[Public-List] alternator

[DAVID JOHNSON]

To: Alberg 30 Public List
From: Dave, #156

If you have a 100 amp alternator (lots of cruising boats have that or larger) and it's charging flat out at 14.4 volts the power output is 100 x 14.4 = 1440 watts which is about 2 HP. Taking various inefficiencies into account it could take as much as 4 HP to drive the alternator. Now, you would seldom be putting that kind of load on your alternator unless the batteries are way down or you're running a water maker as well as charging batteries, etc.

You can disconnect the field of the alternator without harming it but do not turn off the battery master switch with the alternator under load. You blow the alternator diodes for sure. If the "ignition" switch turns off the B+ to the field terminal on the regulator you'll be OK. (Unless you have an electric fuel pump, for example.)

Why not have an extra cup of coffee and stay on the hook until the current slacks off?

Dave
Chuave' 156
 1331865284.0