Dead Battery

I recently experienced my first dead battery in a very long time. This was a big surprise in a car with only 4500 miles on the odometer. But there was a cause that turned out to be my fault. Let me set the stage for this comedy of errors: As you easterners know, we had a blast of winter weather last weekend. It snowed Friday evening and then dropped to around 15-degrees. It continued to snow all day Saturday.

I decided to take the car for a short drive in our neighborhood to see how it behaved in 11-inch deep fluffy snow. When I started the car Saturday afternoon, the starter sort of “bumped” and didn’t start the engine. I was surprised.

A second attempt did nothing. “What?” I was wearing heavy boots that I had not worn in the car before, so I figured the clunky things were keeping me from pushing the clutch in all the way. I made a focused effort to push the clutch all the way to the floor and the car started normally. I only drove a mile, just to see how the VAQ differential felt with traction control on and off.

Although the snow was nice and fluffy, the 10-degree overnight temperature would ensure an icy mess the following day. People in my area are notoriously terrible drivers during icy conditions (or anything other than clear and dry, actually). Even worse, road surface preparation and snow removal are barely practiced anywhere other than the Interstate.

The consequence is that we wind up with a bizarre combination of drivers who think that 5mph is as fast as can be safely driven (and in the left lane to boot), others who don’t understand that wildly-spinning wheels don’t grip (“How does everyone just drive around me? Clearly, I need more accelerator!”), and those who think it’s still okay to drive their normal “55 in a 45” on rutted ice (or 70 in a 60). Any of these drivers can cause an accident without actually being involved themselves. As a result, I usually choose to stay off the roads for the first day or two after an ice event.

The battery was completely dead when I went to drive two days later. My car has keyless access and no visible keyholes. So accessing the interior could have been a real adventure with the owner’s manual locked inside. Thankfully, I had already read about how to remove an access cover to expose a keyhole.

But there was a new problem: the car was positioned in a way so that none of my other cars could be used for a jump-start, it was blocking any other car from exiting the driveway, and the deep snow precluded me from driving any of them through the yard to go around. I figured I would just roll my dead GTI into the street, but the (dead) electric steering wheel lock meant that my only option was to roll straight into the street, blocking it, until I could get another car out for the jump job. Thankfully, I do not live on a busy street and no one was inconvenienced.

I haven’t used a set of jumper cables in a LONG time. In fact, I’m not quite sure where I stashed my other set. As luck would have it, my new GTI was delivered with VW’s “Roadside Assistance” accessory, which includes a set of jumper cables.

They were surprisingly long and the red and black cables were completely separate. Those are two nice features. Even better, the GTI includes a “jump point” for connecting to ground without having to use tricky little terminals (Volkswagen battery terminals are tight to reach with bulky jumper cables).

The car started immediately and we cleared the street within minutes. I drove the car for about 20 minutes to recharge the battery and then parked in a position to enable another jump the following morning, just in case.

I mentioned earlier that this was my fault. I have a few accessories that stay plugged in. Two of them are on switched outlets and were unlikely culprits. I unplugged them just to be certain.

But I had also left my OBDEleven dongle plugged into the OBD port. This had not given me a problem before. Last month, I parked the GTI for a week with the dongle plugged in with no apparent problems. So I wondered if the cold had been a reason.

The colder weather was a factor, but the car itself played a role, too. Apparently, since my car has keyless access, leaving the dongle plugged in can lead to unwanted activity. The dongle itself doesn’t consume much power, only 45mA, but it “talks” to other modules that do. The result was a car that never slept.

Still, how did I get away with this for a week when I traveled to CA? My best guess is that the dongle actually sleeps when it cannot detect my phone. That may be why a day at the office or a week out of state hadn’t drained the battery before.

Since I was home last weekend and within 50 feet of the car (and dongle) for the entire two days, my guess is the dongle, the phone, and the car’s various electronics modules had the best party they could without actually driving the car. The battery was fine overnight, but the party was over after 36-48 hours.

My OBDEleven dongle is unplugged and the car is back to normal, hopefully with no battery damage. LESSON LEARNED. I used an OBD dongle in my Mk6 because it lacked any sort of gauges. The GTI is full of them… all except a VOLTAGE gauge, which made diagnosing a potential alternator problem less convenient. Oh, well… all is good now.

Update: Some people carry a “jump pack,” which is essentially a separate battery that’s used to jump-start a dead car. One challenge with jump packs is that they, too, need to have their charge maintained.

Rather than a jump pack, I purchased a SuperCap2 capacitive jump starter by Autowit in 2020. It stays in the car uncharged until it is needed. Then, even with a “dead battery,” I can connect the SuperCap and wait for it to charge. In my case, though, I can charge it even faster by connecting it to my auxiliary battery. Once at 100%, it can start engines up to 8.0L. Have a look and see if the SuperCap2 can work for you!

Fully Charged,

Scott