Charging a Phone With a Lower Current-Rated Power Supply - Page 1
Forum section: electronics / beginners

author: sspj9
author_rank: Contributor
timestamp: December 23, 2019, 12:58:13 am
content: My friend's iphone charger exploded. She was charging an iPad with it.Since the iPhone power supply has a current rating of 1A while the iPad charges with a 2A current, many are blaming her that she didn't use the iPad charger since the iPad drew more current than the rated of the supply thus causing it to overheat and explode.As far as I know the current rating of the charger used is simply the maximum current that it can deliver to the device. If the device can draw 2A, fine but it doesn't mean it needs to draw 2A by force. If the charger can only supply 1A than it is going to charge the device with 1A which obviously takes slower for it to charge than if the charger could provide 2A.What is the correct reasoning please?

author: atmfjstc
author_rank: Regular Contributor
timestamp: December 23, 2019, 09:08:46 am
content: It really depends on the exact design of the charger, really. A current rating of 1A doesn't necessarily mean that the charger will do any regulation to ensure the output current stays at 1A if the load is too low. It just means that as long as the current stays below 1A, the charger will continuously deliver the desired current at the correct voltage, without overheating or cutting out automatically. Which of the latter happens on higher currents, again, depends on the design of the charger and/or load.While normally I would expect genuine Apple products to at least not blow up under such a scenario, I do vaguely remember some videos about old Apple chargers being crap, especially the super compact ones. And if you have a counterfeit charger, all bets are off, of course.

author: Siwastaja
author_rank: Super Contributor
timestamp: December 23, 2019, 09:26:51 am
content: When you know that the load may take 2A, you need to use a power supply rated for at least 2A.Proper 5V USB supplies that are meant for charging, however, tend to work so that the output voltage drops when even slightly overloaded, and the phones tend to understand this as a "tip" to reduce the current they draw, so usually nothing is damaged. Even if the phone didn't understand to reduce current draw, proper power converters should have protection so that they would automatically turn off instead of blowing up.The supply blowing up is of poor design.

author: GLouie
author_rank: Regular Contributor
timestamp: December 23, 2019, 08:45:00 pm
content: The small Apple 5W charger is supposed to be well designed:http://www.righto.com/2012/05/apple-iphone-charger-teardown-quality.htmlI have not personally seen a problem with interchanging Apple devices and chargers - they just charge slower with a lower power charger. I find it hard to believe they would be designed to ignore power limits and burn up.See also the comparison and additional teardown links, including counterfeits:http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.htmlYes, you could have had a defective unit that burned out, but counterfeits and clones abound. Is the charger under Apple warranty?