Alternator Upgrade Options?

Okay, my understanding is that I have a pretty weak factory alternator in my 92 Supra Sunsport.

This summer I'll be adding a 4x100 watt alpine amp for the 4 speakers and another Rockford Fosgate Punch 360.2 amp that will be running 360 watts mono for a subwoofer.

So, taking that into consideration, I'll be using around 560 watts more than before at RMS. So at 12 volts, 560 watts = another 46 amperes of load on the system, right? (watts = amps * volts)

Eventually I'll probably add another amp and maybe some tower speakers (nothing too extreme, maybe some bazooka tubbies) and possibly some LED spotlights on the tower... But not this season.


So, what would be the ideal size of alternator for me to get? 140 amp? 180 amp? 200 amp?

I know that I need a marine alternator. I know that I have a left hand PCM351. I get really confused with this CW/CCW stuff and want to be sure I'm shopping for the right thing.

Would any of these work for me?
http://www.ebay.com/itm/ALTERNATOR-H...214c82&vxp=mtr

http://www.ebay.com/itm/HIGH-OUTPUT-...90b3cd&vxp=mtr

http://www.ebay.com/itm/HIGH-AMP-ALT...3c2f1a&vxp=mtr

I have heard people mention DB Electrical, but I'm not too keen on spending $300+ on a high amp alternator from them. I'd like to get as much bang for my buck as possible...

Thoughts?
https://lh5.googleusercontent.com/-L...UNSET%255D.jpg

are you going to add another battery? i think i upgraded to a 140, it's been awhile though and that's just from memory.

check with a local electrical shop. they might be able to beef yours up or take yours on trade (plus some $) for a rebuilt. prob a cheaper option that just buying another.

Quote:

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Originally Posted by Salty87

are you going to add another battery? i think i upgraded to a 140, it's been awhile though and that's just from memory.

check with a local electrical shop. they might be able to beef yours up or take yours on trade (plus some $) for a rebuilt. prob a cheaper option that just buying another.

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I already have dual deep cycle batteries with the Perko (1, 2, 1&2, off) switch.

Quote:

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Originally Posted by Salty87

are you going to add another battery? i think i upgraded to a 140, it's been awhile though and that's just from memory.

check with a local electrical shop. they might be able to beef yours up or take yours on trade (plus some $) for a rebuilt. prob a cheaper option that just buying another.

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I recommend the same I have found a local alternator and started rebuild shop and usually FAR less than a retail outlet.

Trayson,

What amperage alt do you currently have? 2nd, i mean no disrespect, but alts from DB are considered price-point upgrades as far as marine alternators go. They basically take a stock alternator and change some internals for a higher output. A quality upgrade marine alternator from someone like Belmar, can run $700+. My best advice is to take your system as a hole, into consideration and how you intend to use it. If you are looking to spend a number of hours at the sand bar/party cove each weekend jam'n the system, I would suggest a larger battery bank and a good shore charger to replenish it. Alternators make for poor battery chargers, even hi-amp ones.

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Originally Posted by Wylietunes

Trayson,

What amperage alt do you currently have? 2nd, i mean no disrespect, but alts from DB are considered price-point upgrades as far as marine alternators go. They basically take a stock alternator and change some internals for a higher output. A quality upgrade marine alternator from someone like Belmar, can run $700+. My best advice is to take your system as a hole, into consideration and how you intend to use it. If you are looking to spend a number of hours at the sand bar/party cove each weekend jam'n the system, I would suggest a larger battery bank and a good shore charger to replenish it. Alternators make for poor battery chargers, even hi-amp ones.

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Well, I was told by another Supra owner that I likely have a 50 amp alternator. I'm not 100% sure though.

How I'd anticipate using it is that I'd be playing music while I'm driving and probably playing music (not full tilt jamming) while we chill out and float along the river. Basically I figured it'd make sense to have a larger alternator so the charge can keep up during the day. At least that was my thought. Again, for this season I'm only running a 4x50 alpine and a Punch 360.2 mono to a single 10" sub. Not hardly impressive in the realm of boat systems!

I agree with Wylietunes add a third battery... I am running a total of 6 batteries in my 242 with 4 amps and have no problems...
But it would not hurt to start looking to maybe find a little stronger alternator in the future... Good Luck...

https://forum.supraboats.com/attachm...8&d=1348094823
https://forum.supraboats.com/attachm...9&d=1348094824

Quote:

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Originally Posted by trayson

Well, I was told by another Supra owner that I likely have a 50 amp alternator. I'm not 100% sure though.

How I'd anticipate using it is that I'd be playing music while I'm driving and probably playing music (not full tilt jamming) while we chill out and float along the river. Basically I figured it'd make sense to have a larger alternator so the charge can keep up during the day. At least that was my thought. Again, for this season I'm only running a 4x50 alpine and a Punch 360.2 mono to a single 10" sub. Not hardly impressive in the realm of boat systems!

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I think your real world stereo current draw will be about 60% of what you think it will be. This will fluctuate with volume levels and music type, but on average, I think its going to be less then what you think. With engine running, I do not see an issue with your current alternator keeping pace with a 2-3 mild amps, although it will add to the total work load. Heres the kicker, no matter the size or output of the alt, it will do absolutely nothing to extend the engine off stereo play time. I would focus my efforts on an adequate battery bank with the Ah's that will get you the play time you are looking for, without having to start and run the engine every 30 minutes. Once off the water, reply on a shore charger to replenish the batteries. A larger bank is also better for the batteries life span. 2 batteries depleted 50% is better then a single repeatedly run down to 0%.

Quote:

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Originally Posted by Wylietunes

I think your real world stereo current draw will be about 60% of what you think it will be. This will fluctuate with volume levels and music type, but on average, I think its going to be less then what you think. With engine running, I do not see an issue with your current alternator keeping pace with a 2-3 mild amps, although it will add to the total work load. Heres the kicker, no matter the size or output of the alt, it will do absolutely nothing to extend the engine off stereo play time. I would focus my efforts on an adequate battery bank with the Ah's that will get you the play time you are looking for, without having to start and run the engine every 30 minutes. Once off the water, reply on a shore charger to replenish the batteries. A larger bank is also better for the batteries life span. 2 batteries depleted 50% is better then a single repeatedly run down to 0%.

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Makes sense. So, currently I have two batteries and a Perko Switch that looks like this:
https://a248.e.akamai.net/f/248/9086...6_L1?$product$

If I got a 3rd or 4th battery, how would you suggest I wire them up?

Wire the 2nd house battery in parallel (+ to +/- to -) with the existing house battery. All loads, except the auto bilge B+, need to be wired to the C post of the switch.

throwing this out there after dealing with all sorts of charging issues for the past two weeks. i just got my new alternator tested as bad from a local well-trusted alternator and starter shop. they said that they have the regular 61-amp alternator for PCM 351's for $160, and a 90-amp for $155. only difference is that the 90-amp doesn't have a provision for the EXC wire, it just has power/ground. anyone know how this would affect a boat with the PCM 351, if the excite wire wasn't hooked up? could be cheap upgrade for everyone if it's workable.

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Originally Posted by jtryon

throwing this out there after dealing with all sorts of charging issues for the past two weeks. i just got my new alternator tested as bad from a local well-trusted alternator and starter shop. they said that they have the regular 61-amp alternator for PCM 351's for $160, and a 90-amp for $155. only difference is that the 90-amp doesn't have a provision for the EXC wire, it just has power/ground. anyone know how this would affect a boat with the PCM 351, if the excite wire wasn't hooked up? could be cheap upgrade for everyone if it's workable.

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Those 1-wire alternators have the exciter built into them. Easy to install and eliminates several wires. I don't see a down-side.

thanks for the response, wotan. i will go that route if the replacement from skidim doesn't work out.