The universal laptop power supply for all lap top chargers is a maximum of 65 watts and the efficiency level will be mentioned in the charger itself very close to the watt specification.

My sister bought a new lap top online directly from the web site. She was staying in a ladies hostel and the power connections were improper leading to great fluctuations in the power and while purchasing we had the warranty card and the dealer gave us the warranty card along with the receipt of the bill for the lap top. She used to charge her lap top in the plug point and within six months of the purchase, the HP battery charger got smoked due to improper universal laptop power supply.

My sister was unable to work in the lap top and gave me the entire lap top set to repair it within two days. I gave the lap top to the dealer and also the warranty card. The dealer after inspecting the lap top with the technician said that I had to replace laptop battery as the battery has burnt due to power fluctuations and improper universal laptop power supply.

I said to him to replace laptop battery using the warranty card and the dealer said that burnt damages are not normally replaced using the warranty card but any how agreed to send the lap top to the head office to replace laptop battery. He asked me to come after 5 days and I left the shop.

After 5 days I made a call to the dealer and enquired him whether the lap top has come after replace laptop battery. The dealer said that the burnt damages cannot be claimed and I got angry at this reply. To add more, the dealer said to come over to the shop and pay 75 dollars as service charge and transportation charge to service the lap top. I never spoke a word and went to the shop and got back the lap top and decided never to visit or refer any friend to the dealer.

Then I went to computer wholesaler and replace laptop battery by purchasing a new HP battery for 250 dollars and checked for universal laptop power supply it in front of the shop personnel and gave back the lap top to my sister after nearly 10 days and advised her to use a different plug point to charge the battery.