Alternator upgrade advice

Maybe if you start a new thread people will be all over it to help you.

Die thread, die.

Bill post a picture when you get it finished so we know who to chear for when we're at the races.

79,
STILL AROUND i am restoring my first race boat a1931 chris craft converted and runung in the vintage and historic circuit.still got my baby ski nautique craft.
TAKE CARE BB

79
IS RIGHT THE BATTERY HAS TO MATCH THE ALTERNATOR.THE REASON ALTERNATORS CHARGE INSTANTLY WHEN THE BATTERY CALLS TO KEEP THE VOLTAGE AT 100%,
YEARS AGO GENERATORS RAN CONSTANTLY WHEREAS IT CHARGED THE BATTERY SLOWLY AND COULDN'T KEEP THE VOLTAGE UP AS NEEDED.
TO OVER CHARGE THE WRONG BATTERY IT WILL BE SHORTLY LIVED.

I'll post a pic. (There will be a black square in front of my face.)

Jim,

Everytime you start talking about holding your speedo in your hand while driving the boat, I get an image that has me scarred for life. This has to stop. BKH

Yes, I really think that I'm going to cut a hole in the dash, I know, I know, but as I said, it will look like its always been there when I'm through, Its more about space and function than anything else, I want to keep the vintage look of the boat and improve its usefulness, I'm going to add a swim platform on the back just for more room and function, remember these boats are tiny and with the SS you basically lose another seat and interior room as well.

This thread has me thinking about my future requirements, so a couple of questions.

I would like to relocate the batery forward in the boat up under the dash forward of the center console (its a barracuda ss). this would free up storage space under the passenger seat which is currently occupied by the battery. Yes Joe, these boats are tiny.
Do you see any problems with this?, I'll probably be doubling the length of the cables, should I go up a size? 79, what is the physical size of the battery which you describe, I would like to fabricate the new battery box big enough to fit a very good battery.

I will be adding a stereo to the boat, what problems will I have? The engine, ignition, and alternator, all appear to be stock 1965 technology, will I have interference problems?

I would like to mount the speakers in semi stealthy locations, again there is almost no room, I am thinking about the foot kick panel for the driver and passenger could hold a pair of 6 1/2 or 7's and If I reshaped the seat angle on the back seat, I could get a pair of 6 x 9's into the vert. surface of the seat bottom of the rear seats. The side panels have very little room behind them to hold a speaker, maybe 1 3/4" at the top and less as you get near the floor.

I would like to mount a small amp and an xm compatable head unit in the dash, I don't want a radio sticking out of the dash, so I'm going to hide them in a glove box, I found a 63 corvair glove box on ebay that will look period correct, (I know, they didn't come with glove boxes, but I won't tell anyone)I'll have to move the clock over by the other instuments and mount the Barracuda emblem on the glove box door, but when I'm done it will look like it's always been there.

Any suggestions on a head unit and amp?

Thanks,

Gary

I will pull it off tommorow and look skidim told me it was a newer model for the fact it had I believe a green wire coming from it.

I can't keep up.... I was hoping to dump a powered sub under the passenger seat, and another back next to the gas tank behind the real seat... I am not cutting any original fiberglass but the whole interior including the floor will be custom so I am hoping to be able to design everthing in somewhere. I hope to save the floor space under the bow as I put a lot of stuff up there currently and dont have any other space... a 1967 mustang is really a tiny boat. Because its so tiny and my friends are so big it is the wettest boat I have ever had so I am trying to keep everything audio marine for the first time in my life. Luckily it being the off season I have been nowhere near list price on anything yet... the Jbl ms920s were 80 a pair from overtons, I got a decent sony marine deck (cdx-f50m) that plays mp3s for 115, and I found the clarion amp for 130, not bad for new marine stuff I thought.. didnt like the scuba tank looking sub though too reminicent of cheap automotive bazooka tubes that did nothing but buzz the trunks of every camaro in the eighties.. the art to most of this is definitely going to be fitting everything into the boat...

Sorry if this is starting to bore people, I can't go out boating or even working on the boat for a couple months so I have nothing better to do...

The way I see it if the max output of the alternator is reached (and it is dependent on alternator rpm, which is determined by pulley size and engine rpm) by a combination of the various loads and the current that will flow into a battery at 14.4 volts (dependent on the internal resistance of the battery at the time) then the voltage will begin to fall below 14.4 and the regulator will not be able to keep it up. Once the voltage begins to fall the battery will charge at a slower rate, eventually with greater loads the voltage will drop below battery voltage and the battery will actually drain even though the alternator is putting out its max current at that alternator rpm.
     I used to be able to see this first hand in my 1985 RX-7 which had a very high current ignition system a lousy little alternator, and would idle around 500rpm. In the winter at night with the lights on and heat blowing I would have to rev the engine to keep it going, and that was with a new alternator and the biggest battery that would fit. The claim from the mazda garage was that the alternator pulley needed to be smaller due to the 7k redline, so it would never charge at such a low idle and that was only a problem if the battery was too cold to provide enough cushion at idle.
     Thanks for looking into the subwoofers, I think the 80w rms each to the 4 jbl 6x9s will be strong and sound good, but I would like to relieve them of the burden of also carrying the low frequency, the amp has a built in crossover and I would like to set it at about 400hz and find some subs that would still get some lows out to off the boat.. I don't think it will be enough for a wakeboarder to hear over the straight pipes, but maybe a wake surfer?
-Joe.

Tonydjd, if you are only going to use that clarion amp then you don't need a bigger alternator, but you do have to worry about the type and size of battery you have. If you are going to add more amps later then ya maybe a bigger alt might help, but when your sitting there with the engine off and the jams kick'n it doesn't matter if you have a 200A or 50A alternator they are going to charge up the battery at about the same rate when you start it up. Now if you have several amps and are crank'n it then you can have an electrical issue and loose power to the ignition and engine if the alt is capable of producing the need amperage.

Slow down you mean to tell me if I only want to use 1 amp and a small powered sub no reason for me to upgrade alternator. Sweet I do have 2 batteries on board using a contionus duty solenoid to help keep both batteries charged I like this set-up better than the isolator been there done it.

79 rewired under dash installed inline protection 50 amp before going to fuse block.

still have the 50amp circuit on rear of engine

Tony,
   There is a standard for amplifier output, the CEA 2006 Mobile Amplifier Power Rating Standard. It is voluntary and not perfect (i dont think they should rate at 14.4 volts personally) but it is a good step, I decided only to buy certified amps and decks since the standard came out. Might as well patronize those that try to compete on an equal footing..
79 Nautique,
    Lets not start comparing the size of our subwoofers ;-)... I haven't even bought any yet... Haven't found anything marine grade that is powered and worth the effort yet, am in the hunt now. Would like to stick with some powered ones simaler to the basslink IIs that I have in my truck so I can avoid a second amplifier, they are 250watts rms each. Might eventually just buy the automotive ones and get my friends in the electrical lab here to conformal coat all the boards. My battery is a marine cranking battery.. its just pitiful in size since that is all that would fit after the last owners hack job on the battery box. I have a few 1000cca (1300 mca) marine cranking batterys in the rotation for my outboards, the Decoy will get the same this year. The rectifier on a mid seventies outboard makes a 35 amp alternator look positively awesome, luckly the outboards can be pull started with a little ambition.
    As for charging quicker, I think it depends on how much power you are pulling when you are charging and how fast you are driving. At 2000 rpm where I am wakeboarding I am only going to get about half the rated output of most alternators, that would give me maybe 30 amps while I am running the stereo, perfect pass, depth finder, and the ignition which could be drawing that much or more if I am cranking it I could see this being a net loss or at the least not enough to help me recharge the battery after running the stereo all day.. and of course I still havent ruled out those powered tower speakers somewhere down the road yet..
-Joe.