Westerbeke 4-91 Alternator not Charging

[marvinjansen50]

I just took possession of a 1975 Glander Tavana as a project boat. The Westerbeke 25hp Four-91 starts and runs great and was rebuilt recently. The problem is that it is not charging the batteries. It has a Delco 3 wire alternator and seems to have a couple of regulators. I don't have a wiring diagram and wonder if there is one available? The house batteries are 4 6v golf cart batteries. Any suggestions?

[Ex-Calif]

If it has external regulation it could have been modified to increase output.

More than one regulator sounds odd. It would be useful to post the models of the devices so we could better guess at what you have.

If you really suspect the alternator you could remove it and take it to a shop to be tested.

If you don't have electrical skills you might want to hire an electrician or take a crash course in marine charging systems. Nigel Calder's "Mechanical and Electrical Manual" is a good reference to have.

The reality of old boat ownership is that you become a mechanic and systems expert or you pay through the nose.

[marvinjansen50]

Thanks for reply. I have some mechanical and elec skills and have always kept cost to a minimum by doing as you say and educating myself on what needs to be done. The Delco alternator has an internal regulator but the previous owner said it has another regulator too, so I am still learning this setup. I did read somewhere that when you have a second bank of batteries it helps to have an external regulator but I have yet to see a wiring diagram. I knew by getting this boat, my first bigger keel boat, that I would be learning a lot of new systems and accept this as a challenge. My previous boats have been smaller and simpler like the West Wight Potter 19 I still own. Again, I thank you and others who are willing to share information from your experiences.

[model 10]

If you want to be a cruiser you need to be able to hot wire an alternator. Unless you have some sort of hand crank for your engine you need to get some power going. 12v right to the field will get it charging like crazy. If it does, you need a regulator, if not you are probably screwed and need an alternator ovhl. You mention maybe an internal regulator, bummer. Check the output at the alternator.
Things like light bulbs and rheostats in the field wire are advanced cruising repairs.

[Ex-Calif]

Originally Posted by marvinjansen50

Thanks for reply. I have some mechanical and elec skills and have always kept cost to a minimum by doing as you say and educating myself on what needs to be done. The Delco alternator has an internal regulator but the previous owner said it has another regulator too, so I am still learning this setup. I did read somewhere that when you have a second bank of batteries it helps to have an external regulator but I have yet to see a wiring diagram. I knew by getting this boat, my first bigger keel boat, that I would be learning a lot of new systems and accept this as a challenge. My previous boats have been smaller and simpler like the West Wight Potter 19 I still own. Again, I thank you and others who are willing to share information from your experiences.

If the boat has an external regulator part of the modification is to bypass the internal regulator of the alternator.

There shouldn't be 2 regulators so before I'd recommend anything specific it is important to know what is actually hooked up.

As a first check, there should be power into the regulator, power at the field terminal of the alternator and power at the B+ terminal.

[GordMay]

A typical 3-wire Delco 10-SI, has a "Bat" (Battery Output, Terminal 3), and connectors for the Field Excite/Warning Light Indicator Input (Terminal #1), and the Remote Voltage Sense Input (Terminal #2) wires.
➥ Diagram circuit: Marine Tachometer Diesel Alternator Wiring Instruction

[marvinjansen50]

It it charging now! About 19volts at 1200rpm and 14 at 800. I used diagrams and info you provided and traced the field wire to one of the external regulators. I removed it and ran it to the starting battery and it started charging right away. So now I need to figure if I need those three regulators and what they are for. It has 4 6v batteries that are on a switch with 4 positions, off, 1, 2, and both. The PO told me that there are 2 6v on 1 and 2 6v on #2. It seemed to overcharge when I put the field wire to the battery, 19volts. But dropped down when the motor was idled. So, good I have charging but not fully right yet. Still open to suggestions and thanks for the help getting this far.

[marvinjansen50]

few more pics and one of the invertor. 2000 watts, 6000 surge. Wonder what this will run?

[model 10]

Be careful. Don't go above idle when you have it wired right to the bat. The job of the regulator is to control field down to something around 3-5v (?.) You can fry your stuff very easy above idle. If you had nothing else connected to the system you could dump a higher voltage into the batts and it wouldn't blow up but it would be way to much for the rest of the system.
This is where light bulbs and rheostats come in, You can put a light bulb in the field wire and it will drop the volts to a lower level.

[Ex-Calif]

Good news! What you have done is called a "full field" test of the alternator. This provides full filed power to the alternator and basically is operating in "unregulated" mode. It confirms the alternator is OK but you definitely do not want to operate in this mode.

The Ample Power website is not great but they did have a manual for your regulator.

Please be careful with the next parts as I am shooting a bit in the dark here.

https://amplepower.com/primer/v3_3stp/index.html

It appears you have the 1021A and according to the link the sense wire (yellow) should be in terminal 1 (counting from left) and based on your picture the sense wire looks to be in terminal 2.

It also mentions a system ground and alternator ground in terminals 3 and 4 which appear to be missing.

The small unidentified box is intriguing and also looks like a regulator. Can you dismount it and get a P/N off the underside?

I could not find a manual for the alternator current sensor but I am guessing this is a sensor for a battery combiner to combine the start battery - Someone with this system may chime in.

This link is a "typical" APC wiring schematic - yours may be different.

http://www.amplepower.com/primer/emnxtel/emnxtel.pdf

I would read as much of their documentation as I could and then trace this stuff out to understand the system better.

Ample Power Manuals

[Ex-Calif]

BTW - The red device with the heat sink appears to be a paralleling device. This may be what the Alternator Charge Current device is controlling.

Also that bronze looking device is a mystery to me but you can see the crimps are not good the wires are corroded and it is probably building up quite a resistance. You might put "replace terminals" on the to do list someday.

[marvinjansen50]

Bronze switch is the starter switch. I see the poor crimps and corrosion you are talking about. I am digesting the info on APC and will try to properly wire the APC 1021A and see what happens.

[marvinjansen50]

Last trip to the boat a few days ago and the battery was at 2 volts. Think I left it switched so the house batteries took it down. I was wondering if anyone uses a simple one wire Delco alternator for a spare get me home solution? It would make it simple now to bypass everything and simply charge the starting battery. This would get me from the current location to the Buccaneer Yacht Club where I am going to keep it.
Amazon.com: Alternator 1 Wire Universal Self-Excited 10SI 10 SI: Automotive

[marvinjansen50]

This is the alternator I was thinking of, a marine one that I can use in more applications later.
http://www.amazon.com/gp/product/B00...A3DQWNDT09WO3V

[marvinjansen50]

Just wanted to let those helping me with this project that I did get the info on the regulator and wired it according to directions, just couldn't try it on a dead battery. I did try to jump it from my truck battery and it made the old battery seem to sizzle and would only click the starter solenoid and not turn it over. I tried it on my truck battery with jumper cables with the boat starter battery disconnected but still just clicked. I made sure to disconnect the old house batteries and left the starter battery on the solar charger to charge up. I was also wondering if the boat starter battery might be bad after hearing that sizzle? That visit was one step backwards it seemed.