Solar charger (was Re: News Openmoko Shop Pulster)

clare johnstone claregj at
Sun May 31 07:38:52 CEST 2009

On Sun, May 31, 2009 at 9:26 AM, Peter Harrison <cheetah100 at> wrote:
> I thought I would provide some of my experience with using solar
> power. My experience involves using a 12v panel. You can get 12v

Hi folks, Another source for  our part of the world is    you can select "batteries and chargers/chargers" and find a
solar panel car charger.  Also dc-dc converter many kinds, with prices.

> panels from all kinds of places. In order to step down 12v to the
> required 5v you will need an efficient dc converter:
> Do NOT use a 5v regulator as you will dump half the power directly
> into the regulator as heat. That is not only a waste of power but
> potentially a fire risk. From there you can get a connector to the NEO
> USB and simply wire in the power. I actually had a PhidgetServo board
> and wired the power directly into it. To get my NEO to charge I had to
> turn on the external charging and set to 500ma.
> The point here is that you will need 5v x 500ma = 2.5W in order to
> supply that kind of juice. This power is only available in full
> exposure. It also does not account for any conversion loss. I
> recommend using a 5W panel. Obviously if you can get a 6v or 5v panel
> you could use a basic regulator without much trouble.
> This is not a kind of panel you can carry around easily. Some
> 'chargers' on the market have such low surface area they have no
> realistic chance of supplying the kind of juice required for charging
> in a realistic time frame.
> Here is panel I'm using:
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