Is there a way to tap into raw pre-regulated alternator voltage?

[crazypete]

I've still got the stock 65 amp alternator. All I have in terms of electronics is the ignition system, the amp, and the stock head unit+rf cd player. Apart from the head unit and the cd player, all of these components benefit from high voltage. The ignition system lists operating range from 11-18 volts and the amps are routinely tested at higher voltages so I assume they can take an extra volt or two and pump out more juice.

Is there a way to tap into this higher voltage juice for my amp + ignition? Actually, do the guages/stock deck and such survive at 16 or so volts?

 

[HISSIN50]

the unregulated juice is too unstable - i would not want to use it. better to upgrade the alt, IMHO.

imagine use EFI guys running a puter and fuel pump off your alt.

 

[crazypete]

It's not the amperage, but rather voltage I am seeking. I think the g3 would regulate back to 13.8 volts too after all is said and done. Is there such a thing as an adjustable regulator?

 

[rd]

The answer is maybe. On older, carbed Fords, Ford used unregulated power from the alternator to operate the choke heater element. It worked with a thermostatic switch that would close at summer temps and heat to open the choke faster. It was the stator output wire, and fed the choke before it went to old style voltage reguator. I still have this in place on my 79 and 82. It works because there is power any time the alt is spinning, and non otherwise, and the heater is not sensitive to regulated current.

On efi cars, I think they did away with the choke heater output terminal on the alt, and I would not run anything else with that power source. A check of the wiring diagram would show it.

 

[HISSIN50]

RD, interesting stuff.
Pete, if this is all for your stereo, why not use a capacitor?

for other components, one can use devices similar to capacitors (i.e. the modules for FP's to keep them at higher voltages and remove voltage variation).

 

[Idwitheld-1`]

The alternator produces an Alternating Current. This is not really useable for the stereo equipment. You need Direct Current.

Lets talk amplifiers:
Some amplifiers will utilize the standard 12VDC system to direct drive the speaker output. This is not very effective at producing large power outputs.

More powerful amplifiers will use a DC to DC converter which is built into the amplifier. In fact other than the aluminum heat sink, the bulk of the amplifiers weight comes from the power semiconductors and magnetics of the DC-to-DC power supply. This power supply will step up the 12vdc input voltage to a higher voltage possibly 40-70 vdc. There are many technical reasons for doing this. These include semiconductor selections, conduction efficiencies and thermal management.

The net result is 12 or 18 vdc makes NO difference. The DC-DC power supply is pulse width modulated and will essentially regulate itself within a Safe Operating Area (SOA). Your limiting factor is not input voltage, but input switching conductance, frequency and overall design. You can not control these factors.

What does this mean to you?
1. The speaker load should be matched appropriatly to your amp's specs. If it says 4ohm out....don't go 2 ohm. Transfer efficiency is a function or your amplifiers drivers, not how many speakers you can parallel to the output. Mosfets do have limits.
2. It is most likely your amp is current starved. Upgrade your alternator.

3. Caps are only temporary storage devices for current. They have associated losses . Especially, Farad electrolytics. IF you need caps, your CURRENT STARVED.

 

[HISSIN50]

The alternator produces an Alternating Current. This is not really useable for the stereo equipment. You need Direct Current.

Lets talk amplifiers:
Some amplifiers will utilize the standard 12VDC system to direct drive the speaker output. This is not very effective at producing large power outputs.

More powerful amplifiers will use a DC to DC converter which is built into the amplifier. In fact other than the aluminum heat sink, the bulk of the amplifiers weight comes from the power semiconductors and magnetics of the DC-to-DC power supply. This power supply will step up the 12vdc input voltage to a higher voltage possibly 40-70 vdc. There are many technical reasons for doing this. These include semiconductor selections, conduction efficiencies and thermal management.

The net result is 12 or 18 vdc makes NO difference. The DC-DC power supply is pulse width modulated and will essentially regulate itself within a Safe Operating Area (SOA). Your limiting factor is not input voltage, but input switching conductance, frequency and overall design. You can not control these factors.

What does this mean to you?
1. The speaker load should be matched appropriatly to your amp's specs. If it says 4ohm out....don't go 2 ohm. Transfer efficiency is a function or your amplifiers drivers, not how many speakers you can parallel to the output. Mosfets do have limits.
2. It is most likely your amp is current starved. Upgrade your alternator.

3. Caps are only temporary storage devices for current. They have associated losses . Especially, Farad electrolytics. IF you need caps, your CURRENT STARVED.

hey bud, how ya been?

hey, we all knew all that already - please dont state the obvious.
ok, so when i turn the stereo on and noise comes out, it is working alright? that is about as far as i can go with this stuff. Idwitheld, i am not!

 

[Idwitheld-1`]

hey bud, how ya been?

hey, we all knew all that already - please dont state the obvious.
ok, so when i turn the stereo on and noise comes out, it is working alright? that is about as far as i can go with this stuff. Idwitheld, i am not!

Oops. I let the geek out. Me bad.

:OT:
I just bought a new house. I actually have a two car garage (insert picture of a grown man crying here). I'm grinnin ear to ear.

Too bad I have no money to buy car parts now. :damnit:
Stupid Ford Dealership. I had the AC upgraded. Dumba$$ mechanic runs a condensor pipe against my header. Not only does a hole finally occur in the AC pipe (which discharges the R134), but now I have a hole in the header pipe. Great put-put sound when I get on the gas. Stupid Frickinn people pay no attention to detail!!! Sorry, Rant done.

 

[crazypete]

I read this interesting article basically complaining about the "circuit city" style fast and furious type overrating of amplifiers based on peak power. It went on to describe that they arrive at the artificial peak power ratings by doing things like giving them a single tone burst after a few seconds of silence and spraying them with freon aaaaaaand.... bumping the voltage to 19 volts.

I said cha-ching! I could do that!

I have nothing really that is voltage sensitive except maybe the head unit but I had a huge power spike that took out my previous amp and ignition system and my headunit survived untouched so I assume those stockers are tough and could survive a few extra volts. I've heard rumors that ignition systems work better at higher voltages too. While instaling my replacement hi-6, the specs on the sheet listed acceptable voltage is 11-18 volts so it seems the ignition would like it too!

Apart from the ignition,wipers/headlights/stops/turnsignals and the radio I am trying to boost, there is nothing drawing power in here. I'm carbed/all mechanical.

I know I'm drawing less than 60 of the 65 amps because I have 2 parallel 30 amp fuses on the alternator black/orange power wire right off the alt (in case it grounds out) and they dont blow while running wipers/beams/stereo in reverse with brakes on and hazards blinking.

Are any of those wires coming off the alternator stator wires? I remember like a green and red on one connector and then the black/org, black/white and one more (yel?).

 

[HISSIN50]

Pete, i would remember that there are different styles of fuses. most automotive application fuses take time to blow - they can see quite a bit more juice than their actual rating (if during a burst or quick spike, which quells very quickly). i.e. a 15 amp blade fuse can see far more juice than that for a very short period of time and it wont blow.

just stuff to remember while making deductions while you are figuring this stuff out.
good luck.

 

[Idwitheld-1`]

I read this interesting article basically complaining about the "circuit city" style fast and furious type overrating of amplifiers based on peak power. It went on to describe that they arrive at the artificial peak power ratings by doing things like giving them a single tone burst after a few seconds of silence and spraying them with freon aaaaaaand.... bumping the voltage to 19 volts.

I said cha-ching! I could do that!

I have nothing really that is voltage sensitive except maybe the head unit but I had a huge power spike that took out my previous amp and ignition system and my headunit survived untouched so I assume those stockers are tough and could survive a few extra volts. I've heard rumors that ignition systems work better at higher voltages too. While instaling my replacement hi-6, the specs on the sheet listed acceptable voltage is 11-18 volts so it seems the ignition would like it too!

Apart from the ignition,wipers/headlights/stops/turnsignals and the radio I am trying to boost, there is nothing drawing power in here. I'm carbed/all mechanical.

I know I'm drawing less than 60 of the 65 amps because I have 2 parallel 30 amp fuses on the alternator black/orange power wire right off the alt (in case it grounds out) and they dont blow while running wipers/beams/stereo in reverse with brakes on and hazards blinking.

Are any of those wires coming off the alternator stator wires? I remember like a green and red on one connector and then the black/org, black/white and one more (yel?).

It doesn't help that you have under drive pullies. This drops your low RPM curent capability.

I would not parallel fuse a single wire. I'm not sure I understand the advantage of this method???

 

[derikt]

When you parallel fuse a single wire, it "splits" the current evenly accross the two. So if you have 2 30amp fuses on a single wire, in parallel, is basically like having a 60 amp fuse.

But like someone already mentioned automotive fuses are slow blow, which means they can take more than what they actually say.

 

[crazypete]

Actually it must be more than 60 amps since I just blew both 30's. I dont understand how that happened since the stock amps are only 65 amps anyway so how can it supply more than it's rating underdriven?

Especially if "they take time to blow" then I must have been drawing much more than that for more than a few seconds. Very confused. I did have a new amp with a 25 amp fuse so I guess it can draw close to that and headlights, wipers, hazards and radio plus the brake and backup lights. Basically everything. Then I noticed the dome light dimmed whenever I stepped on the brake.

The fused alt wire is the big black/orange one that leads into the starter relay + block.

Ok, here's a question. I have a 120 amp circuit breaker. I used paired 30's since they stop at 30 and then you need to use wierd looking ceramic fuses which I dont particularly like to get above that. Would a 120 amp breaker protect anything if the alt wire grounds or is it way too much?

 

[MrKwik]

First of all, what kind of amp do you have? Some have regulated power supplies and some dont. No amp likes to be power starved but to really benefit from upped voltage, you need an unregulated power supply or it just knocks it back down anyway. And those big power numbers on cheap amps are because they are rating peak power at some outragous THD figure. Good amps are generally rated conservatively at lower THD levels that the human ear cant hear anyway.

Second.....whats to say that unregulated voltage will stop at 18? I think your asking for trouble and you would probably start eating batteries as well.

 

[crazypete]

The amp is a "legacy" kenwood kac-646. This baby has been with me through 4 cars. Pre-"fast and furious" amp with tasteful styling and doesnt have wings or blinking lights or swooshes or swirls: just a clean aluminum case that says kenwood with the power triangle above the "W". Power is rated at a conservative 25 wattsx4 rms and 70 rmsx2 bridged. It carries a 25 amp fuse so it must be able to use close to that.

Now I had originally had this amp in with one channel used, bridged to run a single subwoofer and left the stock nugget amp to handle the speakers. All was good and well for years, even with underdrive pulleys until I decided to rewire the amp to power the speakers as well. I unbridged it and ran 4 in and 4 out config and was trying to get door subwoofers to replace the 10 inch jbl powerwedge box in the trunk so I could have a trunk again. It must have doubled the power drain since..like I said... I blew both 30's near the alternator. I must have been drawing more than 60 amps through the underdriven 65 amp alternator. I still dont see how that is possible.

For laughs, after it blew some interesting stuff was going on! I would step on the brake...the radio would go off. I put it in reverse and the cd changer reset. Silly car.

Maybe it already has the 130 amp alternator in it?? That would certainly blow a pair of 30's. I dont know what one of those looks like but the alt looks fairly stock.

 

[tmoss]

When you parallel fuse a single wire, it "splits" the current evenly accross the two. So if you have 2 30amp fuses on a single wire, in parallel, is basically like having a 60 amp fuse.

This only approximately true under ideal conditions. If the wires are the exact same size (i.e. 12guage) and the SAME length, and all the connectors are tight and offer the SAME resistance in both wires. If any of this varies by much, one wire and fuse carries more current than the other and once the first one blows, the other is right behind it.

 

[crazypete]

Aaaah, so then thats what happened.

The question is then...will my 120 amp breaker provide any protection for the alternator?

 

[MrKwik]

The amp is a "legacy" kenwood kac-646. This baby has been with me through 4 cars. Pre-"fast and furious" amp with tasteful styling and doesnt have wings or blinking lights or swooshes or swirls: just a clean aluminum case that says kenwood with the power triangle above the "W". Power is rated at a conservative 25 wattsx4 rms and 70 rmsx2 bridged. It carries a 25 amp fuse so it must be able to use close to that.

Now I had originally had this amp in with one channel used, bridged to run a single subwoofer and left the stock nugget amp to handle the speakers. All was good and well for years, even with underdrive pulleys until I decided to rewire the amp to power the speakers as well. I unbridged it and ran 4 in and 4 out config and was trying to get door subwoofers to replace the 10 inch jbl powerwedge box in the trunk so I could have a trunk again. It must have doubled the power drain since..like I said... I blew both 30's near the alternator. I must have been drawing more than 60 amps through the underdriven 65 amp alternator. I still dont see how that is possible.

For laughs, after it blew some interesting stuff was going on! I would step on the brake...the radio would go off. I put it in reverse and the cd changer reset. Silly car.

Maybe it already has the 130 amp alternator in it?? That would certainly blow a pair of 30's. I dont know what one of those looks like but the alt looks fairly stock.

That amp has a requlated power supply and there is absolutely no advantage pf giving it a bunch of unregulated voltage. And the current draw would actually reduce by unbridging the amp so thats not why the fused blew. So why do you have those 30amp fuses in the alternator wire anyway. There should already be a fuse link in there unless you took it out for some reason.

 

[tmoss]

If your alternator is a 65 amp unit then run a low voltage breaker rated for that or a couple more maps - not much. I run an AMP brand 150A breaker on my 150A 3G alternator. Got it at an on-line RV store for $36.

 

[crazypete]

I completely changed the wiring. There was a pack of...3?..fusible links coming off the starter relay. I moved the whole mess inside the cabin and have the relay zipped to the side of the pedal cage. I detached one of the fusible links which runs the headlights and moved it over to key-on power. Now the lights go off when you shut the car. I never removed any fusible links but I'm pretty sure the black/orange was bare and had no link on it. The double fuse it to protect the car after the loss of an amp and my MSD ignition in some sort of surge or something a week ago. Since then, I 200 amp circuit breakered my trunk mounted battery, 60 amped my alt, and 30 amped every main power lead in addition to what's there already. I 25 amp fused my hi-6 and 25 amp fused my kenwood. I am fused!

Cheap insurance: 10 fuse blocks + 10 fuses = $25
New ingition = $350 and getting towed back when car fails.

My alt is fused because is still dont know how the surge happened. One of the suspects is a grounded alt wire though I havent had any charging problems.