Electrial Drain "Porsche Boxster 986" Electrical drain

[RadioDjKev]

Hi Everyone,

Every morning my Boxster has a very low battery (will not wont start) So I have been charging it everyday. I bought a new Bosche 850CA battery and it still go's low on me, in just one night!. It started about 5 days ago...
My alternator works great! The car will run without a battery. I can tell there is an electrical drain on it, when I have it on charge if I remove the positive cable while still on charge the chargers gauge moves higher, when cable is re-connected it drags it down a little.

Does anyone have idea's of what could be draining my battery..Must me something strong. It is not any of my lights, I already checked. Window's??

1999 Porsche Boxster 5 speed manual 98k miles

See pics at: www.kevingerard.com

Thank you, Kevin

[Ron Broman]

Not a lot of activity on the board!

No advise on your "drain" but running the car with the battery dis-connected will
toast your alternator.. according to the Bentley manual.

You've probably figured it out by now, anyway.

Have a great Thanksgiving.

Ron

[Thorshammer]

Please do not remove the positive lead to the battery while the car is running.

If you have a good multimeter, you can find your problem. First. Check the battery voltage at the battery. Make sure it is 12.6 or better before starting the car. Drive the car for a little bit, and when you come back, check the battery again, Unless you have an amp clamp, then you can look at amps output from the alternator. The drive is more fun, and easier, if you are not familiar with this function.

After coming back and shutign the car off, remove the negative lead, from the battery, then the positive lead. Hook the negative lead back up, and put you meter on VDC. Check between the positive post on the battery and the positive lead and you should see less than .05 of a volt. If it is higher, start searching for things that are still powered. Front trunk light, rear trunk light, door switches, radio and amp.... etc..... I actually start unplugging things until the problem goes away. This is all done with the key off. It is called a key off draw test.

Make sure you don't have a connector that has water in it or a tail or license plate light with the same issue.

Let me know? I have some other people I work with that have seen some really weird Boxster issues. But I suspect key off draw.


Erik

[RadioDjKev]

I tried this test betwen the negative cable, and could not see anything.

This drain is not something small, it is a very powerful drag like leaving headlights on! and you cant even do that without the key on.

So I try between the positive cable you think?

Thanks,
Kevin

[RadioDjKev]

Oh by the way, to all..My car was never run without battery connected. I was only meaning that my alternator is fine.

[RadioDjKev]

If you have a good multimeter, you can find your problem. First. Check the battery voltage at the battery. Make sure it is 12.6 or better before starting the car. Drive the car for a little bit, and when you come back, check the battery again, Unless you have an amp clamp, then you can look at amps output from the alternator. The drive is more fun, and easier, if you are not familiar with this function.

After coming back and shutign the car off, remove the negative lead, from the battery, then the positive lead. Hook the negative lead back up, and put you meter on VDC. Check between the positive post on the battery and the positive lead and you should see less than .05 of a volt. If it is higher, start searching for things that are still powered. Front trunk light, rear trunk light, door switches, radio and amp.... etc..... I actually start unplugging things until the problem goes away. This is all done with the key off. It is called a key off draw test.

Make sure you don't have a connector that has water in it or a tail or license plate light with the same issue.

Let me know? I have some other people I work with that have seen some really weird Boxster issues. But I suspect key off draw.


Erik[/QUOTE]

[RadioDjKev]

I don't understand the test, because if you connect between the positive battery, and the positive battery cable with a voltmeter you will get 12.6, and that is what I get. Also the same on my roommates car.

I am using a sears multimeter, (so it says, but I think it is far short of a multimeter) and I have tried all the settings. The meter has on it: dcv, acv, dcma, dcua, temp, and there are 5 different dials to read from..

I just can't get anywhere with this problem. I have to disconnect my battery anytime I leave the car sit for more than 3 hours. It is a strong drain.
And it will also drain like this with all fuses removed from fuse box.

Kevin

[JMatta]

I assume you remove the key from ignition when not in use? These cars have a lot of trouble with the ignition switch, so I would look at that as a possible culprit. The starter is not on a fuse as far as I know...I wonder if that could be pulling juice, but not enough to spin the motor?

Also post on www.986forum.com and www.renntech.org if you haven't already. Those boards are very active compared to this one.

[Britwrench]

Rarely seen battery drain on 986 or 996 models. If the drain is that much, something is running.

Disconnect the ground wire from the battery and use an ammeter in the circuit, the current drain should be around 40-100 Ma.
To drain a battery in three hours, the drain is going to be in the AMPs region, not Ma, which is unsual to say the least.

There is something running or shorted, I would be inclined to suspect the alternator as have experienced failure of the alternator where the engine stops dead.

You need to check the ignition switch as JMatta said, it's a very common issue. You can remove the key with the engine running when they get really bad.

[RadioDjKev]

No lights on, no Ignition drain, key out.

Yeah I will try that other borad, thanks

[RadioDjKev]

Alternator works great, igition is not a problem, no lights left on, car runs and drives great!
Thanks

[RadioDjKev]

I have tried more test's with Sears mulitimeter, everything that can be done with this meter, but no luck at all. positive negative, negative positive, 10 differt settings, am meter, volt meter, and everything eles from removing all fuses, and all replays. can not find anything
on meter that looks any differnt than my roommates car..

I give up!

[850dunstall]

i have seen you posts regarding the problem over at 986forum too. to say the least it is baffling...
so lets start with the basics.

cables on battery post stif and hard or flexible, and signs of corrosion? if so replace ends and clean cable and coat with protective slime (nonconductive grease etc)

test battery voltage disconnected should be around 13.xx+ volts, let it sit for a day and recheck; still 13.xxv? if not the battery is junk get it replaced on warranty. swap it into some other vehicle and see if it goes flat there, this would indicate the battery is bad, and lastly you can take it back to the supplier and have them do a load test to confirm the battery.

charging system check with alternator running, what does porsche say? id expect 14+ v at say 3500 rpm

if as you say you cannot see any milliamp or amp draw between the ground cable and the battery or the positive cable and the battery

what recent modifications have you made to the car or what service work has been done. i remember you claim no mods, but even service work if not done correctly can screw something up... so double check this and ensure you haven't got something a foul

the biggest draw item on a car is the starter, so now with the advanced age of your "B" its time to check the cable from the alternator to the battery and the starter. check the place were they go thru the "firewall" to the front of the car, is the rubber grommet still there? any chaffing on the plastic sleeve?

thats all i can think off

i had the battery in my r1100 die over winter, if the bike sat for anymore than 1 day, the battery didn't have enough juice to start the bike, and had the same with a 2 yr old battery in a 2 yr old car, sometime you get a lemon, i know it s hard to believe but it can happen.

best of hunting and hope this is of some help


ps

ground straps, can come loose and the battery may have the juice to light the bulbs, but not to spin the starter, ive also seen the grounds straps totally corroded away, and with no ground strap no ground path no go, so this would mean checking the ground strap at the battery and down under the engine and also by the starter if there is one...

[Britwrench]

Have never seen any significant battery corrosion and on a vehicle that has been maintained and the battery regularly checked and replaced when required, there shouldn't be any.

To drain the battery there MUST be either a draw, a short or bad battery.

If there is no drain, correct charge rate, no short and everything works as it should, then the fault, logically, would be the battery. If it isn't, the test proceedure was wrong.

[RadioDjKev]

No battery corrosion..LOL This is a Southern Calif babied garage kept car clean as a whistle cream buff. Alternator charges perfect, battery is new, and I have 2 Good Batteries, no lights being left on, no bad Ignition, battery never go's low when disconnected, but if left connected will drain battery in 4 hours. Will also drain in 4 hours with all fuses removed!

All original never modified. I have pulled out and put my fingers on every relay with battery connected, and made thorough visual inspections. I have tried many times to establish something with a Sears multimeter, can can not find anything. The only thing I can think of is the starter/ starter solenoid...I am not sure how I can test it. But it works great!

I drive the car everyday, it is 9 years old and has 101k miles on it.

Thanks for your help. If I was not out of cash right now I would take it in
to a shop, but can not do that.

[850dunstall]

with all you've described, id think the starter is the next place to check... but in a sense you already have, by disconnecting all the fuses the only thing left connected is the starter (i think). after disconnecting the starter, reconnect the battery

are there any fans in the system?

[RadioDjKev]

Yes, tonight I will disconnect the main starter cable on top of the engine.

And leave the battery connected.

[RadioDjKev]

My car does have 13 different electric motors on it, but all go through fuses.

So tonight I will disconnect the main starter cable on top of the engine at terminal #30.

The thing is this might also disconnect the Alternator? according to my cheap Porsche shop manual on CD I bought at ebay for $7.00. So that is what I am wondering now. I don't want to replace a starter if it's the Alternator.

So after this I might also have to remove front engine cover and disconnect alternator right at the alternator.

But I have never herd of a perfectly working alternator draining the battery,
I have herd of a starter solenoid draining the battery.

Kevin

[speedkillz]

Kevin have you ruled out your ignition switch. My car went dead a couple times from the switch not closing when I removed the key.

[RadioDjKev]

Ignition works perfectly.

Thanks to everyone for all help.

Tonights the big night.. lol