Is this normal?

[nautikaljeeper]

I installed a Electromaxx 140 alternator with the internal regulator left as is. In testing the the system I found the alternator getting quite hot. Taken with a infrared gun, temps would range from 200-250 degrees F depending on where it was shot. I then decided it would be best if I went with a smart regulator as I frequently read on this forum. Now after install of Balmar MC-614 with all battery temp and alternator temp sensors I see the regulator limits the amps charged to almost half when the temp of alternator reaches around 100 degrees celsius and it will max out at 106 C . Then as it has a chance to cool below 100 degrees C it will resume back to a high output charge. The motor is a 3YM30 and when the engine cover is closed it could take many minutes for the alternator to cool below 100 C to resume high output charging. When the motor cover is open alternator performs about 2 1/2 minutes of high output charging and will reduce charging output about half for another 2 1/2 minutes and will continue that cycling from high output to low output. I am assuming this is all normal(or hope so) and now know why the need for the smart regulator as discussed many times on this forum. I understand about the acceptance from a battery depending on it's voltage and the parameters of the test was:

rpm 1400-1600
AGM Battery bank 630 amp hrs
SOC of bank 76%-82%
amps being charged at high output: 90-110 amps depending on SOC
amps being charged when alt temp reached 100 degrees Celsius 45-50 amps
battery bank temp 20-22 degrees C

So after these findings I ducted cool air from a 3 inch blower motor to the front of the alternator (picture below). Now when I have the engine compartment closed I get the same results as when the engine cover was open. I was hoping for continuous running temps below 100 C but it still runs up to 104 degrees C and charges in low output for 2 1/2 minutes and cools down and cycles back to high output faster. My thoughts are that I would only need this fan on for times mooring or at anchor or quick motorings to and from to charge bank up faster.

The reason for this post was to run it by the people in the know and to bring to my attention something that I could be doing wrong. So any feedback would be appreciated.

 

[Bob 04 H260]

Thanks for posting this, quite interesting. I also have the Electromaxx 140 amp alternator, but on a 3GH30F, with a 400 amp hr AGM bank and Sterling regulator with alt & batt temp sensors. We have seen the alternator put out 153 amps !

Our boat came from the factory with a fresh air engine supply and exhaust blower. It cools the engine compartment down. The orange hose is the exhaust, the grey hose behind the alternator is the fresh air supply.

We have not noticed this temperature limiting effect yet. We do only use the boat in the winter time in Florida so probably not as hot an ambient temperature as you are testing in.

So far I believe the alternator output has only gone down with battery acceptance and not been limited by the temperature, but with our smaller bank we are usually back to 95% in no time with this alternator.

I was thinking about adding a wireless thermometer to the engine compartment just to see what is going on down there. I may do that this fall when are back on board. I'll check my alternator temperature as well.

Bob

 

[nautikaljeeper]

Bob I first installed the smart regulator in the engine compartment and while monitoring the temps of the regulator I decided to move it to a cooler position. I seen that the regulator was reaching temps close to 150 degrees F and that was about an hour of motoring. That is interesting your boat came from the factory the way it is set up.

One of my thoughts is the reason I haven't seen the alternator put out more amps is because the SOC is around 80% and the rpms I chose to run at were low. I have check my voltage drop from Alt to Batt and it is .2 or a bit lower. But I could stand to be corrected. I am glad that the Balmar MC-614 is keeping the temp of the alternator down by lowering the output but I would like to know if this is normal in my application. Bob does the Sterling regulator have a temp sensor for the alternator? The addition of the blower has a big effect on cool down time to resume "normal" output.

 

[Bob 04 H260]

Bob I first installed the smart regulator in the engine compartment and while monitoring the temps of the regulator I decided to move it to a cooler position. I seen that the regulator was reaching temps close to 150 degrees F and that was about an hour of motoring. That is interesting your boat came from the factory the way it is set up.

One of my thoughts is the reason I haven't seen the alternator put out more amps is because the SOC is around 80% and the rpms I chose to run at were low. I have check my voltage drop from Alt to Batt and it is .2 or a bit lower. But I could stand to be corrected. I am glad that the Balmar MC-614 is keeping the temp of the alternator down by lowering the output but I would like to know if this is normal in my application. Bob does the Sterling regulator have a temp sensor for the alternator? The addition of the blower has a big effect on cool down time to resume "normal" output.

yes the Sterling reg. came with both temp sensors, battery & alternator, it does not have the adjustability of the Balmar regulator has but is not nearly as expensive either. The alternator, belt kit and regulator were all purchased as a package from Electromaxx so I do not know the actual cost of each item.

I will keep an eye on the regulator temperature and if it becomes worrisome I can easily move it to the back of that bulkhead so it would be inside the cabinet in the aft cabin.

My limited experience has been that the alternator will put out almost maximum at about 1800 rpm's. It can be hard to keep track of because of the acceptance of the battery bank and then the high output of the alternator does fill it up so fast. Usually we are moving when motoring not running at anchor so we have our focus on the charts etc. and not monitoring the battery monitor.

The engine air intake and exhaust were installed in the vessel transom as two s/s clam shells, you can see them in the first picture, second picture shows blower location......the Hunter website has the SOP to install this package on the 356 model, probably would be the same on the H36, it was designed so the dealer could do it, usually came on the vessel if it had a fire suppression system. We found it really keeps the cabin cooler when motoring on the ICW on a hot day and you then stop to anchor out for the night.

good luck, Bob