My 1988 Camaro has developed an issue starting. I’ve checked the draw with the car off, .5 Amps, and that the alternator is charging when it does start, but if the battery is “charged” and the car is turned off it will immediately not start without a jump. Once jumped it fires right up until it’s turned off again, I’m all out of things to check. Thanks.

 

do you mean cranks but will not start,or will not even crank? .5 amps is quite a bit of idle current draw-that will pull the batt low overnight. Also what induction system,{carb swap,TPI etc.) is in place

 

No cranking until it gets jumped, I tried charging it outside of the car then put it in at full charge and turn the key provides no noise. It’s carb swapped electronics are pretty much all the stock lights, a hei distributor and radio which I’ve had unplugged since the issue started.

 

0.5A quiescent load on the battery is way too much. Need to figure out what's causing that and eliminate.

The battery is dead. The car is actually running on the alternator after the jump start. It might take 8 to 12 hours to recharge a deeply discharged battery. Even more time if your charger can't provide much current.

But it's possible that your battery is so damaged from frequent discharging that it is useless now. Rule of thumb, a flooded lead acid starting battery loses 50% life for each time it is discharged. And it will lose "capacity" as the plates are damaged by the deep discharging and recharging process.

Battery "capacity" is like how big is your bucket of energy stored inside the battery. Battery "state of charge" is like what percent full is that bucket of energy. I think what has happened is your battery capacity has been reduced from a bucket to a thimble. And your battery charger is filling up that thimble and saying it's 100% full now.... It's charged! But a thimble full of energy won't run your starter motor. That's why you can charge your battery, put it in your car, and it won't crank. Generally you can't get capacity back, when it's gone it's gone. (That's not always true but beyond this discussion.)

 

I had a similar situation. the draw was .5 amps & was caused by a corrosion issue on the button switch for setting the hour on my radio.

 

Start by finding what's pulling that half-amp of current. Watch your current meter as you pull fuses, one at a time, until you see the current draw go away. You now know which is the offending circuit and, using your car's electrical system diagram(s), you can now start troubleshooting to find the cause.

 

500mA is a big Parasite!!!