Recommendations for (extra) Large Frame Alternators

[sgharford]

Due to recent inverter installation, I am looking to replace one of my 12 volt, 58 amp alternators with a 140 amp alternator. I came to realization that with fridge, TV and salon lights on I use about 50 amps (30 amps with lights off). That only leaves 28 amps to charge 550 amp/hour battery bank after night on anchor if TV and fridge stays on. I figure about 250 amp/hours used by morning so that would take 9 hours to recharge in utopian world. Would like to see bulk charge completed in about 3 hours, so here’s my math: (250 amp/hours to charge) / (140 amp alternator – 30 amp base load) * (1.1 for guessing 10% transmission loss) = 2.5 hours. I plan on putting smart voltage regulator on as I believe 140 amps too much for simple on/off type so reality is will probably take 4 to 6 hours to fully charge, which I am OK with.

By Balmar standards, it's considered the "Extra Large Case" 97 or 98 Series (has 4" space between bottom mounting legs - see http://balmar.net/PDF/Alternator%20D...dimensions.pdf for dimensions). The Balmar 97 series 140 amp model is about $1,200, obviously more than anyone would like to spend.

I read some prior post about using truck alternators (and potential insurance problem that they are not spark shielded for marine use). Also read elsewhere that most are not rated for continuous duty, which most marine models are. This is going on a cummins 903 engine.

So my question is if anybody knows where I can get a rebuilt 12 volt, 'extra' large frame 140 to 160 amp alternator with dual 1/2" belt pulley that has continuous rating, or at least rating appropriate for putting out full load for about 3 hours. Also, if you know other manufacturer's of alternators you think are good choices (other than Balmar), please let me know. Thanks for your help, always regret when I don't ask first.

[doc g]

So , you are going to run a main engine to charge the inverter bank?? Is this just for use while you are underway? .....................Pat

[Boatsb]

Do you have a good starter and alternator shop near by. Take the one on the engine to them and see if there is a larger on that will mount where it was. They can take care of the pullys while you are there too.

FWIW I would measure the clearances behind and around the existing one so a larger case unit will not be a guess if it fits.

[GJH]

Try Vic's DC Electric in Stuart:

http://vicsdc.com/

Also, the Battery Shack in Marathon, or Lauderdale Battery and Alternator, or East Coast Battery in Ft Lauderdale: http://www.eastcoastbattery-delta.com

[sgharford]

Way it's been happening - Leave dock on full batteries with inverter on to run fridge and TV for the kids (about 30 amps which current alternator can keep up with). Get to anchor destination 1 to 4 hours later. Run the batteries down about 125 to 250 amp hours from overnight use. Now typically I come back to dock but the kids have been really good on boat lately so I would like to do another overnight on anchor from there 2 to 4 hours away. It's during this time I would like alternator charging battery so I can have another go that evening on hook without running generator. Is this luxury worth $1200 for new alternator? - TBD. Currently worth $500 if I can get one used/rebuilt.

[doc g]

I've got Sea Power's 10 kw a/c alt's on one of my mains . You could get by w/their 5kw unit which would give you plenty of a/c and therefore power the batt'y charger side of the inverter while you are running. The way you would be using it would be great. It's nice to have another way to make 110v also. We use ours all the time . True sine wave output and depending on what size pullies you use very low rpm req'd. Mine is set up so that at 860 rpm we're at full power . I don't know what the cost is . I'll try and find a contact # or link if you are interested......................Pat

[Brian Degulis]

Try these guys http://www.apimarine.com/ They sell new large frame 170A for under $200 a few years ago. They're foreign made Delco copies I think. I've used lots of they're stuff with no trouble.

Brian

[REBrueckner]

You can also try EBAY for rebuilt or used alternators...POWERLINE is one heavy duty brand making both large and small frame alternators. I have used their 120 and 120 amp small frame in my YF for the last six or eight years, double belts, no problems. You WILL need double belts.

Your calculations are WAY TOO optimistc: you'll never get 140 amps out of a hot 140 amp alternator and you can count on 20% loss due to heating of batteries....unless they are AGM.
With wet cell lead acid, they will accept a MAXIMUM 25% of 550 amp hours....140 amps....but never so three hours, maybe a half hour or so, so you should add a battery or two AND get a bigger alternator if you want to charge in 3 hours.

[sgharford]

Just jumped on good deal from surplus dealer - got his last two new Leece Neville model 110-555JHO 160 amp alternators for $150 apiece. He just so happens to have a rebuilt cummins 903 engine he got off Coast Guard boat for $7500 located in Los Angeles if anyone interested. Never know what you going to find when you pick up the phone and start BS'ing with people. Thanks for suggestions guys - it helped put me on right track.

Reckon I'm going to need some bigger wires next.

[REBrueckner]

Here is the prior post of proper calculations:
http://www.samsmarine.com/forums/sho...=system+design