Stand alone systen with powercell,solarcell,LIpo accu, arduino,XBEE

Hoi al,

To power up my outdoor weather station this is build up as follows, mini-pro arduino 3,3VDC XBEE for transmit data to base station temp. sensor 18ds20 wind direction via reed over resitor to ana input wind speed dig. input reedswitch count rain water counts buckets of water fals over time 6 VDC solar cell 2,5WATT LiPo accu 3,6 1200mAh ( provided the power consumption is in balance overnight ) ( intend to use the sparkfun powercell )

I have my doubts to connect the solarcell to the powercell while this is limited to 5VDC input voltage as according datasheet. The solarcell tend to raise the voltage far over 5VDC this wil harw the powercell and drop to zero in dark.? Can a regulated voltage be the solution? But when the voltage drops below output + reg. level? Is a zenerdiode the solution? A diode to prevent current flow back to solarcell? Any experience nown? Any help aprecieted. IlioSS smiley-confuse

You've posted this twice, you should delete the other one.

It is good form to include links rather than making those helping you look things up.

Is this the Powercell from Sparkfun you intend on using for your LiPo cell? https://www.sparkfun.com/products/11231

If so, the charger chip on there will accept 3.75 to 6V input. So that should work as long as that solar panel doesn't rise much above 6V, as the absolute maximum rated voltage for the charger chip is 7V.

Although you should understand that if the solar cell voltage drops below about 1V above the battery voltage, it won't charge any more. You don't need a diode to prevent discharging into the solar panel, the chip on the Powercell prevents it. The chip even shuts down when the incoming voltage drops below about 50mV above the battery voltage.

This is all in the datasheet for the charger chip, linked from Sparkfun's page on the Powercell. It is rather dense reading for someone not used to reading datasheets.