hook a cell phone up to my e-bike battery

This is probably a dumb question but can I just hook the raw wires off a BEC to a micro USB cable to make it into a cell-phone charger? I use 12s lipo and I see that Hobbyking sells 12s BECs.

A phone contains a decent bms so will usually suck up 5v quite happily. That is what usb provides. Don't provide too much current though. We know all about charging too fast.

The BEC i showed in the picture is capable of outputting 7amps. I presume that would roast the socks off a cell-phone.

Does the cell phone dictate the amperage draw or does the charger itself regulate the amperage output?

parajared said:

The BEC i showed in the picture is capable of outputting 7amps. I presume that would roast the socks off a cell-phone.

Does the cell phone dictate the amperage draw or does the charger itself regulate the amperage output?

Click to expand...

That's a question I've always wondered about. Do all/some cell phone regulate the charging rate or is it really the chargers amperage doing it? My bet it's almost always the chargers amp rating. Just guessing but isn't that why they advertise cell phone "quick" chargers. I see people all the time buying replacement chargers with no idea what size they need or are buying.

Anyone have a true answer? And how would you know if your phone is controlling the charge rate?

Bob

Okay I have revisited this.
Phone's do regulate the charge and it will take maybe half an amp. This is because your not using the data connection. If you short the data wires with the appropriate resistor your telling the phone more is available. Perhaps 1A as most phones like, Or 2.1a as tablets like. It's not quite so clear though. Apple and android have different standards and might make available as much as 2.4A and use different resistances to explain this to the device.


This clears up an issue I have. My car charger can't supply enough to keep the screen on. You can forget satnav or any other app. Just one cable does work properly. That I had to loan out when I arrived on a job to find the fault was a bust cable. It's been killing me not having a car charger since.

Thanks,
I think I will buy a BEC and give in a try.
I'm pretty sure I have an old beater phone I can try this on before I connect it to my "real" phone.