03-18-2009, 11:15 AM | #46 | |
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03-18-2009, 11:21 AM | #47 |
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It's not that it's out of spec. The problem could be too low power and that could cause a problem.
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03-18-2009, 11:29 AM | #48 | |
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03-18-2009, 01:24 PM | #49 | |
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If you apply a high voltage, several things can happen: 1) If the charging system has a regulator between the battery and the port, it charges ok. 2) If there is sufficient series resistance, the battery will charge fast. Note that this will wear out the battery faster. 3) If the series resistance is low, but there is still a fuse, you'll burn the fuse. A simple fuse exchange can fix this though albeit with some soldering. 4) If none of the above apply, most probably you will damage some IC and/or battery. However, I have not seen any device which does apply to this category in the last 5 years. |
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03-20-2009, 01:50 PM | #50 | |
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There are many cases of devices which have adopted the USB plug format for their cables, but don't adhere to the power standards. |
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03-20-2009, 02:10 PM | #51 |
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As I mentioned above, you need to be careful with these 3rd party chargers.
According to Apple's support site, the "Apple iPod Power Adapter" ( with firewire or USB port) outputs 12V at 1A, which clearly violates the USB power spec. http://support.apple.com/kb/HT2537 I don't know if this is the exact same charger mentioned previously in this thread (it looks a little different), but you need to be sure what the power output is before trying to use these on devices that they weren't specifically designed for. |
03-20-2009, 06:06 PM | #52 | |
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The one I'm talking about clearly is printed with 5V output. It's printed clearly right on the adapter. Last edited by thibaulthalpern; 03-20-2009 at 06:10 PM. |
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03-23-2009, 03:31 PM | #53 | |
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In general though, don't just assume it's 5V. Make sure it's either printed on it or that info is given on the manufacturer's/seller's site somewhere. There are other examples besides the out of date one I found on Apple's site where USB chargers don't follow the spec. |
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03-23-2009, 03:41 PM | #54 | |
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03-24-2009, 10:44 AM | #55 | |
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If it's being sold as a "universal" USB charger, then it's probably fine. If it's a charger that was specifically designed for another device and just happens to have a USB connector on the end, then it's a good idea to verify the power output. |
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