Author Topic: Adding a second alternator  (Read 11186 times)

Offline 1979C20

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Adding a second alternator
« on: January 26, 2013, 02:09:04 AM »
Soooo, I installed a steroe system in my 89 burb. Ive got 2 10" kicker comps powered by a 900 watt orion amp wired with 4 gauge power and ground. After installing the system, its killing my charging system. When the bass hits the volts drop from 14 to about 10. Ive been researching and it seems as though i can mount a second alternator where a smog pump would bolt on my serp belt bracketry and parallel one alternator to another and wire both to the same battery. Just wanted to make sure that this is doable in that fashion. Anyone have some input?
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline 79gmc15

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Re: Adding a second alternator
« Reply #1 on: January 26, 2013, 03:48:21 AM »
What kind of alternator do you have now? You could possibly get a higher output one.

Offline VileZambonie

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Re: Adding a second alternator
« Reply #2 on: January 26, 2013, 05:16:48 AM »
Just upgrade your charging system to one good Alternator. Make sure your amp is properly wired and consider installing a capacitor
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Offline gildardo01

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Re: Adding a second alternator
« Reply #3 on: January 26, 2013, 09:01:44 AM »
i agree with everyone on here, just upgrade your alt.. to a 140 amp alternator... you´ll save your self the stress of fabricating and installing the second alternator, and you´ll be saving horsepower by using 1 alt instead of 2.. im talking about at least 10hp loss if you install the second alt..and the capacitor is also a must... you´ll really notice the difference in the bass after you install the capacitor...  i also recommend a deep cycle battery instead of a lead acid battery...   

Offline 1979C20

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Re: Adding a second alternator
« Reply #4 on: January 27, 2013, 11:40:31 PM »
Woth my discount at oreilly i can get a second 97amp alternator(same as my stock) for 50 buvks, where a high output would be closer to 150. My original alt is a 97 amp with a 4 terminal plug, but the stock connector only has 1 wire going to it, so if i put another one of those in it i only have to splice the one wire and run the positive feed. The bracket will be simple, i measured it out all ill really need is a small square of steel plate to drill 2 holes in, one to bolt to the bottom hole of the smog pump bracket and the other to bolt onto the alternator. I already found a belt that will work. And from all the research ive done a capacitor is just an expensive piece of junk that looks fancy, it will barely help with my voltage dropping. The only thing a cap will do is keep full voltage going into my amp, but it wont relieve the strain on my alternator. I will be adding a second battery as well, most likely a deep cycle, or an Optima Yellow top. Im just looking to see if anyone has played around with adding a second alternator before.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline 79gmc15

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Re: Adding a second alternator
« Reply #5 on: January 28, 2013, 03:07:58 AM »
Seems like it to me you will be spending close to $150 in materials, and time not to mention the loss of power/hp and MPG because of the increase of drag.

Offline pholliday1

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Re: Adding a second alternator
« Reply #6 on: January 28, 2013, 09:29:29 AM »
Step one go with the bigger alternator, step two as money allows add additional battery tray on drivers side wire the batteries in series and on the days when your rig is parked with doors open pumping your system the extra battery will handle that for short periods.
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1991 v3500 crewcab SRW 454tbi 480le 6" lift
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Offline 1979C20

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Re: Adding a second alternator
« Reply #7 on: January 28, 2013, 08:13:13 PM »
I understand and respect where you are all standing with your opi.ions, but id like to do it differently. A second alt for 50 dollars, a belt for 15 and an additional idler pulley(if needed) for 15 is more cost effective. Ill take the slight loss in horsepower, its not a race car. And, "materials" are nothing. All it will take is a 6" x 2" wide piece of scrap steel and a couple bolts. I already have wire out the butt. A second battery will be coming not long after the alternator. Like I said, im just looking for someone who has had personal experience with adding a second alternator. I know its very easily doable, heres basically what I will be doing.

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1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline pholliday1

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Re: Adding a second alternator
« Reply #8 on: January 28, 2013, 08:23:59 PM »
Understood..... I made a mistake when I said wire the batteries in series I meant in parallel you would want twice the amps not twice the volts sorry.
VETERAN AND LIFETIME NRA MEMBER. WHAT DO YOU STAND FOR?
1991 V3500 CREWCAB SRW 454TBI GMC
1991 v3500 crewcab SRW 454tbi 480le 6" lift
1990 V3500 crewcab Dana 60 FF 14b 5:38 ratio 40 inch 11" lift
1989 v3500 crewcab 454TBI 5" lift

Offline 1979C20

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Re: Adding a second alternator
« Reply #9 on: January 29, 2013, 02:17:42 AM »
I saw that, but knew what you meant. Definitely dont need 24 volts, but double the amps wont hurt.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline blazing816

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Re: Adding a second alternator
« Reply #10 on: January 29, 2013, 10:26:35 AM »
I hook up car audio for people all the time out of my garage and use to work in a car audio shop. A high amp alternator will work for what you have (in the end decision is yours) but I am running a 800 watt x4 and a 1600watt x 1 amp with a high amp alternator, optima yellow, and a 3.0 fradd cap on the sub amp and runs like a champ.

Quote: "And from all the research ive done a capacitor is just an expensive piece of junk that looks fancy, it will barely help with my voltage dropping."

This is not true, I have run systems without caps and the same systems with caps and they help out a lot. You are true in stating they are there to keep constant voltage to the amp, as what they do is store power. And yes you still need a better amp alternator (you have to think when these trucks were made there was not a lot of electric demand) but what it does do is stop drops in your voltage (14v to 10v) and will stop your headlights from dimming every time you have big bass bumps. If you have ever been in a car that the bass is hitting long and hard, and the dash lights and headlights look like they are bouncing to the music, a cap would help stop that. What needs to be taken into consideration is what wattage your amp is and how you plan on listing to your music. If you have a 1000watt amp and want to listen to your music so people two county's over can hear you then a 0.5 fradd cap will not do crap. If you take everything into consideration a cap will help your system and the longevity of your equipment.

That's my $0.02
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1988 Chevy R20 Scottsdale Crew Cab (350/TH400/4.56)

Offline VileZambonie

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Re: Adding a second alternator
« Reply #11 on: February 01, 2013, 04:25:43 PM »
You need a good voltage stabilizer - Good Battery, Good Generator, good clean connections and a capacitor will surely help. Dual alternator fields may actually cause unwanted noise and be counter productive since you are doing this to satisfy your sound system but as you stated... It's your truck
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Offline werewolfx13

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Re: Adding a second alternator
« Reply #12 on: February 01, 2013, 09:04:22 PM »
The system you've got doesn't justify the problems with installing a second alt, IMO. I run 140a alts in my trucks, and my k20 flatbed is at some point going to get a second 149 amp alt, but for handling a complete second electrical system for the utility loads (omnidirectional service lighting, winch, and my CB/Ham/GMRS gear). As Vile pointed out, running dual alts introduces a second field of line noise, and cutting that out will make you bald very early. A capacitor works wonders for stabilizing your sound system, but it will MURDER a stock alt that is already taxed, much like installing a deep cycle battery without an isolator (and isolators monkey something awful with amps, via voltage differential. I STRONGLY discourage using isolators with an amplifier).  IMO, plan for a cap, drop the coin on the 140 amp alt, plan on buying a new MATCHING SET of batteries from a reputable manufacturer (I prefer batteries made by Deka [Napa Legend batteries]), and thump happy. Or, buy a cap and get it installed and wait for the alt to bite the dust then replace the alt and battery(s), and in the meantime..thump happy.
Chris
'83 Chevy c10 Silverado SWB
'76 Chevy k20 LWB 6.5'x8' Flatbed
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Offline TRAZOII

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Re: Adding a second alternator
« Reply #13 on: October 17, 2017, 01:58:35 AM »
I know it's a little late to the game. But, 1985 chevy caprice came with a 120a alternator. I have 2 in my 85 k10 sub. With a secondary battery and isolator. The second alt and bat power my power inverter, onboard air pump and tank thats built into my bumper. Also looking to add a 200 watt solar array with 4 blue tops. The second alt would keep them charged while I drive
 

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