Solar panel at Tractor Supply Co.

[jen_in_southtexas]

I was at Tractor Supply Company a coupla days ago and came across a solar panel that said 25 watts for $99.00. Says you can power things in your RV, boat, car, etc.
Since I dont know what this means.....what exactly can you power with 25watts? Also they had this 15 watt solar powered outdoor security light fo$25.00. I'd like to do what Ms. Alma did and fiddle with solar power on small things like this. I just dont know what it would power. Also i was reading in this forum about the solar kit of 45 watts at Harbor Freight. What all can you run on 45 watts and what size inverter do you need and where do you get one. Seems like I've seen them at Walmart.
I still dont have any electrical power at my 32' camper trailer on my new 10 acres. At the very minimum I would like to power a small fan because it can be hot and humid some nights and I need air circulating. Some light would be nice to have at least to be able to read. Do laptops take alot of juice to power should the battery go dead? I have an extra lawn mower battery but was wondering if a fan would drain that easily? I have 2 6volt batteries that i bought last year in the deer feeder section. Can you charge those with a regular car battery charger?

[kawalekm]

Hi Jen
With 25 Watts, (~1.6amps) you'll be able to "directly" power a radio, or a small 4-6" portable TV, or a portable DVD player, or some DC lights. *Look on the back of the unit or the back of the charger to see what the voltage and watts are. That will tell you what the power consumption is. Just about any electronic device designed to be unpluged and carried with you will probably be adequately powered. *A better option though is to use the panel to charge a deep-cell battery and use the accumulated charge whenever you want, rather than just when the sun is shinning. *Yes, you can use those two 6V batteries, but you must wire them in series to make 12V that your panel can charge. *If you hook up an inverter to your batteries, you'll be able to produce a little AC power too, about the same # of watthours that the DC batteries have stored.

Line up your two batteries in the same orientation so that the +&- terminals are in the same direction. *Run the postive wire from the panel (red in color) to the positive post (red) of the left hand battery. *Secondly, run a wire from the negative post (black) of the left hand battery to the positive post (red) of the right hand battery. *Finally, run a wire (black in color) from the negative post of the right hand battery back to the panel. *Done this way, your two 6V batteries can be charged at 12 volts and put out 12V required by RV appliances.

That is the very simplest system you can creat, but the panels have the potential to overcharge the batteries. *To better control the charge, you should buy a "charge controller" (a small one is about 25-30$) to put in between the panel and the batteries. *The controller will monitor how high the batteries are charged and stop the flow of electricity once they've reached full charge. *With you low wattage though you are more likely to damage the batteries by draining them than overcharging. *Try not to let the batteries drop below 50% charged. *The easiest way to measure this is with a little plastic hydrometer you can get at the auto parts store. *A new one might cost about 5-10$.
Good luck,
Michael

[12vman]

$4/watt ain't too bad.. Gotta link? :D

[jen_in_southtexas]

Wow! Thanks Michael for all the detailed and very informative information. I made a diagram to help me understand it.

Now the Harbor Freight kit comes with 3,6,9,12 volt DC adapter outlets, easy to read LED charger indicator, mounting hardware, 2 lights(incandesant), 12 V socket, battery clamp. WHERE DO I GET A CHARGER and what kind? Where can i find inverters? thx

[kawalekm]

Hi Jen
The variable voltage adapters would be great. You could use it to charge your phone, little portable appliances, and maybe even your laptop. But first, how will the system be charged? The first thing I need to know is what you would be plugging the charger into? Your typical charger plugs into 120VAC house current, but you don't have that, right? Without house power, you have three options for electrical charging your batteries. If you run a generator, you can produce 120VAC house current and run a regular plug-in charger off of that. That will charge the batteries fast. Method #2 would be 12VDC charging off your car/truck electrical system. It would be very wasteful to run your car's engine just to charge batteries, but maybe what you could do is put the batteries in the car and charge them whenever you drive into town. The best option is do the charging from your solar panel. Quiet, simple, and nothing to do except stick the panel out in the sun.

These days you can get inverters just about anywhere, even K-mart and Target for less then 10 cents a watt. It sounds though that both your batteries and your panel are quite small, so you won't be able to power much with them. You won't be able to run a 1000 Watt microwave off them for example, but you could run a small RV television for about an hour or two each day. If you figure that your 25 watt panel is in bright sun for about 6 hours each day, you'd expect to store maybe about 80-100 watthours per day. Once the batteries are charged, that means you could run something consuming 10 watts about 10 hours, or something consuming 50 watts for only 2 hours. It's hard to say without knowing what exactly your batteries can do and how much sun your panel can get.

[jen_in_southtexas]

Thanks for your reply Michael. You have been very helpful. :)

My bad on the previous post about the batteries i bought last year. They are 12v not 6v. I dont think they may be any good anymore.

I finally bought the solar panel kit that Harbor Freight sells for 199.00. It is 45watts total with each panel being 15watts. It requires a 12v storage battery. I priced the deep cycle batteries and wouldnt you know that the 12v golf cart batteries are much cheaper than the 6v ones. Is there a big difference in storing 2-6v deep cycle batteries than to store 1-12 volt deep cycle battery?

For some reason i was under the impression that they had to be "solar" batteries but i hear alot of people on here use just regular golf cart batteries. Can you clarify because i am new to all of this.

I finally got my week off so i will be off all of this week. I cant wait to set up my solar panel.

[12vman]

Forget the golf cart batteries at this point. You don't have enough panel to keep them charged properly..

Purchase a large deep cycle marine battery.This will be enough for 45 watts of panel..

Be prepared to get another charge controller in the near future for that set up. Many folks that I've been in contact with that have purchased this same system state that the controller is pretty much junk.. :-/

[kawalekm]

I second that! *I have heard that the Harbor freight controllers are junk and should be replaced immediately. *I would also agree with the marine battery. *Actually, the "Real Goods" folks recommend starting out with cheaper marine batteries, because there's a learning curve for battery care, and you're most likely to trash your very first set of batteries. *Once you've ruined a set, you'll know better, and you'll be ready to upgrade to top quality ones. *The one thing to pay attention to is to buy a real "deep cycle" battery, not one advertized as for both storage and engine starting. By the way, how long ago did you by the Harbor freight panels? Is 199$ the current price today?
Michael

[jen_in_southtexas]

Hey guys,

I really appreciate y'alls input on this matter. Any bit of advice or info helps.

I will go and look at the marine deep cycle batteries and go from there. From what i gather, I know that this setup may or may not work but I need to experiment for myself so that i can learn as i go. Its also a good little project to work on on my time off. At some point i would like to get good quality solar equipment but for now this is all i have. I will look into those battery controllers as well.

I just bought the kit for 199.00 this past Friday. I too thought that they were a little more than that.

I was wondering if you can add more solar panels to these existing ones for more power or would you have to have the other setup seperate?

Thanks again guys!!!

[12vman]

Take my advice..
If you plan to build a larger system, go for quality. Use the system that you have for a while to get a "feel" of how things work. Use it as a learning tool. Don't plan for that system to last over 2-3 years because it probably won't. I've never owned that same system myself but I do own some of the same type of panels at a lower wattage. They are around 4 yrs. old and have lost about half of the rated output. Basically a toy..But, A Great Learning Tool!!

You can add panels but with this system, I'd be leary unless you buy another set just like the one you have. If you choose to do that, consider a C-12 charge controller by Xantrex (http://www.xantrex.com/web/id/71/p/1/pt/25/product.asp).

[jen_in_southtexas]

Thx 12v man. I'll check out the Xantrax website on the controller.

Im off to the homestead in an hour or so. I cant wait. It has rained this morning and our first big cold front is coming in today dropping to the mid to lower 50's. Mind you, our area is a hot humid area here in south texas so this is a real treat. Need to air out the trailer, whack some weeds, clean up as i had someone come and brush hog and tear down some dead trees.

I love being at my homestead when its rainy, cloudy, and now the cold. Nothing like sitting in my recliner in front of my window gazing out and hearing the sounds of nature or delighting in a walk through the woods. This is truly heaven on earth.

-j