HELP: Marine grade Alternators?

I know this topic has come up before, but I was hoping to hear from some of you and your experiences. Who makes a good marine-grade alternator?? I am NOT looking for a rewind or rebuild. I am looking for a quality high-output alternator (120A-200A) that is designed for marine engine applications. Does anyone have any past experience with this stuff? Give me the goods.

Your help is appreciated.

Jerry Lembas
Fluid Concepts
http://www.fluidconcepts.net

Hey Jerry I here Ya! People who have one Need only relpy. The reson I say this I asked the same question Like 5 times And all I got was people who have Heard of or Knew a friend of a friend who has one BLA Bla Bla Check this A Actuall install http://svtsupercharged.com/gallery/alternator

www.Bateryshck.com In Marathon FL sell's a High output "Marine Alternator" for $400 It's a 165 Amp Alternator. That's the Highest I have found. I keep hearing Rumors of Higher but thy are All B.S I know you can get "Non Marine Alternators" with Higher output than 165. But who care about thoes. I wouldn't put one in my boat or even want to ride or be around ayone who has one in there boat."Boooom" Battery shack, Bench test's each one of the alternators before they ship so when the say 165 Amp's The are 165 Amp's. I have had one on my boat for about 20 hrs No Problems. Im seeing anywhere from 12.5 to 13.5 volt's with everything On Heater Light's Stereo ect.

how about this sucker, 275 amps @ 5k rpm and about 255 amps @ about 3500 http://www.balmar.net/96-Series%20Alternators.htm
actually i think i read somewhere that engine rpm and alternator rpm arent the same so maybe youd be able to get the full 275 amps without wringing your motors neck??

When bringing in a starter from my MasterCraft to an electrical remanufacturer (A-1 Auto Electric of Denver) I asked what differentiated a 'marine' alternator from a standard and the guy pointed to the vents on the alternator and on the normal alternator, you could poke a screwdriver through them. On the 'marine' alternator, there was a mesh/screen 'flame arrestor' type material inside the vents. He claimed this was the only difference and that different amperage alternators could be built inside a case with this screen. ???

I believe that's true Grant. Marines are a more 'sealed' unit.

Sparks in the motor compartment are a bad thingy!

Wow, a $2000 alternator! You better have one kickin stereo if you spend 2 grand on just the alternator!

You should obtain a catalog from West Marine and take a look at what they have available, and more importantly, the "West Advisor" on alternators.

You can buy alternators that have up to 275 amps of output, but they are expensive. You might be better off to add a second alternator.

Another issue that you should be aware of is that there is a limit to how much power you can put through a V belt. Attempting to drive an alternator beyond 75 amps with a standard 3/8" belt will only cause you problems in the long run. The belt life will be short, and you will have to tighten it so much to keep it from slipping that you will risk wearing out the bearings from the side load, both on the alternator (fairly expensive) and on the engine (Way too expensive!).

For larger outputs you will need either go to a wider belt or double up the belt. Either way may require that you change the pulley on the engine.

When looking at the specifications for an alternator, keep in mind the RPM numbers are for the alternator, not the engine. To get the Alternator RPM divide size of the engine pulley by they size of the alternator pulley. It should be something around 2:1, so 3000 engine RPMs should be around 6000 alternator RPMs.

Thanks for the responses.

I have checked out the different links (Grant and Bob)and both look good. I am questioning the huge differential in price. I would guess that the Balmar types are a serious continuous output whereas the battery shack types peak at the rated output. Rod, I think you are right....something has to give to get more power. Looks like balmar has addressed that issue. I guess I just have to decide what is really needed and how far we are willing to take our project. Thanks again.

Jerry Lembas
Fluid Concepts
http://www.fluidconcepts.net

I talked with the Person at Balamar "WoW" They know the Shizz there. They were saying there is no need for a alternator over 165 Amps for me "A guy with 4 blue Tops" because No matter how much Power I can produce via a Alt My batterys can ony take in so much at a time. Example The only way you would need a 300 Amp Alt, is if you had over 1,200. Amp hrs of Batterys That's Like 30 Blue Top Optimas' So the quest for a 300 Amp alternator should be put away till I get another 26 batteries Haa"
They also said Your Alternator can't produce power for you boat till it goes threw your Bateries! (I didnt know that)

Look at it this way Grant, with 30 blue tops you don't need a ballast system any more!

Grant: Something didn't get communicated properly between you and the Balmar guy.

In all normal applications the alternator directly provides the current that the system is using and any extra (if there is extra) will flow into the battery and charge it. If there isn't any extra, then the battery will discharge despite the fact that the alternator is cranking out its expected amps.

The intended market for a Balmar marine alternator is is actually the sailboat cruisers. These guys want sail (or sit) all day using battery power, then fire up the engine and charge the batteries back up. They are interested in charging the batteries as fast as possible and thus want a large alternator.

There is a limit to how much current you should put into a battery. For best battery life you shouldn't charge the battery at rate that is more than 20% of its amp-hour capacity. A large cruiser, however, may have over 1000 amp-hours of battery and can tolerate a charge rate of 100 to 200 amps, and will use multistage regulators to give the batteries the best possible charging curve.

The monster stereo guys have a different need. You are not really interested in how fast you can recharge your battery, you want to make sure that the battery never gets discharged to start with. What you really want is an alternator that can output just a few more amps than you could possibly consume.

Rod: What you say makes sence: And was right in line in what the Alternator Person was saying. The thing that blew me away was . They say that the Alternator CANT provide Direct Voltage for your system. I.E If your batterys are flat your Alternator No matter how big will not run your system. When the Bats are dead "Game Over" you must allow them to charge. Like you said and Yes 20% Is the Max they can take. So Lets say you have 4 Blue top Optimas They are 55 Amp Hrs each. Total with all 4 Batts you are pushing have 220 Amp Hrs 20% of 220amp Hrs is 44 Amps so What they were saying is A 165 or 300 Amp Alternator isn't going to do anything more the a 44 amp alternator will because your bats can or wont take anymore than 20% This did not make sence to me How about you

Think about it. You alternator is connected directly to the batts, then your amps are connected directly to the batts. An electron doesn't know the difference between going into the battery or just following the copper in the wires. So the alternator has to run acc. . Good example- Everyone has killed a car by leaving a light on. That drains the battery pretty much as low as it goes to the point that the battery is history. Yet you can jump the car and drive around until you turn the car off. If you try and restart the car it's still dead cause the drained battery won't take a charge after being drained too low. So all that time you were driving was on alternator power! Unfortunatly I have used this example too many times. I know you can only charge a battery so fast but the extra amps off a high power alternator will work accessories while you charge. If it didn't work this way you would have to turn off everything and run your motor to get a charge. Grants' guy is right, it just sounds like he left out a few important points.

Ok I was out Yesterday and I got to put my Alternator to the test. With the stock 65 Amp alternator My 02 Air had, It would show like 12.5 volts with Everything turned off and running over 1000 Rpm's. If I would turn Everything on Lights Heater Stereo, My boat would be at 10.5 to 11 volts. Now with the Ho Alternator Im Never diping below 12.5 With Everything you could ever turn on in the Boat at one time. Now when your on Plain or over 1000 Rpm's and Pumping the Stereo, Lights on Heater on ect the Volt meter is showing 13.5 Volts. Im Happy.

One note is do not trust a dash mounted volt meter. Works great for quick checks but they are not accurate. None are isolated directly off the battery, instead they are run through the ignition switch along with many other accessories. Before a component is condemed please use a quality volt meter at the alternator and battery for proper diagnosis.

Grant, good move on the custom alternator for your custom boat I bought an alternator from the Battery Shack. The guy there has been building alternators for something like 20 years. I tested mine out under load at 145 amps on my VAT. As for charging an Optima...well they can take a 100 amp charge. If the battery is dead it will take at least a 60 amp charge to recuperate quickly. I have a battery charger in my work truck that can safely charge even a dead battery in 45 minutes using a computer to test the impedence and voltage as it charges it, without boiling the battery (The only charger/tester approved for GM's AGM batteries). Point being batteries can take more of a charge than you might think, it is just a matter of controlling the voltage and current.

You are correct The voltage on the dash is not very accurate It seem's low. I see that On my dash and my Perfict Pass It read's about the same Voltage. It wasen't until I installed the aftermarket "Stinger Digital Voltmeter" that I was seing the Voltage I spoke of, I trust that one way more than the Volt meter that on the dash. But I think what Rod said earlyer is ture Monster Stereo Guy's want to start with a full charge and try to not dip into there reserves.
I have a Charger that is a slow charge It takes forever to bring batterys back up. Its like a 1 amp charger for each Optima, It would be nice to have somthing Like what Peter has to bring batteries back to life in 45 min for thoes long 3 day weekend when your batteys take a beating

Grant:
The batteries can survive very large currents, which is exactly what they provide when it comes time to start the engine. They take a beating while doing it, however.

When you charge a battery the electron flow will cause the electrolyte (acid/water solution or gel) to react. Gel cells keep things contained, to a point, but lead acid cells bubble out hdyrogen and oxygen gas.

If you have a "maintenance free" battery then I highly recommend that you do NOT charge the battery too quickly. These typs of batteries are not really sealed, they just have a vent cap that contains a chemical that acts as a catylst to get the hydrogen and oxygen to recombine back into water. These work well as long as you don't overload them. Charging too quickly can result in the hydrogen and oxygen escaping, resulting in a water loss that you may not be able to replace.

If you have a battery with removable caps then you should check the water level often and replace with distilled water should the level drop below the top of the plates.

While gell cells won't lose water, they can be damage from charging too quickly. The 20% rule of thumb is what you want to follow to get maximum service life from your batteries.

If you expect to deep cycle your batteries then what you really should look into is getting a multi stage regulator. These regulators use a little bit more intelligence in how they controlt he regulator so that the batteries get charged up quickly, and then the alternator is backed off so that you don't overcharge.

Now that I'm thoroughly confused, I need some help. The stock alternator on my GT-40 is not cutting it. My sub amp cuts momentarily (a few seconds, or until I turn it down)out when I really crank up the bass. No fuses blow or anything like that, it just isn't able to get the juice it wants. It's got 4 ga. power and ground to it, so I'm convinced a bigger alternator is the solution to my problem. My volt meter drops significantly when this happens.

So, I'm wanting to order a high output alt. and I think the ones from battery shack would be a good purchase. However, do I want the 100 amp or the 160 amp? I've got 2 batteries wired in parallel.

Matt, a 1 farad cap may be all you need to eliminte this & is easy to install, (ebay has them for low $$ too) but this is complete speculation without knowing the amp type, ratings, etc. The power supply of the amp may just not allow for the current your subs are demanding...

I have a cap, just haven't hooked it up. From past experiences, I don't think they do much. It will help with this surge one time, then takes a while to recharge.

The amp is a kicker 800.4, rated at over 1000 watts. I can tell you that it's putting out a LOT of power when I crank it up.

Matt: It might not be a Lack of Power thats making your amp Cut Out. If the "Gain" on your Kicker amp is turned up to much and your "Freq" Level is set to high This will make the amp shut off for just a second when hitting a Hard bass Note. Try doing both turning down the gain and a lowering your "Freq" Im just guessing that you a 12 in sub. You should have the Freq Level set beween 10 Hz and 30 Hz try that and let us know

I think you are in az, so you should check out ASA marine electric their # is 602-216-9099. I took my old alternator to them and they rebuilt the whole thing only old part was the internal body. it is now a 110 amp they bench test it right there and it is now a self igniting marine alternator. I have been running one for a year and so has my buddy (both malibu's)and both of us have huge systems 3 and 4 amps, 5 subs etc and they work great. Here's the best part only cost 150 bucks. This place is a little hole in the wall shop but they know their shiznit! With this alternator and 2 lifeline batteries and a optima for starting this setup pumps all day!

(Message edited by tomfish on May 13, 2003)

Matt:
A bigger alternator is not going to help the situation if you are experiencing a momentary voltage drop due to the stereo. Alternators can not react instantly to changing demands, you MUST have a battery to provide quick surges and absorb over currents.

Think of the time that the stereo is quiet, perhaps between tracks on the CD. The amps are drawing very little power, so the alternator has backed off on what it is delivering. Suddenly the drum solo comes on and the amps start pumping a 1000 watts, drawing a hundred amps from the 12 volt system. Your poor little alternator was caught sleeping, and needs to get fired up. The voltage regulator will see the dip in voltage and will start driving more current into the field winding, but this takes a little time. Meanwhile, those hungry amps keep demanding more and more, and it is up to the battery to provide it.

Eventually the alternator gets cranked up and is putting out what it needs to, or at least what it can. The voltage is back up and things are happy, until the drum solo stops.

Now the alternator is cranking at full output and the amps have just stopped taking any power at all. The alternator doesn't like that, it can't stop the flow of current that it has created, and those electrons have to go somewhere. Again, the battery is the savior, absorbing all the excess while the voltage regulator gets things back under control.

Under conditions like this I would expect to see the voltage at the battery fluctuate between 11 and 14 volts. At the amp, however, you may see the voltage drop much lower due to voltage drops in the wire. The longer the run between the battery and the amp, the bigger the wire needs to be. For best results, use the biggest wire you can, and keep the wire as short as you can.

The quality of the amp will factor into play as well. It would be possible to design an amp that would continue to operate until the battery was totally dead. It's cheaper, however, to design one that has a limit to how low the input voltage will go. An amp that cut out at 11 volts may suffer while an amp that can operate down to 10 volts will play just fine.

Ok thanks. You're right-the manual says that it has protection circuitry that will shut it down if the voltage falls below 10.5 volts. Now I feel stupid, but what do I need to do?

From what I understand, my next step should be to increase my battery bank, since I'm only currently using 2 regular batteries. Then upgrade my alt if it can't keep them charged. What do you think???

I would double the size of the wires going to the battery and see if that solves the problem. You also want to keep the number of connections between the amp and the battery to an absolute mininum, each one of those crimp connections will result in a voltage drop.

You should also make sure that the fuse is properly rated. Remember, the fuse is to protect the wiring, not the amp. The fuse should be rated for a lot more than you are actually drawing through it, otherwise it will be a source of significant voltage drop.

A fuse "blows" because the current flowing through it causes it to heat up to the point that it melts. A 10 amp fuse can carry 10 amps, but it will be getting hot when doing it. Not hot enough to melt, but it will be causing a voltage drop.

Don't forget that the negative lead to the amp is just as important as the positive. It should be big, and as direct to the battery as possible.

Rod, thanks for the help, but that's not the problem. Fuses are plenty big. Power wire is competition 4 ga, ground is 2 ga.