What Alternator?

[CapeBob]

What alternator for a Perkins 4.236 on my Prairie?

Thanks,
Bob

 

[Lepke]

Almost any alternator will work. It doesn't have to be the one Perkins dealers sell.
There's several on Ebay from $70 up and some used ones, too.

 

[MurrayM]

What size is your battery bank, and what kind of batteries are they?

 

[CapeBob]

What size is your battery bank, and what kind of batteries are they?

That is my next question. After a 3 hour cruise I was unable to start the port engine. Just click click click. Opening the battery box the problem was evident. The negative terminal of one of the 2 6volt batteries that were wired in series had burned off probably because of a loose connection. The question is, why 2 6volt batteries wired in series when 2, 12 volt batteries wired in parallel would yield the required voltage would, assuming the 6 and 12 volt batteries had the same capacity, yield twice the capacity of the 6 volt setup?

I was very impressed with the single engine handling of my Prairie 36. The return trip took a little longer, but I was able to return to my dock without incident.

Thank-you again ladies and gentlemen. I'm very grateful for all the help I'm receiving here.

Bob

 

[alfamike]

Alternator - ? Need more info

We need more info.

what size house battery bank ?

How do you plan to use the boat ?

Often a regulator can be used to increase the charging profile of the alternator to meet your needs.

Why are you replacing it ? did the old one die & just want a cheap replacement ? or are you trying to upgrade ?

We need more info.

thanks.

Alfa Mike

 

[CapeBob]

I may have answered my question myself. With only one battery installed in that bank the instruments are still powered. They may be 6 volt instruments. Still too warm to spend much time in the engine room so further investigation on my part will have to wait until late tomorrow or Thursday.

Bob

 

[CapeBob]

Hi Alfa Mike,

Don't need a regulator at the moment. I'm making a list of replacement parts so I don't have to research the issue when the time comes.

Bob

 

[Comodave]

I doubt that the gauges are 6V, probably 12V but still may work. Usually you put 2 6V batteries in series to make the 12V because the 6V batteries weigh less than an equivalent 12V battery and are easier to install. I have 4 6V batteries instead of the original 2 8Ds because of size and weight. They are way easier to muscle in.

 

[FlyWright]

My bet: 12V guages.

My standard 4.236 alternators were about 55A, internally regulated. I replaced my stbd one with a 120A Balmar regulated externally to 100A due to the 1/2 inch belt width load limit. You'll probably need the Perkins mount.

 

[CapeBob]

Thanks again everyone. Yes, they are 12V gauges.

Bob

 

[cappy208]

As mentioned, to get the amps required it's easier for DIYers to lift, hoist, lower and hook up 2 6V golf cart batteries in series than wrestling a behemoth 12v battery in there. Unless you have some young muscle. Also from a $$$. Standpoint. Anything with the 'Marine' label attached is $$$$$$. Golf cart batteries are way easier to get a good deal on.