Hi guys!

 

It's been a while, since my Fabia -03 Estate Comfort has been running kind of smoothly. Except for today. I went out and when I unlocked the door I felt that the lock barrel went old school (manual) on me, i.e. I got no central locking assistance. Worries raised immediately, and entering the cabin my fear came true. Dashboard was dead, and when I turned key in ignition nothing(!) happened. Now, last 2 days has been pretty cold (northern Sweden), and today when I found this issue the thermometer showed -17° C. Pretty nasty.

 

I drove car and it started perfectly just yesterday, so it either got empty late last night, or during the night, or this morning, just before I came out. Anyways, rumor has it that car batteries freeze when they're empty, so I'm kind of worried. This is a reputable battery brand, and we bought it new just August 2013, so the battery is not even 1½ year old, would be terrible to just have to throw it away.

 

I have a basic car charger from Clas Ohlson (18-2692) and connected it. After only a minute or so I tried starting the car. No problems. However, I noticed that the charger went from the "Charging" indicator diode to the "Full" diode, just ~10 seconds after setting it in charging mode. Pretty weird. We suspected it could be due to really (too) low voltage in the battery, so since the car now started, me and my lady took it out and drove on ~4000 RPM for two and a half hours.

 

Then we went back to our parking lot, I put the charger cables on again, and watched it. Gosh. Maybe 20 seconds this time, but then it went from the "Charging" diode and back to "Full". It's no way in friggin' hell (pardon my French) that the battery could be filled up with juice this quick. My guess is that what could very well be 12 hours in -15 ° C could somehow have damaged the car battery. Anyone here with real life experience, that could tell me what my odds are like?

 

The only way I could see this happening and being a battery fault rather than a charging fault would be if you have a bad cell.

 

Do you have a multimeter?

multimeter first then (12.5-13+volts)   adjust down for colder, then I would remove the main leads and clean the posts of the battery,   a battery with only 1/3 charge will freeze@ approx. -20'C  1 weak cell may well have been damaged  keep us posted

Had a friend come over with a another charger (CTEK ZAFIR 45) and we thought we'd have it a go. However, first thing he did was grab the clamps on the battery, immediately judging those two be loose. He was right, the positive lead as well as the negative had some play back and forth, i.e. it was not 100% fastened, like it's probably supposed to be. Some tightening with a 10 mm key later he connected his CTEK charger and it lit up; then like <10 seconds later the LED indicator switched to reading fully charged. Yeah, my friend told me, it's simply because the battery is in fact fully charged, and was so all the time, and the only reason that all electricity was stone-dead was because that main connector was somewhat loose. He said he could immediately tell, because engine started immediately when turning the key, the same was it had done after that I had just put my own charger on there at first. The reason it started working again was simply because by connecting the clamps of my CoTech charger I had touched the clamps so that it had contact. The mystery was now solved.

 

Well, all good, but to be honest, I'm still not 100% safe and certain. Like, for as long as I can recall, when being on idle, after putting in 1:st gear, the front lights has begun to flicker (going dim) when just releasing the clutch super-slow, i.e. crawl-driving. For the lights to not go dim, you need to press the accelerator meanwhile, like when you're about to get going real quick. This is the only car that I have driven that has had this behavior. Since buying it, I've installed a sub-woofer in the trunk, and also two 100w aux lights in the front. I hardly ever use the lights, but the sub-woofer is always on, but the mentioned behavior was present before I installed the sub, and has not increased since, so I don't blame that device.

 

I have some strange intuition feeling telling me that something is actually wrong with the battery. I mean, sometimes I'm sloppy e.g. when making a quick stop with someone somewhere, I then leave the 400w sub-woofer on after engine is turned of, listening to music, which of course drains the battery pretty quick. Although I do this occasionally, I have never had a battery failure, ever. It's kind of weird that now it happens all of a sudden, wouldn't you say? Also, judging from my half-sloppy behavior with listening to music with car turned of, it's pretty logical to me that my battery should not be like 99% full. I mean, the fact that both these chargers we tested went from "Charging" to "Full" in <10 seconds after connecting, and I haven't done any "supportive charging" (other than driving the car) ever. Well, there was this time in September, actually, I charged the battery full, but I must have drained so(!) much after that, so, it's weird.

 

It'll be interesting to see if the car starts tomorrow.

Thanks for all your input guys, I'll keep you up to date.

Make sure the battery earth connection to car body is clean and tight.

 

And check that the two thin wires coming from a connector on the alternator to a connector on the front of the gearbox are fully intact (both sides of the connection at the gearbox).

Also use a voltmeter to test the voltage across the battery terminals with the engine idling, at full operating temperature. Less than approx. 14V needs investigation. 

 

Edit: a '400W' subwoofer, in reality is unlikely to be taking anywhere close to what might be expected to be around 28 amps at 14V. Car audio stuff is usually rated with more emphasis on 'sounding like a lot' than actually having any basis in objective reality. 

Second edit: following your link to the sub, and looking at the datasheet, it's only 100W in real power, 7 Amps from your electrical system, and that only when it's at max volume with horrible distortion levels.

Big thanks for your input, guys!

 

I'll check the ground connector on the chassis tomorrow @TMB, although I think it's alright.

I seem to recall that I have checked that one around this summer when I installed the subwoofer.

 

Actually @Wino, you are perfectly correct, it's 100w RMS. I wrote down the "max output power" because I have yet to learn the difference of RMS ("real expected output") from the maximum in specs, although after reading some articles I have some idea, but I reckoned that perhaps it will draw as much as 400w from time to time. Nice thing you informed me about reality, because I've been thinking about that a lot. In fact, somewhere in my head I had a feeling that it was like you explain. Late this autumn I was riding and all of a sudden subwoofer wasn't delivering booms from the back. I pulled over checked in the hood. As it turned out, the cable shoe from the short fuse box cable slid of the cable, resulting in the + from the battery touching the chassis, and the 30 A fuse that had come with this little subwoofer kit had blown in a split second. I wanted my music back, and I didn't have any more 30 A fuses, so I put a 15 A fuse there, and thought that "It will probably burn in next song with a heavy bass line, but just until I get around buying a new fuse", and so I drove on, with a 15 A fuse and subwoofer running again. This was like five months ago, and the 15 A fuse haven't blown so I haven't bothered replacing it for a (recommended) 30 A fuse. So yeah, TLDR; the subwoofer is probably consuming far less than 400/12=33,3333 A.

 

Also, thank you for the tip about the connector between alternator and the front of the gearbox. I'll check it first thing tomorrow. Made me curious though, I have never heard of a connector between these two spots. I mean, the gearbox? I don't get it! Anyways, I'll check it. Also, like half an hour ago I found this amazing forum thread from a Google search on my issue; look here. It's like ten years old so I won't revive it but it illustrates my symptoms kind of on spot, except that this happened to my car overnight, and not over a couple of months. Anyways, I know more about car batteries now than I did one hour ago.

Made me curious though, I have never heard of a connector between these two spots. I mean, the gearbox?

 

It's not connected to the gearbox, it's just a bracket holding the plugs which is bolted to the gearbox.

 

Like this...

 

RMS is actually Root Mean Square output. To get from a headline peak figure to an RMS you divide by the square root of 2 (Use 1.41; it's close enough).

 

Meantime, at your dimming headlights issue, check the alternator belt tension, and if you have VCDS check the health of the steering angle sensor.

RMS is actually Root Mean Square output. To get from a headline peak figure to an RMS you divide by the square root of 2 (Use 1.41; it's close enough).

Meantime, at your dimming headlights issue, check the alternator belt tension, and if you have VCDS check the health of the steering angle sensor.

Or to get rms times by 0.707 which is easier on a non scientific calculator. So your 400w peak subwoofer is actually 282.8w rms

No, read the datasheet in the link supplied in his post. 100W RMS, in black and white, 400W "Peak Music Power"  that's a kind-of made up unit in the audio industry, with no scientific basis, I think.

No, read the datasheet in the link supplied in his post. 100W RMS, in black and white, 400W "Peak Music Power" that's a kind-of made up unit in the audio industry, with no scientific basis, I think.

I admit I didnt check the data sheet. Jist went solely on the 400w peak as if it wasn't an inflated marketing hype. I am technically correct if it was a genuine 400w peak though

Or to get rms times by 0.707 which is easier on a non scientific calculator. So your 400w peak subwoofer is actually 282.8w rms

You say "poh-tay-to", I say "poh-tah-to".