Tuesday, October 14, 2008

Quirky Porsche Features Killed my 12V Battery

The Porsche 914 has a bunch of "distinctive" features that make it different from many other cars. One is the hand-brake being on the left side of the driver's seat (enabling a "racing start"). Another quirk is that if you leave the turn signal on after removing the ignition key, your tail light on that side stays on. This has the unfortunate side effect of draining your 12V battery.

I've left my turn signal on before, but the combination of the LED tail-lights and the deep-cycle accessory battery kept the car alive. Well, today my 12V battery died. I was able to "jump-start" the car by using my 12V fan-power transformer to activate the DC-DC converter relay. This enabled the DLS-45 DC-DC converter to quickly charge the 12V battery off the main pack. Unfortunately, the 12V battery had drooped down to 3.2 volts which is a very bad sign.

I ran out this evening and purchased a 12V AGM battery to replace it. The non-spill properties of this new battery will also prevent acid splash from hurting the front of the trunk.

For the future, I'm going to find that dang wire (it's in the electrical diagram) that enables the "leave light on when turn signal activated" feature and cut it. I'm also thinking about drilling a
small hole in the side of the DC-DC converter relay so I can easily "jump-start" my 12V battery by simply inserting a non-conductive pin to force the relay arm closed.

The adventures just keep coming. Best wishes to all in the process of their EV conversions.



Andrew said...

This quirky feature is an safety feature, albeit in Germany. The germans often park their cars half on the side walk and half in the road since the roads are so narrow or the sidewalks are so broad!

I'm curious to know what your thoughts about converting an 1996 Integra? It should be relatively similar to your Civic conversion as far as chassis and weight are concerned.

TimK said...

Hi Andrew,

quite frankly I don't know much about the 96 Integra chassis. It looks like other people have converted Integras:


Perhaps you could contact them.
Cheers, Tim

Andrew said...


Last time I looked there weren't any converted integras.

Have you heard anything about advancments in lead acid technologies?
These look promising but still too soon to say.