Experienced this earlier in the week (had to leave my 245 vRS unlocked in a train station car park all day 😬) 

 

I have keyless on my Octavia and the battery in my key fob died on Tuesday without warning. Started the car, drove half an hour to the station. Stopped car, wouldn't lock, fob completely dead. No time to read handbook / search how to do it manually, so left car and bought a new battery before I came back. 

 

Subsequent searches have shown it's a common problem and it's highly recommended to change batteries every year. I've checked both spare fobs (unused, in a drawer well away from the car) and both were dead too! 

With KESSY they take CR025 batterys but a CR032 battery will fit and last longer.  Mine needed replacing probably every 5-6 months and I found that cheap batteries drained quicker, so put a decent Duracell in it.

 

Could you not have locked via the Key - My 16 plate with KESSY had a key built into the remote, then remove the cap where the door lock would be and you should find it nestling underneath.

Thanks for the tip re: the batteries, I look to replace them with that type next time. 

 

I knew there was a way of locking them with the key, but it wasn't immediately obvious and I didn't have time to look at the handbook before catching the train. It's a regular journey so I cut it fine.  I read about how to do it, on my phone, as the train was pulling out of the station. 

They don't seem to last long at all and I find they are very quick to report a low battery warning on the dash even with nearly 3 volts left.

 

It was a struggle to get a CR2032 battery in there (dealer did this before I purchased the car) and it resulted in the battery door denting the battery inside. Not sure I recommend that so replaced mine with Duracel CR2025's.

 

Amazon seems to be a place to get them much cheaper than supermarkets.

 

Yes mind did this to me once, manged to unlock the car to get in manualy but then cound start the car!

luckily i was close to home so got a lift back to get the spare.

Reported this to the dealer when it went for service & they replaced the batteries in all the fobs FOC as car still in warranty.

My kessy battery needs changing around every 12-18month depending if it is my key (used daily or the spare).

However, when the battery is low, I've always had a warning on the Maxidot when I open the car that the battery is low & the fob buttons always worked to lock/unlock the car without kessy.

The warning appears at least a few times before the kessy function is disabled & I had to use the fob buttons.

 

Maybe in an emergency you could try the old walkman battery trick & remove it from the fob, roll it in your hands to get it warm & reinsert to give you another few minutes of playback?