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Getting into a locked car with the battery disconnected
There are stretches of 2+ weeks where I don't drive my 997.2 GT3, but I don't have access to power a battery tender, and the car needs to be closed up and locked for security.
I know that when you have a dead battery, you can open the frunk using the battery "jump" terminals in the fuse box and using the key fob to command it open, but does it also work when the battery is disconnected and basically the electronics become an open circuit?
I'm assuming the fuse box jump terminals are just discreetly powering a small ecu/circuit that powers the electronic frunk actuator and the brain that receives wireless key fob commands, so having the battery disconnected shouldn't be an issue for getting into the frunk.
When trying to get back into the locked car with battery already disconnected, my plan is to unlock the door with the keyhole, access the fuse box, use a small pocket sized Li-ion jumper box to energize the frunk opener, use key fob to open, open frunk, reconnect battery, and away I go.
I'm sure you've thought of this, but as a backup plan if no one responds, you could always disconnect the battery, leave the hood open, and see if when powering the jump terminal in the fuse box you can unlock the trunk. That way you at least know that in the future when you lock everything up that you'll be able to get back in. Leaving the hood open is only a test so that if for some reason it didn't work, you can at least know that before closing it. But I'm guessing it should work fine. It should also only take a couple of mins to test out.
Bad plan... If you disconnect the main battery the fuse box jumper will not work in any circumstance and then only solution is to use the emergency release cable which you have to jack the car up, remove the wheel, fender liner and dig out.... If you really want to go that route, remove your front bumper cover, re-route the emergency release cable to hide behind the tow hook cover. Then moving forward all you have to do is just pop off the cover and manually open the front trunk. Real world the car should easily go 2 weeks and still keep enough power to pop the trunk which only takes a few milliamps. It should still start as well, just make sure you then go drive it long enough to actually charge it back up.
Bad plan... If you disconnect the main battery the fuse box jumper will not work in any circumstance and then only solution is to use the emergency release cable which you have to jack the car up, remove the wheel, fender liner and dig out.... If you really want to go that route, remove your front bumper cover, re-route the emergency release cable to hide behind the tow hook cover. Then moving forward all you have to do is just pop off the cover and manually open the front trunk. Real world the car should easily go 2 weeks and still keep enough power to pop the trunk which only takes a few milliamps. It should still start as well, just make sure you then go drive it long enough to actually charge it back up.
Great info.
Agree battery should last 2 weeks. Could also look into an Antigravity battery, they have an emergency jump start feature built into the battery which you can use with a key fob, so that should also work.
There are stretches of 2+ weeks where I don't drive my 997.2 GT3, but I don't have access to power a battery tender, and the car needs to be closed up and locked for security.
I know that when you have a dead battery, you can open the frunk using the battery "jump" terminals in the fuse box and using the key fob to command it open, but does it also work when the battery is disconnected and basically the electronics become an open circuit?
I'm assuming the fuse box jump terminals are just discreetly powering a small ecu/circuit that powers the electronic frunk actuator and the brain that receives wireless key fob commands, so having the battery disconnected shouldn't be an issue for getting into the frunk.
When trying to get back into the locked car with battery already disconnected, my plan is to unlock the door with the keyhole, access the fuse box, use a small pocket sized Li-ion jumper box to energize the frunk opener, use key fob to open, open frunk, reconnect battery, and away I go.
As others have said your battery should last over 2 weeks and if not you really want to see if the battery is bad or if you have something causing a Parasitic Drain on the battery like a defective switch or other issues these cars sometimes get. YOu can check you Parasitic drain with and Ammeter and there are some good Video on how to do that on Youtube. If you do find a large Parastic draw you can also find some good videos on Youtube showing how to track it down by pulling fuses. Those are the key factors in a Car not sitting long before the battery goes dead.
If you really can't stand this happening the we actually make a Lithium Battery that will actually put itself to sleep before being drained completely. Meaning even if your car drained you battery dead our battery would still be able to start it because it will put itself to sleep before it uses all it energy and allow for a few more start attempts, or at minimum the ability for you to still open the frunk on your car....
Bad plan... If you disconnect the main battery the fuse box jumper will not work in any circumstance and then only solution is to use the emergency release cable which you have to jack the car up, remove the wheel, fender liner and dig out.... If you really want to go that route, remove your front bumper cover, re-route the emergency release cable to hide behind the tow hook cover. Then moving forward all you have to do is just pop off the cover and manually open the front trunk. Real world the car should easily go 2 weeks and still keep enough power to pop the trunk which only takes a few milliamps. It should still start as well, just make sure you then go drive it long enough to actually charge it back up.
Do you know this as a fact, from personal experience? Or is this just your educated guess that if you disconnect the battery that the fuse box jumper won't work?
Do you know this as a fact, from personal experience? Or is this just your educated guess that if you disconnect the battery that the fuse box jumper won't work?
Yes, I have a Porsche business and have had several customers over the years do this inadvertently and they called me to help solve the issue, which involved removing the wheel, fender liner and finding the emergency release cable. Not the end of the world but not an easy problem for the average owner to solve. Easier just not to do it.
As others have said your battery should last over 2 weeks and if not you really want to see if the battery is bad or if you have something causing a Parasitic Drain on the battery like a defective switch or other issues these cars sometimes get. YOu can check you Parasitic drain with and Ammeter and there are some good Video on how to do that on Youtube. If you do find a large Parastic draw you can also find some good videos on Youtube showing how to track it down by pulling fuses. Those are the key factors in a Car not sitting long before the battery goes dead.
If you really can't stand this happening the we actually make a Lithium Battery that will actually put itself to sleep before being drained completely. Meaning even if your car drained you battery dead our battery would still be able to start it because it will put itself to sleep before it uses all it energy and allow for a few more start attempts, or at minimum the ability for you to still open the frunk on your car....
I actually looked long and hard at your battery, and I really like the design features, but I just couldn't justify the price. I like that there is a remote fob for the restart, but I wish the fob could actually put the battery to sleep, as well as re-energize it. I even thought about getting your battery in the atx-30 size, but that doesn't come with the remote key fobs, so I would still somehow need to get into the frunk to push the restart button. I'm hoping the prices of lithium batteries will go down soon. I would love to eventually get one of your batteries.
So I got a chance to play with the GT3 today, and so I ran a test to see if the frunk unlock could be energized thru the fuse box jumper with the main battery completely disconnected.
And you can.
Like I theorized, the frunk unlock has its own discreet circuitry that is powered directly off the fuse box jumper. The reason I thought this is that if you had a really dead battery, and you connected thru the fuse box jumper, the battery would suck so much juice from the donor battery/car that it may not get to the minimum voltage for the frunk opener to open.
The "key" is you have to use the unlock button on your key. Not the button in the car.
One note. Before you disconnect the battery, close the doors and lock the car. Then disconnect the battery. If you have to open the door on the car, make sure you reconnect the battery before you close it again, or else the window will not slightly retract and the door closes and seals very awkwardly.
So I got a chance to play with the GT3 today, and so I ran a test to see if the frunk unlock could be energized thru the fuse box jumper with the main battery completely disconnected.
And you can.
Like I theorized, the frunk unlock has its own discreet circuitry that is powered directly off the fuse box jumper. The reason I thought this is that if you had a really dead battery, and you connected thru the fuse box jumper, the battery would suck so much juice from the donor battery/car that it may not get to the minimum voltage for the frunk opener to open.
The "key" is you have to use the unlock button on your key. Not the button in the car.
One note. Before you disconnect the battery, close the doors and lock the car. Then disconnect the battery. If you have to open the door on the car, make sure you reconnect the battery before you close it again, or else the window will not slightly retract and the door closes and seals very awkwardly.
That sums up my experience!
I testee it by disconnecting the battery and it worked very well to reopen the frunk.
Later on my battery die and it was a pain. Couldn’t get it started in anyway. Even bought the cigarette lighter charger from Ctek, let it overnight but no luck.
At the end a local garage guy came with a jumper starter and after fiddling for 10-15mins it opened.
Since then I bought a Liteblox battery and plan on getting the emergency cable accessible.
Maybe the later is not so critical on a 5lugs car but with the CL in the frunk you are really scr***
So I got a chance to play with the GT3 today, and so I ran a test to see if the frunk unlock could be energized thru the fuse box jumper with the main battery completely disconnected.
And you can.
Like I theorized, the frunk unlock has its own discreet circuitry that is powered directly off the fuse box jumper. The reason I thought this is that if you had a really dead battery, and you connected thru the fuse box jumper, the battery would suck so much juice from the donor battery/car that it may not get to the minimum voltage for the frunk opener to open.
The "key" is you have to use the unlock button on your key. Not the button in the car.
One note. Before you disconnect the battery, close the doors and lock the car. Then disconnect the battery. If you have to open the door on the car, make sure you reconnect the battery before you close it again, or else the window will not slightly retract and the door closes and seals very awkwardly.
Good news is I might have learned something, I have always tried using the button in the car and didn't think to try the key fob. Glad to hear that works!
PROCEDURE:
1. Make sure the Jump Starter Battery Pack is Charged
2. Plug in the Car Charger cord into the Jump Starter Battery Pack
3. Plug the male end of the Car Charger into the cigarette lighter recepitcal
4. Turn on the Jump Starter Battery pack and voila, the power will flow into the car with enough juice to light up your dash lights and pop the frunk
5. Open the frunk and un-hook the Battery pack from the Car Charger
6. now attached the Smart Clamps to the Jump Starter Battery Pack and fire up your Porsche.
All the above solutions work, dependent on how often you would start the car, fitting a battery disconnect switch may be the most cost effective. Simply open the switch when leaving the car for a period, Close the switch when you want to start. That said the cost of a disconnect switch would not be too different to a small CTek or similar battery tender - (you didnt mention whether you had access to power a tender near the car when parked)
09-19-2020, 01:50 PM
Getting into a locked car with the battery disconnected
