Alternator Cooling

[captstu]

I'm about to install a 2500 Watt inverter on my 2010 R25 with a Yanmar 4BY2 and a small frame alternator. The inverter will mainly support a small, 4,000 Btu/Hr roof air conditioner I added for use underway because or Mace (means JUNK in Italian) generator is just to loud to run - even after installing additional sound proofing.

I'm concerned about the additional heat the alternator will produce. I had to replace it once when it failed with heat damage - without the additional load.

I'm looking for ideas on how to carry away the heat.

Water cooling? Wrap the alternator with copper coils and pump sea water around it?

Add a fan to blow more air into the engine compartment?

Thanks for your thoughts.

 

[BB marine]

I feel better ventilation is the answer. I spoke with Ranger/Cutwater about this and the response was the compartment is well ventilated and no heat issues at all. Not only the alternator but any electrical device doesn't fair well with heat. I've only boated in the midwest and have experienced tempetures over 140 degrees in my engine Compartment.We plan on boating in southern states this year. I imagine engine compartments get warm in Florida!!!


This vent is outside air and right infront of my alternator so the alternator fan is pulling cool air thru it.


Fan pulling hot air out of compartment. 250 CFM continuous run Fan. Rated for 5000 hours


Discharge of air from compartment.

I have an cockpit enclosure so I may have been getting an even warmer compartment because there was less outside air getting in my compartment. I also added a digital thermometer and installed the transducer next to my engine air intake so I can monitor induction air temperature. It reads out at my dash. Higher induction air temperature reduces horse power and engine longevity.

 

[captstu]

Brian, It seems you suck outside air from the aft end of the engine and blow ii directly on the alternator. Great idea - I can't get to that spot - behind the holding tank on my R-25 - so I was thinking of sucking the cool air from the battery compartment on the port aft end of the boat. ?? /Stu

 

[BB marine]

I actually bring cool air in from outside port side. I converted the fake vents into real vents and bring the cool air in low by the alternator. I suck the hot air out high with the blower and discharge it out the stainless vent that I installed on the port side hull. I have pictures in my album explaining install.

 

[captstu]

Brian, This is beautiful work. I was thinking of drawing air from my air conditioning/battery charger compartment, thru the area you cut out for storage under the port forward seat and feeding it into the alternator area - just letting the output flow out just over the back end of the alternator - not perfect, but much better than the heat retention space tey provided at build.

I'm held up trying to figure how to cut into the under-seat area. In the R-25s, there are apparently many wires in that area - and I don't want to cut into the spaghetti bowl! My last thought is to blind cut with a vibra-saw that is set to not quite cut all the way thru - and just pound out the remaining until the blank comes out - I cut in two other storage drawers under the table this way and it seemed to work OK.

Thanks for the inspiration - taking the air from inside the cabin is a compromise - but I want to draw in some fresh air anyway so this might work out.

I plan to power the blower off the inverter - as a 115 Volt low power device. I may re-think that and add a thermostat above the alternator - since automatic is important to me.

I'd like to add some cooling to the battery charger area - the fan on the charger cycles quite a bit and the charger goes off from overtemp some of the time. Still thinking about that?