Keep Popping Alternator. Help!

I recently installed a sizeable sterro system in my new XLV. Knowing that I needed a larger alternator I looked to the boards here on WW to find out the best marine high output alternator to get. I was looking at the Battery Shack and that is where I went. I got the 150 amp alterntor. Grant, I know you have experience with these alternators. The second time out we burned up the diodes on the alternator. I sent it back and they promptly repaired it and sent it back. The thought that something had arced in the alternator. Then after a few more times out it happened again. Something is going on here. Has anyone else experienced this problem? And how should I go about figuring it out? I have a sub amp that draws 60 amps at RMS and sometimes it can spike up to 100-125 for a millisecond. I also have two Alpine V12 amps for my 6.5" speakers. They each are 400 watt amps. My sub amp is an Xtant X1001 1000 watt. I have a battery isolator/combiner. All this is being powered by two deep cycle batteries and I have one battery on the isolator. I have put the stock alternator in to keep us on the water but I don't thump the subs too much with this alternator in which is a 70 amp alternator. Any help would be much appreciated!

I used to run about 3,400 watts at the ohms the speakers were seeing of an X-Star stock alternator and just two of those amps totalling only 880 of the 3,400 watts were class A that drew 80 amps each or 160 amps at peak power.

I had voltage dips into 11.5 range until I rewired everything with 0 guage wire and the system was very stable after that and remained in the 13 to 13.5 volt range. I think a 70 watt alternator could keep your system at around 13 volts if you you are using 0 guage, the wire distances to the battery were minimal, you used high quality wire and distribution blocks, and there was not a problem elsewhere.

Seems like you would blow fuses in your amps if your amps had a problem, you were having issues on the amp side of the distrubtion block or you were just over driving the system (turning it up too loud). Check you wiring carefully on the battery side of the distribution block or have someone check wiring that is not stereo related.

If your only thrashing the aftermarket alternator and not the OE, I would check with mfg to make sure sur ethe laternator is okay to use with Malibus or else demand a new alternator because there may be defect in the alternator you have that they tried to rebuild.

Ive got 210 amp alternators. Comes with Double 0/1 gauge wire and all the goodies you need to install it.

http://www.wakeboardatlanta.com/litup/

you are not switching a battery disconnect switch while the engine is running are you? If not look into the battery isolator and the way it is connected.

My battery isolator /Combiner is automatic. It's a Hellroaring unit from Hellroaring.com. I wouldn't think it to pop the alternator. I know it is possible with a Perkko switch but don't you think that it's engineered not to pop the alternator? We do run the batteries for a while with the engine off. The batteries still start the engine. One person said that I am draining the batteries, then when I start the engine and charging the batteries that I am taxing the alternator too much as I play the stereo too. Is this possible? It's a 150 amp alternator!

most likely not since so many of us are doing the same thing as you and not having this problem???

I have been on the phone with the battery Isolator/Combiner company and they are telling me that it is fine. What about my grounds? I've been told that if my grounds are too small that it can back up the amps and pop the alternator. Or what about grounding out? Could that draw amps to blow the diodes on the alternator? And again, thanks for all your help direction and suggestions!

Yo Kraig,

I have no answers for you, but have had a similar situation with a friend's boat. Last year, we replaced a stereo in his boat and on the first weekend out, we were riding. We noticed the Volts pinning high and eventually the breaker popped. We disconnected the stereo and after checking the battery, replaced the alternator.

After that, the stereo amps (just a head unit) stopped working, so we have had no stereo in the boat. We are simply running a head unit directly off the main panel in the dash, single battery, no extra amps, 50 Amp alternator. Pretty much a stock, no frills setup, but it works!!

I did notice that several of the connection wires were pretty thin, particularly the power line to the stereo, so I may rewire that. I did check the ground and it was fine and a bit thicker, could not tell you the gauge, all the wires a fairly thin. The stereo that broke got pretty hot when we connected everything, and eventually the amp section stopped working, CD's would play, but no sound.

Your post got me thinking a bit. I have been considering a second battery install and isolating the stereo to that battery. I am assuming you had your stereo isolated from the ignition & ignition battery and hooked to a house load battery.

I had been considering amping out the boat and would have installed some pretty thick power and ground cables to the aux battery and the ground point on the engine. From there I would have used terminal blocks with inline fuses for each component.

I am definately curious about your problem, seems like we may have had something similar happen, but it may have been just the alternator and nothing else. Considering we were only running a 45x4 peak head unit, something is funny. We are gonna put another head unit in this weekend, so we shall see. Please keep up the posting and I will let you know how our simple stereo problem get's solved.

Let's see if I can help out. I'm going to throw out a little info. first. The conventional theory of electricity says current flows out positive and in through negative. An alternator "sucks" out electrons from the negative side and puts them into the positive side of the battery. The purpose of diodes are to change Alternating Current (AC) to Direct Current (DC, like your battery). Now, I am assuming your alternator is internally regulated and the voltage regulator is working correctly. Watts = volts x amps. Your alternator has a maximum of 150 amp output. 1 of your sub amps draws 60 amps, the two 400 watt amps draw approx. 60 amps. the 1000 watt amp draws approx. 76 amps. Thats 196 amps. Then you have your head unit, and your engine operation. So lets say you its theoretical to use well over 200 amps at once. Well that's what your battery is for. Your sound system will not use all of that once anyway. A 150 amp alternator sounds suitable. There are 2 tools you need to properly diagnose this. A VOLTMETER and an INDUCTIVE AMMETER. They have these ammeters that can hook up to voltmeters. Go to SEARS!!! You might be able to get away with just a voltmeter. To see how many amps you are actually using, turn everything on that you are normally would use. But DO NOT turn on the engine. Connect the inductive ammerter either to the positive lead of the battery with the arrow pointing away from the bat., or the negative side with the arrow pointing to the bat. See how many amps are being used. Add 20 amps for the engine operation. Your alternator should be able to exceed amperage demand by 10 amps. So if its more than 140, you need a bigger alternator. Now, does your alternator really put out 150 amps? Crank your engine and put the ammeter on the bat terminal of the alternator w/ the arrow pointing away from the alternator. Turn everything on. make it Loud!! Run your engine up to 2000 rpm. How many amps are there? If there are noticeably less amps now than when you did the first amerage test on the bat., you probably have a bad connection or too small of a wire from the alt. to the bat. If more, you need a bigger alternator. Check the battery voltage w/ the same conditions. It should be more than 13.5 volts, but less than 15.2.
To check your connections: use the same conditions again, connect the red lead on the voltmeter to the alternator BAT terminal and the black lead to the battery positive post. Note reading. Next connect the Red lead to the alternator case, and the Black lead to the bat. negative post. Both of these readings should be no more than .2 volts. If So, you have some BAD connections. There is your problem. Now, it might be possible that you need to upgrade the wire from the Alternator bat. terminal going to the battery. The ground side of the alternator should be just fine. Cranking your engine uses more amps, and it uses the same ground. I hope this helps. If you don't have any tools or don't want to buy any, Check your connections and replace the positive cable from the alternator to the bat. The wire may not be capable of flowing twice the amperage it originally did. By the way, im looking for a new boat. Have about 15 to 20k to spend on one. Throw up some ideas!

Caldwell-
Thanks for the info! You seem to be very knowledgeable in this area. Could I graf out exactly how my system is wired, send that to you with all wire guages and see if you can find a problem with the way I have if wired?
Flux-
I'll keep you posted!

Sure!, send it on. I'll see what I can come up with.

One more thing before you go to all of that trouble.
The wire going from your alternator to your battery: To flow 150 amps, If it is 15 or 20 feet, it needs to be at least a 4 gauge wire. If it is 25 to 40 feet, its needs to be at least a 2 gauge wire. I would guess that the original wire is a 6 or 8 gauge.

Hey sorry to hear about your problem's. I dont know what can be giving you problems?
The battery shack alternators are pretty much No-brainer's. Connect power to your battery's and thats it. My unit is self grounding. Although adding a 2nd ground never hurt anything. I wish I could offer some help but you have me stumped. I would think if it blew one it would be a bad alternator although I think his alternators are pretty bullet proof. He test runs all his alternators before they go out the door. And out of the 10 to 15 people that I personaly know, no one has ever had a problem with there's. But if you keep blowing them I would think its somthing in you set up. With that said

Your power comming from the output of the alternator should be a 4 AGW and directley to the hellroing isolator/switcher for saftey you could throw a breaker in between the batterys and the alternator, Let me know what you come up with.

Niel: I like your alternators I wonder how much it would cost to convert to the serpentine belt on my GT-40. I have the V belt and I think 160 amps is close to the max that belt can handle

Kraig:

You shoudln't be able to overload the alternator in a way that could damage the diodes. Most alternators are capable of putting out thier full output without any problems. If there was a overheating problem it should burn up the windings before the diodes blew.

What kills diodes is over voltage. The most common cause of over voltage is switching off the battery, which was the load to the alternator.

A setup that I have seen used and I advised against is to have a circuit breaker in the path between the alternator and the battery. If yours is set up this way then by increasing the size of the alternator you could overload the circuit breaker. When the circuit breaker opens the sudden removal of the load causes the alternator to go over voltage and the diodes die.

If this was happening then I would expect that you would have noticed that you had to reset the circuit breaker. Any such happenings?


Rod

Kraig:

You shoudln't be able to overload the alternator in a way that could damage the diodes. Most alternators are capable of putting out thier full output without any problems. If there was a overheating problem it should burn up the windings before the diodes blew.

What kills diodes is over voltage. The most common cause of over voltage is switching off the battery, which was the load to the alternator.

A setup that I have seen used and I advised against is to have a circuit breaker in the path between the alternator and the battery. If yours is set up this way then by increasing the size of the alternator you could overload the circuit breaker. When the circuit breaker opens the sudden removal of the load causes the alternator to go over voltage and the diodes die.

If this was happening then I would expect that you would have noticed that you had to reset the circuit breaker. Any such happenings?


Rod

Guys, when I get home tonight I will diagram my setup with wire guages and all see if you two can see a problem with it. Sorry it has taken me so long to get back to you, you guys are being very helpful and I appreciate it, we have been on the water for the past three days. I'll post again tonight and send you an email. Again, thanks!