Portable phone charger using RC lipos?

[BrianG]

Originally Posted by MTBikerTim

Hi Everybody

Long time no post.

I have a question and I think you guys have the knowledge to answer it.

I want to be able to plug some of my lipos into a bec and plug them into my phone so I can basically have a portable charger for my phone. What I would like to have though is a low voltage cutoff and maybe even a fuse. Anyone know of a small bec that has a low voltage cutoff built in or a separate cutoff that I could use?

I think I've seen something at HobbyKing like that. But it was just a buzzer/light, not a true cutoff. What you want is something that will literally cut power and external LVCs simply output a neutral throttle signal.

Also, just about all USB chargers need the "programming" pin tied to ground to tell the phone to charge. The chargers specific to each phone has the appropriate resistor built into the molded plug. If you use a normal USB computer cable, the computer (via the driver) tells the phone to charge. Using a normal USB computer cable hooked to 5v won't put most devices into charging mode by itself. I hope all that made sense.

Originally Posted by MTBikerTim

Note to castle. Add a low voltage cut off to your becs. I know it would be dangerous in RC use but just add lots of warnings or difficult to switch on.

For that to work at all, you would have to plug it into the throttle channel. Either that, or just sound a buzzer (better option IMO).

[sikeston34m]

I believe something from this page will answer part of your Equation.

http://www.all-battery.com/protectiv...terypacks.aspx

One problem I see is, you need to regulate the amperage output from your charging device.

[MTBikerTim]

Originally Posted by BrianG

Also, just about all USB chargers need the "programming" pin tied to ground to tell the phone to charge. The chargers specific to each phone has the appropriate resistor built into the molded plug. If you use a normal USB computer cable, the computer (via the driver) tells the phone to charge. Using a normal USB computer cable hooked to 5v won't put most devices into charging mode by itself. I hope all that made sense.


For that to work at all, you would have to plug it into the throttle channel. Either that, or just sound a buzzer (better option IMO).

My phone uses a standard micro usb plug to charge. Thinking about it now you mention it the easiest thing to do would be to copy the wiring in my car charger. So if that has extra pins grounded I will do the same.