Has anyone ever had their alternator re-wound? I was talking with a car stereo shop yesterday and they said Im probably not fully charging the batteries with a stock alternator. They suggested a rewind to 225 amps (is stock 140 amps?).

Yes I do have shore power and a charger but when you have the boat in the water for 20 mins after being at home on the charger and the stereo cuts in and out 20 mins into the day I know they have power. I took the blue tops into Interstate (they are the Optima dealer) and they load test perfect. Again I think they are designed to give a small steady current and not a but load that are needed to run the amps under high volume.

I talked to the starter and alternator shop here in town (Omaha, NE) and they said they can not increase the charge output on the alternator. I am not sure if I just got the stupid guy or if they really cant do it. I have the same problem with fresh batteries as I do with batteries I have been running all day. I think my alternator is a Mando and has an internal regulator.
Powerquest - if you fin someone who can "hot rod" your alternator let me know, but again I think it is not a charging issue I think it is the battery (s).

I have seen high output alternators, once again, they where for the "Car Stereo" kids who needed huge amperage to run there stuff, cant see why you couldn't have yours redone?, if not, I would suggest buying a higher output one, I know "Powermaster" make some pretty high Amp units, and there are other companies as well.

I have never seen your setup, so, PLEASE dont take offense, but, I know a pile of guys running systems very similiar to yours and are getting A LOT more than 20 Mins at high volume, but, I guess there is only so many things it can be?, like I said earlier I hate to see people throw "good money after bad". If you buy new [different] batteries and an alternator and the problem persists you are gonna be pretty PO'd!, and rightfully so.

If it was me, I think for the few minutes it would take, I would go back and have a really, really good look at the wiring, it doesn't take much when beating around in the waves for something to come loose [or worse "partially" loose] If it IS an intermittant problem and its on the power side, the extra couple of volts [and amps] that the alternator provides MIGHT be enough to overcome a bad connection, the loss of that power when on battery power, might not. Have a look at all the ground connections/power connection, distribution blocks, etc, if the wires are crimped or attached anywhere, make sure those connections are good, I wouldn't just have a quick look, take some time and go over all of it really well, if nothing else at least you can eliminate the idea of it being a wiring problem then. Coming from an automotive background I have seen others, and, experienced first hand how frustrating it can be to chase an electrical problem, I have seen people replace component after component to no avail, only to find a small crack, or partially corroded connection on a small "trigger" wire, or something silly like that. I feel your pain!

Michael

First off, it cuts in and out with the boat on and off. I understand where Powerquest is coming from exactly. Secondly it will do it with fully charged batteries. I don’t want to come across rude but you have the same thoughts as everyone else. I said the wires have been check and re checked, amps and speakers have been swapped out. The problem appears to be at high volume the amps draw more power than the batteries like.

GREAT!, sounds like you have it all figured out then, good luck!

Michael

Micheal-
First off, the ultra high end car stereo kids are probably running Kinetic or similar stereo batteries. Upping the amp output on the alternator is waste. You also have to use a marine alternator that is spark protected.
His batteries are not going dead after 20 mins. They are just not able to handle the constant draw of power for more than 20 mins.

Brian-
I can't tell you for sure what will work, but I can tell you that I am running 2 amps for 1100rms watts off of one Interstate group 31/29M deep cycle battery and it handles it fine. The thing about regular batteries vs deep cycles is that regular starting batteries won't last if you run them up and down a lot.
I can also put you in touch with a friend of mine who does a lot of high end boat stereo installs here and at LOTO. I'm sure he would be able to lead you in the right direction.

GRIFF

NOPE, they where running either Optima or some other form of "Gell" battery, one fella had an Odyssey set up, but, most of them where using eiter red or yellow top Optima's, SEVERAL had aftermarket alternators, which according to them put out more Amperage than the stock ones, I am NO expert, but, I assumed it was done for a reason?

Brian

Good luck with the boat, hope you get it sorted out

What you all are missing iks that it is fine when it s running, it is not the alternator, its the batteries!!!!

You can not really compair car and marine. Marine has two alternators so you already have 280 amps in most twin aplications. You NEED to put a volt meter on the batteries and also the amps and see what your readings are.

BUT if the batteries arent getting a full charge is it the batteries fault of the alternators? Obviously its the alternator. IF the batteries are getting a full charge and not holding it then it falls on the battery.
I understand what you are saying but when the engine is running the batteries are getting a constant recharge..The real test is when the engine is off.