I have one of these beasties, and the battery life isn't brilliant. I have looked on ebay to see if I can get an in-car charger, but I haven't had much success.
I am away from home for a few hours every day, and I was chased out of ASDA yesterday, for plugging it into one of their sockets !
ummmm
I have found that most outlets that advertise free Wi-Fi are happy to allow plug ins,but it is polite to ask beforehand. If your uncle's pub has no Wi-Fi then it is a ruddy cheek to steal his electricity.
Sadly manners are on the decline.
ummmm
You didn't mention he hadn't even bought a drink. Double cheek.
Mikey
Why continue with your quest. The links I have provided for you are for the model you displayed in your title OP. An Acer Aspire Switch 10 !! Not the 10E
Acer Aspire Switch 10 Pro
Compatible Tablet Power DC Adapter Car Charger
2 Working Day Delivery
12 Months Warranty
//This Replacement Tablet DC Power Adapter/Car Charger for your Tablet computer enables you to operate your Tablet or charge the battery from your Car Cigarette lighter. If you are running your Tablet on DC power with a battery installed, the adapter charges the battery (if needed) and maintains its charge. When the system is off, the DC adapter will charge the battery and then maintain its charge.//
Specifications
•Power4Laptops Branded Car Charger - Unlike cheaper Car Chargers, Power4Laptops products are CE Certified to guarantee your safety