Installing a H.O. Alternator

I have decided to Up grade my stock Alternator on my Air(60 Amps) to a High Output Alternator (150 Amps). If done wrong this job could get ulgy. I have talked with a few people about how it should be done but not one them has done it them self. It's all in theroy. I wanted to know what Gauge wire I should run? Where should the heavy gauge wire run "Start and Finish" and how will the extra Amps effect my stock circut breaker. I have purchached a 150 amp circut breaker to run in-line with the Alternator but will the power still need's to go threw the stock 60 breaker? Below are some photo's I can give you more details on Wires and where they are going if this will help. So far people have said. Run the output of the H.O. Alt threw the breaker and a single 2 or 4 gauge wire up to the bat's ??????????????? Is it this easy? what about the other wires on the back of the 60Amp breaker what di I do with them?

Here is the New Alt



Here is the stock 60 amp breaker the "Orange wire" is the output of the alternator, The Red Wire is going into the Main motor plug and into the bildge, The Black wire goes into the Main wire loom and into the EFI box



Any help with this would be great Thanks fo looking

I would ask Vince at www.SkiDim.com ... even though they didn't sell you the alt. they'll often help with advice for installs.

Joe

Ok I couldn't wait Here's how it went


Stock Alt

Remove Alt and up grade wire to 4 gauge

Install New Alt

Install New 150 Amp Breaker and run 4 gauge wire up to the bat's



Im going to hook the boat up to the fake a lake in the morning and run it and see how everything works. Ill let you know!

Assuming the voltage regulator and rectifier are internal to the alternator (99.99% of the time that is the case), it's that easy. Just be sure the wire to the bats is as heavy as the wire you have running to amps or lights. Where did you wire in the 150 amp breaker? It's a nice safety feature, but may not offer any more protection than the stock breakers. With the amount of wiring you have done in your boat so far, I'm sure you have it hooked up right.

Where did you get the alternator and did you look into having the stock alternator rewound instead? I have done that a few times in the past with great success but never with a marine alternator.

Swass The regulator is internal. I bought the Alternator from the Batteryshack.com in FL. It was $400. The 150 Amp breaker is on the back of the Motor. Photo #5 above. The Alternator output Goes to the 150 breaker, then to the bat's all with 4 gauge wire. Battery shack said, "It's a Self extracting Unit" It will monitor the needed volts from the battery's and put out whatever the demand. He said it should be 13.6 volts at idle and 14.2 volts at speed. I never thought about having the stock unit rewound. I don’t know any one who has done it that way. Plus now I still have the stock Alt in case anything goes wrong. I didn't want to take chances on this, I have heard a few nightmare storys about Bad alternators tearing things up. All those digital gauges in my dash, I dont even want to think about it.

You were running that stereo set up with a 50amp alt.??? Did you have problems keeping the batts. charged? I am only asking cause I am putting in a 800 watt amp, and peeps were telling me to up the alt. but I think my 70amp. alt is fine. Any thoughts?

Your 70amp Alternator should be fine... I assume you aren't going to be running 3 batteries in your boat like grant is. Even if you install two the 70 should be fine. I have just installed a 2nd battery and a 1500 watt system with the stock 60amp alternator and I'm not to concerned about it...

I ran the system today. Everything worked fine.
13.2 volts at Idle, and around 14.0 above 1000 rpm's. I turned everything on at once Lights Heater Stereo, ect I could get the volts to drop below 12 volts when the sub hit. But that's a worse case.
S Dub I had to charge the 3 bats when I came back to the house no big deal. I have a portable bat charger. But that not the correct way to do thing's. The old alt 50-amp alt worked. I knew it would give out eventually so I up-graded before it left me out of juice. I knew the old Alt would wait to give out, Like on some dark night on our way back from late night shinannagin's

Grant,
give it a little time for the brushes to seat 100% on the Alt. That voltage will kick up to 13.5 or higher soon enough and run steady all day, even with many accessories running.

KG

Kevin: I have never heard of that "But It sounds good to Me" I hope What you are saying comes true. I will let you know what Happens! Im going to re-do my Amps and Run a total of 3000 watts so we will see what the Volt meter say's when it's all said and done Amps PPI 2500 to a LJ 12W7 PPI 4125 to the Tower PPI 5800 to the Hull and 1 JL 12 W3

Question on sort of the same lines, but a little more complicated. I have an 81 Nautique with 35 amp alt and external regulator. I order from DIM a 51 amp with internal regulator and adaptor kit with new wiring harness. I talked to Vince some and am getting ready to install (as soon as the boat is back from the glass shop). Any suggestions warnings, etc. since this change will include a few wrinkles the one above did not, i.e. the regulator being different.

thanks

Not meaning to get overly technical but because the brushes in an alternator only conduct the field current (2-5 amps max), the output volatge won't change as they seat in. Since the output of an alternator is actually AC current and not DC, the diodes and voltage regulator take care of converting and regulating the final output voltage, not the contact of the brushes.

John, the adaptor kit will take care of the needed wiring changes and should be a simple plug in installation. Installation is really no more complicated than what Grant described and you'll end up with a more reliable electronic regulator instead of the old electromagnetic regulator that you are replacing.

By the way, for anyone considering this upgrade, you can usually get your stock alternator rewound to 150%-300% of its original output by any electrical shop that rebuilds starters and alternators. The last one I had done about two years ago cost about $60.00 to go from a 50 amp to a 90 amp output.

Shawn,
I was only speaking of experience back in the dasy when I ran a towing company. When wer ran the test on new Alt installs, we always ran the vehicle for about a 1/2. Tested in the beginning and then after the 1/2 hour, and the voltage always changed, (even with a new battery, as this was a huge factor). The difference here would be that those were automotive Alt's not marine.

Other then the spark arrestment, is there a huge difference in the two, (marine vs. regular automotive)??? just asking to learn more...

KG

Kevin,

Would the difference that you saw in voltage only happen during the very first time the alternator was run? There is usually an increase in voltage output as the alternator warms up and as it recovers the battery from starting the motor, but this happens every time not just the first time it is started. To be honest, I've never really paid attention that closely. Who knows, could be the brushes but the principles of how an alternator works (compared to an old fashioned generator) suggests that as long as the field voltage is present from the brushes the final output voltage is regulated at the diodes, transistors and ultimately the voltage regulator. (the field voltage creates the magnetic field in the windings that is required to generates the current. A three-pole alternator will generate three AC signwaves, each 120 degrees apart. If you extrapolate that to how current is converted from AC to DC, it explains why alternators are limited on the amount of current (amps) they can produce regardless of how fast you turn them but can make an unlimited amount of volts, but I am getting way off subject).

There aren't many differences in marine vs automotive alternators. In fact, most alternators are simply "marine approved". All that usually means is all of the regulators and eletronics are solid state or sealed so they can't spark. I know the newer GM alternators are identical internally, don't know about others. Externally, they may be a bit different to allow for changes in wiring, more durable cases, increased cooling, etc etc.

good info, thanks