KLC Lewis wrote:
"Jeff" wrote in message
. ..
KLC Lewis wrote:
...
Essie has a Model 20 Universal (5416) 16hp Diesel, fitted with a 50 Amp
alternator. The biggest alternator I can put on this engine, according to
my research, is an 80 Amp.
What is the limitation? I would agree that with size of the bank more
than 80 might not be cost effective, but the small case alternators go up
over 100 Amps.


Balmar has a chart of recommended alternators based upon both belt size and
engine hp, and while they do say that I can use a larger pulley/belt
combination and therefore a larger alternator, every 50(?) Amps means the
loss of 1 hp available for propulsion. Since I rarely run my engine over
2400 rpm out of a rated 2800 anyway, usually running it at 2200, I'm already
only getting maybe 12 hp at the transmission. I'd hate to drop that any
further, as it's just barely enough as is.

You only use the HP that gets converted into electricity. If the
batteries are charged, or if the regulator reduces the demand, it
doesn't cost in engine power.

As for the HP, the torque peak on that engine is fairly low, so the HP
curve flattens out near the top end. You're still getting 14HP at
2100 RPM, a tad less at the shaft.



Why don't I just run it faster, you ask? Makes me nervous. When it's running
at high speed it just doesn't sound "happy." But it'll run at 2200 for as
long as I ask, and sing sea chanties at the same time. Short (very short)
periods of full-power are okay, but we're talking minutes here, not half an
hour or longer.

You're probably right that the Universal is happy at 2200. If I ran
my Yanmar that slow all the time, it would carbon up.