Solar charger shield not charging?

Has anyone ever used a Seeed Solar Shield with the Arduino?

My shield seems not to be charging the battery.

As shown in the figure, the fully charged battery remains at a constant voltage in direct sunlight during the day, drops during the night, then just stays at that voltage in sunlight again, not charging the battery. Is this normal? Shouldn’t it go back up to 4.2 V again?

There should be more than enough current to charge the battery while powering the circuit as the average current consumption of the circuit is around 70mA. The solar panel’s output is 158 mA in the shade and 500 mA in direct sunlight.

Is seems the shield is either powering from the solar panel, powering from the battery, but not charging the battery from solar while powering the circuit? But it should be, according do the wiki and description…

A quick look at the specs shows a minimum voltage of 2.7V and a typical voltage of 3.7. It also says 500mA max, but it doesn't say how much light you need, or how much voltage you get at 500mA (maybe 2.7V).

What are the LEDs showing you? Have you tried charging without the 70mA load? Have you measured the voltage & current from the solar cell? 150mA "in the shade" sounds like a lot for a solar cell that puts-out 500mA in direct sunlight...

That 500mA rating might be at noon, in the desert, in the middle of the summer! :D

The specs say 700mA max input to the shield, I think you’re looking at the older version…

I’m using a switching voltage regulator (S7V7F5) so the solar panel output is regulated to ~5V so as not to damage the Solar charger shield (optimum voltage). The measurements I made on the solar panel are as follows:

No voltage regulator:
Voc = 6.1 V (shade), 7.1V (sun)
Isc = 35.6 mA (shade), 360 mA (sun)

With voltage regulator:
Vout = 5.2 V (shade), 5.2V (sun)
Iout = 160 mA (shade), 500 mA (sun)

Should be fine to power and charge the Arduino, GSM shield and sensors while charging the battery, so I can’t help but think there’s something wrong with the charger shield…