Hi AyersTG,

The design is at a very early stage, it hasn't been designed yet!! Just trying at the moment to get a specification going with some feedback on what would be useful features and what would be pointless for various emergency scenarios in the office, home, automobile, marine or field environments in terms of power requirement over a 2-3 day period for example.

For example an 800 Whr battery pulled from a vehicle would be able to provide continous lighting using the 'solar charger' for a medium sized room for around 60-80 hrs.

A major part cost is going to be the 12 18650 cells. A pair will cost around $9

http://www.dealextreme.com/details.dx/sku.6979

So the cells are going to cost around $54

The SSC P7s costs are around $24 each so for 2 each will be around $48.

The microcontroller will be a PIC18F458, (already have some of these lying around with a PIC development board and PIC programmer etc) so these costs are essentially zero. Other semiconductor costs will most likely be covered by the 'send me a sample' approach.

The microcontroller will be at the heart of the design, using a firmware approach to control the switching DC/DC regulator, AC input switching PSU, Inverter AC output, SSC P7 LEDs and the Lithium ion cell array charger circuitry designs. The 'mains conversion mode' should essentially just be another part of the firmware.




The idea is to be as flexible as possible for the smallest and lightest device possible. Essentially the device would allow the use of a big external sealed lead acid gel cell (or even automobile or deep cycle marine type cells) to be used externally with the 'solar charger' and PV panel but also allow the use of readily available lightweight lithium ion cells to allow portability. (The 100 Whr Lithium ion array weighs only around 580 grams compared to around 3Kg for a lead gel equivalent cell)

When used with the PV panel it would allow charge control to recharge the lead gel cell or it could borrow some of the charge from the lead gel cell to store internally to the Lithium Ion cells to be used later. Some of the charged 18650 cells should be able to be removed and even used to power individual 18650 single cell flashlights for example.