Any Solar Power experts out there?

I went to a meeting yesterday with some folks who are interested installing some of our air quality sensors. However, we have a major problem with this because at the moment our devices are all mains powered. This is mainly because the particle sensor is quite a power hungry beast. It needs to be fed with around 120 milliamps. This is not a huge amount, but it is enough to make long term battery powered deployment a bit of a no-no.

It looks like there are some devices out there, I’ve ordered some of the one above, based on the MCP73871 chip. If anyone has ever used this kind of device and got a happy ending I’d love to hear from you.