A question to the electronics geniusses out there. I was gifted a small quadrocopter, a nice toy. This thing runs on a 3.7V LiPo cell. The charger that comes with it is USB-based. Charger in laptop USB port, LiPo-Cell conncts to charger, charging occurs. Now I didn't want to use the laptop to charge these, and I have two tablet charger wallplugs, that give out 5V via USB, at 2000mA. So tablet charger wallplug in plug, USB-charger in USB, LiPo-cell connected...no charging I turned the wallplug around (we can here) charging works. What the heck does the wallplug do different than the computer USB-port (apart from beeing stronger)?
Retestet it with a different USB-Charger. Similar effect. This is a 4 cell charger, so I connected 4 cells. With the wallplug, one, maybe to cells would charge. On the computer USB-port, all cells charge. 4 Cells means ~1500mA, so the wallplug should be doing fine, while the computer-USB-port should take a lot longer. I don't get it.
Tested with two different tablet wallplugchargers. Same effect Both charge a tablet or a phone or a powerbank fine.
Sounds to me like the battery charger is doing actual USB negotiation for the power - i.e. if you do an lsusb (or your operating system's equivalent) it'll appear as a device. The Sony DualShock controllers do the same thing, which is massively annoying: you can charge 'em by pluggin them into a laptop, desktop, or the PlayStation 3 itself, but they won't charge from a smartphone charger or battery pack.
Ah? Didn't know that, learn something every day. Though I can't imagine why they'd build something like that into a cheap-as-chips charger.
I assume that by turn it around, you mean flip the wall plug around swapping the live and neutral? It's probably a quirk of auto-ranging power supplies. I have a charger for my asus TF101 that does 15V and 5V and it works fine either way in Canada, but when I was in Australia, it would only charge my phone one way around. I think the 15V (for tablet charging) actually worked either way around, oddly enough.
Yes thats what I mean. The weird part is, the tablets charge just fine, no matter which way the plug is in the wall. And my tablets charge by 5V usb.