Engineer Ken Shirriff, who has previously torn down and compared the safety and engineering behind dozens of USB chargers
, iPhone chargers
and MagSafe chargers
, posted on Monday the results of his investigation into counterfeit and genuine iPad chargers
. Unsurprisingly, his findings fall in line with warnings issues on his previous studies: counterfeit and cheap knock-off chargers can be dangerous due to shoddy construction and inadequate safety measures.
Real (left) and fake (right) iPad chargers
In the latest report, Shirriff compares a $3 counterfeit Apple iPad charger sold on Ebay against a $19 genuine Apple charger. From the outside, a typical buyer would be hard-pressed to know that the counterfeit is not a genuine Apple charger, but the differences are more obvious once the unit is cracked open.
Immediately, he found that the fake charger was in fact a 5.9A charger, about half the ampage output of the Apple unit. "The genuine charger on the left is crammed full of components, fitting as much as possible into the case," said Shirriff. "The counterfeit charger on the right is much simpler with fewer components and much more empty space. The Apple charger uses larger, higher-quality components (in particular the capacitors and the transformer), adding that readers "will see that these have a big effect on power quality and safety."
A teardown of the counterfeit revealed far less insulation, lower-quality components, no temperature sensor to shut down the charger in case of overheating, no built-in ground connection, and other issues -- including poor construction quality and fewer components. The Apple charger, by comparison, was packed solid, with many more components and much more insulation between components.
Much more importantly, in addition to delivering half as much power, the counterfeit charger also offered very "noisy" output with a lot of spikes, that could prematurely shorten the iPad's life. Much of the extra circuitry in a genuine iPad charger is there to filter and condition the power to be consistent and clean.
Clean power from the genuine Apple charger (left)
Overall, Shirriff found that "Apple's charger is expensive compared to other chargers, but is a high quality product," saying buyers "should definitely stay away from the cheap counterfeit chargers, as they are low quality and dangerous. " He went on to say that "if you want to get an Apple charger without the high price, the best way I've found is to buy a used [Apple] one on eBay from a US source." Name-brand non-Apple chargers were also considered by Shirriff to be generally safe and of good build quality.
"In any case, the iPad charger is an impressive piece of engineering with a lot of interesting circuitry inside ... overall, you mostly get what you pay for; even if you can't tell from the outside, there are big differences inside the case," he concluded.