Battery drain - what is this?

My new to me 987.2 CS has a battery drain problem. If left undriven or not on a trickle charger for a week or so, it is totally dead. I went to test it using a multimeter and planned to remove fuses. When I got in there, I found this attached to the battery . I cannot tell where it goes yet as the cable seems to go under the car. (I can say the prior owner had a throttle booster device located just under the right side of the steering wheel that I previously removed). There is no brand name on this device. Any ideas? I've disconnected it from the battery and taped the leads so it cannot get power for now and hoping my drain issue is resolved.

I checked the website for the throttle booster and it did not have a separate power source. Thoughts?

My first thought was some sort of antenna. It is common to stick an aftermarket GPS antenna near the battery - usually under the black plastic cowling. But that would only have one cable going through the firewall to the back of the radio. This appears to have several other pairs of wires. Maybe this is some other type of aftermarket antenna - maybe an alarm or remote. Edit: I meant to say GPS , not XM above. Sorry

Certainly doesn't look like a stock item. No idea what it could be, but the most common thing is a GPS tracker. Is your car on a lease/loan or some other reason to track it? It's a good place to start for the drain. But trackers don't normally draw that much power, so you may still need to do the fuse checks. Let us know what you find!

The Sprint Booster does not connect anywhere near the battery . It connects to the throttle pedal. let us know what happens with the power drain after removal of that device. Very curious attachment.

@Alphadawg you stated the car was new to you. Did you check the battery's age and have it load tested? I'd suspect a battery issue and eliminate that before I started disconnecting wires on things I don't recognize. A marginal battery will do what you stated. If it ever got below 12V, it could of been permanently damaged. Update: I see a blue sticker with 5/25 on it. Did you replace the battery or did the previous owner? If the car sat around without a maintainer that could damage even a new battery. There's a lot of electronics on these cars that stay energized when the ignition is off

Whenever a car has a parasitic draw, investigation of any aftermarket powered additions first often saves a lot of time.

How many wires, and what gauge are they? Have you traced any of the wires or checked them for 12 volt feed or which go to ground? Recently while digging under my dashboard on an unrelated issue I too found a black box with several wires attached. After taking pictures of it and running some of the numbers and markings on it, it turned out to be a LoJack device, apparently from a previous owner. Any other markings on it? I also found that LoJack, and I would presume similar devices, don’t identify what they are specifically so that they are not found and removed.

Turns out it is the power source for my aftermarket valved exhaust . I was hoping I found the cause of my battery drain. I will keep looking.

It could still be the problem. Why is is connected directly to the battery , a constantly active power source for something that only needs to function while the engine is running? I'd relocate it to a switched fuse that only see the voltage when the ignition is on. Plus it doesn't look like a pro install with it connected directly to the battery like that...

Get an clamp on amp meter and put it on one of the cables going to the battery or a use wired meter in series on that cable. Read the load when the car is off. It should read less than 50 milliamps. If you see a much higher reading, start pulling fuses one by one until the reading suddenly drops. That will identify the circuit creating the draw. Look at the electrical schematics for the circuit and see what that fuse is powering. Could be multiple items. This will narrow down where the draw is coming from. Could also be a corroded ground screwed to a body panel or some failing component on that circuit. That is a good place to start. It may take some further digging after you identify the circuit. You might also test the battery as well to see if it is performing properly, or if it has bad cells. Good luck. Electrical issues can be difficult to isolate.

Hi @Alphadawg - Looks like the remote control box from a Fabspeed Valvetronic valved exhaust (I have one that I from memory looks identical). Who manufactured your exhaust? You have power going in, and two separate leads coming out of it -- each of which distribute to a solenoid on each side of the car's exhaust. The key thing that I'd check is to make sure whoever installed it -- they connected the power to "switched power," which is only on when the ignition is on. If the installer incorrectly tapped the power off the "always on" power, that would cause a battery drain. The instructions show that this box is supposed to be installed in the trunk firewall (987 Boxster) -- which gives me pause that maybe the installer put it in the wrong place and is tapping off the wrong power source. Let us know what you find out, and I hope all this helps.

The way I read his initial post, it was directly wired to the battery. Not even a mention of a fuse. So it sounds like it always was powered. That begs the question, what controlled the solenoids? Is there a separate switch to toggle the valves?

Sorry to not explain further, and my guess is that this is the (or at least a) parasitic power drain culprit, @RSchwerer - The power supply to that box needs to be connected to "switched power." That box is a wireless receiver box. In short, pressing a dedicated key fob or the HomeLink garage door opener buttons will activate the solenoids. So if it's connected directly to the battery (probably an in-line fuse, which if I remember correctly), it's always "listening" for a wireless remote control signal to switch the valves to either open or closed. That receiver box only needs to listen to a signal when the car is switched on. The original exhaust installer likely didn't install it in the correct location, let alone off the wrong power supply.

I'm going to respond to several posts - so sorry for the multiple quotes - it will make sense eventually - maybe. Thankyew, thankyew, thankyew - for coming back and clearing up the mystery. Too often people leave us dangling.. so thanks for letting us know. It saved me posting what I thought it was - which wasn't hugely off, but enough off to be worthless. Well - you have to remember - most mechanics are MECHANICS - they aren't electricians, and some have very limited knowledge of electrical systems and how to work on them. In many cases the guys who install exhausts are the ummm.. less skilled, apprentice mechanics (or the guy they dragged in off the street) - so the electrical skill set is such that if the car doesn't catch fire and gets out of the shop under it's own power when they're done with the exhaust work - the job is considered "good.." Good suggestion - but - I don't know of any clamp-on meters that will read DC Amps and have high-sensitivity and are available at a price the average home mechanic is going to think reasonable. If you know of one (I searched for one a few years ago) - please do provide a link. The AC ones are available in inexpensive versions, but that's because it's easy to measure AC current (magnetic fields are the magic), and not easy at all to measure DC current with a clamp-on. There'ya go - you now know exactly what it is, and can probably ask Fabspeed (are they a sponsor - might be) for the installation manual and see where they think it should be hooked up.. Great thread - lots of good input. Thanks ALL!

For owners installing the Fabspeed Valvetronic exhaust without an existing PSE , meaning there are no vacuum lines to activate the exhaust valve, one had to add the accessory Valvetronic Controller. I wasn’t able to locate an entire .pdf of the installation instructions but this screenshot of a partial install manual indicates it needs to be connected to a switched/accessory 12V+ feed for power. Apparently an uninformed install, hopefully this will be tracked down as the culprit in your battery drain.

@WTFChuck - The Fabspeed (and similar valve-activated) exhausts, including PSE, are actually vacuum activated. The hose-tees you see above in your picture are so you can tap off the car's vacuum line. The solenoids just open and close the vacuum. Hope that helps.

Yes, thanks for clearing that up for me. When I saw the vacuum tubing pictured in the description I mistakenly assumed one needed to provide vacuum to the valve, but your explanation, and presence of those tees clears that up. My current, nor former P-cars had the sport exhaust so I’m not well versed in the system. Although I did the Fister exhaust mod on an earlier 996 and loved the results. Especially considering it cost me only about $600 to upgrade to a nicer tailpipe note, without being annoying or droning.

@WTFChuck - Of course. Heck, it was very confusing as all when I originally installed it -- but eventually it made sense. I'm currently experiencing Fister and Carnewal GT envy - LOL!

"Well - you have to remember - most mechanics are MECHANICS - they aren't electricians, and some have very limited knowledge of electrical systems and how to work on them. In many cases the guys who install exhausts are the ummm.. less skilled, apprentice mechanics (or the guy they dragged in off the street) - so the electrical skill set is such that if the car doesn't catch fire and gets out of the shop under it's own power when they're done with the exhaust work - the job is considered "good.."" Properly installing a low current power unit does not require an electricians certification, same goes for installing a simple relay to power a higher current component. It does require a basic understanding of automotive electronics which any "mechanic" who has an ASE certification or even a few years of experience should have. Especially one who handles such installations on a customers Porsche, I would think (customers expect) these types of shops would require a higher level of competence especially considering the liability risk of working on high end cars and not to mention the fact they are likely charging the customer premium hourly rates.

As is obvious in this case - the shop - or home wrench (we can't discount DIY installation) didn't require the higher level of competence. If it was a "mechanic" - it was probably one who wasn't ASE certified. A shop can have a wall full of ASE awards - but the guy doing exhaust work - might not be on that wall.