Continuous 9V Solar Power Supply Schematic?

First off.... Click this link.

There are hundreds/thousands of products readily available online ranging from $20 and up. All you need is one of these chargers that can not only produce the correct voltage range but also enough amperage to supply ample power to run the camera by itself on a cloudy day. At that point all you need is a decent bank (or one single) 9V rechargeable battery. Hook the three components together as stated in the chargers instructions and you're done.

Hope this helps!

A quick solar design calculation results in a 12V solar panel (a standard voltage) of at least 3W output plus a 12V 10Ah battery (giving a standard 10 day, 24 hours a day reserve capacity to handle seasonal solar variation).

Additionally you would need a small 12V solar regulator and a 12V to 8V DC 30mA (or better) converter.

All the parts (including the DC to DC converter) are available as off the shelf items although you may find a solar regulator with a variable output voltage adjustment (allowing you to do away with the DC converter), same thing if your security camera can handle a 12V input (check the data sheet).

You can build your own DC converter (for instance using an inexpensive voltage regulator chip) and even your own 12V solar regulator. I don't have any circuits to post but others may have.

How about a voltage regulator on the solar battery, with a diode to the rechargeable battery for one-way current flow?

As Jack of all trades, has already mentioned, use a voltage regulator chip. I suggest you use 7809 chip mounted on a small heat sink, even a small aluminium piece will do. This will regulate the solar voltage to 9 V DC and can safely handle upto 200 mA, which is 1.8 W. Connect a 1N4007 diode in series with the regulator output to drop the voltage to approx. 8.3 V & then connect diode output to the security camera.

You can use 12 V 6 Ah battery used in scooters/motorcycles directly to solar panel and then connect the battery to the regulator.

Battery overvoltage protection circuit can be made using simple op Amp like IC 741 or LM308. Output of this can be used to drive a relay through a transistor. Connect the relay contacts in series with the module, but before battery. This contact will open if battery is fully charged and close when battery voltage becomes normal, thereby protecting the battery from over voltage. This will marginally add to the cost but will improve battery life.

Thanks and regards

Ashok Toshniwal, Bangalore, India.

There's already ready-made remote WiFi cameras available with properly-sized and dedicated PV solar array. You do not have to modify the gizmo in any way! Most are powered by a 12 VDC solar array and include a charger and battery. All you have to do is look online for a decent and cheap unit:

ebay.com

or

amazon.com

In the product search window just type in "solar" and you'll get a GodZillion hits!

Good luck hunting!

Here you go 200mW at 8V. I think it is probably higher than eight volts. 8.4V?

But anyway, 200mW/8V = 25mA. 25mA x 24h/d = 600mA/d. System Efficiency will be about 65% at worst. 600mA/65% = 924mA/d. Go allelectronics.com and see if they still have a PV charge controller at 9V. You do not need 8V here. A small 10W panel at 12Vnom and about 1A will do the job if have good sun. If not, 20 to 30W will cover it. You will need SLA gel 7Ah battery at 12V to get this done and have a day or so of cloud coverage. Double the Ah if you want about 3-4 days of coverage. A smaller panel will do the job but its cutting it too thin for reliability. You will have to modify the power input to the camera. If takes a standard 9V battery socket, then buy a 9V connection, reverse the polarity from the output of the CC on the connection and snap into the input and weather seal. Oversimplified but it will work.

Thanks to you all for the information. Just to give a little more background on the situation, the camera I'm looking to use is left over from another project. It's a cheap little night vision camera that I would like to mount inside a birdhouse (yet to be built as well) at the far end of my backyard for my 7 yr old niece. As for the power scheme, I think you have provided enough information for me to go on for now, though I may have more questions as I get deeper into the project. Thanks again to you all for your help!

Glenn