I had a little experience of this type of thing over the past fortnight. Here in Ireland , if 3 flakes of snow fall in a 24 hour period the entire country shuts down
I have a roughly 12 mile drive to work. The last bit is up quite a steep hill with a left turn mid way. On several mornings this road was blocked with stuck cars and vans and everyone spinning wheels and ending up in the ditch. I just stopped , turned the key to acc and listened to the radio while they sorted themselves out. The heater would have ran a full 24 hours from the traction pack in that scenario. I'd have died of boredom before hypothermia set in.
Of course we all know the big disadvantage of lead acid in an ev is weight. Last few weeks it was an advantage as I had the only rwd car that could make it up that hill. I pulled 2 people out of the ditch with it. Including one obnoxious soul who had made a point of calling my car an abomination on several occasions. Not so talkative now.
The journey home in the evenings was a real tour de force. One particular night getting home took 2 hours. Heater on , lights on , creeping forward , diversion etc etc. Not a problem. Did i check the soc gauge? yeh , but no more so then if it was a petrol car.
I'm not saying those experiences are the be all and end all but just my own thoughts and findings.