Solar Charge Controller.

[Ranwire]

Hello all.

I am member of a Church group, that just completed the building of a School in Africa.
The school is about 50 miles away from the Grid.

So we would like to go Solar, make the school Green with solar power.
The plan is to use 12 volt batteries for the sauce, & connect to the Solar pannels.

What I would like to is, to be able to build a charge controller, to add to the system.

Is there anyone out there, who can help.


Thanks

 

[davenn]

hi there
welcome to the forums

remember google is your friend
there are many many links to ccts for such... a couple of examples...

http://www.solorb.com/elect/solarcirc/ccntlvd-orig/index.html

http://simpleelectronic.com/2009/06/29/solar-charger-controller-circuit-diagram/

cheers
Dave

 

[(*steve*)]

You should also look at commercial charge controllers.

There are a number of reasons for this.

Primarily, the potential costs of lower efficiency and inadequate battery protection can end up dwarfing the money you may save in building your own controller.

On the charging side, you want to look for a controller (or a circuit diagram for a controller) that does maximum power point tracking (MPPT). This is a method of extracting the most power from the panels. This can result (from memory) in 20% more energy delivered to a battery.

Also on the charging side, it is best to look for a controller that has a more sophisticated way of handling the batteries than just charging to a set voltage. Lead Acid batteries are quite rugged, however their life (and indeed their capacity) can be optimised by correct charging.

On the load side, you definitely want something that disconnects the batteries if the charge level drops too low. This will also extend the life of the batteries.

If you are running an inverter, look for one that is both highly efficient, and that has a low quiescent operating current. Some inverters can significantly discharge a car battery in under 24 hours even with no load connected!

If you are using this for lighting, you may be best running low voltage volt LED lighting, using switchmode LED drivers for the highest efficiency. When running 12 volt wiring, use quite heavy wiring as the resistive losses can be more significant.