My Car Battery Wont Hold A Charge.

Posted in Car Batteries

In my 1990 300zx my battery wont hold a charge. i have a brand new battery in it. (less than 1 month old)…. i went out the other morning and it did not have enough charge to start my car. though my car jumped just fine. i drove my car down the road and back, it took probably ten minutes or so and i parked my car and turned it off. about ten minutes later i went out to start it and it would again did not have enough charge to start. so i jumped it again, and while it was running i turned on my cd player, lights, rear defrost and heater. no change in the car performance was noticeable while idling. while these were on i unplugged the negative battery terminal to test the alternator. i let it run with the negative cable unplugged for about 20 seconds and no change was noticed. the car ran just fine and the electronics were going just fine. any ideas? did i maybe not let the car charge the battery long enough the first time on my 10 minute drive? any ideas?

There are 7 Answers for "My Car Battery Wont Hold A Charge."

    1. idontgivafork says:

      yeah i got an you have a schematic?that is the roadmap to know where your going and where youve been,now locate charging system,follow the wire that goes to the +bat,checking continuity.if you cant fix it with $2 after my answer, you cant fix it.

    2. eric says:

      could be your connections on your battery, possibly the cables or ends, also a defective battery but that would be the last thing i would think of

    3. TooTall says:

      This is a common question here. and i’m sorry but i’m going to give the same answer i always do. Check your cables for corrosion on both ends (+ and -) also make sure both are tight (both ends)and the battery is tied down properly.

    4. Harry says:

      Your alternator will NOT charge a DEAD battery. That it will is a hold-over from the days of generators which would. It just replaces what is used to start the car and run it. You probably used more than the alternator could have kept up with. Charge the battery with a charger and then see what happens.

    5. Bill says:

      flow your ground to the block it might not be getting a good ground clean up the cable and where it go to the block take the battery to auto zone to get it tested they will do it for free

    6. Jimmy B says:

      I’ve had this same problem and I know how frustrating it can be to try and troubleshoot. So far it’s not been the battery in most of the cases I’ve dealt with, however I’m not ruling out that you might have just gotten a battery with a dead sell in it. It’s rare, but it happens. First I would suggest hooking an actual battery charger up to the car and letting it get a good honest charge. Then take it to your local AutoZone and have them test your battery. Their equipment can diagnose a dead cell but it will give a false positive if your battery is already low.

      Once you’ve ruled that out and while still at Autozone, remove your ALT and have it tested. What I’ve found through “The Hard Way”, is that your ALT can give out, without actually giving out. What happens is one of the diodes in the ALT will burn up or otherwise fail, and it will stop charging the battery. It will still provide power to the car and your Check Engine Light will not go on. You can even do the “Shade Tree” method of unhooking the terminal to see if the car dies, to troubleshoot the ALT without causing the car to die. Which makes you think the ALT is good. However what’s really happening is that it’s providing enough constant power to run the vehicle, while not giving anything back to the battery. So it runs fine, everything works and nothing is dim like you would expect from a dieing battery. This is what I would bet money on if I had to pick one thing that’s causing your battery to die. Their test equipment will be able to tell you if this is your problem or not.

      4 out of 5 times I’ve dealt with this problem with my own or friends vehicles, that has been the issue. However the other possible problem could be that you have a parasitic drain somewhere in your system. What that means is that while your car is off, something is drawing more power than it should be in it’s off state. This could be anything from the stereo not shutting down properly, to an loose connection that’s grounding out when it shouldn’t be. First I would check all the chassis ground locations just to make sure that your tight all around. Then I would go through the steps with a Multimeter to diagnose a parasitic drain in your system. I’ve provided a link below on how to do this. ^(

      Like I said. It’s probably an issue with your ALT, but I hope with the following steps and ideas, you can figure it out on your own. Because having worked at a dealership, it can cost ALOT to have it done, being that you have to follow a flowchart to find out whats wrong. And that takes a lot of time. Hope this helped.

    7. Stephen says:

      The charging circuit is just a circuitous circuit. If you ran the battery down just 1 volt,you would experience trouble starting your car. With today’s cars they actually need 13 volts to start the car, it takes about an hour of driving to raise your voltage approx. 1 volt. You drove it for ten minutes and shut it down, that battery didn’t have time to fully recharge.You need to make sure your grounds are good and tight,clean them if there not. Also make sure your cables are tight and clean them if there is rust on them Did you apply grease to your battery terminals to prevent corrosion? If you checked all of these issues you should have seen something that warranted your attention. I think it would be a good idea to check the whole charging system.