AirxCru

Hey, need the experts here.

Im about 3 weeks into ownership of my first porsche!

Relevant back story:
- PO installed new battery and radio prior to delivery.

- delivered the car via transport from CA to NC

- battery completely dead on arrival in NC. jumped it, drove it

- zero battery issues for 1.5 weeks. Sat for 4 straight days, started no problem.

- drove it for a date night with my fiancé to impress her obviously

- parked the car for the night, dead battery in the AM. My portable jump starter wasn’t strong enough. My Tundra was, after about a 2k rpm rev for 30 seconds.

- drive around for a bit (get gas, grocery etc) park it for the night.

-Next AM see above 2 bullets, repeat sequence.

So. Pulled the engine Lid light bulb. I took the Lead cable off. Stuck a multimeter in between. Pulling 12.26. Started pulling fuses one by one. With all fuses pulled, no change. Something else is draining it. I don't know what else?! Thoughts?

Igooz

Of course, I am hoping that you completely turn the ignition off and the key out?

If I were you, I would first pull the battery and take it to an auto parts store and have them put a load on it and properly test it for you to make sure that it is actually a good battery.

Then, I would bring it back home and charge it on the bench with a proper battery charger for something like 24 hours. This way you know that the you are back to 100% State of Charge (SOC). (Measure your open circuit voltage with the charger disconnected.) Often the alternator cannot fully charge a battery that is already low on SOC back to 100%, specially if all you are just running around town with the car and in the lower RPM.

Now put the fully charged battery in the car with all the fuses back in the right slot, and place an ammeter inline with the battery (either positive or negative) side and measure the "dark" current draw? Is there any draw? There has to be some current draw if "somehow" your battery is being fully discharged...now you can pull the fuses again, and I would start with whatever is powering the radio.

Also, if you have to replace your battery, replace it with an AGM vs. Lead Acid. AGMs are designed to now only provide high CCA, but also can handle many deep discharges whereas the Lead acids cannot deep cycle as often as the lead plates, break. I recommend Interstate AGM having bought millions of dollars of these for my business.

Finally, I have a CTek charger for all my cars trickling the batteries when not in use...

r911

does "drive it a bit" mean on the freeway for an hour?

and if not driven for a week or two it needs to be on a battery maintainer, like the Ctek noted above

AirxCru

ok, thanks for the advice, Its an interstate, put them in all my vehicles. Ill pull it and charge. Yes, 1-2 hours. With pulls to 5-6k rpms. Also, ive pulled the radio, to rule that out (upgrading soon)

I appreciate the insight!

AirxCru

battery was at 53% and battery tested good. ill give it a good charge and attempt things tomorrow.

can you verify im doing this correctly. Makes sense to me, but thats gotten me in trouble before:
Pulling lead off battery. Voltmeter set to batt. Negative still connected to car. Placing voltmeters black connector on on positive lead on battery, placing the red on the red battery cable coming from car. Testing for drain? Pulling fuses for the amps to go to zero, thusly highlighting fuse thats remaining hot.

AG81

Just asking.....because I have been thru this..... is there an amp that is associate with the installed radio ?

AirxCru

not that I can find by following wires. Where was yours installed? Under passenger seat?

theiceman

you want to put the meter in series with the battery . In laymens terms you want to have the current run through the meter and give it no other passage. also set the meter to " amps" hopefully its an auto ranger , if not set it at its highest setting and click it down until you get a reading. ( amps, milliamps etc) .

BTW your pulls to 5 or 6 K are irrelevant . you will charg the same at 2k as you will at anything above that.
you are looking for a "parasitic draw" in case you want to look it up on you tube as there are some excellent videos about it. also keep in mind it be caused by a defective diode in your alternator that is draining it , this would mean a new alternator, but one step at a time.

r911

post a pic of your multimeter if the above doesn't make sense

TheTorch

There are also fuses in the engine compartment. I recall recently a thread about a drain due to the rear fuse panel...I can't seem to find it now.

r911

IIRC the Quartz clock draws in the dozem mAmp range. The battery will also self-dischargeover time, even if not connected. My Optima is ~15 years old and will last at least 2 weeks at moderate temps.

If you are up high in the NC Mtns. then lower temperature will also limit the time the battery can crank over the engine.

But it sounds like the battery is failing, or alternator/VR is faulty, or you have a bad current drain going on.

AirxCru

im leaning towards alternator as well, but in light of the recommendations from this post, going to do a bit more trouble shooting!

AG81

^
I wish. It was under the dash.

AirxCru

was it a small silver box? To the right of the radio?

Igooz

This is right on the money. Note what the man said: place the Ammeter initially on the highest range setting. IE) AMPs and NOT Mili Amps. And then click down to until you get a reading on Amps. Note: once you are on the lower Amp ranges, do not go and turn on head-lamp or crank the engine with the Ammeter in series or you may burn it up.

so:
1) Fully and properly charge your battery to 100% SOC. Measure open circuit voltage.
2) Install Ammeter in series with the key off and with ignition key off and look on Ammeter for any draw. This is where the Amp-hr rating on your battery comes in. Pull fuses if there are any dark currents.
3) If you can not measure dark currents then measure the open circuit battery voltage again. It should be pretty close to step 1.
4) Secure the car properly: neutral, park brake, wheel chock; start the car and turn on the headlamps on high beam, fan blower full speed, 4-way flasher, etc. This is your chance to break in your fiancé in this wonderful(?!) hobby! Have her hold the brake pedal down for the brake lights to be on and raise engine RPM to ~3k. Now measure battery voltage. Are you charging or discharging? This is also a test to see if the fiancé is real!

If discharging then it can be one of multiple issues. Report back.

This thread makes me sad! It reminds me of how many batteries I have bought in the past 30 years. 30 years X 4 batteries per truck X 130 trucks = at least 15,600 batteries. If I add in my small pickups probably close to 20,000 batteries at $100/each = $2M! I am glad that I am selling and retiring.