September 5, 2022
I’ve been pretty unhappy with our Balmar 100 amp alternator for quite a while and especially since we put in our lithium batteries. At best, we get about 60 amps from this alternator once it’s hot. Well, it failed completely in New Caledonia and I put my original, 60 amp Hitachi alternator back on the engine. Once it was hot, I got a continuous 50 amps from it, and it stayed relatively cool compared to the Balmar.
I ordered a marinized Bosch alternator (and new regulator) from Graeme at SmartRegulator in New Zealand. It’s installed now and wow, what a difference. Here are some pictures (please excuse my dirty engine compartment!)…
I made the alternator adapter bracket, designing it in the Fusion 360 CAD program, 3D printing a test-fit part in plastic and then having it CNC machined in aluminum in Gladstone. I gave the design to Graeme and he’s going to be selling the brackets soon.
Graeme did a great job marinizing the alternator, painting all the parts vulnerable to the marine environment. The alternator is now mounted rock-solid and putting out a ton of power.
We’re getting better than 100 amps continuously from this new marvel. Its temperature is leveling off at about 88C which is really great. I thought I’d have to install better ventilation for the alternator, but it’s fine without it due to its increased efficiency and big, external cooling fan.
I was also worried that I’d have to go to a serpentine belt system to drive this load but the 1/2″ Gator v-belt is driving it just fine with no dusting visible yet and no signs of slipping.
Another major advantage of this change is the price and availability. The alternator from SmartRegulator is about $330 USD. It’s a standard alternator (though marinized by Greame) that can be purchased in about any auto parts store. It’s used on Ford trucks among other cars. The Balmar alternator it replaced is over $1000 USD and from what I understand, Balmar isn’t selling service parts and instead insisting that it be returned to them for service.
If you’re making this change, keep in mind that some alternators (like the Balmar) are positive switching and some or negative switching like this Bosch. Make sure your regulator will work with your new alternator. It might be necessary to have your new alternator converted, but that’s easy and inexpensive at almost any automotive electrical shop.
-Rich
