Will a 2nd alternator help me?

[thegnman]

I'm running 2 Skar Sk1500s strapped to 3 hds3 12s in 8cu ported box and 2 PPI power amps for mids. I'm still having light dimming and major voltage drops with a true 240amp alternator and a xs power 3400 battery. 5 farad cap. 0g everywhere and big 3. The electrical was the 1st thing I did when building the system and I thought it would suffice. I never run the stereo with the truck off. I have been looking at a dual alternator setup. I can order a dual alt. Kit for $300 and have my local starter/alternator shop build me another alternator for $300. Am I wasting $600+ or should I spend the money somewhere else and take a different approach. I eventually wanna upgrade to hdc's 12s and 3 sub amps one on each Hdc3 12 but not until I have the power to run them. Thx for any help

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[Popwarhomie 5,000+ posts]

What is your voltage dropping to?

 

[tommymilan311]

Whats is your vehicle. Year, Make and Model. I'll talk to R&D and see if we got a bigger ALT we can do or if we might have a dual alt for a little less. PM me

 

[gckless 5,000+ posts]

When you say "true 240A alternator", what exactly do you mean? What brand? Also, how did you set amp gains? What voltage are you seeing, where is that measured, and with what? Pretty sure you're going to need at least one more battery, or a bigger one at a minimum. Or ultracaps.

 

[Popwarhomie 5,000+ posts]

When you say "true 240A alternator", what exactly do you mean? What brand?

Was going to ask the same but figured he had a stocker beefed up by a local shop.

 

[thegnman]

Yea its a stock alt. Beefed up was bench tested@ 240amps peak , idle was around 110amps at 800rpms. 2001 Silverado 5.3l 3door. Right now the only voltmeters I have in the truck are on the cap which I can't see , on the audio control epic center , and the one in the stock cluster. From what I can assume I'd say it's dropping into the low 10s. I've seen the epicenter drop into the 11s but I don't think it's very accurate. I can put a meter on the battery if anyone needs an exact reading when the bass is hitting. I thought extra batteries only help when the engine is off. Am I wrong to think that?

 

[big scott]

not 100% true. it does help.

if your dipping that low then yea look into another alt.

or get a 1 good audio alt.

and ya hook up a volt meter and see exactly whats its going down to.

 

[hispls 5,000+ posts]

I'm a big fan of batteries, though alternator(s) is best if space is an issue. I would want to see a proper high output alternator (from one of the reputable manufacturers) and a good size extra battery to feed your amps properly.

 

[gckless 5,000+ posts]

Are you taking readings when the alt is at peak output RPMs? Either way that alternator probably isn't putting out what they say. I'd say you need a good alt or another one. Really I'd rather sell your current alt and spend all that on a big unit.

https://www.dcpowerinc.com/fit/Chevrolet~Silverado~2001~5.3L-V8/gm-and-chevy-vortec-dual-alternator-kit-with-270-amp-xp-series-alternator.html

https://www.dcpowerinc.com/fit/Chevrolet~Silverado~2001~5.3L-V8/8237-300-spx.html or this if you want bigger: https://www.dcpowerinc.com/fit/Chevrolet~Silverado~2001~5.3L-V8/8237-370-xp.html

I still think you're going to need more storage also.

 

[tommymilan311]

Yea its a stock alt. Beefed up was bench tested@ 240amps peak , idle was around 110amps at 800rpms. 2001 Silverado 5.3l 3door. Right now the only voltmeters I have in the truck are on the cap which I can't see , on the audio control epic center , and the one in the stock cluster. From what I can assume I'd say it's dropping into the low 10s. I've seen the epicenter drop into the 11s but I don't think it's very accurate. I can put a meter on the battery if anyone needs an exact reading when the bass is hitting. I thought extra batteries only help when the engine is off. Am I wrong to think that?

Battery or a Cap will somewhat help. If you don't have enough power your don't have enough power. If your lights "flicker" with the initial hit you'd be fine with another battery, if they stay dimmed on long bass notes, its probably not going to help much. We make a few Alts for the 5.3L, the affordable one isn't much better than the one you have, the one you want is a completely custom Alt and your at $1000+, no average person wants to spend that.

Question? When they beefed up you Alt, did they change out parts or jumper some wires? A good dealer is going to swap out your stater, rotor, and rectifier. I'll PM you a number to call our R&D so you can explain to him your specific situation, or there are a few HO Alt companies out there for car audio, that isn't our expertise.

 

[mylows10 5,000+ posts]

Might wannabes check your wires make sure they are secure as well. A 275-320 hairpin alt is what you need. But you'll need an extra battery as well I doubt that beefed up sly is doing what they say. Most local alt builders will only build up to 200 amps. Because they don't want comebacks from bad bearings

 

[tommymilan311]

Are you taking readings when the alt is at peak output RPMs? Either way that alternator probably isn't putting out what they say. I'd say you need a good alt or another one. Really I'd rather sell your current alt and spend all that on a big unit.
https://www.dcpowerinc.com/fit/Chevrolet~Silverado~2001~5.3L-V8/gm-and-chevy-vortec-dual-alternator-kit-with-270-amp-xp-series-alternator.html

https://www.dcpowerinc.com/fit/Chevrolet~Silverado~2001~5.3L-V8/8237-300-spx.html or this if you want bigger: https://www.dcpowerinc.com/fit/Chevrolet~Silverado~2001~5.3L-V8/8237-370-xp.html

I still think you're going to need more storage also.

Yeah, thats about our prices and rating, although the 370 amp is a little cheaper than we can do.

 

[wew lad 5,000+ posts]

Yea its a stock alt. idle was around 110amps at 800rpms. 2001 Silverado 5.3l 3door. I thought extra batteries only help when the engine is off. Am I wrong to think that?

idle output is the reason why its dropping so much, and extra batteries will help with the engine on as well. it helps stabilize your voltage at a higher voltage. i have the same truck, but a 00 ext cab. they made dual battery auxilary mounts for these trucks. $40 for it at the dealer with the tie down. i have two east penn AGMs, 200 amp HO alternator, for 3 amps about ~1500-2000w rms and i drop to battery resting voltage if im at idle and the batts havent had time to fully charge from the last song lol

fyi this is a cheaper option for our AD244 alternators

AD244 High Output Alternator Upgrade From CS130, CS130D, and AD230

 

[thegnman]

Yes the parts where swapped out when the local shop built the alternator. It is a reputable local company. I'm going to take some readings with a voltmeter and post back. Thx for everyone's help.

 

[wew lad 5,000+ posts]

i would highly recommend getting at least dual batteries. it'll cost you only about 150. i can get you the part numbers for the GM dual aux battery mount.

new alternator would be more than double that.