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Phone charging with power supply USB port


New Member
I wrote a thread about this problem earlier, only I have Samsung Galaxy S4. The S4 and SP2 charging had no problem.
First off: I have tried different usb-chargers, phones and sockets.
1. charger: The SP3 and S4 (and S4 active) would not charge simultaneously
2. Charger: Sometimes it works, sometimes it doesn't. I sometimes get it to work if i plug them in and out a couple of times..
I havent bothered to ask for a 3. Charger from Microsoft

Btw. is this looking like a Samsung problem(?)

Ben Freedman

New Member
I have had this same issue, where when plugging my note 3 into the USB port on the Surface charging brick, both the surface and the phone blink on and off charging every 10 or 15 seconds or so...

This doesn't always happen. Just sometimes... Because of this, I've basically stopped used the power brick to charge my phone. Oddly enough, I can use the SP3's USB port to charge my phone without an issue..




My Galaxy s4 + SP3 is charging with no issues.
Do you are on European network 220V or US 110V?

I tested plugged in 220V


New Member
What is the power draw of your phones when charging? The USB port is rated at 1mAh I believe and if your phones are anything like mine their default chargers actually charge at 1.2mAh or higher. That could be an issue as well. I think the Samsung charger is a mini USB 3 version for data


New Member
I have similar issues, except with my Lumia 930, for some reason it seems to work fine with some USB cables but not with others. Some cables cause the power on my Pro 3 to dip every few seconds. I didn't think there was that much difference between USB cables, but there must be or I wouldn't get this issue.


Staff member
Some of the confusion about chargers that work or don't work, have enough current, or don't have enough current comes from this:

Generally, smartphones require more power to charge when the phone battery is low.

When the battery is *very* low, there may not even be enough power to supply the phone operations, due to the phone also trying to charge the battery.

When the smartphone battery is not low (varies by phone), the charging control circuit generally starts trickle-charging, to protect the battery.

So a charging circuit from a transformer (brick) or USB port that is able to charge a smartphone with 50% battery power may not work very well with that same smartphone at 10% power.