Setup question. Simple setup.

[ScoHaz]

I just set up a small 45W solar system we are going to use to power fans in our greenhouse. It is one of those you can get from most tool stores that comes with all of the cables and regulator etc.. It comes with a regulator with a 12V DC female car-style accessory plug and another just like it marked for the inverter. We are using two small 12V fans and the instructions say you can plug a 12V accessory into the receptacle marked "inverter". So we plan on plugging both of the small fans into the two female receptacles.

What my question is, is that since we only want the fans to run during the heat of the day, do I really even need a battery? The voltage regulator that came with it seems to be all I need unless I want to store power and use it when the sun is gone. I have read about the need for capacitors etc. to regulate power flow. Is that what this voltage regulator will do?

The fans consume 8.5 watts each, so I should have plenty of power for them as long as the sun is out, which is when I need them to run.

Am I correct in this assumption?

Thanks for any insight you can provide and greetings from East Texas.

[daz]

What my question is, is that since we only want the fans to run during the heat of the day, do I really even need a battery? The voltage regulator that came with it seems to be all I need unless I want to store power and use it when the sun is gone. I have read about the need for capacitors etc. to regulate power flow. Is that what this voltage regulator will do?

The fans consume 8.5 watts each, so I should have plenty of power for them as long as the sun is out, which is when I need them to run.

Am I correct in this assumption?

First off...Welcome to Solar Panel Talk!

Unfortunately, your assumption is not correct. The charge controller needs to be connected to the battery, otherwise you will damage it (the controller)!
However, you can use a voltage regulator (either linear or SMVR) to step-down the voltage, without having to use a battery. The voltage regulator is what I would recommend in your case, as buying the kit is a waste of money. All you need, for what you are trying to do, is a solar panel and voltage regulator. You just need to make sure you get a solar panel with a Vmp as close as possible to your fans voltage (ie 17V, or a 12V nominal panel), so that you do not waste too much power. Then you will need to either build (easy enough) or buy a voltage regulator capable of supplying the voltage range/current that you require.

Alternatively, you can buy a DC fan that accepts the wide voltage input from a solar panel (ie a 12V fan that accepts 8-17V input). If you can, then you do not need the voltage regulator at all. Just the fan and solar panel!

[daz]

The voltage regulator that came with it...

Sorry, forgot to include; there is a difference between a voltage regulator and charge controller. Most solar kits/systems use charge controllers, not voltage regulators (there is a slight difference in the way they are designed). A charge controller needs to be connected to a battery. A voltage regulator does not necessarily have to be connected to a battery to operate. Which one do you have with your kit?

[ScoHaz]

Which one do you have with your kit?

Thanks for the info. I must have a charge controller that is also a voltage regulator. At this moment, the system is working beautifully. The two fans are plugged in to the charge controller and/or voltage regulator and are humming right along.
I will look in to a voltage regulator as everything I read says the ones that come with the kits are not good. I am not trying to get too fancy with this, just get some breeze on my veggies here in this East Texas heat.

Thanks for the welcome and, again, thanks for the info. I'll keep you posted.

[daz]

Thanks for the welcome and, again, thanks for the info. I'll keep you posted.

No problem. Please keep us updated!
I would definitely look at a voltage regulator as they are really cheap, with the beauty being you do not need a battery. The downside though, is it is not very efficient, but for what you need it will work well!