Circuit for charging from multiple sources: turbine and solar

[tommygdawg]

Hey all,

 

Basic question here. I'm a noob starting out with electronics and I've had a hard time getting an answer to the question this topic poses. I've got a basic electronics project I'm putting together: I have a small wind turbine I've put together that generates some electricity. I also have a small solar panel I'd like to wire into this circuit to basically add to my total output and charge a small battery. What would be the best way to go about this?

 

I've heard that charging from multiple sources of varying voltage can be bad, this will obviously be the case considering the wind turbine will not always be spinning and the solar panel will not always be receiving light, and sometimes they'll both be going at the same time. Do I just want Schottky diodes on everything and then basically wire it all in parallel down to the battery? Or am I thinking about this totally the wrong way?

 

I'm starting small: one small turbine and one solar panel just to get the hang of it. As soon as I know I'm generating and wiring properly, it's onward and upward!

 

Thanks everyone!

[Acme]

Maybe you just need a charge controller? I think you need one even if you have just wind-turbine or solar input so that you don't overcharge the battery.

Here's a hybrid that looks like you can connect both solar & wind turbine inputs:

Hybrid Charge controller

[Danijel Gorupec]

Do I just want Schottky diodes on everything and then basically wire it all in parallel down to the battery? Or am I thinking about this totally the wrong way?

 

This might work, although probably very poorly (not efficiently) and possibly even dangerously to your equipment, as Acme said.... As you probably guess yourself, to make this simple diode-circuit idea work, both sources (turbine and solar) must be capable to provide higher voltage than that of the charged battery (if, as I understand, you want both sources to contribute simultaneously). Note that, while charged, a battery might increase its voltage above its nominal value, so it might happen that one of your sources will stay below this level and will not contribute.

 

You will learn that charging batteries efficiently is not easy. Take datasheets of your equipment (solar, turbine and battery) and determine their optimal working/charging points/curves. You will see that these probably do not match to each other. Therefore you should build a charge controller that will keep all of your equipment happy, and at the same time the controller itself must be efficient.

 

So... I would... take two diodes and try it ASAP