Alternator Controls

George ( C&C 40 ) · Post by **George ( C&C 40 )** » Thu Dec 29, 2005 2:18 pm

Hi All,

I have a 55 amp alternator on a Yanmar 3QM30 that goes through an old SpaCreek Inc. "AutoMAC" alternator control panel. The AutoMAC allows you to select higher amounts of amperage to flow through the system so the "bulk charge" phase of battery charging cycle is completed more quickly than if the stock alternator control was running the show. Even though the "AutoMAC" is rated to 75 amps it is unhappy pushing 50 amps into the four big marine six volt batteries that make up the boat's 440 amp hour house bank. It shows it's unhappiness by getting hot to the point that it deforms ( melts ) the plastic splines that hold the amperage selector knob in place. The "AutoMAC" is from the 1980's and it appears not to have been designed with the somewhat long charge times caused by a 55 amp alternator trying to fill a 440 amp hour house bank. This is just conjecture on my part though.

My question is "What is a good external alternator control to replace it with?"

BTW, it would be nice if the control unit could handle up to 150 or 200 amps. That way, if I decide to add another battery set to the house bank sometime in the future, I can upgrade the alternator itself to better fit the 660 amp hour house bank without having to upgrade the external alternator control again.

Thanks in advance for all the help,

George Jones
C&C 40 "Delphinus"
Wavelength 24 "Poco Loco"

Post by **Tim** » Thu Dec 29, 2005 7:36 pm

I think you should already upgrade the alternator for your 440 amp-hour battery bank. That's a lot of potential capacity to replace, and while the internally-regulated 55-amp alternator you have will do the job, you could optimize the system using a heavy duty, high-capacity alternator and external regulator--especially if you're drawing those batteries down enough to be puching 50 amps worth of charging power back in. If I were your AutoMac controller, I'd overheat too!

I haven't looked at these components in some years, so don't know what's currently on the market. My Ample Power regulator seems to be doing a good job after 5 seasons.

Invitation · Post by **Invitation** » Fri Dec 30, 2005 11:15 am

George,

I would highly recommend that you contact Jack Rabbit Marine. Here's a link to their home page:

http://www.jackrabbitmarine.com/(stupxx ... c=0&type=0

They will advise you on what current products are available, their prices are excellent and anything they sell you they back up and provide consulting for as long as you own your boat. I have had them design my entire electrical system for my boat and I could not be happier with their service and advice. I have heard nothing but good things about them, they are certified marine electical engineers and really know their stuff.

Post by **Tim** » Fri Dec 30, 2005 3:43 pm

JRM is where I got all my stuff 5 years ago. Good service and selection.

George ( C&C 40 ) · Post by **George ( C&C 40 )** » Fri Dec 30, 2005 9:38 pm

Thanks guys. I appreciate the information. I'll give JRM a call and get it handled over the winter.

George