 High Output Electrical System, I know you guys are laughing at me |
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| r_towle |
 Dec 14 2009, 08:51 PM
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#21
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Custom Member  Group: Members Posts: 24,579 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States 
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your system will draw 120 amps.
Your alternator will produce 120 amps. This is a problem. No other accessories will function without draining the batteries. You need to redesign so your total draw on the electrical system...lights, wipers and stereo, is less than the total output of your alternator or you will never keep the batteries charged enough to start the car. Batteries are stored energy. You are drawing more out of the batteries ( no matter how many batteries you use) than you are putting back in. Consider mounting an additional alternator in the position of the AC compressor to compensate...this is typical of RV's and custom cars with large draws of current. Rich |
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| orange914 |
Dec 14 2009, 09:14 PM
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#22
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http://5starmediaworks.com/index.html Group: Members Posts: 3,371 Joined: 26-March 05 From: Ceres, California Member No.: 3,818 Region Association: Northern California |
i used to have a bumper sticker on my olds 442 that read 'if it's too loud- your too old"... thats before i got old (IMG:style_emoticons/default/biggrin.gif)
seriously more power to you just don't overdo it. hearing loss IS acumulative and once it's lost it's lost. mike |
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| SGB |
Dec 14 2009, 10:56 PM
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#23
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just visiting Group: Members Posts: 4,086 Joined: 8-March 03 From: Huntsville, AL Member No.: 404 Region Association: South East States |
QUOTE(r_towle @ Dec 14 2009, 08:51 PM)  your system will draw 120 amps. Your alternator will produce 120 amps. This is a problem. No other accessories will function without draining the batteries. You need to redesign so your total draw on the electrical system...lights, wipers and stereo, is less than the total output of your alternator or you will never keep the batteries charged enough to start the car. Batteries are stored energy. You are drawing more out of the batteries ( no matter how many batteries you use) than you are putting back in. Consider mounting an additional alternator in the position of the AC compressor to compensate...this is typical of RV's and custom cars with large draws of current. Rich Thats what I thought too, but my son put a whoppin 1000w system in his E 30 BMW (65 amp output) that I thought would be unusable, but the thing NEVER draws anywhere close to full load, and he runs it pretty LOUD. IDK, I'm sure it is possible to truly overpower the alternator, but I would be more concerned about heat.... Anyway, it might work, or it might smoke the belt. Hehe. Just kidding. I wanna see pics of Chappy's install. |
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| Spoke |
Dec 15 2009, 07:55 AM
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#24
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Jerry Group: Members Posts: 6,984 Joined: 29-October 04 From: Allentown, PA Member No.: 3,031 Region Association: None
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I believe to correctly specify the electrical system needed to drive the sound system and car, one would need to consider more about the characteristics of the music.
The peak current draw is one of the specs needed. The other is the RMS current which is the average current. Peak and RMS values are generally associated by the square root of 2 such that: RMS = Peak / sqrt(2) Also with music, it is a good design practice to allow at least a factor of 2 or more between the absolute peak and average peak. This is obvious if you have a power meter on your stereo and watch the peaks which usually occur on drum beats or the bass chords. So the average current would be: RMS = Peak /(2 x sqrt(2)) = 120/(2 x sqrt(2)) ~ 42Amps Consider also that even though all this power is available, there may be few times where the volume is cranked all the way to its maximum and the music amplitude is at the constant peak of the amplifier. |
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| jsayre914 |
Dec 15 2009, 08:32 AM
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#25
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Speed Up !!! Group: Members Posts: 3,188 Joined: 10-February 08 From: Timonium MD 21093 Member No.: 8,696 Region Association: MidAtlantic Region |
I dont believe i will ever be running at constant peak current draw.
Amplifier 1 Continuous current draw @ full power 55amps peak current draw @ full power 85amps Amplifier 2 Continuous current draw @ full power 30 amps peak current draw @ full power 40 amps The rest of the processors and head unit do not pull a noticeable amount. The extra kinetik battery is more powerful than 200 of the 1 farad caps i just took out of the trunk (IMG:style_emoticons/default/happy11.gif) I dont think I will have any problems with 120 amp alternator charging the batteries. Time will tell (IMG:style_emoticons/default/popcorn[1].gif) |
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| flipb |
Dec 15 2009, 08:35 AM
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#26
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Senior Member Group: Members Posts: 1,722 Joined: 2-September 09 From: Fairfax, VA Member No.: 10,752 Region Association: MidAtlantic Region
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Worst case, shut off the sound system for the last 10 minutes of driving before you park the car... make sure the battery is ready to go next time you go to crank it. (The car, not the volume)
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| iamchappy |
Dec 15 2009, 11:41 AM
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#27
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It all happens so fast! Group: Members Posts: 4,893 Joined: 5-November 03 From: minnetonka, mn Member No.: 1,315 Region Association: Upper MidWest  |
I have one of the amps mounted under the dash stereo, and the other inside the gauge console, the 5.25's are driven by the head unit.
Sub enclosures are a pair of Stainless steel mixing bowls recessed into the firewall. Attached image(s)    
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| SirAndy |
Dec 15 2009, 11:48 AM
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#28
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Resident German Group: Admin Posts: 41,651 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
QUOTE(Spoke @ Dec 15 2009, 05:55 AM) RMS = Peak /(2 x sqrt(2)) = 120/(2 x sqrt(2)) ~ 42Amps WOT: Speaking of Math, i was recently asked to help out a very well known wall street investment group with one of their main investment matrices. First of all, it's just one GIGANTIC excel spreadsheet. (IMG:style_emoticons/default/wacko.gif) But more importantly, it had a very peculiar hard-coded multiplication factor that was added to a lot of the cell formulas: sqrt(100) Anyone see anything wrong with that? (IMG:style_emoticons/default/lol-2.gif) Andy |
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| Dr Evil |
Dec 15 2009, 12:40 PM
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#29
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Send me your transmission! Group: Members Posts: 23,000 Joined: 21-November 03 From: Loveland, OH 45140 Member No.: 1,372 Region Association: MidAtlantic Region
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it = 10 (IMG:style_emoticons/default/av-943.gif)
After all this, will the 1.8 be a 50hp output monster? |
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| SirAndy |
Dec 15 2009, 12:46 PM
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#30
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Resident German Group: Admin Posts: 41,651 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
QUOTE(Dr Evil @ Dec 15 2009, 10:40 AM) After all this, will the 1.8 be a 50hp output monster? Think positive! He can now use the stereo as a emergency brake! (IMG:style_emoticons/default/w00t.gif) Andy |
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| zymurgist |
Dec 15 2009, 12:48 PM
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#31
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"Ace" Mechanic Group: Members Posts: 7,411 Joined: 9-June 05 From: Hagerstown, MD Member No.: 4,238 Region Association: None |
QUOTE(SirAndy @ Dec 15 2009, 12:48 PM) Kind of like E = mc^2 where c is a constant, therefore c^2 is a constant? |
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| zymurgist |
Dec 15 2009, 12:49 PM
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#32
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"Ace" Mechanic Group: Members Posts: 7,411 Joined: 9-June 05 From: Hagerstown, MD Member No.: 4,238 Region Association: None |
QUOTE(SirAndy @ Dec 15 2009, 01:46 PM) QUOTE(Dr Evil @ Dec 15 2009, 10:40 AM) After all this, will the 1.8 be a 50hp output monster? Think positive! He can now use the stereo as a emergency brake! (IMG:style_emoticons/default/w00t.gif) Andy Either that, or it will feel like he's got a bad TPS whenever the music hits a big bass note. (IMG:style_emoticons/default/rock_band.gif) |
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| Spoke |
Dec 16 2009, 05:17 PM
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#33
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Jerry Group: Members Posts: 6,984 Joined: 29-October 04 From: Allentown, PA Member No.: 3,031 Region Association: None
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QUOTE(SirAndy @ Dec 15 2009, 01:46 PM) It's kinda like railroad locomotives use their drive motors as dynamic brakes. Want to slow down? Crank the stereo. |
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| underthetire |
Dec 16 2009, 05:24 PM
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#34
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914 Guru Group: Members Posts: 5,062 Joined: 7-October 08 From: Brentwood Member No.: 9,623 Region Association: Northern California |
QUOTE(orange914 @ Dec 14 2009, 07:14 PM) i used to have a bumper sticker on my olds 442 that read 'if it's too loud- your too old"... thats before i got old (IMG:style_emoticons/default/biggrin.gif) seriously more power to you just don't overdo it. hearing loss IS acumulative and once it's lost it's lost. mike Huh? Did you say something. |
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| jhadler |
Dec 16 2009, 05:31 PM
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#35
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Long term tinkerer... Group: Members Posts: 1,879 Joined: 7-April 03 From: Lyons, CO Member No.: 529 |
Looking at the numbers, it would appear that at steady state, you're pulling 85 A. Now, a 120 A alternator can push that much current. But at what RPM? Can a 120 A alternator push 85+ A at idle speeds?
-Josh2 |
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| jsayre914 |
Dec 18 2009, 10:30 PM
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#36
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Speed Up !!! Group: Members Posts: 3,188 Joined: 10-February 08 From: Timonium MD 21093 Member No.: 8,696 Region Association: MidAtlantic Region |
i will let you guys know, once i get her installed. I recieved my new alternator today.
(IMG:style_emoticons/default/beerchug.gif) I am now waiting on Jeff to send me my custom, mega harness to hook it up. Attached image(s) 
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| Krank |
Dec 18 2009, 10:47 PM
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#37
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Member Group: Members Posts: 140 Joined: 11-October 09 From: Winnipeg, MB Member No.: 10,922 Region Association: Canada |
what?
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| jsayre914 |
Dec 18 2009, 11:17 PM
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#38
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Speed Up !!! Group: Members Posts: 3,188 Joined: 10-February 08 From: Timonium MD 21093 Member No.: 8,696 Region Association: MidAtlantic Region |
QUOTE(Krank @ Dec 18 2009, 11:47 PM) what? (IMG:style_emoticons/default/confused24.gif) Did you have a question?? |
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| Spoke |
Dec 18 2009, 11:40 PM
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#39
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Jerry Group: Members Posts: 6,984 Joined: 29-October 04 From: Allentown, PA Member No.: 3,031 Region Association: None
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QUOTE(jsayre914 @ Dec 19 2009, 12:17 AM) QUOTE(Krank @ Dec 18 2009, 11:47 PM) what? (IMG:style_emoticons/default/confused24.gif) Did you have a question?? I think you have to talk a little bit LOUDER. Good luck on the installation. The proof is in the pudding. I'm sure your sound system will kick ass. Let us know how it works out. |
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| jsayre914 |
Jan 12 2010, 09:46 AM
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#40
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Speed Up !!! Group: Members Posts: 3,188 Joined: 10-February 08 From: Timonium MD 21093 Member No.: 8,696 Region Association: MidAtlantic Region |
figured i would post the pics of my swap. Basically I orderd a VW bus 75 amp alternator brand new. Got it wound to 120 amps, got Jeff Bowlsby to make me a custom harness with 2 runs of 8guage to handle my maddness. Got a few much needed parts from Detoxcowboy and my plastic seal from the samba.
have a look. (IMG:style_emoticons/default/icon_bump.gif) Picture of the original 55 amp alternator in its snug home  Picture of the original 55 amp alternator stolen from its home  Pics of the alternator, inside and out and the krusty boot   |
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