batteries draining.

miisterMK3 · 10-31-2005, 09:56 AM

batteries are always draining eventhough nothings on and gauge shows 12v.
i konw its draining because when i crank it ,somtimes it doesnt start if a havent used the cars for about 2 days ,i crank it a couple of times and it get weaker after every go -the gauge still shows 12v. so i charge it up and it starts. does anyone have any idea why this happens? and by the way i did not leave anything on for sure, because its happned before and i made sure i didnt leave anything on.

nickvash0104 · 10-31-2005, 10:14 AM

Any accessories other than stock components? Sound system? Remote starter? I believe the average draw from a battery is around 100 mA when the cars is turned off, which is insignificant. The addition of other electrical accessories speeds this up somewhat.

SupraMan1784 · 10-31-2005, 02:29 PM

something is draining the battery...something that takes a lot of power, i would go with nicks advice...if you got a sound system check your subs and your amps and speakers, check if its your remote starter...pretty much any electronics that did not come with teh factory...check the connections

mrnickleye · 11-02-2005, 03:47 AM

You can now buy a battery/alternator tester for under $25 at places like Harbor Freight. They are handheld with 2 big jumper clamps and a couple of rocker switches. We use one at the shop all the time.
or.....
Place a volt meter (don't have one?? go buy one, cause you'll need one the rest of your life)....across battery terminals and read voltage. S/B 12 to 13.5v.....start car and measure alternator output. S/B 13v-14v

NO??? then alternator is not keeping the battery up. Replace alternator (and maybe battery too, as batteries need to stay charged).

Yes?? turn off car, then take the negative terminal off the battery and place the volt meter leads between the battery post and the terminal.

Are you reading any voltage?? More than like 0.5 volt?? No? then there is not enough drain to cause your problem...drop by a shop to have the battery load tested.

Yes?? then start pulling fuses until the draw stops. That will be the circuit that is draining the battery.

Now....we just had a Honda in here that had an "intermittant" problem with the 'main relay' (which also is the fuel pump relay). It would stay on sometimes (like over night) and drain the battery, and if she did not start it for 2 days, the battery would be to low to crank it over. We finally discovered it because the relay was 'hot' one time while we were trying to diagnose it. New main relay took care of that.

nickvash0104 · 11-02-2005, 12:21 PM

If you've got an Autozone or an O'Reilly's Auto Parts nearby (not sure where you're located) they test batteries and alternators for free on the car with a load tester.

10-31-2005, 09:56 AM	#1
miisterMK3 Stock Join Date: Aug 2005 Posts: 15	batteries draining. batteries are always draining eventhough nothings on and gauge shows 12v. i konw its draining because when i crank it ,somtimes it doesnt start if a havent used the cars for about 2 days ,i crank it a couple of times and it get weaker after every go -the gauge still shows 12v. so i charge it up and it starts. does anyone have any idea why this happens? and by the way i did not leave anything on for sure, because its happned before and i made sure i didnt leave anything on.

10-31-2005, 10:14 AM	#2
nickvash0104 3" Exhaust Join Date: Aug 2005 Location: Dallas, TX Posts: 78	Any accessories other than stock components? Sound system? Remote starter? I believe the average draw from a battery is around 100 mA when the cars is turned off, which is insignificant. The addition of other electrical accessories speeds this up somewhat. __________________ Black '87 N/A Auto

10-31-2005, 02:29 PM	#3
SupraMan1784 SP58GT Join Date: Jun 2005 Location: Dirty Jerz Posts: 691	something is draining the battery...something that takes a lot of power, i would go with nicks advice...if you got a sound system check your subs and your amps and speakers, check if its your remote starter...pretty much any electronics that did not come with teh factory...check the connections __________________ Now: Saving for an MKIV Broken Rides: (Sold) 91 supra turbo 5speed with a 1jzgte motor 421whp 400(399) ft*lbs of torque on tap @ 15 psi "Always outnumbered, never outgunned."

11-02-2005, 12:21 PM	#5
nickvash0104 3" Exhaust Join Date: Aug 2005 Location: Dallas, TX Posts: 78	If you've got an Autozone or an O'Reilly's Auto Parts nearby (not sure where you're located) they test batteries and alternators for free on the car with a load tester. __________________ Black '87 N/A Auto

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11-02-2005, 03:47 AM	#4
mrnickleye 1000whp postwhore Join Date: Jun 2005 Location: Mojave Desert, Calif. Posts: 1,705	You can now buy a battery/alternator tester for under $25 at places like Harbor Freight. They are handheld with 2 big jumper clamps and a couple of rocker switches. We use one at the shop all the time. or..... Place a volt meter (don't have one?? go buy one, cause you'll need one the rest of your life)....across battery terminals and read voltage. S/B 12 to 13.5v.....start car and measure alternator output. S/B 13v-14v NO??? then alternator is not keeping the battery up. Replace alternator (and maybe battery too, as batteries need to stay charged). Yes?? turn off car, then take the negative terminal off the battery and place the volt meter leads between the battery post and the terminal. Are you reading any voltage?? More than like 0.5 volt?? No? then there is not enough drain to cause your problem...drop by a shop to have the battery load tested. Yes?? then start pulling fuses until the draw stops. That will be the circuit that is draining the battery. Now....we just had a Honda in here that had an "intermittant" problem with the 'main relay' (which also is the fuel pump relay). It would stay on sometimes (like over night) and drain the battery, and if she did not start it for 2 days, the battery would be to low to crank it over. We finally discovered it because the relay was 'hot' one time while we were trying to diagnose it. New main relay took care of that.