I've had my fair share of battery issues with my 2007 1.3 Copen & have read every single battery-related thread here at least once. Here's a new battery-related mystery that I hope someone can shed some light on. The latest mystery happened while I was swapping batteries as a result of not being able to start my Copen without jump starting with a battery pack, even though 2 different trickle & pulse chargers I use say the battery is fully charged. While lifting out the battery, I pulled out a ground strap that was wedged in between the battery and the battery sleeve--in the attached pic this is labelled as "Ground Strap 1". One end is currently bolted to a part of the car that I don't know the name of. The left end of the strap was the end I found wedged in between the battery and the sleeve. Then there's a wire I've labelled "Ground Strap 2?", which is currently connected and (wrapped in electrical tape) to the negative terminal connector, which is then connected to an isolator valve someone put in for me to disconnect the battery during long-ish periods of non-use. The right end of this strap is bolted to underneath the car frame which you can't see in the photo. My questions are: 1. Should "Ground Strap 1" be connected to the negative terminal connector? 2. Is "Ground Strap 2?" actually a ground strap? 3. Do Copens have 2 ground straps? 4. My recent problems with staring the Copen include when I turn the ignition without starting the engine I'm getting a 9.4V reading off my cigarette ligher-powered voltmeter, even though my 2 trickle/pulse chargers have charged the battery to full. Could the loose Ground Strap 1 be a culprit to my starting issues? BTW, I bought the Copen used, and I can't remember whether "Ground Strap 1" was always wedged in between the battery and battery sleeve like how I found it, nor do I know whether "Ground Strap 2?" was added at the same time by the person who put the isolator valve on.
My German-spec Copen does not come with two ground straps. Maybe the second one is for the dreaded Cobra alarm system?
This is what it looks like. The little red and black wires on the terminals are for my battery charger connector, so just ignore them.
Difficult to make out from your pictures, but if you look at the thickness of the yellow and black cable shown on @Salieri picture, that’s about the thickness of cable you’d expect the main cable to be as it will carry a huge current (amps) during starting. Ground strap 2 looks like it’s running the same way as @Salieri so that’s probably off to the alternator, but Ground strap 1 is clearly wrong as it’s not connected (obvious) but also running to a painted section of bodywork. You’d expect it to run to something more substantial such as part of the engine block or subframe. Your chargers will correctly report the battery status across the terminals but your plug in cig meter is trying to measure the voltage after it’s run through the various points of resistance. If your car was correctly earthed, with a proper gauge cable, the loss is negligible so you definitely have a problem. For the likely cost, I’d take it to a local auto electrician who can sort it properly.
Thanks @Salieri and @BarnsleyRob. Here's a clearer photo so you can compare apples to apples--it should look more like @Salieri's now except that there is another mystery cable that is cable-tied to the thick yellow & black cable and runs to past the bottom of my photo. I wonder if this new mystery cable is for the Cobra alarm... For now, I've moved Ground Cable 1 out of the way of the battery and will probably remove it completely rather than tucking it back into the battery sleeve. Tomorrow I'll connect my spare battery and see if that will start the Copen normally before giving up and taking it to the auto electrician.
All good after putting the new battery in, tightening up all the terminal connections and moving Ground Cable 1 out of the way. It makes a nice change to be able to drive the Copen on a hot sunny day straight out of the garage without having to jump start the car! Knock on wood this keeps up.
Hopefully the voltage reading is much better now which proves you’ve got rid of the resistance issues.
