[CWO4MKC]

Good morning all,
I ran into a situation where I left my lights on (the don't shut off automatically) while the car was parked for the week and came back to a fully depleted battery. The surprising part for me was just how difficult it was to get the car started and a few issues that I ran into by being impaitent.
It took along time, best guess about 30 minutes before the engine would even roll over. I was hooked into a 2011 Golf TDI no less and also tried a very stout 12VDC jump pack. I made various attempts to start the car when it seemed that the amount of time I waited was more than reasonable. It wasn't and caused some pretty spooky electronic indicators to flash irratically, my displays to brown out etc. even after I stopped the crank cycle. After I got the car started (luckily I hadn't fried everything) I found the glow plug indicator flashing and had to make most of the trip home without cruise control and a few other items. Fortunately for me at the five hour mark I shut the car off for a few to get some coffee and when I came out to restart it EVERYTHING returned to normal.
So my advice would be DON'T rush the process. It is warm out and I would say that if I had been wise enough I wouldn't have even tried to crank the car at all for about 30 minutes. In the cold it would likely be worse.
The book doesn't have any special instructions regarding the situation. Even though my connections were very good I found it surprising that it took sooooo long!
Thanks to Kevin for sticking around and giving me a hand. Matt

 

[Seatman]

Lol I've seen that sort of stuff before when the battery's got that flat, strange lightas etc, dashboards flashing, all the warning lamps going on and off, I think you might need a new battery at some point if it's gotten that flat though, I think it can damage the plates inside or something and they just don't hold a charge the same anymore.

 

[chittychittybangbang]

If your battery is fully depleted, it's best to put it on a charger for at least a few hours. Just hooking it up to another car or a jump charger won't be enough to start the car as you've found out. The alternator is designed to maintain the battery, not charge it up from dead. Jumper cables work but it's best for a car which is only a little low.

TDI are also designed to not inject fuel unless the cranking speed is high enough so low cranking means you don't even have a chance for engine start.