charger (or similar) to connect the house bank with the start battery.

Most factory installed alternators were meant to charge a start battery only. The starter only draws a small amount of charge (large current for seconds) from the start battery. It is best, IMO, to ensure that the house bank is first in line to get charged.

[markperil]

I had two extra 4Awg cables - one of which I have now wired from alternator positive to the starter positive terminal (thx smac9999) and I replaced the ground wire as well with the other (eloquently wrapped in black electrical tape )

I disconnected the Orange cable. I couldn't believe it - It was wired to the ammeter in the cockpit/engine control faceplate. Red wire from starter to ammeter then orange wire to alternator (both were 10awg - exactly smac9)...I suppose it was basically using the voltage running through the ammeter and using the same wiring to put juice back into the batteries!?!? Crazy stuff. Thankfully that's outta there/done and dusted. . Long story short, it seemed to be wired incorrectly/with insufficient gauge wire.

I still need to do a full run of tests, but I fired up the engine and took some initial readings at 1500rpm (idle)- output on the alternator positive was 14.4v, and batteries were reading the same on house bank. I'd call that a success, no? it's the first time ever I've seen any voltage higher than 12.8-12.9ish...

Next I need to install my link pro battery monitor, and pick up an echo charger too.

Thanks to everyone for their help! CF = Best community on the web. Hands down.

[smac999]

the old ammeters the cable itself ran though the gauge. if it's in the cockpit it's way too far. the new ones use a shunt and can be mounted near by, and then the small gauge cables run to gauge. I almost mentioned something but since you said shunt eairler I assumed it was near by and not a gauge. running an 10awg alt cable to cockpit and back is just crazy. but have seen it before. you'd probably need a 2/0 or bigger for that. the battery monitor is the way to go.


I assuming you have a 1-2-all switch and run the engine in all ?


if you want to use the echo charger you'd have to run the alt wire to he house battery. and then charge the start through the echo charger.


if you leave the alt on the start post, an ACR will work just fine. but not the echo


this allows you to run the swtch in one or the other and still have both charge. instead of always having to put the switch to all to charge both.

[mitiempo]

Originally Posted by DeepFrz

What you need to do then is ensure that your sense wire is connected to the start battery.....

The sense wire should be connected to the same battery bank that is receiving the output, the house bank being the best choice as it is the bank most in need.

The start battery can be charged either with an ACR or an Echo Charge.

[DeepFrz]

mitiempo, that really was an unnecessary post and you picked only part of my earlier post. It would be more helpful to keep the quote in context if you feel the need to post?

[mitiempo]

Originally Posted by DeepFrz

mitiempo, that really was an unnecessary post and you picked only part of my earlier post. It would be more helpful to keep the quote in context if you feel the need to post?

The way I read the post is that you suggest the sense wire should go to start battery then in the next paragraph have alternator output going to the house bank.

[DeepFrz]

Perhaps I didn't word it as well as I could however it was part of an ongoing conversation...perhaps with myself.

[Stu Jackson]

Originally Posted by markperil

This suggests the power runs from battery to starter, then starter to ammeter to alternator...is this possible? It doesn't make sense to me that you would push current from the alternator to the starter positive terminal???

Here's why:

OEM 1-2-B Switch Wiring History Alternator/Batteries & "The Basic" 1-2-B Switch BEST Wiring Diagrams

Ammeters & Shunts 101: http://c34.org/bbs/index.php/topic,6032.0.html

[DeepFrz]

Also Maine Sail's writeup here
1/BOTH/2/OFF Switches Thoughts & Musings - SailboatOwners.com

[cwyckham]

Hi Mark,

Great to hear things are going better. Nice crash course in marine electrical.

We still haven't heard where the ARS-5 sense wire is going to right now (or did I miss it)? I echo everybody's recommendation for moving your input to the house bank, but for now if the current is going to the starter bank (and then to the house via the switch on "all"), then the sense wire should be at the starter battery's positive post.

[Boatyarddog]

Yes, check the voltage drop between the alternator outputs and the battery's.


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