Battery switch for '96 993?

[gordonmacwilliam]

I have been recently retired and now drive less than 1,000 miles per year. Lately I have been recharging the batteries on my 944S and 993 weekly. I installed a battery switch on the 944S so that I would not have to charge this battery, but was leery of installing one on the '96 993 as I was unsure if the lack of power over a long period would have adverse affects on the electronics such as the ignition disabling mechanism. Does anyone know if installing a battery switch would be a problem for this vehicle?

[JFP in PA]

You DME will reset, which you need to allow for when state inspection is on the horizon; but why not just put a good battery maintainer on it and leave it connected? I do this for very long periods of time with no problems, you just disconnect and start the car...................

[gordonmacwilliam]

Thank you for your response, JFP. I apologize for not getting back sooner.

Here in Jacksonville, Florida, vehicle inspections were discontinued more than a decade ago, so fortunately, this is not a problem for me.

I have an (admittedly old) Schumacher (Sears) 1.5 amp on-board battery maintainer. The output during charging is only 0.6 amps (instead of the advertised 1.5) which I can live with. The output when the red charged light is on is 0.4 amps which I cannot, because this translates to almost 10 amp-hours each day overcharging the battery. I had been charging the battery 24-hours prior to use which was a pain.

I had to fix the ubiquitous horn problem, so I left the battery disconnected for a week. Since I had no problem when the battery was reconnected, I installed a battery switch. Getting to the switch handle under the floor mat would have been yet another pain, so I installed a bolt through the battery switch handle and made a notched lever handle that would insert through a drilled hole in the floor mat and grab the bolt. The trunk light indicated whether the battery switch is engaged or not.

Edited December 21, 2010 by gordonmacwilliam

[JFP in PA]

Not to sound overly critical, but wouldn’t have been both easier, and less "agricultural", to just buy a decent maintainer?

[Bartruff1]

See Battery in or out below....I have switches on several cars and they work fine..the only thing I have to do is reset the clock. I have disconnected and reconnected the battery in my 993 as per the owners manual for long term storage with no problem except the clock so I don't know why you couldn't use a disconnect...

[JFP in PA]

The reasons not to disconnect the battery are fairly well documented; Excellence magazine recently did a detailed article on some of the issues it can lead to, particularly with 911 variants. My personal favorite was the cars that lost fuel level calibration, resulting in having to drain the fuel tank, refill it with a precise amount of fuel, and then reset the dash gauge using a PST II/PIWIS unit. Not exactly easy or fun...............