bigaltexas Posted September 8, 2010 Report Share Posted September 8, 2010 okay so i just bought a new dc alternator... and priority shipping so its gonna get here soon... and i was thinking, like... i mean? i have a battery up front.. its not that good. but it powers a 1000 and 600 watt amp daily... 2 twelves and 2 6x9's... but i mean. should i just keep everything the way its hooked up but with my new alternator, or am i going to have to do a lot of changes? or are they not necessary, but beneficial? like. do i NEEED, another battery in the back, i plan on throwing a 1800 watt amp in there, a fi bl 15, and keep my alpine 1000 watt amp and 2 comp vr's in there, and 600 watt amp and 2 6x9's in there. but, could i do all of that with just having my stock battery but new 230 amp alternator? or do i NEEED to replace my up front battery with a bigger better battery, and leave everything else hooked up... or what... i need some helpppp but i know theres a lot of people here willing to help... so thanks if yall even read this! - al. Quote Link to comment Share on other sites More sharing options...
raolito1980 Posted September 8, 2010 Report Share Posted September 8, 2010 Change out stock battery and add the second battery for a reserve with the H/O alty. Quote 2012 GMC SIerra CC System Build Headunit--Stock Sub Amp--DC 2.0k Subs--2-SA8v2's Enclosure--Need one made!! Highs Amp--Sundown SAX-100.4 Front Highs--Rockford Fosgate T2652-S Rear--Sundown Neo Pro 6.5 XS Power D2400--XS D3400 No Big Three yet! http://www.youtube.c...ser/raolito1980 Link to comment Share on other sites More sharing options...
bigaltexas Posted September 8, 2010 Author Report Share Posted September 8, 2010 so your saying i should add a better battery to replace my stock battery, and then but another one in the cab in my truck? Quote Link to comment Share on other sites More sharing options...
audiofanaticz Posted September 8, 2010 Report Share Posted September 8, 2010 (edited) dont even worry about buying a battery. if its doing decently now, it will be doing better with the new alternator! Even with 2000wrms you should be fine imo. But at that time when you get the bigger amp or whatever you may want to buy a new AGM battery after depending on performance (like a XS Power, kinetik, deka, stinger, etc). Your BIGGEST concern after you put the new alternator in is upgrading your wiring under the hood. You should do the big 3 wiring (preferably in 1/0 wiring). Doing the big 3 upgrading the factory wires alone will make a HUGE difference without an alternator!! if you dont know what the big 3 is, you can find the thread stickied at the top of the page in this electrical subforum. Edit: PS: just re read what you are going to do, with keeping your alpine 1000watt amp powering 2 cvr 12s, and then getting a 2nd 1800watt amp to power a fi bl 15... That is 100% GHETTO It will not sound good since your cvr box is going to take up valuable room for the better fi bl subwoofer. not to mention its bad to mix different brand woofers together, let alone mix a different brand and size.... Edited September 8, 2010 by Audiofanaticz Quote Link to comment Share on other sites More sharing options...
EclipseChris Posted September 8, 2010 Report Share Posted September 8, 2010 (edited) There is actually a legitimate mathamatical equation using simple math that can tell you EXACTLY what you will need. If you want it i will explain it. BTW audio does not take current directly from the battery until it needs it, like if you have a 100a alt it will power the audio with about 40-20a depending on the car. Anything after that come from the battery. And to Audiofanaticz, there is a ton of variables and there is no way to make a rule of thumb in this area. No offense but its math not opinion. So having a 230a alt will go like this. 40-60a will go to keeping the car running, powering the lights windows heater ac etc etc etc. After that everything will go to audio as needed. Lets say you have 60a of current draw for the car, this means you have potential of 170a for audio. 170(a)*14(v)*.70(70%efficiency)=1666 So anything after 1700 true watts rms you will need extra batteries and recharge time after demos. Edited September 8, 2010 by tercelchris Quote i resolve to be a nicer moderator. Tercel build R.I.P. Eclipse build Old New V-Dub My feedback. Link to comment Share on other sites More sharing options...
audiofanaticz Posted September 8, 2010 Report Share Posted September 8, 2010 There is actually a legitimate mathamatical equation using simple math that can tell you EXACTLY what you will need. If you want it i will explain it. BTW audio does not take current directly from the battery until it needs it, like if you have a 100a alt it will power the audio with about 40-20a depending on the car. Anything after that come from the battery. And to Audiofanaticz, there is a ton of variables and there is no way to make a rule of thumb in this area. No offense but its math not opinion. So having a 230a alt will go like this. 40-60a will go to keeping the car running, powering the lights windows heater ac etc etc etc. After that everything will go to audio as needed. Lets say you have 60a of current draw for the car, this means you have potential of 170a for audio. 170(a)*14(v)*.70(70%efficiency)=1666 So anything after 1700 true watts rms you will need extra batteries and recharge time after demos. From your one post of saying you run a boss or pyle amp, I wont take any advice from you too serious. you have no amplifier that will ever put a strain on a 6 volt battery let alone a 12volt. LOL If your math is so right, how come my buddy can win north america finals with a 156.7db from 1 battery and the car off using a 12,000wrms amp. You should read this thread, you may learn a bit of good info: http://www.stevemeadedesigns.com/board/topic/86606-wtf-is-up-with-people-thinking-they-need-2-alts-or-3-batteries/ There countless other professional installers that have been working for a shop for years, or own very well shops that will tell you 2000wrms is fine off 1 battery, let alone having a 230 amp dc power alternator, which being dc power im sure it will do close to 250-270 amps. Quote Link to comment Share on other sites More sharing options...
audiofanaticz Posted September 8, 2010 Report Share Posted September 8, 2010 Oh, and you cant use 14 volts as a voltage standard, since that again is a variable, and 8 out of 10 vehicles see that kind of voltage with a cold alternator, let a lone a hot alternator. 13.5 is a more realistic number. As for your 70% efficiency rating. That is also wrong. That rating is based from Class D monoblock amplifiers rand at a 1 ohm impedance load. From 1 brand to another brand you could see a difference of +/- 10% if not more. And it will also be a variable due to impedance rise! He is currently running a alpine 1000watt amp. Which means its a older pdx.1000, or a mrp1000 either way those amps are not 1 ohm stable, and most likely he is running it at 2 ohms and its not just math... its not opinion, its EXPERIENCE. I dont know how many pairs of 10s and 12s i thru in a car with a 1000-2500wrms amp and 1/0 wiring with just a big 3 done if the customer would pay for the extra labor. No fancy alternator, no fancy battery, no 2nd battery and these cars did any where from 142-148db from the trunk of a car. Quote Link to comment Share on other sites More sharing options...
ch0sen Posted September 8, 2010 Report Share Posted September 8, 2010 now, how many alts does you buddy run? Quote My current 95 Jetta Build w/ pioneer h/u 2 RD Sonance 10's with flatwind coils 2 Audiopipe apsm 1500.1s 1 Hifonics Brutus Elite 60x4 1 XS d925 1 Stinger spv35 1 1000 amp lead acid 50 ft of 0/1 ofc from Audiotechnix all powerbass components, and coaxils, 4 sets buildlog = http://www.stevemead...2-rd-10s-build/ My build for my wife. http://www.stevemead...01-f-150-build/ Link to comment Share on other sites More sharing options...
JPagan Posted September 8, 2010 Report Share Posted September 8, 2010 I run a SAX 1200 @ 1ohm and a SAX 50.4 on dead stock electrical,no big 3 or anything, and I never drop below 13v Quote Link to comment Share on other sites More sharing options...
audiofanaticz Posted September 8, 2010 Report Share Posted September 8, 2010 now, how many alts does you buddy run? 1 crx 1 stock alt. 1 nsb 90 battery. 1 cactus sounds elt 12 12,000wrms 2 digital design 9512s Quote Link to comment Share on other sites More sharing options...
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