amperage/alternator/battery

After swimming my boat across the river in the dark due to the alternator going out and boat dying I decided to look into my alternator problems. For those of you who have not seen me post about alternators....I have probably replaced 10+ alternators on my 01 x-30. It turned out that after years of replacing them, my dealer realized the bracket was warped/torqued and replaced it. Since then, we have gone 2 years on this alternator. I have the std. 55A alternator on the boat now. The new mechanic had asked me what all I run on off the battery, and stated that he had burnt up alternators after 2 years from overload. After thinking about it I run 2 clarion amps (1 large=400W and 1 small-250W?) as well as 3-4 Tsunamis and all the other standard boat accessories off the ONE battery.

My question is; does anyone know how many watts those larger 4channel Clarion amps push, as well as the smaller one that MC put in the boats from say 00-04?

I guessed that at 650w for the stereo, and 14amps on the tsunami that I am pulling around 65+ amps....that being said- my 55A alternator can hardly keep up at times. Obviously I am looking into a second battery, I am just looking for some #s to verify how much I am drawing from the battery

My math gives me 60 amps for your setup. You should not be going through alts. I would add another battery for sure. I have a 1000 watt stereo and 330 watts worth of lights on my tower with stock alt and dual batts. Never had any alt issues.

Keep in mind current draw on music is dynamic and way less than what you would calculate.

We don't have enough info to try and guess as to why you burned up this alternator. Assuming that the alignment is fixed we need to know more info.

First off, is your belt in good condition.
Are your cables/connections all adequate? Are you seeing any voltage drop from your alternator to your battery?
How do you use your boat? Do you just sit in a cove with the boat off, draining the battery and then run home? Do you do a lot of idleing with the stereo turned way up? If you do sit in a cove how long is your run home to the dock/launch? When you run home is your stereo on full blast?
Is the alternator a cheap Chinese knock off or an OEM unit(Prestolite/leece Neville or Delco) or a good quality rebuilt unit?

Let me know some of or all of these answers and I will let you know what I think.

This is only a generalization and may not be specifically related to the cause of the above failed alternator. But in consideration of charging systems go with highly efficient Class D amplifiers that provide the same power with 60 percent less current draw. Presently you can get as much power as you want from Class D offerings. Secondly, since audio systems constitute the largest current draw, focus on every aspect of audio system efficiency. I have seen and heard systems that are so poorly designed and tuned that there is an inherent loss of 10 dB of output and ten times the power is required to reach a comparable dynamic audio level. Add that with inefficient amplifiers and your alternator doesn't stand a chance.
I would think that alternators are rated at higher rpms and for intermittent duty. Bill would definitely be the reference on this point.
Larger battery banks with larger reserves when fully depleted after a long period at rest only compound the strain on your alternator. You never see a fishing boat with the trolling motor battery bank hooked up to the alternator/stator. And there is good reason for that. So you have to introduce a more complex charging scheme as audio systems cross certain thesholds. Plus, a larger shore AC battery charger becomes essential.

David
Earmark Marine

Brett,

-Belt is in good condition, no nears, snags..etc
-As far as the cables, there is a, orange, purple and black. HOWEVER, the service tech and I noticed that the ground has some funky splice and drops gauge in wire size.
- As far as using the boat....We usually sit with stereo up at a decent level, and fill bags for about 15-20 minutes using 3 tsunamis that are plumbed into the boat. Then we wakeboard (stereo usually up). Then we sit and empty doing the same thing.
- The alternator that I just picked up from the MC dealer is a MANDO. ????

David,

So are you getting at the fact that adding the second battery will help, but will not relieve any load off the alternator?

Brett,

I am also assuming the alignment is fixed as well, I plan on taking the old alternator in and having it checked out which can tell me a little about the nature of why this one went out.

Matt,
A second battery is really a 'must have' for anyone with external amplification and who plays their audio system at rest for more than a few minutes. A dozen fully charged batteries do not represent a challenge for your alternator but a few fully discharged batteries will add a serious current load to your alternator in addition to the boat operations and the continued stereo draw. So there is no singular solution. As systems get larger and larger then battery reserves must follow suit and at some point you have to address the alternator with an upgrade or take steps in your system design to protect the alternator. There is no static prescription for this. The scheme must be altered as the system size and demands grow. There is always trickle down issues that cascade into other areas as you build.
And, as mentioned above, since audio is the largest draw by far it only makes sense to start with a comprehensive audio system design that reduces some of the complexity instead of compounding it.

David
Earmark Marine

Originally Posted by crowem87

Brett,

-Belt is in good condition, no nears, snags..etc
-As far as the cables, there is a, orange, purple and black. HOWEVER, the service tech and I noticed that the ground has some funky splice and drops gauge in wire size.
- As far as using the boat....We usually sit with stereo up at a decent level, and fill bags for about 15-20 minutes using 3 tsunamis that are plumbed into the boat. Then we wakeboard (stereo usually up). Then we sit and empty doing the same thing.
- The alternator that I just picked up from the MC dealer is a MANDO. ????

Should of asked this earlier. So when you are sitting filling up/emptying the bags and listening to the stereo is the boat on or off? I don't think it really matters but may have something to do with it and this is why.

If your boat is off your alternator isn't putting out anything(obviously) so you are discharging your batteries for 15-20 minutes. Then you start your boat and wakeboard with the stereo turned up. I am guessing your stereo is using up 40-50 amps(if your wiring is perfect). That means you only have 5-15 amps in reserve to run the gauges, fuel pump, lights, PCM. So you are either just barely breaking even in input and output amps or you are drawing more then your output. Either way your alternator is running as full of output as it can all the time and your battery is probably never getting up to it's full state of charge.

Nowif you are sitting with the boat on and listening to the stereo as well us using pumps you are still probably using more amps then you are putting back in. i wouldn't be surprised if that alternator puts out 25 or 30 amps at idle.

Do you have the corvette 330hp engine? Does the alternator have a 2" (pivot) mounting foot and a single threaded mounting ear? If it does I think I can build up a 90 amp Prestolite unit that is all brand new except I will have to pull off the front housing because it has a wide mounting ear with 3 threaded holes. The wide mounting ear doesn't clear the manifold on that engine. I can throw on a single threaded front housing that should clear. If you do go up in amperage though you are going to have to upgrade your battery cables(both positive and negative).

The other option or you could do in conjunction with a higher output alternator is to add a 2nd battery with a battery selector switch and/or a sure power combinor/seperator. This will leave you with a full battery(if you use them right) for starting, help protect the alternator and give you longer play time. The other thing I would consider is to add a 10+ amp dual bank charger to hook up every night.

I just looked. i wouldn't even have to swap front housings as that one already has a single threaded ear.

Brett, let me look at the alternator when I get home and I will get back to you with details on its set-up. I may even post pics. My only issue is I just bought this one yesterday and can not return it...so now I have a core and a good one, so I am looking for options with the 230$ i just spent in mind

Originally Posted by crowem87

Brett, let me look at the alternator when I get home and I will get back to you with details on its set-up. I may even post pics. My only issue is I just bought this one yesterday and can not return it...so now I have a core and a good one, so I am looking for options with the 230$ i just spent in mind

Then, I would go with an extra Stereo battery and some sort of way to isolate the battery banks whether it be manually or automatically.

Thanks for all your help. Just wondering, so I can have my alt. wound to put on an increased amperage correct? How much does this run?

Won't adding a second battery actually increase the load on his alternator (unless it is completely isolated and recharged only via shore charger)? Upgrade the alternator.