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Capt John Capt John is offline
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First recorded activity by BoatBanter: Jul 2006
Posts: 159
Default Can an alternator be to big?


Glenn Ashmore wrote:
I have been offered a really good deal on a high amp (325 amp) fire engine
alternator by the city vehicle maintenance shop. It was purchased as a test
unit but due to some budget cutbacks ended up being to expensive to equip
the whole fleet. This monster is hot rated at 200 amps at 2,000 rpm and
275 amps at 4000 rpm. I am thinking about buying it and keeping the 200 amp
Leece Neville as a spare.

My battery bank is 850AH of L16HC wet cells that can take 200 amps in bulk
charge. Is my Xantrex smart regulator going to keep this monster from
cooking my battery bank?

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com


Everything you attach to the engine reduces the HP output. How much,
good question. But having an alternator that is far bigger than your
needs is a waste. Additionally, to make use of that power you need to
get it to the battery banks. If the wire between the alternator and
battery is too small to handle the current, or the wire between the
battery and load center (electrical pannel) is too small, it could burn
up under a heavy load if it's not fused properly. Your probably going
to end up cooking something, lets hope it's not the boat while your on
it. Also, if it's not CG approved, and you have a fire because of it,
your insurance company is going to walk away, it's your problem. I'd
stick with the normal marine alternator if I was you.

John