Solar Panel to Piezo Siren

[90Alpha]

I am trying to make a 12V piezo siren work with two 9v 1.5W Solar Panels and am having no luck. A 9V battery runs the siren fine. I am a real novice here and could use some help.

 

[Norator]

Load the 9v battery until the voltage drops 10% or so and note the current or resistance value it takes to do this.
Repeat for solar panels.
You're looking for the Thevenin Equivalent circuit for each.

If you don't have resistors, 120v incand. bulbs will do if you measure their 'cold' resistance. We're not looking for precision here, it's more of a go/no-go test.

 

[90Alpha]

I'm not sure how to do that. How do I measure cold resistance? I have some resistors but just used them following step by step directions to make an led light project last year. Are you thinking I need resistors between the solar panels and the siren? I thought the battery was more powerful and maybe the two panels were not enough???

 

[Mr RB]

THe piezo siren contains an oscillator, and might have trouble starting if the peak supply current is limited (liek a solar panel).

Try putting a large cap electro 1000uF etc across the solar panel leads. That will help supply peak currents.

 

[Norator]

The cap may work; otherwise you need a multimeter to tell you what is going on in your circuit. A meter like this will pay for itself as soon as you use it to troubleshoot appliances or house wiring.