Friday, October 17, 2008

Fixing the Aux Battery Killer

I took the time today to research the 914 wiring diagrams and find the annoying connection that leaves my tail light on after I turn off the ignition switch.

If you remove the front dashboard cover and look under the steering column, you should see two connectors. Remove the right one as shown above.

On the rear of the connector should be three wires colored grey, grey/red and grey/black. Snip the grey one and seal BOTH ends with heat-shrink tubing or end-wire crimp. After cutting this wire, you will no longer have the feature that turns on your tail lights when you leave the turn signal lever activated. It's important to protect both ends because one is tied directly to the 12V battery through a fuse and the other gets 12V when you turn the tail lights on. You don't want either of these touching any part of the grounded chassis.

I really hope I'll never kill my 12V battery again by leaving on the turn signal. Other critical functions (like the emergency flashers) still work fine.

Okay, back to driving and finishing up the open-source Civic project. Best wishes to all.

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.