Tuesday, December 28, 2010

solar iphone charger for bicycle touring: not as simple as I thought

Yes, I got a solar charger for christmas. Great! But it took a small extra purchase to get it working.

What did I want? A stand-alone charger that didn't need to be connected to the iphone. Yes, on a rest day I might put it on top of the tent and charge it up. But more likely I would use it as an emergency charger.

I wanted to strap the charger to the top of a pannier bag without the phone. Don't want the phone on, and don't want the drama of rushing for the phone in the event of a sudden downpour.

Asmann charger seemed ideal. Two AA rechargable batteries, USB. Two modes "IN" charging and "OUT" powering by the USB. You can charge the battery pack via the USB port also. Very convenient.

So I charge it up. Connect with the Apple cable (iphone USB) : nothing happens. Try the same setup on Nokia with the Nokia cable. Works fine.

Back to the store.

Turns out that iPhone is picky about the connection. This is some weird thing the Apple engineers are doing.

The helpful guy at the shop has a non-Apple lead that works fine. You can see it in the picture. It's a "Watts clever" connector. So third party connector works, Apple one fails. No, I don't understand it either.

So for around $A70 I have what I wanted. I'll report back later on how it goes as an actual emergency supply for the iphone.

I got both items from Jaycar (Frankston, Australia store). They were very helpful.

 Update 26/4/11

Unfortunately the solar panel here is so small that it is very difficult to get a decent charge. I will be looking into a larger rechargeable battery as a better option. A roll-up solar panel that is larger might be a good option.

For better, more reliable options have a look at http://mareebiketouroz.posterous.com/sustainable-energy-for-your-bicycle-tour-or-l

Update 10/5/11

I now add a larger battery to this setup. So the solar charger charges the larger battery (iphone extra battery) and the battery charges the iphone. Works better and I can use the iphone cable with this setup. But still the panel is too small.


Andrew said...

My understanding is the iPhone expects a charger to comply with the USB battery charger specs whereas many cheap power supplies just provide 5V on the power pins and hope for the best (which to be fair often works). What your 3rd party cable will be doing is shorting the data pins (with some resistance between them) so the iPhone detects your battery pack as a compliant charger. Google will find you the circuit diagram if you are interested.

Andrew Jennings said...

I now ride a Vivente World Randonneur with a dynamo on the front hub. I find that one day's riding will charge battery enough for a week of using the iphone, including playing music and taking photos.

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