Alt temp concerns

Maine Sail · Nov 10, 2015

jlp0217 said:
View attachment 116979 I looked at my Balmar 612D regulator the other day thinking about looking at the advanced programming to see if I thought anything needed tweeked. Found the following Error codes:
E54 - Alt 2 Temp Sense Mode
E23 - Alt 2 Hot
E22 - Alt 1 Hot
E17 - Alt 2 Temp Open
I cleared the codes but still had E54 & E17. Checked the alt 2 temp sensor and it is indeed open circuit, so I ordered a replacement.

A few days later, I was warming my engine for my fall oil change and decided to look at alt temp. I measured 245 Deg F. with my infrared thermometer at the center, where the thin magnetic plates are, but both ends, and the wire terminals were only warm to the touch, maybe 110 deg.
When the new temp sensor arrived I went about replacing it. It appears the old one failed because it melted. The Alt 1 temp sensor also has glue squeezing out of the heat shrink the the new one doesn't. The Alt 2 sensor had the alt ground wire pressing against it which probably caused it to deform and break the connection.

I wrote & mentioned when I installed the regulator that I clamped the temp sensor to the alt case with a large hose clamp because it was much to large to install on the case bolts as instructed by Balmar. You responded that I should/could mount it to the the power terminals preferably the neg. I chose not to because the terminal was to large even for that. The terminal posts are smaller than 1/4 in(m4 or 5) and the hole in the terminal is greater than 5/16.

Anyway, it appears there is poor thermal conductivity between the middle of the alt, and the ends, allowing the alt to get and stay very hot long before the regulator is able to sense it.
On the other hand, if I were to manage to get the sensor in contact with the hot middle part of the alt, I'll probably never get any significant current out of it.

My system: Perkins 4.236 with 2 Prestolite Leese Neville 8MR2069A 90 Amp Alts modified for external regulation. Balmar 612 Dual regulator. Alts wired directly to house bank with 4 #2 wires aprox 10 ft. Regulator grounds and voltage sense also direct to house bank. House bank is 3 4D Lifeline AGMs. Also 2 Optima Group 31s in bow for thruster/windlass connected by ACR and 2/0 wire(30 ft one way), and a flooded group 24 start battery also connectd by 2/0 wire and ACR. Each of the 3 battery banks have their own Victron BMV 700 battery monitor. On dock with shore power charging most of the time.

While those alts a decent little buggers, for the price, they really are not suited to that type of duty for the duration you are expecting. Automotive based alts, and the 8MR is a slightly tweaked version of an auto alt, are really intended for about 10-15 minutes of bulk, max, then having the current decline due to the battery exiting bulk and catching a break in absorption.

You will want to dial the reg back using "amp manager" or, depending on the age of the regulator, "belt manager". You will want to take them down to 60-65A Max output then set temp sensing at approx 225F... If you are melting the temp sensor you are literally cooking the alt. Often the best place for a temp sensor is the negative stud, if it is an isolated ground model. This puts you in direct contact with the negative rectifier.

Current Limiting:
Simply put there is no small case alternator on the planet that can run at full bore for multiple hours into a large load in boats engine bay and survive for very long doing so..

Amp Manager or Belt Manager (same thing) help save and extend the life of your alternator. Balmar calls this BELT MANAGER, it was formerly called AMP MANAGER, which I still feel is a better term, but it works for both belts and saving the life of your alternator.

Current limiting the regulator output allows you to essentially derate the output of your alternator by limiting the maximum field potential to the alternator. The blue field wire from the regulator is what drives the alternator. Simple stuff. By limiting the capability of the field wire you, in turn, limit how much current the alternator can drive.

This is a simple adjustment in the settings menu. A SMALL CASE ALT LIKE THE 8MR SHOULD NOT BE RUN AT FULL BORE into a large AGM bank....

Every alternator will be slightly different but usually Belt Manager level 3 or 4 is a good place to start. If your reg uses Amp Manager it had more steps so you'll need to figure that out. I generally suggest buying an alternator that is larger than where you want the expected hot rated output to be and then dialing it back in Belt Manager to a survivable charge rate..

As an example I run a fully custom built 160A Mark Grasser DC Solutions alternator on our boat and she is current limited to 120A. She will drive at 115A - 120A all day long and never break *220F (*with good cooling). This is exactly what I want to see.

I do this during the set up and commissioning stage of the install by limiting the regulators max potential using Belt Manager. This keeps the alternator from melting itself down and prolongs its useful life.. It also gives you a known value for charge current that won't vary nearly as much due to temp limiting or heat inefficiencies...

RPM, Engine Room Temp & Current Limiting:
What does low engine RPM have to do with alternator heat? Many sailors and cruisers want to charge at low RPM while on the hook. Today's high performance alternators can put out a substantial portion of their total output at just a fast engine idle. This is good as it keeps your neighbors happier in the anchorage. However it is bad for most alternators.

The problem with low RPM charging is that with a fast idle we have a very slow alternator fan speed. The speed of the rotor actually keeps the alternator cool because it is direct coupled to the fan.

The most abusive loads for a high performance alternator are not always at cruise RPM, they are usually at fast idle when the alt can't dissipate the heat for the current it can produce. Keep in mind many of the new small case alternators can handle 17,000 - 19,000 shaft RPM. This would create excellent cooling but we never get there on most cruising boats.

Because of this the alternator is best set up and hot-load tested to fast idle RPM. This is where it will get the hottest.

Alternator Set Up & Load Testing:
It is not just good enough to program the regulator and walk away but sadly this is "how it's done"... Every alternator will respond differently to the field wire from the regulator. Proper set up will lead to a long alternator life and an alternator that can survive the abuse a large AGM bank can throw at it.

You will need the following:

#1 An on-board inverter capable of exceeding the alternators current capability, usually 2000W or more, or a portable inverter capable of at least 2000W or more.

#2 A good restive AC load such as a heat gun, hair dryer or portable heater. If the alternator and inverter are large enough you may need two of these devices.

#3 A remote temperature sensor attached to the alternator case that can be read with the engine room 100% closed up and sealed tight. Most DVM's offer a remote temp probe. I use the one that came with my Fluke.

Hot load testing and set up:

Step #1 - Connect temp sensor to alt and close engine room

Step #2 - Go out and run the boat under load, with the inverter loaded down by the heater, and at cruise RPM for at least 30 minutes. The longer the better. Remember we are using the inverter the whole time to simulate a full field / bulk situation and loading the alt to its maximum output.

Step #3 - Does the alt go above 225F? If so move to Belt Manager #1 and keep running. If it exceeds 225F again drop to level #2 and repeat. Once it stays below 225F go to step #4..

Step #4 - Return to dock or mooring and leave the motor running at fast idle and continue to monitor the temp.

Step #5 - Keep inverter/AC load running. This load should be well in excess of alternators capability.

Step #6 - Monitor alternator temp, does temp exceed 225F?

Step #7 - If so, adjust Balmar Belt Manager down again.

Step #8 - Continue load testing and monitor temp, did the alt still go over 225F?

Step #9 - If so move to Belt Manager down once more.

Continue this process until the alternator stays below 225F loaded to max output in the sealed engine room. Using your engine room blower to remove heat from the top of the engine room, heat rises, can also help.

TIP:
I usually start at Belt Manager Level #4 and work my way up but this is with higher performance alts than the 8MR. Most high performance alts do best with level #3 or #4 but some wimpy factory conversions require going as deep as level 6 or 7.

NOTE:
Balmar's Belt Manger used to be called Amp Manger in previous regulators. It is the feature you use to current limit your alternator and prevent it from cooking itself.

Temp Compensation:
Alternator temp compensation should always be used and will become your redundant insurance policy beyond Belt Manger/current limiting. Belt Manager is your primary alternator protection feature then, the temp sensor.

Stu Jackson · Nov 10, 2015

Maine Sail's right.

Like these:

Alternator heat, Regulator Controls, Small Engine Mode

http://c34.org/bbs/index.php/topic,4454.0.html

Small Engine Mode - discussion with link to the picture of the toggle switch: http://c34.org/bbs/index.php/topic,4454.msg27149.html#msg27149

Small Engine Mode - the picture of the toggle switch http://c34.org/bbs/index.php/topic,4669.0.html

PLEASE NOTE that these links ALSO discuss the use of the "Amp Manager" feature, too.

Stu Jackson · Nov 11, 2015

jlp0217 said:
Stu
That link implies temp compensation and small engine mode are the same because they use the same input pins on the regulator. The regulator knows the difference between the temp sensor and a short. It knows and displays temp in deg. Celsius, and presumably uses that info for finer control of alternator output. My problem seems to be that the alternator case is a poor place to monitor temperature because it takes a long time for the heat to get there. Seems the right place would be to monitor the temp of the cooling airflow out the front of the alternator, like computer fans do.

jlp,

It is not that it "implies" that, but it IS that it is the SAME connection. And it is not a "short" but rather the OPENING of a circuit that makes the Small Engine Mode work. Either the toggle switch or the sensor performs this function. You could wire them both.

As Maine Sail has noted many, many times, the older MC-612's sensors cut back the output by 50%, just as the SEM toggle switch does. the newer MC-614 has a gradual sensor that cuts back in stages from 100% until the sensor is satisfied, getting more out the alternator. A slight change to the algorithm goes a long way.

While you may be right about the "immediacy" of measuring the air vs. the case, eventually one could make the point that they'd be measuring the same variable and perhaps with different setpoints. If the air gets to X degrees, that would be one indicator; if the case gets to Y temperature that would be a different situation.

Maine Sail knows better than I do just what the sensors are "set" for. Personally and professionally as an engineer, it wouldn't matter as long as the resultant controls to avoid overheating meet the design criteria.

It'd be like the difference between using an outdoor thermostat to start your air conditioning system, or perhaps just the outdoor air component of an air handling system: either an air bulb or a strap on sensor to something, both in the shade.

Stu Jackson · Nov 11, 2015

jlp0217 said:
k, but I thought that's why I paid the $160 for the temp sensors. Maybe I'll try to clamp the sensors to the hot part of the alt, turn off the shore charger for a couple days, and then start the engine and monitor the charging process, amps and temps.

As noted in those links, I specifically CHOSE to perform this function manually. I have enough instrumentation (my Link 2000) and experience, to do this.

The sensor is actually "better" as a "set it and forget" but one should recognize and have instrumentation to know that the output of the alternator is less than "usual" when the house bank is depleted and the alternator is being "taxed to the max" when it would start cutting back because of the sensor.

It is both an operational and management issue.

That's why a battery monitor or at least a Smart Gauge is so handy for recreational boaters.

Your boat, your choice.

Stu Jackson · Nov 11, 2015

jlp0217 said:
Maybe I'll try to clamp the sensors to the hot part of the alt, turn off the shore charger for a couple days, and then start the engine and monitor the charging process, amps and temps.

Not sure why you'd do this when Maine Sail just provided a detailed "How To Do It" step-by-step.

Stu Jackson · Nov 11, 2015

Maine Sail said:
I generally suggest buying an alternator that is larger than where you want the expected hot rated output to be and then dialing it back in Belt Manager to a survivable charge rate..

This part is understated, but CRITICAL to the system operation.

jlp0217 said:
Ok, but I thought that's why I paid the $160 for the temp sensors.

The Amp or Belt Manager feature derates the alternator output to make it last longer and stay cooler. The temp sensor is a safeguard.

These are two SEPARATE things.

Maine Sail · Nov 11, 2015

jlp0217 said:
Ok, but I thought that's why I paid the $160 for the temp sensors. Maybe I'll try to clamp the sensors to the hot part of the alt, turn off the shore charger for a couple days, and then start the engine and monitor the charging process, amps and temps.

You paid for the temp sensors as insurance against cooking your alternator. Unfortunately you still got one so hot that it physically melted. A properly set up small case alt, feeding a large bank, especially AGM, should always include current limiting the alternator so it can safely run at a temp where it won't kill itself.

Rule #1 of small case alternators:

NEVER EXPECT NOR DEMAND THE RATED OUTPUT FROM THEM FOR LONG PERIODS

Yes the max your 90A 8MR can safely run for long duration's will be around 60A - 70A nowhere near 90A. Trying to run it at full bore will simply murder it well before it is due. It is a great little alt for the PRICE POINT, but it is really not a high performance alternator.

So FIRST current limit the alternators with Belt Manager

Next mount the temps sensor to the negative stud or back of the case where the rectifier is. The alternator case draw-bolts can also work on some alts. If you sized your negative #4GA terminal correctly then the temp sensor can stack on it and then a washer on top of the temp sensor then the lock washer then nut. A high performance alternator would have a 5/16" negative stud and this is why the temp sensor is a 5/16" lug.... Positive could also be used, and is another good location, but is NOT recommended because a temp sensor can not be fused and still sense temp correctly.

If the temp sensor is not sensing the heat correctly then it is up to the installer to adjust the regulator and compensate for this. For example if the rectifier is at 245F yet the aluminum on the back of the case is only 185F then you reduce the temp limit to about 170F and give it a test run.

Properly setting up a high performance alternator system should always include hot load testing where the alt is fully loaded to max as I described above using a dummy load such as a heater and an inverter. Anything less than this is simply not going to result in the optimal performance from the system one expects. Just this portion of the job alone can take upwards of two to four hours to get the system fully dialed in. Installing and wiring the system is only part of it, the programming, set up & hot load testing is the rest of it...

woodster · Nov 12, 2015

jlp0217 said:
but on the other hand it doesn't make sense to limit alt output when it is not hot.

those alts get really hot no matter what the ambient temp is .... some time when it's cold outside try to lay your hand on it when it's been running for 30 min.....