Full Moon Behavior

Last night while driving home my headlights and dash lights began to dim. My tach went into the redline, then back to zero, then into the redline and then went dead. I was not far from home so I tried to speed up to get there. My car began to miss, lose power and then began to die on me. I pulled into a grocery store parking lot as my car died completely.
Living in Dallas and not having any cool weather and rain for a while I wondered if it was related somehow, not to mention the full moon last night.
I opened the trunk and checked the battery. the lights inside and the radio still worked so I knew I wasn't completely out of juice.
I noticed my spark plug remover and oil filter remover were up next to the battery. I took them away, shut the trunk and called my wife to come get me.
5 minutes goes by and while sitting there waiting, looking at the moon I tried turning her over(not my wife, the car) and it started right up! Lights came on full, everything was working. I was happy that it started right up, but a lot perplexed. I drove home a couple of miles without incident. I have had this car for 8 months and have never experienced anything like this.
The car is a 1980 SC with 58k original miles and a 1 year old battery that is to spec. What gives? Anyone ever experienced something like this? Was it the full moon?
I am a novice at fixing things and would appreciate any help or suggestions. Thanks, John

These intermittent electrical problems are the toughest to explain. Especially when they seem to disappear. My wife's Volvo quit in the very same manner a few nights ago. Called the hook and had it delivered home. Battery at 7 volts. Alternator wailing a good 14. Put the charger on it overnight and it hasn't done it again. Check all grounds and connections and move all tools away from the battery. Did any of the tools have any signs that they had arced to the battery? May want to charge battery overnight to get it back to spec. (Give that alternator a big break) Good luck.

John,

I'm not much of a believer in the moon controlling the behavior of my vehicles, but if that helps you, fine!

Lead-acid batteries can develop intermittent internal shorts that are dependent on the internal temperature of the battery. And, an internal short is just about the only way a battery can read 7 Volts one time and 12 Volts a few minutes later, since you gave no indication it was charged in between!!!

I suggest a visit to K-Mart or Wal-Mart for a new battery! And, just for the record, I find that automotive batteries are much less reliable these days, than they were 30 years ago! Pressures of the competitive market mean shortcuts to reduce cost of manufacturing, and hence, reliability suffers ... but you won't get any admissions from the industry, they are too wrapped up in advertising hype!

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Warren Hall
1973 911S Targa

Yes, and modern electrical systems tax batteries more than they used to. I've heard the industry is interested in going to 24 volt systems. I think that won't make them cheaper. Like electric power deregulation. Oops.

The thing I find most irksome about car batteries is there are WAY more battery kinds than there needs to be. There are no purposes, other than marketing ones, for more than about ten battery 'groups.' They would be much less expensive.

Some of today's batteries deliver nearly 1000 amps. Wow!

I wonder if your tools were shorting your battery.

You know, a while back somebody had a shorted cable to the starter. This interests me because it's a huge cable and it should definitely be protected. I'm not sure how it's routed or what went wrong when the other guy had this dangerous short.

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'83 SC



[This message has been edited by Superman (edited 11-11-2000).]

Just a thought that you might want to check the water level in your battery if it is not the maintenance free type..

John,

If you need help on this, there are a lot of us in the Dallas area who are glad to help.

JoeA
FM/Lewisville area

I believe all 911's have the battery cable covered in a heavy PVC 'sheath' and secured to the underbody by 1/2" tabs that are spot-welded at 18" intervals all along its' intended path to the starter. Unfortunately, there is no guarantee previous owners or inept wrenches will see to it that the cable stays in the original, secured location! In Jack's cross-country adventure with the 'pre' version of Black Beauty, the cable had been held up by bread-wrapper ties or something equally substantial ... and somewhere in the nether regions of New Mexico/Arizona ... an axle managed to rub through protective sheath and primary insulation on a dangling/dragging cable. The resulting short brought Jack's trip to an abrupt end!

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Warren Hall
1973 911S Targa

I believe a trip to the local shaman or medicine man could solve the cool weather and lack of rain. The moon comes and goes on its own. Don't worry too much about the car turning over, although getting the wife to turn over should be a priority. Then go to see Manny, Moe, and Jack for a new battery.

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E. William Reinecke
1988 Carrera Targa

The industry is actually going toward a 42 volt standard soon, not 24 (too bad, all those military and construction vehicles would have it made). The change is being made due to the vastly increased demands being put on the electrical systems of modern cars. Used to, your average car could get away with 6 or 12 volts-they only had a few accesories to deal with, and most of the power was consumed by the ignition system. Now you've got distributorless, multiple coil ignitions, ECM's, TCM's, electric fuel pumps and injectors, ABS/TC/VS systems, HVAC systems, navigation systems, multichannel high power CD changer stereos, alarms, electric windows, mirrors, heated/cooled/lumbar supported(with memory)seats, locks, power tilt/telescoping steering columns, HUD's,-geez, I could go forever. Is it any wonder batteries don't seem to last as long as they used to? They gotta start the car, run all this crap while hopefuly getting enough current from the alternator to maintain thier charge, AND provide enough power for all the things that continue to suck current even after the car's shut off and just sitting there-all while only being able to supply 12 volts. The more things attached to a circuit of a fixed voltage that draw power from it, the more current the power source (in this case, the battery) has to supply-which in this case, means the faster the battery will discharge. Going to a higher standard voltage system will enable vehicle desginers to lower the current draw of many components-but it's REALLY gonna screw up the after market parts industry. In the meantime, check your grounds, clean your terminals, and make sure the regulator isn't allowing the alternator to overcharge your battery-anything over 14 volts will boil the electrolyte out of your battery (well, wet cells, anyway.) Optima dry cells are WONDERFUL-you can mount them upside down, shoot a hole in them, and they will STILL crank over and start a hot, 11.5:1 big block Chevy. Technology CAN be your friend.

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Clay Mcguill www.geocities.com/the912guy

I had a similar problem. It ended up being a bad alternator.

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Roger Shadel
78 911SC

John, your from Plano, Texas!! That's the hometown of America's greatest cyclist and two time winner of the Tour de France, Lance Armstrong.....

My guess: check the grounds, belts, wiring connections, and the alternator.

I don't know your car well enough to be certain, but most contemporary cars have things like the tach being fed via the ECU. When the voltage drops too low, the ECU, depending on the type, can go into an ether-land like state where it does all types of wierd things until the voltage either drops down low enough for it to completely shut off (usually stopping the car), or it comes back up high enough for the ECU to run in a normal state. I'm guessing your voltage dropped because you also stated seeing the lights on the dash dim, and they usually aren't computer controlled on all but the newest cars.

When a battery gets drained, it starts to develop a high internal resistance. What this means is that internally 12 volts may be generated by the battery, but at the terminals the voltage can read substantially lower. When this happens, if the battery is left unloaded for a period of time (like waiting for your wife at a store), the internal resistance will drop and the normal voltage will appear at the terminals again. I think this is what happened to your car, and I've listed what I think are the most common causes at the top of this post.

In most cases, the alternator should be capable of supplying enough power to keep the car running even without a battery once it's started, so even though the battery may be a lemmon, I would look at the charging system, grounds, etc. first as the primary culprit.

Hope this helped,

Bill Wagner

Thanks for all your replies. I will go thru a checklist this morning to try and find out what happened the other night. It's great to have this wealth of experience out there. John

Make sure your voltage regulator is OK, I'm still repairing the damage to my 88 Carrera after the battery melted down.

Crank the thing up on a dark, moonless night... go into the engine compartment & look closely for any signs of arching. That's how I found a similar problem I had in a 914 I owned 20 yrs. ago.
regards,
jlex.