Thinking of running 2 Alternators

[eXcali]

I think the regulators will still hinder you for what your trying to accomplish. It's not a constant 14v of power coming from the alt, once it senses your battery hitting 12v it will stop the current. I'd hate to see you do all this custom fab and stuck in the same boat.

 

[eXcali]

thanks bro, i just googled pwm and yeah class d's are pwm.
btw, so do you have any idea on how to re route the power steering reservoir?

You don't have a whole lot of room in there. Look into an electric power steering pump that you can relocate where ever you have the room.

 

[kentb]

I think the regulators will still hinder you for what your trying to accomplish. It's not a constant 14v of power coming from the alt, once it senses your battery hitting 12v it will stop the current. I'd hate to see you do all this custom fab and stuck in the same boat.

the point is to not reach 12v

 

[rhauf]

thanks bro, i just googled pwm and yeah class d's are pwm.
btw, so do you have any idea on how to re route the power steering reservoir?

cant help you much on the PS reservoir since i've never owned or even worked on an SOHC Ex. but I do have a couple ideas... the lines which go the tank are not high pressure lines, so you should be able to cut them and extend them with something like transmission cooler line, then i suggest having a welding shop make you a small metal reservoir made to fit somewhere else in the engine compartment. (possibly out of pipe, drill/tap a couple hose fittings into it for the inlet and outlet, and get a vented cap for it and it should be fine) you can always talk to an exhaust shop, they're usually pretty good at fabricating stuff, and will probably have some ideas for you. oh, and be sure to keep you're reservoir tank higher than the P/s pump.

 

[rhauf]

I think the regulators will still hinder you for what your trying to accomplish. It's not a constant 14v of power coming from the alt, once it senses your battery hitting 12v it will stop the current. I'd hate to see you do all this custom fab and stuck in the same boat.

i've never heard of an alternator that cuts output when the voltage gets LOWER. most voltage regulators are designed to run a float voltage of 13.8 volts, some have a 14.4 volt peak charge which runs for a moment after the vehicle is started (to compensate for running the starter) when the battery is drawn down below 12v it will be discharging, but that's not to say the alternator isn't doing everything it can to charge the battery back up (and maintain their 13.8 volt float point)

 

[kentb]

i've never heard of an alternator that cuts output when the voltage gets LOWER. most voltage regulators are designed to run a float voltage of 13.8 volts, some have a 14.4 volt peak charge which runs for a moment after the vehicle is started (to compensate for running the starter) when the battery is drawn down below 12v it will be discharging, but that's not to say the alternator isn't doing everything it can to charge the battery back up (and maintain their 13.8 volt float point)

i was waiting for someone to say that lol.
to the guy that said that, i already posted the link about alternators so you at least know the basics.

 

[techieman33]

look up expo5.0 he had a dual alternator setup. He hasn't been around in quite a while, but there may be a write up or pictures of it around here somewhere.

 

[kentb]

look up expo5.0 he had a dual alternator setup. He hasn't been around in quite a while, but there may be a write up or pictures of it around here somewhere.

cool, thanks bro!

 

[eXcali]

the point is to not reach 12v

I just threw the 12v number out there, different alts charge the batt to a certain voltage then stop sending juice so you don't cook the batteries. If your wanting to maintain no less than 14v you may have to look into an old school alt and bypass the regulator so it keeps the voltage constantly at full current.

 

[kentb]

I just threw the 12v number out there, different alts charge the batt to a certain voltage then stop sending juice so you don't cook the batteries. If your wanting to maintain no less than 14v you may have to look into an old school alt and bypass the regulator so it keeps the voltage constantly at full current.

they don't STOP sending current, they just lower the voltage and put out more current just to compensate for the current demand of the amp. thats the reason why the voltage is dropping.

no alt can keep a voltage constant even if you have a regulator if you pull more than its maximum ratings. cause if that's the case people can just run one alt and stay 14v forever even if you have gazillion watts

edit: i mean pull not push pull on the last line

 

[eXcali]

they don't STOP sending current, they just lower the voltage and put out more current just to compensate for the current demand of the amp. thats the reason why the voltage is dropping.

no alt can keep a voltage constant even if you have a regulator if you push pull more than its maximum ratings. cause if that's the case people can just run one alt and stay 14v forever even if you have gazillion watts

*sigh* Maybe I'm just not stating things correctly tonite..... Let's say you have 5k watts max power amps.... They aren't pulling 5k the entire time, only when peaking right? Well your alternator has a fancy thing called a Regulator which will stop charging your batteries once it detects a certain voltage. So let's say your battery hits the magic number let's say 14.4v, it will stop sending juice to the battery. Then your "beat" kicks in and drags the voltage to 13.0 before your regulator kicks back in allowing voltage to hit your battery again. Now do you get what I'm saying or do you still wish to Educate me?

 

[rhauf]

they don't STOP sending current, they just lower the voltage and put out more current just to compensate for the current demand of the amp. thats the reason why the voltage is dropping.

no alt can keep a voltage constant even if you have a regulator if you push pull more than its maximum ratings. cause if that's the case people can just run one alt and stay 14v forever even if you have gazillion watts

Actually, the alternator is whats called a current source, in other words, it outputs current (think amperage) the "voltage regulator" monitors the voltage, and when it becomes less than 13.8 volts (same for all alternators) it will increasing the voltage to the alternators field winding, increasing the magnetic flux and therefore increasing the current generated. if you disconnected the load from an alternator, it's voltage would spike very, very high because the current would want to maintain and the voltage would just increase until the load was the same (sort of the way a cars coil makes spark when the points disconnect) likewise, as the voltage rises above 13.8 volts, the field voltage is decreased by the regulator, regulating the voltage at 13.8 volts, hence the name regulator.

think of the alternator as a guy pushing a shopping cart, the guy wants to push the cart at a continuous speed, but if you put something heavy in the cart he has to push much harder to make it go the same speed, likewise if you were to somehow take it out instantly, the cart would go shooting forwards. well, in this analogy speed is voltage, force applied to the cart is current (or amperage) and weight in the card is load on the electrical system.

 

[rhauf]

*sigh* Maybe I'm just not stating things correctly tonite..... Let's say you have 5k watts max power amps.... They aren't pulling 5k the entire time, only when peaking right? Well your alternator has a fancy thing called a Regulator which will stop charging your batteries once it detects a certain voltage. So let's say your battery hits the magic number let's say 14.4v, it will stop sending juice to the battery. Then your "beat" kicks in and drags the voltage to 13.0 before your regulator kicks back in allowing voltage to hit your battery again. Now do you get what I'm saying or do you still wish to Educate me?

this part you are correct about. the voltage regulator can not adjust the output of the alternator instantly, there is a slight delay (a couple tenths of a second at least) which is why in my earlier post i suggested an extra battery.

 

[kentb]

*sigh* Maybe I'm just not stating things correctly tonite..... Let's say you have 5k watts max power amps.... They aren't pulling 5k the entire time, only when peaking right? Well your alternator has a fancy thing called a Regulator which will stop charging your batteries once it detects a certain voltage. So let's say your battery hits the magic number let's say 14.4v, it will stop sending juice to the battery. Then your "beat" kicks in and drags the voltage to 13.0 before your regulator kicks back in allowing voltage to hit your battery again. Now do you get what I'm saying or do you still wish to Educate me?

here is another one for you
http://www.youtube.com/watch?v=5Ckuc2dfVV4

we're going off topic here.
lets just stop this and stay on topic please.

 

[kentb]

Actually, the alternator is whats called a current source, in other words, it outputs current (think amperage) the "voltage regulator" monitors the voltage, and when it becomes less than 13.8 volts (same for all alternators) it will increasing the voltage to the alternators field winding, increasing the magnetic flux and therefore increasing the current generated. if you disconnected the load from an alternator, it's voltage would spike very, very high because the current would want to maintain and the voltage would just increase until the load was the same (sort of the way a cars coil makes spark when the points disconnect) likewise, as the voltage rises above 13.8 volts, the field voltage is decreased by the regulator, regulating the voltage at 13.8 volts, hence the name regulator.

think of the alternator as a guy pushing a shopping cart, the guy wants to push the cart at a continuous speed, but if you put something heavy in the cart he has to push much harder to make it go the same speed, likewise if you were to somehow take it out instantly, the cart would go shooting forwards. well, in this analogy speed is voltage, force applied to the cart is current (or amperage) and weight in the card is load on the electrical system.

that spiking is a given.

 

[2000StreetRod]

Pulley arc

I've been looking for a spot to put another "device" on my SOHC serpentine belt. The problem is that any added pulley needs at least 45 degrees of contact with the belt. The more the device resistance to turn the greater the arc needed to prevent slippage. For example, an A/C compressor needs more arc than an alternator. Your proposed location where the power steering reservoir is will reduce the arc on the power steering pulley so much that the belt will probably slip.

I hope that you realize how aggravating and inconsiderate it is to others nearby when they are forced to endure your choice of extremely loud "music". On several occasions I have wished I had a "pulser" that would destroy the audio in the vehicle next to me.

 

[kentb]

I've been looking for a spot to put another "device" on my SOHC serpentine belt. The problem is that any added pulley needs at least 45 degrees of contact with the belt. The more the device resistance to turn the greater the arc needed to prevent slippage. For example, an A/C compressor needs more arc than an alternator. Your proposed location where the power steering reservoir is will reduce the arc on the power steering pulley so much that the belt will probably slip.

I hope that you realize how aggravating and inconsiderate it is to others nearby when they are forced to endure your choice of extremely loud "music". On several occasions I have wished I had a "pulser" that would destroy the audio in the vehicle next to me.

i respect your opinion and i agree with it, i "bump responsively".
90% of the time i listen to music at normal listening volumes.

anyways yeah you are right on the coverage part, if ever i will put an alternator on the spot i wanted, i'm sure i would need an additional pulley to have better coverage.

 

[2000StreetRod]

another idler?

. . . anyways yeah you are right on the coverage part, if ever i will put an alternator on the spot i wanted, i'm sure i would need an additional pulley to have better coverage.

So you're considering adding another idler between the existing power steering pulley and the new alternator pulley. That would shift your new alternator location more clockwise reducing the arc on the A/C compressor pulley causing it to slip. You may have to add idlers on each side of the new alternator making the belt extremely long.

One of the previous posts mentioned that the alternator could turn in either direction. As I recall the serpentine belt tensioner is below the stock alternator location. Perhaps you could eliminate the tensioner and use the second alternator to tension the belt. In "the old days" belt tension adjustment was done with the generator. One problem with running an alternator backwards is cooling. There usually is a cooling fan behind the pulley. I've never seen one for the counterclockwise direction but they may exist.

 

[spankmeplz]

2000streetrod hit the nail on the head. The alternator would need a certain amount of belt around the pulley. Here are my suggestions for a dual alternator setup.

1) add a pulley to the crank, make an adjustable bracket for the alternator, and put it anywhere you have room.

2) ditch the p/s pump or use an electric one, and do the above, skipping the pulley on the crank.

3) if you are dead set on your system running at 14 volts, why not use a 14 volt battery? Visit your local material handling company or forklift repair shop. They can make you one. A forklift battery is split into cells. Each cell has 2v. They will add 7 cells together, making a 14v battery. Your car runs on 14v, so odviously you will not damage anything.

 

[BrooklynBay]

My modified 88 has an electric P/S pump with an external reservoir. You won't save any current by adding an alternator in place of the P/S pump if you plan on using an electric P/S pump. That pump requires a great deal of current. I have an electronic module controlling the timing cycle of the pump since it's can't run @ 100% duty cycle.