Solar Li-Ion Battery charger

[drkidd22]

Hello,

I'm working on a project to charge a Li-Ion battery using only solar power.
The battery is 3.7V, 2600mAh.

I would be using microchip MCP73831 charge controller due to its simplicity.
I'm having some difficulty trying to calculate what solar panel I should get. I want something small and adequate for the intended use and load applied to the battery.

For example, the load that will be connected to the battery is going to be drawing 90mA at 3.7V.That would be a power consumption of 333mW. With the battery @ 2600mAh(3.7V) = 9.62W/hr.

Given everything is ideal not counting on any losses --> 9620mWHr/333mW = ~29Hrs of continuous operation.
So I was looking at a mini solar panel of 6V, 100mA output (600mW).

I'm confused at determining if this solar panel I'm interested in will be enough to charge the battery correctly. The battery for fast charge should be at constant current of 1C (2600mA). Some help here (where I'm stuck) will be appreciated.

 

[nickelflippr]

The 1/2 watt panel seems a little on the light side. If you can find a few 1W mini panels for a reasonable price, then I think the bases will be covered. The load is only at night (LED)? cell phone recharger? You never really have to worry about constant current, unless the solar is way overdone.