Gauges going crazy [Alternator Regulator Issue]

[Coronadoe38]

I have weird gauge problem. My gauge panel shorted and almost set the boat on fire. Rewired everything install new temp gauge and sender, both had died a few weeks ago. My problem is every thing works fine until I get to 1400 rpm temp and fuel gauge peg high and tach acts weird. Can’t figure it out any help from one of our electrical wizards would be greatly appreciated.
Everyone stay well.

 

[1911tex]

For step #1, I would disconnect the fuel guage. Most likely inaccurate anyway and shorting something out. Mine never worked and disconnected. All other gauges work, even the original hour meter RPM gauge. See if that solves the problem?

 

[supersailor]

Check the alternator also for steady output. A bad short could adversely effect it. If it is cutting in and out the tach will act weird (read normal, peg out, read normal). Also, the ignition switch could be bad. I've had three go bad and I carry a spare.

 

[Frank Langer]

Check the alternator also for steady output. A bad short could adversely effect it. If it is cutting in and out the tach will act weird (read normal, peg out, read normal). Also, the ignition switch could be bad. I've had three go bad and I carry a spare.

I'm no electrician, but twice in 14 years, when my instruments created havoc, it was due to a bad or loose ground wire. So I always check there first now, especially if more than one goes wonky (technical term) at the same time.
Frank

 

[Coronadoe38]

For step #1, I would disconnect the fuel guage. Most likely inaccurate anyway and shorting something out. Mine never worked and disconnected. All other gauges work, even the original hour meter RPM gauge. See if that solves the problem?

Although the fuel gauge has always worked I’ll try anything at this point..

 

[Coronadoe38]

Check the alternator also for steady output. A bad short could adversely effect it. If it is cutting in and out the tach will act weird (read normal, peg out, read normal). Also, the ignition switch could be bad. I've had three go bad and I carry a spare.

I was leaning in that direction and I’m going to hook up a meter tomorrow while running the engine.

Check the alternator also for steady output. A bad short could adversely effect it. If it is cutting in and out the tach will act weird (read normal, peg out, read normal). Also, the ignition switch could be bad. I've had three go bad and I carry a spare.

 

[Coronadoe38]

I'm no electrician, but twice in 14 years, when my instruments created havoc, it was due to a bad or loose ground wire. So I always check there first now, especially if more than one goes wonky (technical term) at the same time.
Frank

I have checked d the ground several times and it’s new but like I said I’ll fry anything.

 

[supersailor]

Frank's track is a good one. There could be several other grounds or busses in the system especially if a PO has tried a little home brewed wiring. I put a little dielectric grease on the terminals after cleaning them up so the don't corrode away.

 

[eknebel]

I have weird gauge problem. My gauge panel shorted and almost set the boat on fire. Rewired everything install new temp gauge and sender, both had died a few weeks ago. My problem is every thing works fine until I get to 1400 rpm temp and fuel gauge peg high and tach acts weird. Can’t figure it out any help from one of our electrical wizards would be greatly appreciated.
Everyone stay well.

Since you have been checking and rechecking, and verified grounds, it may be a marginal crimped terminal connection. A firm pull on the crimped connection should tell you if it is good, as all being new, corrosion shouldn't be a concern. As suggested, eliminating the new temp gauge is a good idea, just to eliminate possible cause. Not knowing the circumstance of the fire, if the engine was running, there may be damage to the alternator, but if the tachometer readings were realistic until 1400 rpm, it would seem far-fetched that it is the alternator.
In my experience, "possessed" DC devices almost always end up being intermittent connections, in this case perhaps made critical by vibrations at 1400 rpm. Have patience, good luck!

 

[Christian Williams]

If you moved the tach the settings may have been dislodged. Check the rotary switch and the calibration (settings on the back of the tach). I just had this problem after removing and replacing the instruments.

If you have the standard Teleflex, see Page 338: http://www.jamestowndistributors.com/userportal/pdfs/Teleflex/TMTechCat-Instruments(v4_0)Tech Reference.pdf

 

[Tin Kicker]

If you have the standard Teleflex, see Page 338: http://www.jamestowndistributors.com/userportal/pdfs/Teleflex/TMTechCat-Instruments(v4_0)Tech Reference.pdf

Christian - That's a nice resource to consult. Another to add to the PDF collection.

Coronado - you believe you've already checked the grounds, but also said you re-wired the collection. That raises suspicions about weak connections as already mentioned, but also sneak circuits. My approach would be:

First, take apart, clean, and check EACH alternator and battery connection. Give a slight tug on each connector. I can't tell you how many times I chased ghosts and found the darn basics weren't solid. btdt

Check for positive voltage at each instrument while the alternator is running. I actually prefer to use a cheapie meter for this like the one below (unless of course you happen to have an oscilloscope), because it's easier to see the needle waver if the supply is not steady, than it is to spot this with the digital display on my Fluke.

With things powered and you or somebody watching the displays, lightly flex, pull, and push each wire individually.

Give a solid tug on each connector. Even 16AWG should be able to take a 30 lb pull. https://www.abqindustrial.net/store/images/products/WTTM/wire_pull_test_standards.pdf

If still no change, label the panel wires not already labeled, then disconnect the lot of them. Reconnect each gauge and test individually.

By this point you'll probably have something isolated.

 

[Coronadoe38]

Thanks everyone for the great response and suggestions. After completing a bunch other projects I got back to the crazy gauges and found the voltage regulator had gone bad. Fortunately the boat came with a ton (literally) of spare parts. One of which was a voltage regulator. Alls well on the gauges.

 

[william.haas]

Now I’m curious... where is the voltage regulator? I have not had to replace one before and while I’m sure I’ve come across it I wouldn’t know what it looks like. Universal M2-12 with the original panel here.

 

[1911tex]

In the olden days with generators, the voltage regulator was a small separate box, cheap and easy to replace. With an alternator the VR is internal (built in). Not external. If you believe the problem is the VR, remove the alternator and take it to a starter/generator/alternator repair business...most every town has one. Get the alternator overhauled (recommended)..not expensive or get a new one...expensive.

 

[william.haas]

Hence why I’ve never come across one... I don’t have one as a separate unit. Thanks @1911tex for your response.

 

[Christian Williams]

Internal vs. External regulators

The stock (Motorola) alternator on Ericsons was rated about 50 amps. It has an internal regulator of limited intellectual capacity. It charges the batteries while the engine is running at a calm and steady pace, undistracted by greater expectations.

Upgraded alternators (100-amp Balmar etc.) have external regulators, also known as smart regulators. They are educated to vary the charge output according to the needs of the battery bank. If the battery is low, they flood it with juice, but as capacity declines they carefully back off so as not to boil the baby in the bathwater. Such smart regulators can recharge batteries much faster than their internal brethren. That cuts down the daily engine recharge time and saves fuel and noise.

However, a Balmar 100 and smart external regulator costs somewhere around $1,000+. It justifies its cost of education over time, but of course if you only write poems in the cellar an expensive college is a highly questionable investment.


External regulator on a Universal M25

 

[Tin Kicker]

Related thread:

M25XP alternator

need to replace alternator on Universal M25XP, one with internal voltage regulator. Universal wants over $500 for a 51 amp or 65 amp unit. Any suggestions for a cheaper alternative, or what is the corresponding Kubota unit (marine use)?

ericsonyachts.org

The Motorola alternator on mine is typical for what I've seen on these boats, and is indeed the 12V51N, which means 12 volts at 51 amps. (Spin them faster and they can get up to 55A.) As you can see, the model number is stamped on the top case. Type the number into a Google search and you'll find used ones for $50 and new for less than $200. Rebuild kits are available too.

The regulator is the big bump on the back and is replaceable. This photo of the owner's manual has captions for the terminals:

One thing to note if you want to go to a higher output alternator is that you will also need to change the pulleys, belt, and possibly the bracket. A 100A alternator is a lot of drag on an old V-belt and while it will work for a while it'll leave a lot of black rubber dust and have a short belt life.

 

[Christian Williams]

Good to know we can change an "internal" regulator.

There are a couple of popular solutions for belt drag on the larger alternators. One is simply to reduce the output (there's a selector). We can also install a cutoff switch, so the alternator doesn't start when the engine does (turn it on after the engine gets going, avoid the big drag as it starts).

The initial charge output relates to the state of the house bank, and since I rarely let the battery state go below 60 percent, the initial output of my Balmar 100 is only about 60 amps, which quickly starts to decline. I shut down the engine when the output declines to 15 amps, which means my batteries are about 85 percent charged. (Keeping the battery state between 50-85 percent is efficient practice, and means that offshore I only run the engine about 45 minutes a day to recharge).

I kept the original belt and pulley system and have no belt dust or slip. I'm told that every 25 amps requires one horsepower, and if the batteries are low and the Balmar is putting out 75 amps, you can hear the engine labor. So, for a bigger alternator and huge house bank that can accept a lot of charge suddenly, a more robust belt system is probably necessary.

 

[Baslin]

Here is a picture of the Balmar 120 Amp Alternator and serpentine pulley conversion installed on our 5432

 

[Coronadoe38]

Internal vs. External regulators

The stock (Motorola) alternator on Ericsons was rated about 50 amps. It has an internal regulator of limited intellectual capacity. It charges the batteries while the engine is running at a calm and steady pace, undistracted by greater expectations.

Upgraded alternators (100-amp Balmar etc.) have external regulators, also known as smart regulators. They are educated to vary the charge output according to the needs of the battery bank. If the battery is low, they flood it with juice, but as capacity declines they carefully back off so as not to boil the baby in the bathwater. Such smart regulators can recharge batteries much faster than their internal brethren. That cuts down the daily engine recharge time and saves fuel and noise.

However, a Balmar 100 and smart external regulator costs somewhere around $1,000+. It justifies its cost of education over time, but of course if you only write poems in the cellar an expensive college is a highly questionable investment.

View attachment 34241
External regulator on a Universal M25

The 2 PO’s of my boat had it on the Sea of Cortez for a number of years. So I have all double of everything on the boat. Pictures attached are the voltage regulator ( replaced with the spare) and the “emergency backup” the small one . My alternator also has the built on regulator.