DIY Solar Panels

[antp510]

Thanks! I appreciate it, its on the list!

[91cavgt]

Thanks! I appreciate it, its on the list!

and to add to that, if the Harbor Freight controller does not put out at least 2.1 amps on the USB outlet then just find a cigarette lighter adapter that has a USB outlet on it that is designed to charge your Ipad. The Harbor Freight charge controller has a 12 volt outlet that you could plug that cigarette adapter into. Problem solved on the cheap.

[Brazos Hunter]

I know this is a solar thread but I'm going to bring up something a little different. Still green energy though.

I am about to start fabricating a large wind turbine to replace my little 50watt 12v one. I will be running a Permanent Magnet DC motor as the generator. 2.5hp, 180DCV, 7.5A, 4,000RPM. If my math is correct, using the power equation, at 4k RPM this will produce 1,350 watts of power! Grant it, it will not see 4k but still...

[Dusty Britches]

I finally had a quasi free hour so I removed the three little 12v panels totaling 45 watts off my shop and installed the completed 435 watt 72v panel. As soon as I purchase a quality meter I will post values. BTW, I plan to add two more on my shop.

[ATTACH]732343[/ATTACH]

that sure looks well shaded, BH.

[Brazos Hunter]

It is actually in full sun most of the day. Right now it is kicking out a little over 400 watts!

[Backwoods101]

Awesome thread What do you think it would cost me to run an 800sq ft cabin off grid?

[Brazos Hunter]

It all depends on what all you want to provide power to and how efficient they are.

[Backwoods101]

Pretty much everything. The cabin will be our retirement home one day.

[Brazos Hunter]

The average house tied to the grid consumes 2 1/2-3 1/2kW per day. With that said, if not designed and built for off grid, somewhere in the neighborhood of 2kW solar plus a generator or other means to charge the batteries when it is cloudy for days on end.

[huntr51]

Good info

[huntr51]

[Backwoods101]

The average house tied to the grid consumes 2 1/2-3 1/2kW per day. With that said, if not designed and built for off grid, somewhere in the neighborhood of 2kW solar plus a generator or other means to charge the batteries when it is cloudy for days on end.

What would be a ballpark figure on the cost of a system that could produce that?

[Brazos Hunter]

DIY Solar Panels

What would be a ballpark figure on the cost of a system that could produce that?

$1/watt plus $1,500+ in charge controllers, inverters, batteries, and wire. So, $3,500 on the very bottom end. Realistically, closer to $5k for a descent setup

[Backwoods101]

$1/watt plus $1,500+ in charge controllers, inverters, batteries, and wire. So, $3,500 on the very bottom end. Realistically, closer to $5k for a descent setup

Not bad, I was thinking closer to $10,000. Thanks

[91cavgt]

Not bad, I was thinking closer to $10,000. Thanks

Let's put together a basic setup that is solely based off of being off the grid, and setup in mind that you are not going to use as much power as you currently use.


Solar Panels;

There are a LOT of places that you can find panels. You can either score the way Brazos Hunter did with the broken panels, and put some work into them to make them useable again, or you can buy new ones. SolarBLVD.com is a pretty good place to find some decent prices on solar panels.

https://www.solarblvd.com/product_in...oducts_id=3028

Here are some that are 24 volt, 250 watt, and put out around 8 amps of peak current. Add to that the fact that they are $170 each and it is a good deal! (68 cents per watt)

Let's say 6 of these for a total of $1020 for panels.



Charge controller;

Here is a Xantrex charge controller. Xantrex makes some good things. I've got one of their 1k watt pure sine wave power inverters and it is a hoss.

https://www.solarblvd.com/product_in...oducts_id=2552

This one can take in up to 40 amps of current and up to 140 volts DC input. But wait, if you add up the above solar panels, in direct light you end up with 48 amps which is too much, right? Well hold on. That is at 24 volts. Let's separate the 6 panels into groups of 3, then let's wire each of those 3 panels in series giving us 72 volts at 8 amps! Now we will wire both sets of 3 panels in parallel which gives us an output of 72 volts @ 16 amps which is in the specifications of the charge controller. Not only that, but you can use smaler gauge wire without power loss since the voltage is now higher(72 volts vs. 24 volts), but the amperage is now MUCH lower (16 amps vs. 48 amps).

$1267.20 for the charge controller.




Cables;


Don't skimp here. Poor quality cables can decrease total power available to charge the batteries. Poor quality battery terminals are also a fire hazard as they will heat to the point of melting plastic and catching fire when asked to provide a lot of power. In general, about a 20% or so of what you spend on everything else should be spent on cables.

Let's say $600 for cables.



Batteries;


I prefer AGM batteries for the simple fact you can install them inside in an enclosed area and you don't have to worry about venting of gases. They are also absolutely zero maintenance. If properly maintained, they also last a LONG time. Brazos Hunter has 2 batteries he got from me that are Hawker 50 amp/hr. They were made in the year 2000 and I bought them in 2009 used from a guy. 15 years after their manufacture date, they are still in great condition. Now this is not typical as a typical AGM battery is designed to last 10 years.

Here is a guy in Dallas that sells AGM batteries and for a good price. I have bought some other batteries from him before and have been happy.

http://dallas.craigslist.org/dal/mad/5155364635.html

These are 6 volt 250 amp/hr batteries that are 2 years old and are $90 each. For a modest system with the above panels, I would say to have 6 of these batteries. Wired at 12 volts, that would yield a 750 amp/hr battery bank. That means you could use 37 amps constantly for 20 hours straight before the battery bank would need to be recharged.

$540 for batteries.



You are looking at around $3300 or so just for the basic system. This would allow you to use any 12 volt DC device directly off of the battery bank and you could also use a 12 volt DC power inverter for any small to medium size 120 volt items you may want to run. Add a good size generator and a good size 120 volt battery charger and you could recharge the batteries if, for example, snow covered the panels and power output dropped.