# Solar/Wind Power Battery Regulator Circuit Design

#### markmain

Joined Dec 28, 2008
21
As a fun project I want to build a battery regulator that will charge up a 12V battery for a solar power / wind power project.

Does anyone have some nice schematics to help me learn some various approaches to this?

What is the correct limit for a 12V battery? I've seen 14.3V as a limit on some circuits. having said this, I've also read that it's good to overcharge the battery a bit sometimes... is the the 14.3V as "overcharged" or something higher?

What would be the most efficient way to amplify the voltage so that it is always 14.3V (or whatever the correct maximum should be)?

And the reverse of this, what if I now have too much power, what is an efficient way to increase the amps and reduce the volts? I'd rather do that than simply burn off the excess as heat.

And how do I determine a maximum amperage is now reached for the battery so I'm now forced to start burning off excess as heat through a resistor (or fan cooling off my battery )

Is there an ideal pulse frequency rate to charge batteries?

If I have a temperature sensor on my battery how do i make use of it? I don't know how to best slow down or increase based upon the temperature.

Is there a cheap and easy way to convert my design to 24V or 48V later if I desire.

I hope this was not too many questions, thanks for your help; I like doing quality work and I'm just trying to make a nice regulator.

#### wayneh

Joined Sep 9, 2010
17,475
I hope this was not too many questions..
It is! Let's start by talking about what you have. Battery chemistry makes a big difference. Sounds like you probably have lead-acid? How big a system are you thinking of?

And your generators - what are they capable of? For instance if your solar panel is small compared to your battery, you might not need anything more than a blocking diode to prevent reverse current when the panel is dark. Do you intend to "OR" your generators together, so that either or both might contribute to battery charge?

Experts here will have many more questions for you. I suggest a divide and conquer approach. It's too hard to follow a thread with multiple topics, although it's fine to discuss overall strategy before you dig into specific tactics.

#### markmain

Joined Dec 28, 2008
21
It is! Let's start by talking about what you have. Battery chemistry makes a big difference. Sounds like you probably have lead-acid? How big a system are you thinking of?

And your generators - what are they capable of? For instance if your solar panel is small compared to your battery, you might not need anything more than a blocking diode to prevent reverse current when the panel is dark. Do you intend to "OR" your generators together, so that either or both might contribute to battery charge?

Experts here will have many more questions for you. I suggest a divide and conquer approach. It's too hard to follow a thread with multiple topics, although it's fine to discuss overall strategy before you dig into specific tactics.
Thank for you kind help. I really want to learn this, I'm determined. You are right, I'm trying to make sure that I have all of my items covered as I dive into learning this.

Regarding size, I would like to build my first one for a single 12V deep cell battery.

As I re-read my post, most of my questions are trying to get knowledge around the theory of what is the best way to charge a deep cell battery--e.g. frequency and voltage. Then it gets into how with regard to temperature monitoring and over voltage, etc.

I will divide my questions up as suggested once I have more details about my strategy here, but for this thread I think that it would help if someone can show me some examples of schematics that cover what I am trying to do.

I want to have my wind power and my solar power work together to charge the battery. I intend to have 1 marine battery but may later get 2. The size of the panels will be about 150W and my wind power will be small too; maybe later I might want to double that, but for now I am just going to stay small to learn.

What is the difference in procedures to properly charge for the different types of solar batteries?

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#### wayneh

Joined Sep 9, 2010
17,475
I highly recommend a visit over here.

For any battery chemistry, there are a multitude of schemes to achieve ideal charging. There are also dedicated ICs to help streamline design. Depending on the application, we sometimes sacrifice optimality for simplicity or cost. So the problem for a newb is that there is no single right answer - one has to understand the situation well enough to make informed design compromises.