The recent tragedy of the three climbers on Mt. Hood made me think how cell phone batteries could be “field recharged” in emergencies where one dose not have access to household current or a car with a power port.
A hand-cranked dynamo…something that can easily be stowed away in a backpack. Hold it in your hand, plug in the cell, and crank away.
Is this feasable? Already on the market?
I suppose the biggest issue would be some sort of capacitor to slowly charge the phone, as there’s a limit to how fast you can pump charge into a NiMH or Li battery.
Unless you want the user to sit cranking for a long while. (most phones charge properly over a four hour-ish period, you could cut it down to fourty five minutes without too much damage so long as it’s not often)
I suppose in an emergency damaging the battery is not really an issue.
Just checked the output of a few mains chargers around my shop, and the highest one I can find is 800mA at 6V. Perhaps an electrical person can tell us if thats more or less than the cranking radio they released a few years back.
Such things already exist. I haven’t bought one yet, but I hear good things about the sidewinder phone charger.
Yep, it’s been done. Of course, you’re dealing with guys who celebrate shaving ounces of weight off their gear, so I don’t think they’ll be in the market unless it gets smaller and lighter. But there’s this, too.
That’s only 4.8 watts, well within the hand cranking ability of a human. You can easily keep that up for an hour or two without tiring.
You wouldn’t have to completely recharge the battery, either. Just enough charge to make a phone call.
Calling on a cell phone from near the top of Mt. Hood works because it’s a clear line of sight to cell phone towers way down off the mountain. It is more of an unintended anomaly than deliberately set up to work that way.
Cell phone connections by and large do not work once you get off the beaten path. We don’t know if the Kims had a cell phone or not when they got lost in southwestern Oregon in early December. It would have made no difference if they had; there are no cell connections there.
And in the worst of the storms, making contact wouldn’t do much good as the rescuers couldn’t reach them in those conditions. Making contact isn’t always a guarantee of rescue. It’s nice, but it’s better to be self-sufficient in the mountains and/or not get yourself into those situations.