voltage drop after big 3 new alternator

[Lube]

I just put in a new alternator. 140 amp

800 Watts rms ran with 4 gauge wire

1/0 gauge big 3 done.

It's fine driving at around 13.4 with heavy bass hits

but as soon as i idle it'll go down to 12.7

Would adding my capacitor back in help? 500k Scosche cap. Or do I need a bigger cap (recommendations??)

Also at night headlights will dim during heavy hits still (the big 3 helped a little)

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[Spl4200]

Check all ur grounds then double check em

 

[Lube]

triple checked, all ok

 

[tc300 10+ year member]

Add a battery.... ABSOLUTELY FORGET ABOUT THE CAP!!!!

What is your set up also..??

 

[fatboytyler]

What was Big 3 ran with?

It still sounds like a ground issue. 800 RMS shouldn't give you any voltage drop on a 140A alternator.

What battery do you have? What quality of music do you have? If you're pirating music, make sure its quality. You could be clipping the hell out of it, causing the voltage drops.

Also, ensure your gains are set properly.

 

[Lube]

Sorry,

- 96 Cadillac Eldorado

- JVC KW-AV61BT Deck

- 4 Gauge power & ground

- Stock Bose 4" front and 6x9 rear

- 2 Pioneer 12" TS-W309D4

- Pioneer Amp GM-D8601

Tomorrow I will remove the grounds and re-sand. I don't have room in my trunk for a 2nd battery.

I listen to rap. iTunes downloaded.

I'm considering getting an O-Scope for gains for a better setting, but it's okay according to DMM

I have a superstart premium 34/78 battery

Big 3 was ran with 1/0 Execution big 3 kit OFC

 

[Lube]

It hasn't been dropping too bad now (I haven't touched anything) but when I have my lights on my voltage will be at 13 volts and go down to 12.6 when hard bass hits

 

[brian84corvette 10+ year member]

alot of "high output" alternators are just re wound to produce better electrical at higher rpm - but the cost is they produce worse than stock at idle rpm.

a clamp meter capable of measuring dc amps when its arms are hooked around the wire - would be capable of measuring amps produced as a test so you could see exactly what your alternator is producing at what rpms with heavy bass music playing.

you might find that your only getting 65/75 amps at engine idle - and 140 amps at 2000 engine rpm and up.

that might not be the case tho - so it would be cool if you found a buddy with that clamp meter to test your alt out and measure / record what its doing

 

[Lube]

alot of "high output" alternators are just re wound to produce better electrical at higher rpm - but the cost is they produce worse than stock at idle rpm.a clamp meter capable of measuring dc amps when its arms are hooked around the wire - would be capable of measuring amps produced as a test so you could see exactly what your alternator is producing at what rpms with heavy bass music playing.

you might find that your only getting 65/75 amps at engine idle - and 140 amps at 2000 engine rpm and up.

that might not be the case tho - so it would be cool if you found a buddy with that clamp meter to test your alt out and measure / record what its doing

Actually my alternator is stock. But if I can find someone with that, It'd be very helpful.

 

[brian84corvette 10+ year member]

o i see - in the title it looks like you did the big 3 and put in a new alternator.

possibly if you still have your stock alternator in the viechle - you can go down to your local parts store that isnt filled with iddiots - and find a pulley for your current alternator that is just slightly smaller around than your stock pulley is.

installing a smaller pulley on your alternator will spin it just a touch faster. alternators produce power at rpm and at engine idle this will help you as your alt will be spinning slightly faster than it used to - while engine rpm at idle stays the same as before.

 

[Kangaroux 5,000+ posts]

If you rev up to 1.5k - 2k rpm while idling and playing does your voltage go back up? As said above, cheaper high output alts are just rebuilt stock alternators designed to produce more current at the cost of losing some power while idling. It's not a terrible thing for your voltage to drop into the high 12's, so long as your battery is good enough to prevent it from dropping any lower. At 800rms, I wouldn't worry about it, however your voltage should not be dropping at all.

 

[RayRay1417]

Sounds like a bad ground or maybe a bad cell in the batt. I would go to discount or auto zone and have them do a load test on the alt and batt. Have them test it once without music and again with it wherever your voltage drips volume wise.

 

---------- Post added at 06:14 PM ---------- Previous post was at 06:13 PM ----------

 

Did you replace the wires during the big3 or just add to the wires that where there with 0g?

 

[Lube]

Sounds like a bad ground or maybe a bad cell in the batt. I would go to discount or auto zone and have them do a load test on the alt and batt. Have them test it once without music and again with it wherever your voltage drips volume wise. 

---------- Post added at 06:14 PM ---------- Previous post was at 06:13 PM ----------

 

Did you replace the wires during the big3 or just add to the wires that where there with 0g?

I might upgrade the battery but it should be okay. It is brand new afterall. Superstart premium 34/78. I will look into an Optima redtop or diehard platinum for later use.

Well, stock wires go to the side posts. Big 3 + amp is on the top posts. Same locations as the stock wires for grounding. Did big 3 over stock wires.

If you rev up to 1.5k - 2k rpm while idling and playing does your voltage go back up? As said above, cheaper high output alts are just rebuilt stock alternators designed to produce more current at the cost of losing some power while idling. It's not a terrible thing for your voltage to drop into the high 12's, so long as your battery is good enough to prevent it from dropping any lower. At 800rms, I wouldn't worry about it, however your voltage should not be dropping at all.

nope it doesn't go up unless i drive. It like gradually goes lower(driving). from 14.5 in the driveway to 13.6 driving. 13.4 music on. 12.9-13.1 headlights on with music. As low as 12.4 idling music on headlights on

 

[Kangaroux 5,000+ posts]

I might upgrade the battery but it should be okay. It is brand new afterall. Superstart premium 34/78. I will look into an Optima redtop or diehard platinum for later use.
Well, stock wires go to the side posts. Big 3 + amp is on the top posts. Same locations as the stock wires for grounding. Did big 3 over stock wires.

nope it doesn't go up unless i drive. It like gradually goes lower(driving). from 14.5 in the driveway to 13.6 driving. 13.4 music on. 12.9-13.1 headlights on with music. As low as 12.4 idling music on headlights on

Did you rev it up to 2k and hold it there? Whether or not you're driving makes no difference to the alternator, it should be producing its full amount of current at around 2k regardless if you're idling or in gear.