Top positive review
24 people found this helpful
on February 25, 2011
I forgot to bring my AC power supply on a recent last minute trip. I decided to use 1-day shipping to get a power supply sent to my father-in-law on Saturday (only $3.99, w Amazon Prime) and was reluctant to spend the money for an Apple AC power supply for a day of use and the cheaper third-party AC power supplies had fairly poor ratings. I decided to try this 12V unit to charge the computer on this trip and as something that would be useful in the future.
The unit was at my father-in-law's when we arrived on Saturday. I charged the computer, a 15" Macbook Pro, in the driveway, starting the car every now and then to be sure the battery didn't discharge too much. I also charged it on some short trips in town. This brought the charge from under 20% to around 90%, IIRC, enough for me to use the computer that evening. The next day we headed home. I let my wife drive while I worked on a local copy of a web site that I just took over. Starting at ~30%, the computer was fully charged in 4-5 hours. It stayed charged for the rest of a 10 hour trip.
I have a 12V power supply for a Powerbook G4, with a pre-MagSafe connector, and the Westronics unit is much nicer. It smaller, cooler, has thinner cables, and the green/amber indicator works on the connector, just like a standard power supply.
I had no problems at all and the unit stayed cool. It's not something I'll use often, but it's nice to have it around.
We were without power for a little over 4 days after the recent tornadoes, and I used the adapter to keep the laptop and cell phone charged. Eventually I ran a line into the house so I didn't have to leave the computer in the car. I used a heavy duty 3-prong extension cord. It was drawing 1.55 to 2.1 A so the voltage dropped to 8.5 volts inside teh house when teh engine wasn't running, yet it kept charging.
At one point I was running a USB-powered TV tuner and a USB-powered external drive, and this was too much. It started charging again when I took these devices offline.