svRuby

Would it be possible for you to post the rough (approximate) dimensions of the alternator? (diameter, height, center distance between the mounting "ears") I've been trying to find the details from other sources but failed. I am leaning toward this unit for my own system on my Beta 25 motor and if it will generally fit, Im going to buy one soon for testing. Thank you DanKim! Chris

Totally agree, I would need a programmable external regulator for sure. Here's some more specifics of my setup We are a race boat, we don't run the engine unless we need to charge batteries on long legs. If we are "cruising" or on a "return trip" we are likely to be running the motor for hours/days at a time, the battery bank will be at 100% SoC and hopefully the alternator is not drawing much power. Our current setup has a Balmar 614 controller. It has the adjustable ramp up on the field current. Hopefully this is good enough to keep the belt and engine happy. We also sail in very warm waters, we are in the west side of florida, the Gulf of Mexico waters here are very warm. Our biggest issue is with heat. And so, im oversizing the next alternator. Our current air cooled 70a alternator unit reaches 120c. While I think a water cooled alternator will be cooler, it's still a lot of heat for a small engine floating in very warm water (30c is possible in the summer near shore) My first assumption is that we will try to design around a 190a alternator and program whatever controller max out at 150a and see if temperatures (and belts) are ok. As for spindle speed of the alternator, for sure, we will need to make sure we are driving the unit at the most efficient speed. I just got a quote from Beta, they have a 6pk crank pulley that is 210mm in diameter. My next efforts need to find out what diameters are going to be available on these alternators. I think we will likely run the motor at a crank speed of 2-2500 rpm (in neutral). What RPM's are you'all running at for peak power and or efficiency? What do you estimate the alternator speed is? FInally, if I do need to be like a "Hot Rod" I'm hoping I can leverage this feature of the Balmar 614, "small engine mode" which apparently allows for a discrete switch to be flipped to reduce the current by 50%. Of course, if everything is well enough balanced thru programming and belt speed, maybe we don't need this, but here it is! Thanks again for all the responses, this is truly useful for me.

thank you for the insight! This is perfect. Currently, my thought is to get my hands on one of these alternators first. Then see about making a bracket and crank pulley to fit. I have a Beta 25, much smaller. However, the factory has an optional 6pk crank and water pump pulley kit. External regulation is probably something that must be done for my setup. Thanks for that picture!

Are you taping into the engine coolant lines or having a completely separate heat exchanger system for just the alternator? If the later, are you running a seperate coolant pump too?

DanKim, Thanks for posting this. I have been searching around for water cooled alternator solutions for my sailboat powered by a Beta 25 (Marine Kubota). My current system is an Air cooled 70amp alternator with a Balmar MC-614 external regulator. We charge directly into a LiFePo4 battery and want maximum current for the shortest time. Since we are racing, the auxiliary engine in neutral is our own source of power on long distance races. We found, like you all, that the alternators cannot stay cool when pushed to the max output, so I started looking at water jacketed units. I would like to keep the regulator external, but have not found a suitable alternator yet. You mentioned that the VW Touareg can be externally excited? Can you tell me the model/year that alternator came from? Also what is your opinion on other units? Do they even need external regulators? The common knowledge in my region is that the built in regulators voltage is set a hair too low for Lithium. Regardless of the other heat and efficiency concerns, if we cannot get a full charge (BMS cell top leveling state) we aren't exploiting the batteries full potential. Thanks! Chris