Dead battery after 3 weeks of no driving
- Thread starter Dshavers
- Start date
Same for my '09 Escape. Also true for newer GM's, etc, etc...
Same with mine. Waiting for my daughter to get out of school and mine shut off. Didn't time it but was close to 10 minutes.
This is why your battery goes dead after 3 weeks.
FYI-You have to actually drive the car to get the alt. to charge the battery.The batteries in the new Mustangs will last about 3 weeks while parked.The electrical systems on these cars are what we call on the network.While these cars are parked and turned off the network actually powers 7 modules,anti theft switches and the amps in the stereo.After 30 minutes the network goes into sleep mode but still powers all items mentioned.If you pop the trunk or open the door the network wakes up and stays awake for 30 minutes as long as nothing else is used in the car then goes back into sleep mode.The reason you hear sometimes to turn your radio off before you turn the car off is the ACM or audio module draws 4 amps and usually the most likely module to go bad.If the ACM goes bad it never goes into sleep mode and draws 4 continuous amps till the battery is dead,which doesn't take long.Hope this helps.
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FYI-You have to actually drive the car to get the alt. to charge the battery.The batteries in the new Mustangs will last about 3 weeks while parked.The electrical systems on these cars are what we call on the network.While these cars are parked and turned off the network actually powers 7 modules,anti theft switches and the amps in the stereo.After 30 minutes the network goes into sleep mode but still powers all items mentioned.If you pop the trunk or open the door the network wakes up and stays awake for 30 minutes as long as nothing else is used in the car then goes back into sleep mode.The reason you hear sometimes to turn your radio off before you turn the car off is the ACM or audio module draws 4 amps and usually the most likely module to go bad.If the ACM goes bad it never goes into sleep mode and draws 4 continuous amps till the battery is dead,which doesn't take long.Hope this helps.
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Dshavers, an underdrive pulley can reduce the effectiveness of your alternator while your engine is running, may not allow your battery to maintain a charge under certain driving conditions or may even prevent your battery from ever getting fully charged.
Voltage measurements of the battery while the engine is running is the output of your alternator and should be approximately 13.7-14.7 volts. If you don’t have a multimeter, you can test this by starting the car and turning on the headlights. If they are dim, it indicates the lights are running off the battery and that little or no juice is being produced by the alternator. If the lights get brighter as you rev the engine, it means the alternator is producing some current, but may not be producing enough at idle to keep the battery properly charged. If the lights have normal brightness and don't change intensity as the engine is revved, your charging system is probably functioning normally.
I have not made measurements for the tracking system you have, but I do know that some alarms and tracking systems will completely discharge a battery within a few weeks.
I agree with everyone who recommends checking your key-off load and buying a battery tender/maintainer, especially with the way you have your car set up. They are a great investment, which will help extend the life of any battery.
I hope you get your situation resolved soon!
Jim McIlvaine
eCare Manager, OPTIMA Batteries, Inc.
Optima Batteries | Facebook
Voltage measurements of the battery while the engine is running is the output of your alternator and should be approximately 13.7-14.7 volts. If you don’t have a multimeter, you can test this by starting the car and turning on the headlights. If they are dim, it indicates the lights are running off the battery and that little or no juice is being produced by the alternator. If the lights get brighter as you rev the engine, it means the alternator is producing some current, but may not be producing enough at idle to keep the battery properly charged. If the lights have normal brightness and don't change intensity as the engine is revved, your charging system is probably functioning normally.
I have not made measurements for the tracking system you have, but I do know that some alarms and tracking systems will completely discharge a battery within a few weeks.
I agree with everyone who recommends checking your key-off load and buying a battery tender/maintainer, especially with the way you have your car set up. They are a great investment, which will help extend the life of any battery.
I hope you get your situation resolved soon!
Jim McIlvaine
eCare Manager, OPTIMA Batteries, Inc.
Optima Batteries | Facebook
I'm pretty sure this part of your statement doesn't apply to to a overdrive supercharger pulley as long as a larger idler or an external idler tensioner is used to maintain proper belt tension. I am thinking that Dshavers went to a smaller pulley to add boost. This is a very common mod for GT500 owners. So what you are saying does not apply to this situation.
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cdvision, you are correct about proper belt tension being critical to the proper function of an alternator. I'm not going to speculate on what Dshavers goals were or how he went about making changes, as he only mentioned “installing the a pulley and tune” and has never provided any additional information. Here's what I do know- when people start making pulley changes, electrical issues often follow, whether that is due to a belt slipping or because the alternator simply isn't able to properly-maintain battery voltage. People think serpentine belt systems are immune to belt slippage issues, but my friends at Powermaster tell me that is not the case. Those guys see alternators returned with signs of slipping belts like we see discharge-only warranty returns- lots. Whatever the case may be, we've never heard back from the OP on what the resoltion was to his situation.
Jim McIlvaine
eCare Manager, OPTIMA Batteries
OPTIMA® Batteries on Pinterest
Jim McIlvaine
eCare Manager, OPTIMA Batteries
OPTIMA® Batteries on Pinterest
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