These new "luxury" cars have a written read out warning about using the electrics too much when parked.
Why is Battery Dead
Addict
Rennlist Member
Rennlist Member
Joined: Jun 2001
Posts: 7,029
Likes: 49
.21V on the Optima? Wow, that thing is flatter than a pancake.
To discharge that deep and remain there, it must have seen quite a load for the duration of connection.
Most batteries will "bounce" back up a few volts when disconnected. Good luck resurrecting this one.
To discharge that deep and remain there, it must have seen quite a load for the duration of connection.
Most batteries will "bounce" back up a few volts when disconnected. Good luck resurrecting this one.
Drifting
Joined: Dec 2009
Posts: 3,035
Likes: 15
Test amperage as follows: Disconnect positive lead to battery, put ammeter negative to positive on battery, put ammeter positive to the unattached positive cable. Just to be totally clear: we are measuring amps here not volts; set meter for amperes not volts.
You should have a very small draw when the car is parked and shut off with keys out and doors closed. Don't know what it is for your car all I know is it should be much much less than 25 milliamps. Probably should be almost a perfect zero if the car has no alarm or computer stuff; the clock would be the only thing running? I hope that helps.
You should have a very small draw when the car is parked and shut off with keys out and doors closed. Don't know what it is for your car all I know is it should be much much less than 25 milliamps. Probably should be almost a perfect zero if the car has no alarm or computer stuff; the clock would be the only thing running? I hope that helps.
I haddah Google dat
Rennlist Member
Rennlist Member
Joined: Nov 2008
Posts: 11,501
Likes: 5
From: Fresno, CA
wow, .21v would meant the battery is toast.
We should start a battery thread on deep cycle vs. starter batteries. I was looking at Exide gel batteries, and they look very interesting to me. I was also looking at Optima deep cycle gel batteries.
As for the drain, just keep the ammeter hooked up, and start pulling fuses. One circuit will have a relay or something that is stuck, or have a bad switch. Try the rear heater blower circuit.
We should start a battery thread on deep cycle vs. starter batteries. I was looking at Exide gel batteries, and they look very interesting to me. I was also looking at Optima deep cycle gel batteries.
As for the drain, just keep the ammeter hooked up, and start pulling fuses. One circuit will have a relay or something that is stuck, or have a bad switch. Try the rear heater blower circuit.
Drifting
Joined: Dec 2009
Posts: 3,035
Likes: 15
I thought deep cycle were heavier. Nevertheless I hate it when I'm waiting in the car and that warning comes on the PCM about battery use, "blah blah, only a short time." Who's gonna test it to see how long you can enjoy music or learn the Nav system while parked without getting stranded?
Drifting
Joined: Dec 2009
Posts: 3,035
Likes: 15
Thread Starter
Advanced
Joined: May 2009
Posts: 94
Likes: 0
From: Orem, Utah
Before I put my battery back in or a new battery, I need to figure out where the drain is.
Thinking back to last week and what I did differently. The only thing I did different than any other time I go for a drive is that I turned the Rear Defroster on and off. Didn't notice if it worked because it wasn't that fogged up.
Someone mentioned that a relay could be stuck. That is my guess. How do I test for this.
Thanks,
Rob
1980 911 SC
Thinking back to last week and what I did differently. The only thing I did different than any other time I go for a drive is that I turned the Rear Defroster on and off. Didn't notice if it worked because it wasn't that fogged up.
Someone mentioned that a relay could be stuck. That is my guess. How do I test for this.
Thanks,
Rob
1980 911 SC
Rennlist Stories
The Best Porsche Posts for Porsche Enthusiasts
Every Era of 911 Owner Explained in One Sentence
Verdad Gallardo
Thinking of Buying a Porsche? Do These 10 Things First
Joe Kucinski
Pixar Pals Turned Into 1-of-1 Porsches!
Michael S. Palmer
Theon Goes Full Carbon Fiber With Stunning New Build
Verdad Gallardo
Genius Porsche-Themed Gifts That'll Make Any Dad or Grad Smile
Joe Kucinski
10 Used Porsches Are Selling for Way Too Cheap
Joe Kucinski
Tuner Is Converting Porsche 911s Into Shooting Brakes
Verdad Gallardo
This Coachbuilt Creation Is A Modern Take on the Legendary Porsche 917
Verdad Gallardo
Is This Convertible Cayenne A Steal, Or A Returnless Investment?
Verdad Gallardo
Addict
Rennlist Member
Rennlist Member
Joined: Oct 2001
Posts: 1,001
Likes: 3
From: Sunny Oregon
Rob:
Find the fuse for your Rear defroster. Remove it. Set your test meter to 10 amps and with your key in the run position, touch both terminals where the fuse used to be. If you read more than 0 amps, go to a lower setting on your meter to verify that there is indeed 0 amps. If more than 0 amps, the relay is stuck.
Again, the way to find a drain is to connect your amp meter to the batery as described above. Note the current draw and start removing/replacing fuses one at a time. when you pull a fuse that is on a circuit drawing power, the ampmeter will reduce it's reading. Verify if that circuit is supposed to be off.
Find the fuse for your Rear defroster. Remove it. Set your test meter to 10 amps and with your key in the run position, touch both terminals where the fuse used to be. If you read more than 0 amps, go to a lower setting on your meter to verify that there is indeed 0 amps. If more than 0 amps, the relay is stuck.
Again, the way to find a drain is to connect your amp meter to the batery as described above. Note the current draw and start removing/replacing fuses one at a time. when you pull a fuse that is on a circuit drawing power, the ampmeter will reduce it's reading. Verify if that circuit is supposed to be off.
Rennlist Member
Joined: Feb 2002
Posts: 1,907
Likes: 0
From: NY
I have a red top in my car and I have all kinds of electronics hooked up to it. Amps, stereo, etc.
I can let my car sit for a month and still cranks over and starts with authority.
If the car sits for some time and it barely started and you take it out for a 20 min ride, that is not going to be long enoeph for the battery to charge it self. Do a draw test, if it all looks ok charge up the battery to full capacity and you will have no problems with it.
I can let my car sit for a month and still cranks over and starts with authority.
If the car sits for some time and it barely started and you take it out for a 20 min ride, that is not going to be long enoeph for the battery to charge it self. Do a draw test, if it all looks ok charge up the battery to full capacity and you will have no problems with it.
Drifting
Joined: Sep 2001
Posts: 2,467
Likes: 16
From: redmond wa
Test amperage as follows: Disconnect positive lead to battery, put ammeter negative to positive on battery, put ammeter positive to the unattached positive cable. Just to be totally clear: we are measuring amps here not volts; set meter for amperes not volts.
You should have a very small draw when the car is parked and shut off with keys out and doors closed. Don't know what it is for your car all I know is it should be much much less than 25 milliamps. Probably should be almost a perfect zero if the car has no alarm or computer stuff; the clock would be the only thing running? I hope that helps.
You should have a very small draw when the car is parked and shut off with keys out and doors closed. Don't know what it is for your car all I know is it should be much much less than 25 milliamps. Probably should be almost a perfect zero if the car has no alarm or computer stuff; the clock would be the only thing running? I hope that helps.
Also, while this may be obvious, DO NOT attempt to start the car with the ampmeter connected, unless the ampmeter is rated for 300-400 AMPS.
I check for alternator operation by measuring the terminal voltage of the "fully" charged battery(~12.35 volts), starting the engine and turning on EVERY voltage load available and verifying that the battery terminal voltage is now above the non-running no-load voltage(>12.50 volts).
Drifting
Joined: Sep 2001
Posts: 2,467
Likes: 16
From: redmond wa
Before I put my battery back in or a new battery, I need to figure out where the drain is.
Thinking back to last week and what I did differently. The only thing I did different than any other time I go for a drive is that I turned the Rear Defroster on and off. Didn't notice if it worked because it wasn't that fogged up.
Someone mentioned that a relay could be stuck. That is my guess. How do I test for this.
Thanks,
Rob
1980 911 SC
Thinking back to last week and what I did differently. The only thing I did different than any other time I go for a drive is that I turned the Rear Defroster on and off. Didn't notice if it worked because it wasn't that fogged up.
Someone mentioned that a relay could be stuck. That is my guess. How do I test for this.
Thanks,
Rob
1980 911 SC
Well, bottom line, you don't....
It would not be at all unusual for a well used/worn relay, especially a fairly high current (window defrost heat), and even moreso a relay used to switch power for an inductive load (fuel pump, blower motors, etc.), to have the contacts so corroded/worn that they stick/"weld" closed once in awhile. The bad news, sorta, is that once the power is switched off even the slightest bump or vibration will often cause the stuck relay contacts to open.
And that "sticking", may only occur one of each 100 cycles, even for a well used/worn relay. The best solution, IMMHO, is that if you suspect a relay to be sticking occassionally then open it up and inspect, up close, the condition of the relay contacts. In days of yore there was always a small file set, relay contact burnishing kit, in my travel, field service case.
Left over from my days in the USAF, keeping B47's and KC97's flying.
I haddah Google dat
Rennlist Member
Rennlist Member
Joined: Nov 2008
Posts: 11,501
Likes: 5
From: Fresno, CA
We did a drain thread a while back. I believe <40ma was the consensus "normal" range for constant draw. I believe Loren calculated that it would take about a month at that rate to drain a battery. I would probably think something was wrong if there was >50ma draw.