Opto....anything to charge small battery?

[fastline]

We are working on a simple project that will use a microcontroller and a couple sensors. the actual power requirement is very low and could probably run for a year on the battery but we would like to explore PV charging. This device will be subjected to daily sunshine and actual charge rate really is not a factor. If it took days to charge, no biggy! The real requirement is keep it very simple and keep the cost down.

The battery will likely be Lion and I know we need to get voltages right. I am not sure if we really need a proper "charge controller" for such low charge rates but would need to disconnect at the top charge threshold. Could probably just do a small mosfet fired from the uC for that.

Anywho, are there any simple optos that could be made to do this?

 

[Bluejets]

Once again, there are off-the-shelf option open to you but more information would be required such as battery size (electrical) current draw of the load , type and size of the pv array.

 

[fastline]

We might select an 18650 battery and current will be variable as the PIC will hibernate much of the time. I could estimate about 20mA. Could you give an example of what you are thinking of?

 

[Bluejets]

As I said, it depends on what supply you have (pv) and if you have just one or more 18650.
This board below should cover most of what you need for a couple of dollars.

Don't be put off by the 2A, that is just maximum rate.

They should be available just about anywhere, so shop around , probably many places cheaper also.

https://www.ebay.com.au/itm/322655498326?hash=item4b1fc43056:g:6x0AAOSwfDhZgxLf