Increasing your alternator voltage output.

p8ntman442 · Post by **p8ntman442** » Sun Feb 10, 2008 8:45 am

This is something I found while looking for a voltage regulator for my passat. It does not increase alternator current output which is what most look for. It does however increase the voltage output by half a volt. Its a good short read, and I figured I would share it. The mechanics of doing this to a Fiero would be different, as the alternators differ, but the simple change woudl be easy to do.

http://www.detomaso.nu/~thomast/alternator/

crib notes is that the guy adds a diode (.5v drop) between his voltage regulator ground and the alternator caase ground, thus raising the ground voltage at the regulator and in turn raising the alternator output voltage.

Pyrthian · Post by **Pyrthian** » Mon Feb 11, 2008 9:58 am

changes nothing.
it already puts out more voltage than needed

p8ntman442 · Post by **p8ntman442** » Mon Feb 11, 2008 11:41 am

did you read the whole thing? his application required a higher voltage. Im not telling anyone to do this to their fiero, but if you are having charging issues, you may want to look into changing the voltage. Remember, as the voltage potential increases, so will the current, unless the alternator is maxed out.

Pyrthian · Post by **Pyrthian** » Mon Feb 11, 2008 12:21 pm

sorry, no I didnt read it.

I am just going on the basis of everything in the car is 12v. the alt already puts out more.

tho, I guess I should look - more current is always good. tho - I dont see how that happens. power is in watts. watts = voltage X current. usually, if you raise the voltage, the current goes down. the stator creates so much power in the magnetic field as it spins.

Series8217 · Post by **Series8217** » Mon Feb 11, 2008 1:21 pm

Pyrthian wrote:sorry, no I didnt read it.

I am just going on the basis of everything in the car is 12v.

It's not. All car batteries are at least 12.6V. Car batteries will not charge without at least 13.2V, and many require up to 14.4V.
A car battery is fully discharged at 11.89 volts.

By the time you go through all the crappy old undersized wiring in our cars, voltage may have dropped by a volt or more between the alternator or battery and whatever you're trying to get power too. Upping the voltage is a bandaid fix though. The best solution would be to use adequate wiring and connectors that don't have so much resistance that they create significant voltage drops under normal operating conditions.

EDIT: to clarify

Pyrthian · Post by **Pyrthian** » Mon Feb 11, 2008 2:48 pm

yes, I see whatcha are saying.
and, yes - finally read it....fooling the ground as the guy did will raise the output at the regulator, if you need more voltage to charge your battery.

slow'n'steady · Post by **slow'n'steady** » Sat Mar 01, 2008 4:31 pm

OK, i have seen this on a few sites now but didnt wanna say anything. HOWEVER you all already know i am fuckin retarded so i might as well ask here. First does this work on all types of alternators? I want to do it on my eldorado. Secondly doesn anyone know if/where i can get and OVERDRIVE pulley for my alternator? I am tryin to get something decent right now until i can fork ove the money for a 250+ amp alternator but that wont be for a little while (prolly may).

I have a pretty decent sound system getting ready to go in which is about 10X bigger than my current one which already has dimming issues so... Here is my setup in case someone cares:

Optima yellow top
Stinger terminals
2awg wire for the "BIG 3" upgrade
0awg for the power wire split in trunk to 2)0awg and 2)4 gauge wires
2) Audioque 15" HD3 subs (10ft^3 ported box tune to 32hz)
1) Autotek MM4000.1D (for subs)
1) Orion 300.1 amp (for rear speakers)
1) Alpine (something) older 100W amp for theweeters
Clarion DXZ785USB deck (pushing the four front speakers)
front speakers: 4" Eclipse SE8245 and 5.25" Eclipse SE8355 (in doors)
rear speakers: 6X9 Eclipse SE8495
Tweeters: Power Acoustik 1" 200W Titanium (in mirror pillar things...)
Kole 5.0 Farad cap (soon to be replaced with a Kinteik battery)

The Dark Side of Will · Sat Mar 01, 2008 7:37 pm

That can't possibly be going into your Fiero...

AntiCooter · Post by **AntiCooter** » Sat Mar 01, 2008 7:39 pm

slow'n'steady wrote: Secondly doesn anyone know if/where i can get and OVERDRIVE pulley for my alternator?

I got one for the Caprice from here-
http://www.alternatorparts.com/pulley_size.htm

slow'n'steady · Post by **slow'n'steady** » Sat Mar 01, 2008 8:15 pm

The Dark Side of Will wrote:That can't possibly be going into your Fiero...

LOL... no that is all in the cadillac... The fiero is getting some little things...

JVC KD-S30 deck (50WX4)
2) 10" Power Acoustik FX series, 4ohm DVC (running them at 1ohm)
1) MD Sound 2400W amp (1600RMS @ 1ohm)
MTX 6X9s in the dash (took them off my old 3000GT, they sound NICE!)
Not sure what is going in for rear speakers... Probably some Eclipse

Keeping that pretty mild! Those two HK4000D's would are abot 1' X 2' X 2.5", and the subs need about 5ft^3 each so not even CLOSE to enough room for that... not to mention the other two amps and stuff... I dont know what the hell i am doing with that damn car. I have a nice built short block laying here and was suppose to be getting cam carriers and heads form an OE member but dont know what ever happened to that... It has a lifter tick right now, i was thinking about just throwing all the turbo stuff on it, boosting about 15psi or so an dseeing how long it will last until it blows up. My RX7 swap just has WAY more potential so i am finding it hard to throw any more money into the fiero. I already have about $8K or so in it and cant even sell teh damn thing for $2K so.... IDK

Back to the subject, sorry!

slow'n'steady · Post by **slow'n'steady** » Sat Mar 01, 2008 9:43 pm

So if i do that little trick along with a smaller pulley, is there any thing else i can do to increase the output at all? Do they sell any type of "high output" kit or something...? I mean they build high alt. up to 300A so they must get the parts form somewhere... Honestly i have NO IDEA what even controls the output of an alternator but i have had a few apart and managed to get them back together and working fine so...

The Dark Side of Will · Sat Mar 01, 2008 10:10 pm

Where are you mounting the subs?

p8ntman442 · Post by **p8ntman442** » Sun Mar 02, 2008 9:18 pm

Weather or not this mod will work on your alternator, is not really pertinant. You need more CURRENT, this mod Produces more VOLTAGE. Your dimming issues an easily and safely be solved with a Capacitor. I'm assuming your trying to avoid the $150 for the capacitor, but its the best solution to your situation.

But you asked so, I will answer. I dont know if it will work on your alternator. I assume its a delphi, and uses some sort of voltage regulation, but from what I have heard some Caddys had expensive alternators that varied output for windshield heaters and stuff. Get a wiring diagram from a factory service manual and I can answer for sure.

The Dark Side of Will · Sun Mar 02, 2008 9:22 pm

Not sure if they varied the voltage output, but the Caddy alternators for the cars with windshield heaters have external outputs for THREE PHASE 12VAC.

slow'n'steady · Post by **slow'n'steady** » Sun Mar 02, 2008 9:51 pm

p8ntman442 wrote:Weather or not this mod will work on your alternator, is not really pertinant. You need more CURRENT, this mod Produces more VOLTAGE. Your dimming issues an easily and safely be solved with a Capacitor. I'm assuming your trying to avoid the $150 for the capacitor, but its the best solution to your situation.

But you asked so, I will answer. I dont know if it will work on your alternator. I assume its a delphi, and uses some sort of voltage regulation, but from what I have heard some Caddys had expensive alternators that varied output for windshield heaters and stuff. Get a wiring diagram from a factory service manual and I can answer for sure.

I have a 5 Farad cap in the car now and it isnt helping a whole lot... I knwo i need more current for the dimming problem HOWEVER... The more power to an amp the more power it will put out to the subs. Right now i am getting 14.4V at the battery and about 13.V+/- at the capacitor. If i can bump the voltage at the battery it will in turn pump the voltage at the cap which of course will pump the voltage at the amp thus giving me more power.

p8ntman442 · Post by **p8ntman442** » Sun Mar 02, 2008 9:54 pm

ok cool. Lets see a wiring diagram and I will figure out a way to boost the voltage.

slow'n'steady · Post by **slow'n'steady** » Sun Mar 02, 2008 9:59 pm

not sure if this is AT ALL what you are looking for, pulled up alldatapro.com and found this for teh starting/charging system...

EDIT: wow, that is HUGE resize if needed...

p8ntman442 · Post by **p8ntman442** » Mon Mar 03, 2008 7:44 pm

ok, see the line next to the words "regulator solid state" thats the regulator ground and thats where you want to drop .5 volts across. Find that point in your alternator that grounds the voltage regulator and Put in a diode that allows current to flow to ground. Should be fairly easy, as long as there is room for it. I suggest picking up a spare unit at the yard to play with. Not sure how big a deal it is to swap them out on the N*, so I would bench test b4 and after to ensure it worked.

slow'n'steady · Post by **slow'n'steady** » Mon Mar 03, 2008 9:25 pm

OK gonna make myself look stupid again:

So can you drop it more to make it put out more? like say an entire volt? That would get me a good 14+ at the amp which would be SWEET!

p8ntman442 · Post by **p8ntman442** » Thu Mar 06, 2008 8:40 pm

yes you can put 2 diodes in series, to raise the ground potential.

Think of it like water. If you have a float with a flag in a tank of water, and the flag is 5 feet from the surface of the water, what happens if you raise the water level 1 foot. the flag is still 5 feet from the surface of the water, but the actual height of the flag from sea level is up 1 foot. Your voltage regulator is the float. by adding the diodes, your raising the water level. The output voltage is the flag.

Now, this assumes the voltage regulator electronics in your alternator are rated for the voltage they are actually handling. You may end up frying a regulator. you also might end up with a cooler regulator, which will last longer, but your voltage may not be stable, if you alternator only puts out 14.5 volts and varies to 13.8, you may end up with voltage fluctuation.

Your voltage output does already fluctuate, so theoretically you shouldnt have any problem.