Alternator Upgrade & 2nd Battery
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=65121
Printed Date: May 02, 2024 at 8:46 PM
Topic: Alternator Upgrade & 2nd Battery
Posted By: LqDFx
Subject: Alternator Upgrade & 2nd Battery
Date Posted: October 27, 2005 at 3:19 PM
I need to upgrade my alternator since I installe dmy new amps. The amps I have are in my sig. They output about 800w RMS combined and 2200w Peak combined (if the birthsheets are right). What would be the amprage that I am looking at drawing? A=W/V? I was thinking about going from the 90 Mustang stock 80 amp to a 130 amp unit and I want to make sure it is going to be good enough. It outputs 80 amps at idle and 130 amps at 3000 rpm. Also, should I look into placing a second battery in my trunk with the setup that I am running? And could the second battery just be a matched Ultmia Red Top like I have in the engine bay?
Replies:
Posted By: LqDFx
Date Posted: October 27, 2005 at 3:21 PM
Sorry I forgot to show my sig! I have a RF P4004 @ 400w RMS and a RF P3001 @ 350w RMS ------------- Sony XAV-A1 HU, RF P4004 AMP, RF P3001 AMP, 2 RF 10" P1S410 Subs, LA S2.35.2 Dash Speakers, LA S2.525.2 Door Speakers, RF FRC3268 Rear Speakers
Posted By: geepherder
Date Posted: October 27, 2005 at 8:48 PM
Actually, I'd be surprised if you needed to upgrade anything. Hook it up and see. It can never hurt to upgrade your alternator, but a second battery would be completely unnecessary in your case. The exception would be if you were to play your system on the secondary battery with the car off for long periods of time. Then I'd recommend a deep cycle (yellow top) and battery isolator. Good luck. ------------- My ex once told me I have a perfect face for radio.
Posted By: LqDFx
Date Posted: October 28, 2005 at 1:05 PM
Well something must be wrong with the alt or something, since you are the second on eto tell me that the setup should be fine. I have a Red Top in the car now btw. After hooking up the stereo and testing things out, I get the voltage gauge dramiticly dropping! I am thinking, after reading a couple great forms, about doing a couple of the big 3s. I more than likely am not going to be doing what looks to be one of the more critical one though. The power from the alt to the battery I am not sure I can do because of the way the alt hooks into the elec. system. It is through two plugged connections, so I have small guage wires running to a plug harness and then into the alt. If I upgrade the alt, I can use a 4ga wire witha ring terminal going to the battery.
Posted By: ragoal12
Date Posted: October 28, 2005 at 1:56 PM
lqdfx.. ur going about this the right way... upgrade the big 3.. and put a 4ga wire from ur alt. to ur battery with a simple ring terminal will work fine.. u still may need to upgrade the alternator.. as people neglect the amps that ur car needs to run before u added the stereo system.. and with ur wattage u need about 80 just for the system and ur car needs 20-30 amps.. so if ur alt. will put out around a 100 amps ur fine but if not u may need to upgrade.. ------------- S.O.B custsoms.. South Omaha, Nebraska
Posted By: geepherder
Date Posted: October 28, 2005 at 9:34 PM
If your voltage is dropping like crazy and your cables/grounds check out okay, then it sounds like your alternator has taken a dump. Go ahead and upgrade.
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My ex once told me I have a perfect face for radio.
Posted By: weldaround
Date Posted: October 30, 2005 at 3:15 AM
You could take the alternator out and have some shop bench test if first. Then make your chioce of replacing it. Just a thought John........
Posted By: steezs
Date Posted: November 03, 2005 at 9:34 PM
Where do you test for voltage drops from the alternator and where do you put the DMM needles when testing for good ground.
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THE DUCE
Posted By: arrow12
Date Posted: November 03, 2005 at 9:42 PM
Sorry for being a little off topic, but I have a question regarding the big 3. Do you need to fuse the power wire from the alt to the battery?
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That's my opinion. Take it, leave it, or correct me.
Posted By: stevdart
Date Posted: November 03, 2005 at 9:45 PM
steezs: voltage drop is measured at the battery and at the amplifier. Resistance reading is from the ground of the unit you're testing to the car battery negative. Usually an extension of heavy wire is necessary to reach both places with the meter probes, so you measure resistance of that wire and figure it in your calculation. Any two ground points can be measured for resistance. Read the grounding stickies at the top...it's covered there. arrrow: I don't think you do but it sure is a good idea to fuse all power wires. ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: steezs
Date Posted: November 04, 2005 at 1:49 AM
Ya, but i wanted to know where to put the needles of the meter. So you get a spare wire attach it to the car batter negative then you go to the back of the car (usually where you ground the amp) unhook the wire from the amp, put one needle on the ground wire of the amp and the other on the wire form the car battery negative right? reading should be 1 ohm or less for good ground correct?
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THE DUCE
Posted By: speedwayaudio1
Date Posted: November 04, 2005 at 3:45 AM
I would go ahead and put in a ho alt. If you have the money go ahead and get a 200 amp alt. upgrade your wire and grounds. then you will be set for anything you wanted to do. As far as a second batt, well if you want to play your system with the motor off. A second batt is for you. If not then save your money.
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Big Dave
Posted By: bigboi11
Date Posted: November 05, 2005 at 11:42 AM
WHEN you say go from the battery to the alt are you talking power or ground.
Posted By: steezs
Date Posted: November 05, 2005 at 4:37 PM
power, and they say put a fuse too one with the same amperage as the max imum amperage that your new cable can handle not what your alt can handle. Make sure th fuse is closer to battery .
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THE DUCE
Posted By: steezs
Date Posted: November 05, 2005 at 4:38 PM
oh ya and forgot to mention leave all original cables hooked up too your really suppose to be adding cables not replacing.
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THE DUCE
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