Bypass voltage regulator?

[Supertramp]

Away on a cruise and yesterday I noticed my tacho and charging light (on start up) weren't working. Engine still starts and runs but no charge for domestic or engine batteries. Later in the day, while motoring, the tacho and charging restarted. Then today, nothing.

Beta 60, single alternator, dual control panels, both with the same no tacho or charging light.

After talking to Beta, checking connections and investigating why no continuity in the D+ alternator to ignition cable I think the problem is with the Sterling Digital 4 step alternator regulator which shows no sign of life beyond one LED for battery type.

Two questions. Can I bypass the regulator and run a wire from ignition to alternator without changing anything else to restore alternator function? And what make or.model should I replace the old regulator with?

I have a small amount of solar and suspect the engine would run all day off the battery if needed so not in crisis. Yet.

 

[VicS]

If the trouble is only with the Sterling regulator you should be able to simply disconnect it and revert to operation with the alternator's own regulator.

Have you cured the lack of continuity between D+ and the panel ?

 

[Supertramp]

Thanks.

Yes, the discontinuity is over the Sterling regulator and I think bypassing it and connecting the D+ direct to the panel will give me a short term fix.

Because the alternator is not energised, both tachos fail as well. Running the engine uses hardly any battery and it's a 180 Ah so I will continue home (60 miles) and only change the wire if the engine battery voltage drops to 12.1 or 12.2. After 6 starts and 6 hours running and it was still resting at 12.7v. Domestic tops up with solar on a good day.

 

[Amlov]

We had a similar problem which turned out to be one of the wires (W) at the back of the alternator shorting out on the alternator bolt. It is rather tight down the back of the alternator and reports of wires rubbing through are not that uncommon.

 

[Boater Sam]

Sick Beta multi plug? I don't think the Sterling reg will be the problem, you can disconnect it completely and the system should still function correctly on the internal reg in the alternator, unless that is duff of course

 

[Supertramp]

Sick Beta multi plug? I don't think the Sterling reg will be the problem, you can disconnect it completely and the system should still function correctly on the internal reg in the alternator, unless that is duff of course

Back to home base safely and spent several hours checking connections. When the Sterling 4 stage regulator was added the original D+ wire was cut and a new wire run via the regulator to the ignition switch. The old wire is still in place and sound. There is no continuity via the new wire and the regulator. The regulator shows one LED indicating the battery type setting but nothing else happens on running (and the alternator doesn't energise). It's fuse is not blown. I believe the unit automatically breaks the sensing wire continuity if it detects a fault within itself.

Use the old wire connected to the alternator and the warning lamps on both panels light up as expected before starting. I haven't tried running direct from the alternator as I am not sure if there should be a second red wire connected to the alternator. Beta didn't seem to think it was needed.

Based on the above I strongly suspect the Sterling unit. It's a black box to me and while I could connect a new one I have no idea how to functional check the existing one.

 

[geem]

My Syerling unit failed a few years ago in a similar manner. I threw it away and installed more solar. Never missed it

 

[Boater Sam]

Back to home base safely and spent several hours checking connections. When the Sterling 4 stage regulator was added the original D+ wire was cut and a new wire run via the regulator to the ignition switch. The old wire is still in place and sound. There is no continuity via the new wire and the regulator. The regulator shows one LED indicating the battery type setting but nothing else happens on running (and the alternator doesn't energise). It's fuse is not blown. I believe the unit automatically breaks the sensing wire continuity if it detects a fault within itself.

Use the old wire connected to the alternator and the warning lamps on both panels light up as expected before starting. I haven't tried running direct from the alternator as I am not sure if there should be a second red wire connected to the alternator. Beta didn't seem to think it was needed.

Based on the above I strongly suspect the Sterling unit. It's a black box to me and while I could connect a new one I have no idea how to functional check the existing one.

That is not how the reg is supposed to be wired. Can I suggest that you ask Sterling?
The reg showing one light, battery type, suggests to me that it only has a live feed, no D+ connection.
The connections should be battery+ from ignition switch, battery-, D+ from alternator, sensing wire from battery, and the control wire into the alternator brush.
The new wire running from D+ to ignition switch is wrong, it should go to the warning lamp! And the D+ on the reg.

 

[Supertramp]

Sorry, my mistake - the new D+ wire goes to the regulator, then the feed out of the regulator connects to the new wire to the ignition. It's all wired as the Sterling manual and all wiring and connections outside the regulator are OK.

 

[VicS]

The relevant wiring diagrams are attached. ( click to enlarge)

I also note that the instructions say the the existing wire on the D+ terminal ( which connects to the warning light on the Beta panel) should be left in place,


There is only one ( moderately heavy) red wire connected to the alternator B+ . If in any doubt about the original engine wiring you can see the wiring diagram in the Installation and Operators Manual.

Disconnect the Sterling regulator, reinstate the D+ to warning light connection and check that everything operates correctly. Then reconnect the Sterling regulator and check again. If things do not now work correctly the Sterling regulator is almost certainly defective.
You could return it to Sterling but they will most likely sell you a new one if it is defective.

 

[Supertramp]

Thanks for this which I hadn't got - it is wired correctly, the yellow to ignition runs via a new wire outside the panel loom. Don't understand why as it would have been simpler to return the yellow to the alternator and use the old D+ wire.

When you say "the existing wire on the D+ terminal should be left in place" does that mean the Sterling unit should connect via an additional second wire leaving the original direct connection in place? In my installation the brown wire to the regulator replaces the original wire (so the energising and control is done via the regulator).

I agree with your next step suggestion and am back at the boat at the weekend. Will update then.

Thanks for the advice.

 

[VicS]

Thanks for this which I hadn't got - it is wired correctly, the yellow to ignition runs via a new wire outside the panel loom. Don't understand why as it would have been simpler to return the yellow to the alternator and use the old D+ wire.

When you say "the existing wire on the D+ terminal should be left in place" does that mean the Sterling unit should connect via an additional second wire leaving the original direct connection in place? In my installation the brown wire to the regulator replaces the original wire (so the energising and control is done via the regulator).

I agree with your next step suggestion and am back at the boat at the weekend. Will update then.

Thanks for the advice.

The yellow wire can be run to D+. It says that in the writing .

Yes the brown wire connects to D+ and the original connection remains in place. ( if the yellow wire goes there as well you'll have three wires on the same terminal !)

The original wire is the connection to the "no charge" warning light(s) on the panel(s). If disconnected the warning lights on the panels will not work.
It also normally supplies the initial excitation current that gets the alternator so start generating but this function may not be necessary with the Sterling regulator installed. I don't know if it is or is not but either way I would want the no charge warning lights on the panels to continue to work

( Just a thought though. I wonder if having two control panels caused complications that were solved by cutting the original connection. You might find the answer to this in due course)

The Sterling regulator supplies and controls the field current, and hence the alternator output, via the white wire which is connected to the additional connection made to one of the brushes during the installation.

 

[Supertramp]

Thanks, really useful. The original single D+ wire activates both panels via a split hidden down by the engine loom. Will report back when I've done the next test.

 

[Supertramp]

Problem solved by adding a 2:1 connector to the D+ and reinstating the original brown/yellow wire as per the Sterling regulator instructions. Now the regulator lights up properly and I have tacho, engine warning lights and charging to both batteries.

I think the root cause was the brown/yellow wire had been bodged into a single connector with the regulator brown and had frayed and broken after many years.

Many thanks for the ideas and advice which have enabled me to understand and repair.

 

[Boater Sam]

There you go. I knew it was not wired correctly, These Sterling regulators are reliable, I have used then in their various guises for nearly 30 years.