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17

This is another of those questions that can only be answered by a few people at VW, clearly the car could turn the headlights off after it is stopped; or after it is stopped and a certain amount of time has elapsed; or, as you suggest, by monitoring the battery and not allowing the battery to drain past the point where the car is likely to be able to start ...


10

The most likely cause is that the cable that runs down to the starter motor has been rubbing against the body or the engine and has worn through the insulation.


9

Lead sulfate crystals form on the battery plates as the battery discharges. As the battery becomes more discharged the crystals go from being soft and fluffy to much harder. Recharged in time, the lead sulfate is converted back into sulfuric acid and lead. A month is entirely too long for a battery to remain discharged. Reversing a serious sulfation ...


9

Since you have a battery which isn't that old (most batteries have about a five year life span), I'd suggest you put it on a charger and try to recharge it. This will allow the battery to come back to full charge without putting an undue stress on your alternator. You have to decide if the time spent in recharging the battery is worth your time. To me, ...


9

12.45 to 11.94 in 6 days seems like a significant discharge. You should be able to leave your car for a month or longer and still have enough power to start. At your current discharge rate, I wouldn't be surprised if you couldn't start after 10 days. I would be looking at parasitic drain. Here is a guide. You can find YouTube videos also. Some ...


8

That wire will have been the main power connection from the alternator to the battery it is used for powering the car and charging the battery while the engine is running. By forcing this onto the chassis you will have shorted out your battery and hopefully you have blown a fuse-able link. Needless to say, this was very dangerous to do. If a fuse-able link ...


8

There a number of possible causes: An old battery that can no longer handle the load of the "always on" accessories (clock, alarm, etc.). A new load (like the inverter my son left plugged in) that is draining the battery. A high resistance short that draws enough current to bring down the battery, but not enough to blow a fuse – a "short" is any path that ...


8

Similar batteries are used for motorcycles, and many people don't use those very often at all. They sit in the garage for months at a time until the weather is just perfect for that 20 minute ride. Batteries that just sit in the garage loose their charge, and when the voltage gets too low, real permanent damage can occur. The situation is the same as ...


7

I'm not going to tell you to try and utilize a battery charger to fix the issue as @MoveMoreCommentsLinkToTop has suggested in the comments, but it has been my experience when a battery has sat for an extended period of time with a constant power draw on it, the lead plates get sulfide crystallized over and will no longer take a charge. If it does take a ...


7

Sounds like a dead short, one large enough like that should be easily visible, either through burn marks on a metal edge or bracket or a hole in the insulation. Check and follow all the main or thick wires.


6

How old is the battery (if it has a date stamped on it)? If it is over five years old, I'd replace it as a maintenance item. Remember too, a healthy battery should actually be over 13vdc at rest and fully charged. If your battery was only reading 12vdc, this is an indication of a weak battery to me. It may have a bad cell and accumulate what I call a surface ...


6

It is very important to charge back the battery as soon as possible. As per how fast does the alternator charge the battery?, it may take as much as 10 hours or more for the battery to be re-charged if it was truly fully discharged (which might not necessarily have been the case in itself, due to the potential Negative surface charge?). It is much cheaper ...


6

All of these other answers go into weird philosophical directions... The answer is much simpler than that: Yes, it is possible to have the car turn off the headlights when the car turns off - many cars have an "Auto" setting for the headlights, and it does just this. They usually have a manual mode too, for those cases where you want the headlights on but ...


5

I don't think you are likely to "put undue stress on the alternator." It is a myth in my opinion that alternators can't handle charging a battery, Alternators are literally motors run in reverse and are designed to handle a lot of current. The only issue with charging a batter is it will get a bit warmer than usual and that shouldn't effect it as long as it ...


5

You may have a bad stator As @paulster2 stated, you should have your battery tested. You could have a lead plate the broke free inside the batter and grounding out that cel to another cel. Your voltage test could be an indicator that it is not your battery though. Here is a method you can use to test your stator. Testing Your Stator There are three ...


5

Many times you can start a motorcycle with a low battery This answer has a push start method You can also coast down a hill and let out the clutch with the ignition 'on' and the start switch set to 'on' Use jumper cables and get a charge from a car battery. You can use the jumper cables and allow the car to just idle. You don't want to charge your battery ...


5

You're probably better off starting and driving the car everyday or leaving a battery tender on the car. Some cars learn and store values like idle, etc... When the battery is disconnected it loses these values. There's no real harm in disconnecting the battery, just some inconveniences that may or may not require scantools to resolve.


5

A battery should be able to run the flashers for several hours and still start the car. There should be a sticker on your battery which tells the month and year it was manufactured. The sticker will either be M/YY indicating the month and year, or a code such as D6, where D is the fourth month of the year (sequentially mapped months A-L), and 6 is short for ...


4

One other thing that happens when a multi-cell battery is completely discharged is that one of those cells may be driven into reverse polarity. This will have a drastic effect on a battery's life. Most will tolerate this only a few times, some types only once.This from Wikipedia:Damage from cell reversal Subjecting a discharged cell to a current in the ...


4

If the battery puts out just 2V across the terminals then it is severely discharged; in all probability beyond the point of recharging. There's no point in trying to charge it. I've had a battery that put out only 9V which couldn't be revived.


4

Since the drain is very repeatable, connecting an ammeter in series with the battery and disconnecting each fuse in turn is a good idea as @jphil1618 suggested. You could find that the problem is associated with multiple fuses, for example it could be the fuel pump that is running (I know you would hear the pump) and while pulling the fuel pump fuse will ...


4

Welcome, Mike. I hope you kept your receipt as you likely have at least one defective diode in your new alternator. If you replace it and experience the same problem, you will want to check the wiring and connections between the positive battery terminal and the alternator BAT terminal to make sure it's not causing the diode(s) to fail. Or, if you prefer, ...


4

There's no specific time that will determine how long a battery will last without damage. There are a number of factors, not limited to temperature, age of the battery, what the "open circuit voltage" was when it was last charged, and most importantly: the load drains that are created by various "keep alive" computers, memories, and other modern electronics ...


4

So after looking up what a GEM was (its the Ford name for the thing that controls the majority of the interior and some of the exterior electronics, if anybody else was wondering), A reasonable first guess is the aftermarket alarm. Aftermarket electronics are rarely designed in a way that is electrically sound, and even more rarely installed correctly. ...


4

Basically: sometimes, you need your headlights on even though the engine is off cars with "smart" systems like this are annoying if you i) don't know how to operate/disable the "smart" system or ii) the "smart" system is interfering with what YOU are trying to do. "smart" systems are expensive to engineer and need extra components/sensors, all this adds to ...


4

To put it simply; Your alternator was working very hard to charge the battery while you were driving. The additional load of flashing your high beams added to the amperage draw which in turn added to the load on the engine turning the alternator. As the battery became charged, it was able to help buffer the amp draw until the charging was minimal and the ...


4

You are asking the wrong question. The question should be: for how long should you drive the car, once you have started it? A battery in proper condition should last for at least a month in a car that doesn't have a smart key system (your -00 model almost surely doesn't). A smart key system means the car detects the key in your pocket, and thus, you don't ...


4

Solar chargers are impacted by many factors: Glass: especially tinted glass filters light, you won't get maximum charge behind glass Direction: solar cells work best when pointed at the sun Sun intensity: you won't get full power on a cloudy day, and in the winter sun is less intense If you want to test your charger then take it out of the car and see what ...


3

A 12v lead acid battery is flat dead at no less than 10v. If it really were 2v, that would indicate that several cells had shorted out, and you wouldn't even be able to jump start it, as the battery itself would be burning off most of the power the jumper cables can transfer as heat. The fact that you managed to jump it indicates that you read it ...


3

From personal experience 2V is way under the safe discharge zone (considering yours is the typical lead-acid). Your battery is now damaged. Even if you charge it with an industrial charger and miraculously get it back to 13.2 Volts (of full charge) you will still get a lousy capacity and current discharge. In the best case scenario you will get a few seconds ...


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