[Public-List] Alternators

[Kirk Little]

Before I was aware of the (potential) problems with turning off the key while the engine is still running I would do it on a regular basis but never to increase HP, rather to reduce noise and allow me to make a contact on the SSB radio that I would not have been able to accomplish with the interference produced from the Alternator.  So far there has been no damage to the system that I am aware of, even though I avoid doing it now.  Since I am running a 70Amp Alternator with a 600AH bank, when the batteries are low I can FEEL the HP drop.  I have a Universal (Kubota block) M3-20 (17HP I think), and with a new bottom and new 3 blade prop I have done  6.2kts wide open.  Now days its more like 5.5 with my dinged up prop, sloppier bottom and tiring motor.   Unless you are running the engine close to flat out, 100% throttle the HP loss is not very relevant in my case. However I have a friend I have cruised with on a 29' boat with a 10HP diesel, and he often has to kill the alternator to push through situations where the remaining 7 or so HP available while charging just isn't enough.  
 		 	   		  
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