Page 1 of 3 123 LastLast
Results 1 to 10 of 25

Thread: dual altenators on the same system

  1. #1
    Constant Bitrate Phobos0001's Avatar
    Join Date
    Dec 2004
    Location
    Melbourne, Australia
    Posts
    165

    dual altenators on the same system

    Hi everyone,

    this question is probably not the most relevant to mp3car but there is a lot of electrical experiance floating around so i figured ill try my luck.

    Is it possible to wire up two altenators on a single electrical system, without running dual batterys and an isolator? ive searched through google, 4wd forums, auto-audio forums but havet found anything yet.

    ive probably got the wrong idea of electrics but if i used 2 50 amp altenators on the same circut could i hope for a 100 amp (probably less through resistance and whatnot) generation?

    thanks in advance, and i apologise if this is in the wrong section, it looked most apropriate to me..

    cheers,
    Daniel
    New carputer install starting soon!
    Project status: 0% still in the planning stages
    My Crappy site

  2. #2
    Variable Bitrate Uraijit's Avatar
    Join Date
    Aug 2007
    Location
    Utah
    Posts
    305
    It would be possible to get two alternators running, but why? The fab work, etc would be a waste of time and money. Just buy an upgraded alternator. Or upgrade your battery system. No need to reinvent the wheel.
    Greedy
    -Adj.
    Anybody who makes significantly more money than you do.

    The Hoe-Puter Worklog

    Progress (Phase one):

    Planning:
    [----------] 97.3%
    Parts Aquisition:
    [----------] 95%
    Install:
    [----------] 95%

  3. #3
    Constant Bitrate Phobos0001's Avatar
    Join Date
    Dec 2004
    Location
    Melbourne, Australia
    Posts
    165
    i have a bracket for the altenator and a spair altenator ready to go, all i need to know is if it is possible to wire it up as a single system and if so, how to do it. i have all the parts lying around so i'd rather do it this way then buy things (call me a cheapscate or whatever)

    im not trying to reinvent the wheel, just want to be sure of what wires can go together to produce the results i want rather then cooking components
    New carputer install starting soon!
    Project status: 0% still in the planning stages
    My Crappy site

  4. #4
    Variable Bitrate
    Join Date
    Oct 2006
    Posts
    274
    Unless you need 300+ amperes there is no reason for more than one alternator.

    If however you do need that much power, it is possible, and has been done before by a few people.

    www.stevemeadedesigns.com sign up for the forums and make a thread, maybe PM meade, he's the only one I can think of that I know for a fact has done it, and he's done it several times.

    I doesn't look all that complicated, alternator wiring is very simple. You'd need an extra belt or a different belt to drive two alternators, and some more wires, but not much more.

  5. #5
    Constant Bitrate Phobos0001's Avatar
    Join Date
    Dec 2004
    Location
    Melbourne, Australia
    Posts
    165
    cheers for the link mate, ill go bother the people over there then
    New carputer install starting soon!
    Project status: 0% still in the planning stages
    My Crappy site

  6. #6
    Constant Bitrate
    Join Date
    Sep 2004
    Posts
    211
    Each alternator can be thought of as a battery. Now if you connect two batteries in serial, you get 24 volts or more..........

    If you connect in parralell, you get 6 volts.........so its not just a case of wiring, you may need something to convert the voltages.

  7. #7
    Maximum Bitrate TimmyM's Avatar
    Join Date
    Aug 2003
    Location
    Federal Way, WA
    Posts
    713
    Parralell give you 6 volts? you sure about that? wouldn't it be 12v with more amps? Just like if you were to do the same with batteries?

  8. #8
    Maximum Bitrate fixerofallthing's Avatar
    Join Date
    May 2005
    Location
    Lawrenceville GA
    Posts
    769
    Series gives you 24V and parallel gives you 12V but increased amps.
    The Car 2005 Scion xB

    The Truck 2004 GMC Canyon

  9. #9
    Newbie
    Join Date
    May 2005
    Posts
    13
    Resistance/impedance will halve if you put two electrical objects in a circuit in parallel, and double if in series. Voltage on the other hand only doubles in series. Think of the old Walkmans.. you put in 2 batteries and the unit runs off of 3 volts. Thats a serial power source. now think of a car from the factory. You have, effectively, two power sources. you have your alternator and your battery. You can have as many power sources as you want, and as long as they are in parallel, the difference in potential (voltage) determines which one is the primary power source. So in other words, parallel power sources retain voltage.

    This is also why when you have more power consumed by your audio system than your alternator can pump out, your lights dim. At that point you are using the output capacity of your alternator at 13.9-14.4VDC, and the battery momentarily becomes your supplementary power source, so it causes a drop in the system's potential because the power source with the higher potential is maxed out, and the next in line has a 1.8-2.4VDC difference in potential. this generally happens on bass notes because it takes more power to move a heavy magnet at low frequency.

    So the short and long of it is that your primary power source will always be the power source with the highest voltage, and that will be used until it gets to it's capacity, at which point the next power source in line will supplement it. so if you have two alternators running at the same voltage, the current draw should effectively split itself between the two, and then, god forbid you use the 220A that your dual alternator setup is producing, the battery will still supplement the system, and it will always run in the 11-14.4VDC range.

    The one other thing you have to worry about is how the alternator is designed. If you have a secondary alternator that requires pulse width modulation, you would need a signal for it to run properly.

    Consensus: You can wire two alternators in parallel, at which you would need a power wire to energize the fields, ground should be going through the bracket, but a ground wire from the mount to the chassis wouldnt hurt, and you need a heavy gauge power return wire to either the battery or the fuse/relay B+ terminal with either a fusable link or an inline fuse just incase all goes to hell and you arc out to your chassis.

  10. #10
    Constant Bitrate
    Join Date
    Aug 2007
    Location
    New Orleans, LA
    Posts
    138
    Quote Originally Posted by modena0 View Post
    Resistance/impedance will halve if you put two electrical objects in a circuit in parallel, and double if in series. Voltage on the other hand only doubles in series. Think of the old Walkmans.. you put in 2 batteries and the unit runs off of 3 volts. Thats a serial power source. now think of a car from the factory. You have, effectively, two power sources. you have your alternator and your battery. You can have as many power sources as you want, and as long as they are in parallel, the difference in potential (voltage) determines which one is the primary power source. So in other words, parallel power sources retain voltage.

    This is also why when you have more power consumed by your audio system than your alternator can pump out, your lights dim. At that point you are using the output capacity of your alternator at 13.9-14.4VDC, and the battery momentarily becomes your supplementary power source, so it causes a drop in the system's potential because the power source with the higher potential is maxed out, and the next in line has a 1.8-2.4VDC difference in potential. this generally happens on bass notes because it takes more power to move a heavy magnet at low frequency.

    So the short and long of it is that your primary power source will always be the power source with the highest voltage, and that will be used until it gets to it's capacity, at which point the next power source in line will supplement it. so if you have two alternators running at the same voltage, the current draw should effectively split itself between the two, and then, god forbid you use the 220A that your dual alternator setup is producing, the battery will still supplement the system, and it will always run in the 11-14.4VDC range.

    The one other thing you have to worry about is how the alternator is designed. If you have a secondary alternator that requires pulse width modulation, you would need a signal for it to run properly.

    Consensus: You can wire two alternators in parallel, at which you would need a power wire to energize the fields, ground should be going through the bracket, but a ground wire from the mount to the chassis wouldnt hurt, and you need a heavy gauge power return wire to either the battery or the fuse/relay B+ terminal with either a fusable link or an inline fuse just incase all goes to hell and you arc out to your chassis.
    +1

    Going dual alt was something I was planning on, however, I don't have the parts already, so I'm going to go with a higher amperage alternator. Something you may also want to take into consideration is the amperage that is produced at different RPM levels. As you rev your motor, more amps are produced. Conversly, at idle, it isn't generating as much. So, if you have a 100 amp alternator, you're only producing somewhere around 20 amps at idle. So, if you are looking to eliminate the voltage drop at idle, a single higher amperage alternator will fit the bill better. If you spend the right amount (in the $700US range), there are alternators that produce over 100 amps at IDLE. Once I get everything running in my truck, I will need that kind of power (think LOTS of electrical goodies, including welding maybe...), so, a single high-amperage alternator is for me. You also may want to consider moving to a dual battery setup as well, if you want to increase power-off runtime. Or, switch to a deep cycle battery, if you live in a warm climate, otherwise forget about a single deep cycle. A deep cycle coupled with a regular battery for starting would be a happy medium. Of course, dual batteries has its issues, namely needing a battery isolator. Ok, I'm going to stop for now....

Page 1 of 3 123 LastLast

Similar Threads

  1. New EWF + MinLogon and CF instructions
    By SFiorito in forum WinNT Based
    Replies: 319
    Last Post: 03-12-2010, 01:39 PM
  2. My Dual Xeon, Dual Booting System...
    By greenman100 in forum Off Topic
    Replies: 12
    Last Post: 04-29-2006, 10:08 AM
  3. Honda Accord System Theory
    By GeoLogic in forum General MP3Car Discussion
    Replies: 10
    Last Post: 04-03-2006, 12:43 PM
  4. Escalade PC and Audio System Install
    By accentsound in forum Car Audio
    Replies: 3
    Last Post: 11-02-2005, 11:50 AM
  5. Replies: 8
    Last Post: 04-30-2005, 08:05 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •