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View Full Version : Alternator Voltage: Is it still okay to run subs?



twofast4u
06-03-2007, 08:59 AM
Hey guys, I'm going to be installing a 12 inch sub in my car next week, I just want to know if it is okay if my alternator is running at 12.6-14 volts even during the day. Will i blow the alternator If I add in the subs? Thanks for you input

88accordSF
06-03-2007, 10:00 AM
if you don't have a voltmeter in your dash, may be good to buy one and install it.

you're regulator should keep your voltage up, as the sound system draws significant power... but if you spot your voltage dropping below 13 when the car is running, i'd think about getting a new alternator... i generally prefer keeping voltage at 13.8 or above when running, to make sure i'm not thirsting any electrical components...

a fuel pump can take a dump on you from low voltage... lower voltage can mean spikes of higher amerage (not all the time, but sometimes), and that fries electrical components...

twofast4u
06-03-2007, 11:52 AM
well I have one in my deck like this at night the voltage will drop to the high 11s at some points...like the following picture

http://i10.photobucket.com/albums/a128/twofast4u/DSC00715.jpg

88accordSF
06-03-2007, 12:18 PM
either...

1) your alternator is starting to go out the window

2) you need more amps than the stock alternator for all your extra electrical stuff

3) both #1 and #2

not sure what the stock alternator rating is... i'd probably look into grabbing a higher-output unit...

i used to run stock 37 amps in one of my old schools... switched to 100amps... i could bump 3 12" subwoofers, four 6x9s, two 3.5 speakers, with a 10" tv and xbox going and still make 13.7 V on full audio blast...

thegreatdane
06-03-2007, 02:09 PM
You need to measure how many amps your alternator is able to put out. Should be around 45-60amps. Also the voltmeter in your deck might not be showing the correct voltage. Measure it directly at the battery to be sure.

88accordSF
06-03-2007, 03:29 PM
You need to measure how many amps your alternator is able to put out. Should be around 45-60amps. Also the voltmeter in your deck might not be showing the correct voltage. Measure it directly at the battery to be sure.

i would measure both the at the battery, and at the furthest distance from the battery (like a tail light, or your subwoofer amp positive terminal) to get clear information as to the voltage going to particular components. the battery will always get more voltage than other parts of the car, due to it being connected very closely to the alternator. wire lengths can drop electrical efficiency (such as the positive lead at the steering column key ignition will get slightly less voltage... etc etc)

MessyHonda
06-03-2007, 05:32 PM
when my car runs i get 14.4 on the dot....i like my amp cuz it tells you...you can also see it spike down when the bass hits....time to get a CAP.

jschatte
06-03-2007, 08:24 PM
nice DEH6800-MP lol i got the same deck

buttaz1
06-26-2007, 11:20 AM
sorry for the thread jack but does this mean that i should het two gauges.
on for the battery one for the alt voltage
thanks for any advce

russiankid
06-26-2007, 06:54 PM
Check the battery. My volt meter says 12 volts on ACC and when i put a volt meter to the battery is has 10 volts, which is why im going to get a new one tomorrow.

AccordB20A
06-26-2007, 09:13 PM
10 alternators later my car still blowing them but the one i gots going okay, with my system on half volume driving at night i can see the headlights dimming so i need a cap too

buttaz1
06-26-2007, 10:23 PM
i donno i think farad caps are guy
like i have hook up regualler batterys (fully chargeD) and hook everythinguplike a cap and i think it works better as usall i might be wrong but i onno

HostileJava
06-27-2007, 12:03 PM
i donno i think farad caps are guy
like i have hook up regualler batterys (fully chargeD) and hook everythinguplike a cap and i think it works better as usall i might be wrong but i onno

Most of that I found totally incomprehensible.

buttaz1
06-27-2007, 01:42 PM
im sorry i used my phone gat fingers and small buttons dont go good togeather

MessyHonda
06-27-2007, 06:57 PM
i get 13.4 with subs on...my car dipped to like 12.9 when a full bass song came on.

shepherd79
06-28-2007, 05:48 AM
your alternator should be putting out around 13.5 and 14.4v. anything below or above those readings at any givin time should tell you that your alternator is dead. low voltage = regulator or brushes. high voltage = regulator.

russiankid
06-28-2007, 07:43 AM
your alternator should be putting out around 13.5 and 14.4v. anything below or above those readings at any givin time should tell you that your alternator is dead. low voltage = regulator or brushes. high voltage = regulator.
Odd, with everything off even the interior blower fan i get around 14.4 volts at the battery. If i turn the blower fan on it drops to 14.2-3 volts, then with the a/c it drops to 14volts. If i turn the headlights on it drops to 13.7ish and if i turn my fogs on it drops to 13.2(sometimes lower). Note that this is on idle, when the engine is at higher rpm's it reads 14 volts. Is this normal?

P.S Sorry for hijacking the thread.

Hazwan
06-28-2007, 07:37 PM
I'm pretty sure with the loads on idle the voltage drops a little, its normal.