Alternator overheat solution

[wmcunninghamii]

Originally Posted by wsmurdoch

GM used the 10DN alternator from 1963 to 1972. That was a long time ago, and they have made progress since. https://alternatorparts.com/how-to-i...lternator.html For some idea of the improvements that have resulted in the open frame alternator designs look at https://www.electronics-cooling.com/...%20electronics. It is more than a few holes.

Bill

On the Balmar alternator I have installed I donlt know how you would increase the size of vents. Both ends of the alt are basically a cage, a certain amount of metal is necessary to hold the thing together.

I am seeing temps of 240F which I verified with an IR gun, engine and alt loaded up. That is too hot.

At this point I feel like In need to improve ventilation. I have

1. Inspected the alternator on the bench with no (obvious) signs of bearing failure

2. Retrofitted the engine with serpentine belt to eliminate possibility of belt slippage and associated heat and dusting

3. Verified the alternator is functioning when cool - albeit the output current is suspect pending a reverification after hearing comments from others here

4. Implemented belt management to derate the 70 amp alt by 15% - this was accomplished years ago based upon engine size (Yan 2GM20F) and in accord with Balmar recommendations based upon my bank capacity of 230 AH

So I think the next step is to improve air flow and see what that buys me. I am going to see if I can do this without doing any drilling. May even go out for some testing with the engine room open and a fan directed at the alt just to see if I can prevent overheat.

[wingssail]

I really wonder if the use of Belt Manager is appropriate. With a serpentine belt you should not have to worry about the belt, which is the purpose of the belt manager setting.

Your problem is over heating. The ARS5 with alternator temp sensor will reduce the output when temperatures get too hot. You can adjust temperature setting on the ARS5 to a lower point, but the standard setting for AGM batteries and the standard settings for temperature should keep things cool enough and still have about 50% output. You could also reduce the bulk and absorb voltages which will reduce the maximum output and temperature, if you feel the alternator is trying to put out too much.

On my Balmar 110amp with the ARS5 I have left the standard settings and the alternator does run hot. But when the temp gets over 100 and the ARS5 reduces the output to about 50%, the temperature comes down immediately, in less than a minute.

I do not have any airflow into my mostly sealed engine box which sits in the middle of the salon.

I honestly think that extra cooling will help, but it should not be necessary.

[wmcunninghamii]

Originally Posted by wingssail

I really wonder if the use of Belt Manager is appropriate. With a serpentine belt you should not have to worry about the belt, which is the purpose of the belt manager setting.

Your problem is over heating. The ARS5 with alternator temp sensor will reduce the output when temperatures get too hot. You can adjust temperature setting on the ARS5 to a lower point, but the standard setting for AGM batteries and the standard settings for temperature should keep things cool enough and still have about 50% output. You could also reduce the bulk and absorb voltages which will reduce the maximum output and temperature, if you feel the alternator is trying to put out too much.

On my Balmar 110amp with the ARS5 I have left the standard settings and the alternator does run hot. But when the temp gets over 100 and the ARS5 reduces the output to about 50%, the temperature comes down immediately, in less than a minute.

I do not have any airflow into my mostly sealed engine box which sits in the middle of the salon.

I honestly think that extra cooling will help, but it should not be necessary.

Yes, I also thought I ought to tweak the belt management once the serpentine was in but I have held off pending the resolution of the heat issue.

What you are describing is exactly what I am experiencing, that is the alternator heats up, the regulator reacts by logging an overheat event and simultaneously the regulator cuts the alt field current to 50% and things cool down.

The Balmar manual specifically warns that this should NOT be a standard operational mode. They assert the heating problem needs to be rectified and that the purpose of SEM is to give the skipper with a smaller engine a bit of increased engine power in circumstances where when more propulsion power may be desirable.

SEM basically simulates an overheat alarm by shorting the alternator temp sensor. BTW SEM also, annoyingly, causes an overheat alarm log entry in the regulator SW which are a pain to clear.

I do not want to alter bulk/absorption/float voltages. I have them set per battery manufacturers spec.

Interestingly, different manufacturers have different set points for their AGMs. I am also seeking a customizable shore power charger because my Zantrex has a fixed dip switch "battery type" setting with incorrect bulk/absorbtion/float voltages for my new AGM batteries. The Balmar ARS5 and my Kidd SA controller both have custom settings.

[wmcunninghamii]

Just a quick update after fussing with the overheat problem for another six months.

I further reduced load on the alt via BLM setting on my regulator. Helped a bit but still heating up, even in the colder winter weather with my newly installed engine room blower turned on.

Something is definitely wrong.

Quicjk review of actions taken
1. installed serpentine pulley/belt to replace old single V belt
2. Installed 200 CFM blower into engine room, outlet located adjacent to alternator
3. Further reduced BLM setting in ARS-5 to 30% field reduction
4. Verified to extent possible bearings were running smooth
5. Replaced alt temp sensor and while doing so Found a potential on stator tach stud despite engine not running

It so happens my Balmar alt temp sensor failed (or the third time in six years), I purchased a new one and during installation I got some sparking from the stator tach output on the alternator even though motor was stopped. On my Balmar alternator the stator output connection is pretty exposed on the back fo the unit and is easy to contact as I withdraw the case bolt for installation of the sensor.

This looks like I my have a failed diode(s) in the alternator. I had been planning to do a rebuild in any event, the alt is 14 years old with maybe 1500 hours on it, so the overheating combined with age was driving me to a rebuild as a "I have tried everything else" sort of solution.

Meanwhile I noted Compass Marine has a pretty good deal on a complete replacement alternator which has a greater output spec by 40% and is not much more expensive than a rebuild kit plus labor to accomplish the job. I spoke to Rod at Compass Marine a kicked my issues around with him, Very nice fellow. He heard my description of what was happening and thought a diode failure was likely.

At the end of the day I decided to purchase a 120 amp alternator from Compass. He will fit with a new Balmar serpentine pulley and I will be good to go plus I get a lot more headroom for charging my 240 AH house bank.

I plan to upgrade to Lipo when my current AGMs reach EOL so this alternator will serve for that future upgrade too.

My plan is to retain the old balmar and when budget is available I may consider the rebuild so I have a spare alternator available.

I should have the new alternator is a month or so...there is a lead time since Compass builds the alternators in house. I will do another update when I have it installed.

[wsmurdoch]

Interesting that you have had multiple Balmar alternator temperature sensor failures. I have too except that I have had only one. I took mine apart to see what was inside. The sensing element is a LM235H if I read the markings correctly. The failure was due to a bad solder joint.

[wmcunninghamii]

Originally Posted by wsmurdoch

Interesting that you have had multiple Balmar alternator temperature sensor failures. I have too except that I have had only one. I took mine apart to see what was inside. The sensing element is a LM235H if I read the markings correctly. The failure was due to a bad solder joint.

I was going to ask about you actually. I noted your discussion re the poor engineering of this sensor and I agree completely.

In that vein I also disassembled my latest failed unit (what a pain) and did some heating experiments with the sensor (still encased in the stud though). Sure enough, the sensor still functions but looks like the solder joints failed. I do note that one of the sensors tiny studs looks loose, so that may also have been a contributor. Funny because I have the sensor (and stud in which it is encased) right next to my keyboard as I write this.

How on earth did you get the sensor out? In my case it looks like it is potted with hi temp epoxy or some such.

Have you attempted a DIY build?

BTW, on my Freedom 30 the oil filter is right below the alternator so when I do oil changes the cable/sensor shrink wrap is exposed to the roughhousing associated with filter removal and reinstall. Now that I finally realize how fragile that darn thing is I will be much more careful.

another BTW...looking at the LM235H online I see three leads to the device. How are these connected, there is an extra lead?

[wsmurdoch]

All by memory as it was some time ago...

I cut the heat shrink tubing away. I split the lug with a Dermal abrasive wheel and peeled it a bit. I warmed up the lug with a hot air gun to make the potting material cheese or leather like and took it apart. In my experience warm potting materials are sort of like cheddar cheese and can be torn away from the enclosed electronics although there is frequently damage to the electronics. I have also dismantled a failed Balmar regulator that way. It failed due to corrosion when water entered the gap between the aluminum extrusion and the potting compound and got to the circuit board.

I talked to Balmar about the sensor failure, but they did not offer a free replacement. I thought about making my own, but bought a new one. It just was easier.

In the photo you can see that one lead on the device is clipped off. I assume that Balmar has decided that calibration was not necessary. https://www.ti.com/lit/ds/symlink/lm...=1614759661738

Bill

[wmcunninghamii]

Originally Posted by wsmurdoch

All by memory as it was some time ago...

I cut the heat shrink tubing away. I split the lug with a Dermal abrasive wheel and peeled it a bit. I warmed up the lug with a hot air gun to make the potting material cheese or leather like and took it apart. In my experience warm potting materials are sort of like cheddar cheese and can be torn away from the enclosed electronics although there is frequently damage to the electronics. I have also dismantled a failed Balmar regulator that way. It failed due to corrosion when water entered the gap between the aluminum extrusion and the potting compound and got to the circuit board.

I talked to Balmar about the sensor failure, but they did not offer a free replacement. I thought about making my own, but bought a new one. It just was easier.

In the photo you can see that one lead on the device is clipped off. I assume that Balmar has decided that calibration was not necessary. https://www.ti.com/lit/ds/symlink/lm...=1614759661738

Bill

Thanks for the tech data. The temp sensor device is pretty interesting however It does seem like purchasing new makes sense from a hassle factor standpoint.

[MarineEscape]

Hi people, is anyone able to chime in here about making thier own temp sensor?

I'm going to do it and was after other people's experiences and advice.

[GordMay]

Greetings and welcome aboard the CF, MarineEscape.