TheBackShed.com

Forum Index : Electronics : Simple solar regulator

Author

Message

SSW_squall

Senior Member

Joined: 20/03/2010
Location: Australia
Posts: 111

Posted: 12:44pm 02 Apr 2010

Copy link to clipboard

Print this post

Heres a real simple linear float regulator, that i chucked togther for the lighting system in the hayshed and horse yard.
2x 1W LED's in the shed and a 20W down light on the yard

The trimpot can be used to adjust the float voltage, factoring in the voltage drop of the shottky diode at typical charge currents.
The solar panel hooked up to it is only good for a couple of watts, and the regulator will handle this fine without a heatsink.
Before using this regulator the 7Ah SLA battery was getting overcharged >14v!!

Could be improved by using a Pch MOSFET and comparator to short out the regulator to ensure max current is delivered when the battery voltage is below 13v say.

The wife was spying on my post and doesn't know what a MOSFET is but likes the light cause the horse doesn't get scared in the dark

Might post some pic's tomorrow...

AB

Einstein: Everything should be made as simple as possible, but not one bit simpler

Downwind

Guru

Joined: 09/09/2009
Location: Australia
Posts: 2333

Posted: 04:49pm 02 Apr 2010

Copy link to clipboard

Print this post

On simular circuits used in alarm systems some years back included a 5w resistor on the output for sla batteries and some others had a light globe for the resistor.

The reason being if the sla was deeply discharged, it would draw more than the 1 amp rating of the LM-317 when it was power up again.

The resistor limited the max current to under 1 amp.

In your case the max panel rating is under a amp so no problem.

It is a handy adjustable voltage regulator circuit for many applications.

Pete.

Ps. All ways like seeing pic's.

Sometimes it just works

SSW_squall

Senior Member

Joined: 20/03/2010
Location: Australia
Posts: 111

Posted: 01:30pm 04 Apr 2010

Copy link to clipboard

Print this post

Here's a couple of pic's:

The solar panel is an amphorous altronics http://www.altronics.com.au/index.asp?area=item&id=N0704
rated for 5W which it did manage initally.
After 1.5 years it currently struggles to deliver 2W. Would advise anyone against buy one of these...
The shottky diode is necessary to stop the battery from discharging back into the regulator.
The white LED is on 24/7 to help see the light switches when it's dark. Connected via a 10k resistor it uses approx 1mA.
I've got the battery insulated with some celair and bubble-wrap to help keep it happy during the cold nights.
Given the potential for any hay shed to be burn for about a day or two, a fuse is always a good addition

Einstein: Everything should be made as simple as possible, but not one bit simpler

Print this page

To reply to this topic, you need to log in.