Hi, does anyone know whether laptop battery chargers/power supplies have a built in surge protector?
All appliances have the equivalent of surge protection. Long before the IBM PC existed, international standards required a 120 volt electronics to withstand surges of up to 600 volts. Intel standards for computer now require over 1000 volts without damage. All other appliances also have equivalent protection. Otherwise we would all be trooping to the hardware store daily to replace clock radios, dimmer switches, dishwashers, and smoke detectors.
So that a rare and typically destructive surge does not enter the building, we earth only one 'whole house' protector. Therefore protection inside all appliances is not overwhelmed even when a direct lightning strike occurs. A protector so effective that nobody would even knows a surge existed. No damage even to the protector.
Once inside the building, a surge hunts for ground destructively via appliances. Overwhelms internal protection. We install one 'whole house' protector for a surge that typically occurs maybe once every seven years. Protection inside appliances makes other lesser transients irrelevant - even in eletronics long before the IBM PC first existed.
Not all surge protectors provide effective protection. Anything performed on an appliance's power cord is already inside the appliance. Those adjacent protectors are missing one thing - a numeric spec that defines protection from each type of surge. Most only hear the phrase 'surge protector'. Then automatically assume it is surge protection. If it does not list that protection, specifically (with numbers), then the protection is probably near zero. Enough to claims surge proetction. But still near zero surge protection.
A UPS typically is as close to near zero as possible. Most claim that UPS provides protection only on subjective hearsay. No spec numbers is the first indication why that tiny part inside a UPS does not stop what three miles of sky could not.