Is my alternator/controller dying?

[bridge100]

Barrus (Mitsubushi) 80 watt alternator, Stirling advanced regulator - both about 8 years old, 1700 hours.

 

I noticed while cruising along the domestic voltage on the Smart guage was reading 15.2v, also the high voltage light was on on the controller. Stopped the engine, re-started, no problems, normal voltage but kept rpm low. Back in the marina found a small wire from the back of the alternator, which connected to the main battery feed stud, had not been crimped correctly and was loose. I remade the connection and cleaned up all alternator connections. Ran the engine for about 10 mins at various revs, all normal.

 

I have a battery charger on shoreline and this keeps the SOC 100%. This weekend took the boat out and after a few minutes at low rpm the low voltage buzzer came on and stayed on, and domestic voltage was down to 13.5 from approx 14.4. Stopped the engine, re-started, buzzer and voltage still misbehaving. At 1200rpm, buzzer beeped every 2 seconds or so. Rechecked all connections and found satisfactory. Found by putting the headlight on the buzzing stopped, even at tickover and voltage was normal. SOC 100%.

 

Next day, after using the inverter overnight, SOC 76%, buzzer and voltage normal, even when SOC up to 100% and no headlight on.

 

Do I need the alternator or Stirling regulator tested? Any other suggestions? Thanks!

[Gibbo]

...small wire from the back of the alternator, which connected to the main battery feed stud....

 

Are you sure about that bit? Or did you mean a small wire form the controller?

[bridge100]

http://s1136.photobucket.com/albums/n483/bimble100/

Thanks for the prompt reply Gibbo.

 

Hope the pics will post its my first time with Photobucket!

 

Its the green wire on the back of the alternator which goes to the stud with a heavy red wire that goes to the domestic battery bank

[WotEver]

Hope the pics will post its my first time with Photobucket!

 

Copy/paste the "IMG Code" from Photobucket's page. Like this:

 

 

[bridge100]

Thanks for that Wot Ever.

 

So much to learn so much time! now i am semi retired

[Sir Nibble]

Barrus (Mitsubushi) 80 watt alternator, Stirling advanced regulator - both about 8 years old, 1700 hours.

 

I noticed while cruising along the domestic voltage on the Smart guage was reading 15.2v, also the high voltage light was on on the controller. Stopped the engine, re-started, no problems, normal voltage but kept rpm low. Back in the marina found a small wire from the back of the alternator, which connected to the main battery feed stud, had not been crimped correctly and was loose. I remade the connection and cleaned up all alternator connections. Ran the engine for about 10 mins at various revs, all normal.

 

I have a battery charger on shoreline and this keeps the SOC 100%. This weekend took the boat out and after a few minutes at low rpm the low voltage buzzer came on and stayed on, and domestic voltage was down to 13.5 from approx 14.4. Stopped the engine, re-started, buzzer and voltage still misbehaving. At 1200rpm, buzzer beeped every 2 seconds or so. Rechecked all connections and found satisfactory. Found by putting the headlight on the buzzing stopped, even at tickover and voltage was normal. SOC 100%.

 

Next day, after using the inverter overnight, SOC 76%, buzzer and voltage normal, even when SOC up to 100% and no headlight on.

 

Do I need the alternator or Stirling regulator tested? Any other suggestions? Thanks!

Ooooh boy. Firstly, the green cable is the sensing lead for the regulator so this bit..

I remade the connection and cleaned up all alternator connections. Ran the engine for about 10 mins at various revs, all normal.

Suggests that the aternator's internal reg is doing the job and the sterling is a passenger. Unfortunately the rest of your observations all suggest contradictory things.

Prime cause of failure on these mitsubishis is brush wear and some of the symptoms suggest that but again others contradict it!

This one could run and run.

[Gibbo]

I'm trying to spot a pattern and I can't. Nothing makes sense.

 

So much so that I'm wondering if the report has missed some vital info or we've been given a wrong description.

[Sir Nibble]

I'm trying to spot a pattern and I can't. Nothing makes sense.

now THAT'S what I was trying to say!

[WotEver]

Rechecked all connections and found satisfactory.

Including those on the batteries? And the earth stud?

 

Tony

[bridge100]

Thanks for the replies.

I've re-checked my description and it's just as it happened (see end para.). I had checked and cleaned the battery stud and the battery conections.

The buzzer stopped IMMEDIATELY I put the headlight on and returned IMMEDIATELY when the headlight was switched off.

So I left it on (covered with a woolley hat as folks kept telling me it was on!!)

With overnight use the battery SOC 76% it all worked,no buzzer or low volts indication even with the headlight off.

The only thing that was different was a new Numax shore powered charger.I think the voltage at 100% SOC was 13.5v

Could this be having an effect on the voltage in the batteries.i.e. being in a totaly full charged state, and the engine charging system shuting down!! as it detected mabye too high a voltage.

I did omit, to keep it simple, that it happened two days running both times after an overnight shore line battery charge. It was only on the second day that i tried it with the headlight on.

[Sir Nibble]

Thanks for the replies.

I've re-checked my description and it's just as it happened (see end para.). I had checked and cleaned the battery stud and the battery conections.

The buzzer stopped IMMEDIATELY I put the headlight on and returned IMMEDIATELY when the headlight was switched off.

So I left it on (covered with a woolley hat as folks kept telling me it was on!!)

With overnight use the battery SOC 76% it all worked,no buzzer or low volts indication even with the headlight off.

The only thing that was different was a new Numax shore powered charger.I think the voltage at 100% SOC was 13.5v

Could this be having an effect on the voltage in the batteries.i.e. being in a totaly full charged state, and the engine charging system shuting down!! as it detected mabye too high a voltage.

I did omit, to keep it simple, that it happened two days running both times after an overnight shore line battery charge. It was only on the second day that i tried it with the headlight on.

This is where the difficulty is. Turning on the light to kill the buzzer, especially after an overnight charge STINKS of a full charged battery and freewheeling alternator, but the voltage readings give the lie to that.

How has it been since?

[bridge100]

I will not be back at the boat for about a week.

I will monitor the voltage at variuos stages and load up with lights etc if the problem persists

I will post back on here the results

 

Thanks all

 

I will not be back at the boat for about a week.

I will monitor the voltage at variuos stages and load up with lights etc if the problem persists

I will post back on here the results

 

Thanks all

[Robin2]

Reading through the OPs posts it looks like there may have been a problem with strange voltages caused by a loose wire which he corrected and now there is a problem with the buzzer.

[bridge100]

UPDATE

 

I had the alternator checked, all satisfactory.

Refitted alternator,disconected battery charger.

Turned on isolators. SmartGauge SOC 100% domestic volts 13.6.

Started engine low volt buzzer went out at 1500rpm volts 14.75.

Reduced rpm to 1100 after 2 mins the buzzer came on and volts read 13.5.

At 1400.rpm buzzer intermitent 2-3 seconds volts now at 14.2.

Switched on headlight and buzzer stopped. turned it off and buzzer returned.

Overnight i used the inverter and 12v lights (charger not connected)

in the morning SOC 94% v12.6.

Started engine ran for 10mins at 1100rpm all ok

Turned on all 12v lights, h/light inverter working 240v fridge,reduced down to 900rpm for about 20 mins all ok.

Then set 1100rpm and SOC 100% after 1hr 35 mins

I have not connected the charger, so I will update when we have next been out for a few days.

If all seems ok i will use the old 6amp charger and see what happens

Just seems a coincidence that its been a problem since i have used the Numax 30amp charger

[bridge100]

I had not conected any charger and this last visit all behaved correctly

I do think it is my new Mumax 30amp charger "topping up the batteries to much"

 

I have reverted to my 6 amp charger so i will report what happens

[by'eck]

Barrus (Mitsubushi) 80 watt alternator, Stirling advanced regulator - both about 8 years old, 1700 hours.

 

I noticed while cruising along the domestic voltage on the Smart guage was reading 15.2v, also the high voltage light was on on the controller. Stopped the engine, re-started, no problems, normal voltage but kept rpm low. Back in the marina found a small wire from the back of the alternator, which connected to the main battery feed stud, had not been crimped correctly and was loose. I remade the connection and cleaned up all alternator connections. Ran the engine for about 10 mins at various revs, all normal.

 

I have a battery charger on shoreline and this keeps the SOC 100%. This weekend took the boat out and after a few minutes at low rpm the low voltage buzzer came on and stayed on, and domestic voltage was down to 13.5 from approx 14.4. Stopped the engine, re-started, buzzer and voltage still misbehaving. At 1200rpm, buzzer beeped every 2 seconds or so. Rechecked all connections and found satisfactory. Found by putting the headlight on the buzzing stopped, even at tickover and voltage was normal. SOC 100%.

 

Next day, after using the inverter overnight, SOC 76%, buzzer and voltage normal, even when SOC up to 100% and no headlight on.

 

Do I need the alternator or Stirling regulator tested? Any other suggestions? Thanks!

 

Sounds like the sensing wire (red) on the Sterling regulator was not making good connection with battery(s). This regulator would then force alternator output up to the point where it exceeded 15 volts, at which point high voltage alarm would trip (red light) shutting down alternator until engine re-start.

 

It may even explain the strange behavior requiring tunnel light to be on.

 

BTW the Sterling regulator can be effectively disconnected by breaking the connection of its (green or white) field wire, leaving just the alternators built-in regulator. As well as being useful for fault finding, its a neat way of seeing what improvement in charge rate/voltage this alternator booster gives.

Edited April 5, 2011 by richardhula