Charging circuit question

[oasamostexianu]

I'd like to power a small circuit from a solar source, but also continue to have the circuit operate during night-time hours when solar power is unavailable. My hope was that there would be a simple way to hook up my solar panel and a rechargeable battery to continually operate the circuit.

Here's what I have:
- a 12V/190mA solar panel (regulated to constant 12V output)
- a rechargeable battery (was thinking 12V, but uncertain)
- a 3.6V/95mA load (via step-down regulator that accepts 12V input)

Would it then be possible to put the battery and solar panel and load all in parallel, or do I need a more complicated power circuit to handle this? Again, my end goal is to ensure that the load is always powered - any solution that uses the solar panel to do it would be appreciated.

Thanks!

 

[batdin]

No.
You cannot charge a 12V accumulator with a 12V source.
When charged,battery voltage usually reaches 14.4V.
So you need a step-up or charge-pump battery charging circuit.
The good news is that the panel is more powerful than required.

 

[otuzsubat]

i have similar project. i used 12W solar panel and a 12V 17A battery. i designed a charging circuit with pic mcu and used a mini relay as switching element. i used a relay because if you use semiconductor, you lose some power over it.
the output voltage of my solar panel is about 16V. my mcu and circuit needs 5V. for this reason i used a 7805.
you can connect all your loads in parallel but you should disconnect solar panel when battery charged. otherwise it is damaged because of overcharge.