IMPORTANT: CMI Alternators are hand built and may require a 1-2 week lead time.
For the first time ever MarineHowto.com brings you a sub $300.00 externally regulated alternator. In order to bring better value to our customers we're using custom castings/frames designed as a drop in replacement for the very common Hitachi 3.15" saddle mount /dual foot alternators such as the LR180-03C Hitachi alternators.
Because we can share internal components of the CMI-90-ERH (H = Hitachi), with the internal components of the CMI-90-ERM (M = Motorola), we can save on manufacturing costs by purchasing these components in bulk.
We start with the best aftermarket & OEM parts we can source & then build these from the
ground up as a better & more cost effective alternative to the stock Hitachi
internally regulated alternators found on most Yanmar marine engines. You will not find a better price, or quality, externally regulated alternators anywhere.
WARNING: In order to keep costs down these alternators are for use on DIESEL ENGINES ONLY. They are not spark protected as is required for a gasoline engine.
External Regulator: If
you select the drop down menu you will see that this alternator can be packaged with a Balmar MC-614H or ARS-5H external regulator, or with these regulators and a temp sensor. I recommend
setting the Belt Load Manager feature at level 3 to 5 when setting up
the regulator. This alternator is capable of 110A of output when cold and a 1/2" or 3/8" belt can not handle that. It is strongly recommended to utilize an alternator temp sensor and only Balmar regulators with the CMI-90-ERH.
I also offer the Sterling ProReg-D external regulator. This regulator is a value regulator and does not offer any way to limit alternator output in order to pair it with your belt. While the ProReg-D is less money, the Balmar regulators are a better match.
is not a cheaply built run of the mill automotive grade alternator with a dumb
internal regulator. This is a direct drop in for the very common dual foot alternators found on many Yanmar's.
Built in Maine:
These alternators are hand built in the shop right here at Compass Marine Inc.. CMI is the parent company of MarineHowTo.com. This
ensures a quality product at a very, very fair price. This alternators is not just a few dollars less, it costs hundreds less than the competition. Some of the components are
made overseas, some in the USA, but we sourced the best components we could possibly find,
and tested them, to meet the value to performance ratio we were
For example the rectifier used in the CMI-90-ERH costs us 5X what the rectifier used in an automotive grade alternator would cost. The rectifier in the CMI-90-ERH uses six 70A diodes for a cooler running alternator.
This CMI-90-ERH is specifically designed to fill the gap between a true
high performance alternator and the
factory alternator (see the other alternator offerings from Balmar, CMI or Grasser Dc Solutions). It was designed to meet a price and performance
niche not available to boaters previously.
CMI-90-ERH comes standard with a tachometer output, called a stator tap or AC tap. This is for Yanmar diesels that run the tachometer sense off the alternators AC pulse. Not
all diesel engines drive the tachometer from the alternator, but many
do, including some Yanmar models.
The CMI-90-ERH is set up for external regulation only.
It has no internal regulator, although it may look like one. We are manufacturing our own field connection pathway for this alternator and it uses what looks like a stock internal regulator but it is not. The conversion from internal to external regulation still uses the factory located plug positions as opposed to a Mickey Mouse level pig tail of wires dangling out of the alternator frame for the field & stator.