I had the Twizy charging overnight that is essentially in my internal garage at home. I woke up to a very pungent chemical smell in the entire house and I could taste it in the air. I had no idea where it was coming from. That evening I set out to drive the Twizy, and there was no ignition. Checked the battery and it was in a complete mess. It had ballooned on two of the long sides and the top. Took a bit s skill to get it out from the vehicle. This, I think, was the smell in the house.
It sill read 12.4v, but not enough power to light the dash!
I managed to accidentally drain the battery twice in two months, I guess this didn't help!
Feel free to recommend a quality battery replacement.