Alternators burning out

[Glenn Spilsted]

Brains Trust

I am constantly burning out my stbd alternator, 3 in the last 4 years. They are Alternator Delco Type 12V 105Amp 19SI from Baxters. This is their recommended model for Cummins 6BTA 5.9 . It is connected to 2 x 12volt 280AH AGM batteries; this is stbd start batteries and house bank . All wiring is as originally fitted.

I was returning from Smiths Creek after an extended stay( house batteries may have been a little low but no problems starting engine with them) and checked engine room when I berthed. There was smoke and an electrical smell in engine room. Alternator was extremely hot and smoking. The battery bank was cool to touch. Connected to shore power and battery charger started charging this bank.

I went back next day and the alternator was still hot, obviously still drawing power so I disconnected all wires to it.

I have done a bit of googleing and there are plenty of posts with people having same problems.

Any thoughts,

Topic

[Tony Athens]

Battery Terminal Voltage ?

So, the real answer to the question I asked should be , I am not monitoring Battery Terminal voltage

Trying to sort out issues like you describe begins with that, so IMO, you are driving blind regardless of whether you are asking too much of your alternator.

[Richard G Cook]

Improved alternator/regulator setup

On my 330hp 6BTA 5.9 M3, I replaced the stock 19si alternator with Tony’s 145A version.  Had an alternator shop modify it to use external regulation, and installed a Balmar MaxCharge 614 regulator. The regulator senses both battery temp and alternator temp, and reduces charging output if it needs to to maintain low enough temperature. In extensive use cruising the Inside Passage from WA to  Southeast AK, it charges a total of nine group 31 AGM’s without getting too hot. Has worked like a charm for five summers.

While messing with the alternator, also replaced the bolt holding the idler pulley with Tony’s 7/16″ bolt and spacer kit – well worth doing.

[JimmyK]

sounds like you’re asking the alternator to do too much.  do you have a huge battery bank or maybe other high DC loads like an inverter?

you either have to reduce the demand on the alternator or get a more capable unit in there.

as far as reducing the load, start by telling us about your DC loads and also tell us about your air pre-heaters…still installed and hooked up?  do you have any idea how often they’re ‘on’ when you’re using the boat?  they draw a ton of current which translates to a wicked load on the alternator.  if you don’t need them then it’s best to just disconnect them.  if you do need them it’s best to put them on a control switch at the helm so you can turn them on when needed (cold starts, cold running), and turn them off when warmed up.  I do a lot of trolling in cool temps and those things would be on & off literally all day long until I finally put them on a switch and just used them when needed.  big reduction in wear on the alternator.

[Glenn Spilsted]

This is the model of alternator.

 

[Glenn Spilsted]

Tony

Thanks for the input, next time I am on boat I will get some pictures.

The voltage meters on the bridge are the standard models fitted to 1999 Rivs. I monitor these during transits. There are also 2 as fitted in the saloon on the switch board that I monitor when at anchor.

There is nothing actually to see as far as external damage goes. It cooked internally as I could smell the distinct electrical smell and my hand would have blistered if I touched it. I noticed the Tacho stopped working on the way back from my trip and the voltage metre dropped to around 12.8 volts, unlike the other engine voltage  meter which showed around 13.8 volts.  I started the engine today and there was a squealing noise coming from it, probably buggered bearings.

I am loathed to replace it with the same model of alternator on the off chance that it is not suitable for my setup. Three of this same model have cooked themselves. 

[Tony Athens]

How about posting good pics from all angle of one of your “burned out” alternators.. Want so see it all–his re and clear and in focus. 

 

Exactly, how are you measuring “Battery terminal voltage” while running the boat? Be accurate in this answer.

Start with that

[Author]

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