Charley B

I was thinking of mounting a battery off switch at the positive jump terminal, but something tells me that plan may have drawbacks. Any comments?

greg928GTS

I had one on my 89 and I had problems with how the engine ran. I was told that disconnecting the battery can have an affect on the computer that manages the engine. I had the oddest experience after taking the battery off-switch out. The car ran worse and worse on a daily basis, until finally one day I thought it was going to just stall right in the middle of the road. Just as it was about to cough and spit the final time, the engine snapped back to life and ran fine for years.

heinrich

been planning one myself

Alan

Well the problem with the positive battery post is its still really hard to get to and hardly any room either.... Not exactly quick to get to in an emergency - or convenient under any conditions...

The jump terminal is useless - since it only shuts off some items...most of the CE panel but not all - just not enough..

Instead put it where the battery ground strap connects to the Ground point - easier to get to and relatively easier to do... still tight space though.

Also get a really good switch - one that can handle a few hundred amps constant current and ideally about a thousand amps for a few seconds.

Incidentally never turn it off with the car running you could wreak havoc with your electrical system - the battery is important to the voltage regulation. Use the ignition switch for that. The battery switch is great for general work on the car with the doors/hood/hatch open - or emergency disconnection of the battery - there are fair number of non-fused always live circuits on a 928...!

Alan

Ron_H

I have one where Alan has placed his. I also have an electrical gremlin that was intent on bankrupting me until I installed a cutoff switch. Now everytime I park the car for more than four hours, I cut the bugger off. No effects yet on the car's running condition. I simply turn it back on before I start the car. The only drawback is having to reset my clock all the time.

Charley B

Thanks Alan. The switch I have is the same as in your picture. I wasn't thinking of the positive battery terminal, but rather the positive jump terminal under the hood. I was thinking the switch might mount onto the black plastic cover that the terminal pokes through for a fairly clean, though not too solid, mounting. My concern is, am I not thinking of some electrical consequence by interupting the circuit at that point.

Alan

Charley - See what I said - it doesn't turn everything off... no good.

Alan

Charley B

Jeez Alan, I don't know how I missed the one sentence in your first post that I was looking for. Thanks, thats what I was afraid of.

Tony

thanks for that pic Alan. I picked up a switch from Mark at 928intl lasy year, made by Hella. He had a few of them....apparently they are on the dealer deilvered Cayennes . They are taken off once they go on the lot. Just havent gotten around to putting mine on.
FYI..i understand it is better to put the switch on the GND rather than POS lead

Dave H.

they come on Touregs too...

Alan

Here is the business side of mine - the part at the bottom is the battery ground strap (you need a 90 degree bend in the brass end). the clearance is quite tight - you need to plan & measure carefully - also the battery gnd strap is only just long enough for this... measure carefully

Alan

UKKid35

If you have leaking pipes in your house do you switch off the water each time you go out, or do you fix the leak?

Charley B

If the leak originates from any one of a 1000 sources that might take days weeks or months to locate I'll probably shut the water off when I'm not using it. At least for awhile.

UKKid35

I think it worth checking with one of the LH ECU experts, but I suspect that continually switching on and off the power to this fragile ECU is likely to hasten its demise. This is because of the spike that occurs when switching off the supply and the poorly designed 'tile' in the ECU. Not to mention the fact that you will lose your idle settings and would have to run the idle adaptation using a spanner or hammer to get your idle back if it's not on spec.

Hopefully John Speake will advise.

Normy

I think I saw for sale in an auto parts store a little kit that allows you to connect a 9-volt battery to your car's electrical system. It has a diode, and the 9 volt does nothing but allow your radio and clock settings to stay in place when you have the battery disconnected. I bet on later cars that it would prevent the LH from losing its calibration as well.

N