1970 challenger new battery will not hold a charge

[stang13]

  hi guys I have a 1970 challenger rt se with a 440 six pack . I installed a new replica mopar red cap battery about a month ago. Recently the battery is dead after sitting in the garage for a few days. I fully charged it and pulled it out and had it tested  and it checks out fine this will happen every couple  of days now  . all i can think of is that something is draining the power as it sits in the garage . There are no electronics in the car stock AM radio etc .  Does anyone have any idea what could be causing this ?


Thanks
Tom

[440STRKR]

Same problem! Bump!

[Super Blue 72]

Hi Tom, I'm not an electrical expert, but I was wondering if you run your car every so often and if the altenator is good as well?

Aside from the altenator, you might want to disconnect the positive battery cable and put an ammeter inline/between the battery and the clamp.  This will let you know how much amperage is being drawn.  I forget what is an acceptable value but perhaps others may chime in on this.

If there is a large enough current draw, you may try to isolate the problem by pulling fuses.  When the current draw drops, then that may be the system at question. 

There may be a short to ground somewhere.... hope you find it!

[stang13]

I usually ran the car every couple days , I have had this car since July and this problem has started about a week ago so Im not sure , I hate electrical problems

[Super Blue 72]

If you ran the car every couple of days, I'm a little surious about the altenator.  The altenator, if running right, should run the ignition system and charge up the battery, so running it every couple of days should be good so I'm wondering if the altenator is an issue.  I think you can take it out and have it tested at most autoparts places.

[72cudamaan]

How long do you let the car run after starting it? Typically it takes roughly 1/2 hour of idle time to bring
a battery back to the charge it had before starting. You could also just disconnect the battery for a couple of
days, reconnect it and see if the car starts. That would narrow down the problem to the battery or something in the car.

[Topcat]

With the postive cable off, put a voltmeter from the battery to the battery cable post. Read the voltage draw (if any)

If the voltage is high...like above 8-10 volts, you have a short.