gmrulz4u Posted January 5, 2003 Report Share Posted January 5, 2003 I've been dealing with battery and alternator issues for the past 2 months now. Friday, I bought a nice brand-new Interstate MegaTron after using an ever better(supposed to be the best batteries in the world) Optima battery for the past 10 months. The reason I changed batteries was because I thought my Optima was dead due to a bad cell. It seemed like it wouldn't "hold a charge". Every time the car sat parked for any more than 4 hours or so, the voltage of the battery would go below 12. A batteries open-circuit voltage should ALWAYS be around 12.5-12.8. But anyways, tonight, after my Optima has been sitting in my living from for about 12 hours, I decide to check the voltage, and it's 12.5!! If it was in the car, it would be like 11.7, which for those that don't know, is a 0% state-of-charge. I then decide to go check the NEW Interstate battery voltage, after being parked for 10 hours, and it's only at 12.1 volts!??? I had checked it when I shut the car off and it was at 13.5, which indicated a VERY healthy battery. SO, I now FINALLY know that SOMETHING is draining that battery when the car is off. This is called "parasitic load". I do have a lot of stereo equipment, as well as an alarm. But I know it can't be the alarm because last week I purposely did not turn it on to see if the voltage would be any better, and it wasn't. Even though I doubt it, I'm gonna ask anyway: Does anyone have any experience with this or have any suggestions on how to pin-point the problem? THANKS:) Quote Link to comment Share on other sites More sharing options...
Guest Botan Posted January 5, 2003 Report Share Posted January 5, 2003 My best friend works for store, and he says that as long as teh battery does not drop below 10.5 volts while in the car, then it is good. He also said that the new batteries that they sell are also somtimes a little low. Make sure that your key is turning all the way off, or that nothing is grounded and shorting out. If the batteries positive cable is grounded, then it will drain the battery. Quote Link to comment Share on other sites More sharing options...
gmrulz4u Posted January 5, 2003 Author Report Share Posted January 5, 2003 I can give you few hundred links, but instead I'll just tell you that your friend is incredibly wrong! http://www.uuhome.de/william.darden/carfaq4.htm There's just one of many... 10.5 volts is a completely DEAD battery, just 11.7 volts is a DEAD battery...it MAY still start your car(an engine could technically start with 9.5 volts), but not for long... Quote Link to comment Share on other sites More sharing options...
Redfox340 Posted January 5, 2003 Report Share Posted January 5, 2003 I had my car lose power and a battery drained since the radiator fan was cutting into my negative battery cable... now I doubt its that for you, but check all major connections and home wiring that you've done. You're right, it's draining power from somewhere but your best chance is to locate the problem visually, if possible. - RedFox340 Quote Link to comment Share on other sites More sharing options...
BlackZ34Lumina Posted January 5, 2003 Report Share Posted January 5, 2003 Along with my coolant problems I also have a battery that goes dead overnight. Now my car overheated severely and I suspect it has something to do with that. I can not locate what is doing it yet because my priority is my coolant not flowing correctly through my system. Quote Link to comment Share on other sites More sharing options...
OldsmoBeast Posted January 5, 2003 Report Share Posted January 5, 2003 well you might think i'm stupid but when we go to Egypt in the summers, we have a Mitsubishi Lancer (Evo5) in storage there. every year we have our battery refilled and charged when we arrive and we get it drained when we leave. I never like to do a lot of driving there at night because when you get on some of the desert highways, they're exactly that.....desert...ie EMPTY, and dark and shit. so we stay away from it. well, somehow, my battery kept losing it's charge within a few hours...I'd jump it, drive, then about a half hour after the drive, it would start to drop again....we changed batteries and tested the alt.....then realized there was a maplight on one night when we were all down in the garage looking at it! since i never drove it at night, i could never tell! D'OH! (this prolly isn't ur problem but hey wat the fuk) Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted January 5, 2003 Report Share Posted January 5, 2003 If your car still cranks, the battery is fine. If it gets so weak it won't crank, then you do have a parasitic load. You can test for this using an ammeter. Most decent multimeters have an Ammeter built-in, just plug the positive lead into the jack labeled mA (or A), set the function dial to mA (or A), disconnect ONE battery terminal, then connect the multimeter's lead to the battery and the other lead to the car-side terminal. You will then be able to see the load. My '94 Cutlass Supreme has 16mA of drain which is very good. Anything above 100mA is too much. Quote Link to comment Share on other sites More sharing options...
jesse Posted January 5, 2003 Report Share Posted January 5, 2003 Had a problem such as this awhile ago. Everytime I used the passenger door on my `94 Cutlass the theater lighting would not go out everytime I shut the door. And when it did go out the KEY HOLE FINDER would be illuminated on the drivers door, this would drain the battery enough that I could not crank it after only 4 hours. Funny thing is that when it was allowed to drain comepletly, there was no signs of trouble after it was jumped. What ever the problem was draining the battery made it go away until I used the passenger door again. Tried to troubleshoot it myself and could not find anything. Took it to the shop and the problem went away befroe they looked at it. Took it home and it was there agian, and then the problem just simply went away for good after much worry. Quote Link to comment Share on other sites More sharing options...
crc Posted January 6, 2003 Report Share Posted January 6, 2003 gmrulz4u, It's very easy to find out if you have a current leak in your car. Just get a nice heavy duty multimeter and hook it up in series to your main battery connection (under red plastic cap). Make sure you have everything turned off on the car that can be turned off (interior lights, etc)... The meter should read in the milliAmps range.. It's easy to tell if there is a significant current leak because even a small interior bulb will register a reading in the signal digit amp range, a big jump from milliamps. I've had to deal with a current leak in my cutty about 3 or 4 months ago. What was eating up my battery overnight was a faulty switch on the driver side seatbelt mechanism. I had to replace my battery under warrent because batteries that are drained via current leak and then recharged more than once or twice don't last long at all.. Here's the catch though: they warned me if I didn't fix the leak they would not replace the battery again... I asked them what it would cost to get rid of the leak.. minimum $150.. getthefuckouttahere It took me about an hour to find the source of the leak.. no more leak... I haven't had problems starting my car since then. Quote Link to comment Share on other sites More sharing options...
gmrulz4u Posted January 6, 2003 Author Report Share Posted January 6, 2003 Thanks for the info:) BUT, I just realized something tonight: My NEW Interstate battery is actually about 12.4 volts, and not 12.1 It DOES however drop to 12.1 volts with my door open, and interior lights on. I'm assuming it's NORMAL for interior lights to affect the battery voltage THAT much, right? If I'm reading the voltage would the doors closed and all lights off, it's at 12.4, if I open the door(interior lights ON) it immediately drops to 12.1 volts, and then right back to 12.4 when the lights go out. I just always that that a car batteries voltage strength was a lot better than that, but I guess not? I thought it would take A LOT of amperage drain to make the voltage drop 0.3 volts...oh well, I was wrong... THANKS PS I'm still trying to figure out why my Optima battery that I replaced on Friday is now showing 12.4 volts after sitting in my living room for the past couple days. Cause normally it's only 11.7 when it's in the car? Maybe it has something to do with temperature? I'm bringing to the place I bought it tomorrow anyway and their going to check it out... Quote Link to comment Share on other sites More sharing options...
bumping z34 Posted January 6, 2003 Report Share Posted January 6, 2003 i think the optima's can charge themselves if they have any charge in them lol mine does it to my monte alot sense the alt went lol i drove around 3 weeks with no alt Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted January 6, 2003 Report Share Posted January 6, 2003 Like I said, if it cranks, it's fine! If the battery is bad, the engine won't crank. Doesn't matter what the voltage is, if the car still cranks easily, the battery is A-OK. Quote Link to comment Share on other sites More sharing options...
JPaganel Posted January 6, 2003 Report Share Posted January 6, 2003 I'm having a similar problem. If I don't drive my car for two days it's completely dead. I'm thinking that if I hook up an ammeter at the battery and pull fuses one by one I stand a reasonably good chance of isolating this bastard. Any other ideas on diagnosis? Quote Link to comment Share on other sites More sharing options...
jesse Posted January 7, 2003 Report Share Posted January 7, 2003 This one got me a couple of times in the last two years.... The map light on the rear view mirror!!! check that it is off......... And one that you will never see unless you look for it, the key hole finders, look at the key hole when it is very dark and make sure the finder is shutting down after a few seconds of pulling the door handles. Quote Link to comment Share on other sites More sharing options...
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