Solar Generator

I made this solar generator to power lights, a radio and recharge batteries for my trip to Burning Man 2008.

Parts list:

1. Sunforce 15 watt solar charger with with 7 amp charge controller - Kragen Auto - $99.99 part #50033

2. Pro X One 800 watt power inverter - Kragen Auto - $49.97 on sale - part #64009624

3. Nautilus Gold 24 NG24 deep cycle battery - $84.99 - Kragen Auto - part #6228613

4. 12 volt outlet (cigarette lighter type) - 10.99 - Kragen Auto - part #6261044

5. Digital multimeter - $2.99 - Harbor Freight Tools - part #90899

6. Crimp style electrical connectors (butt and 3/8" ring) - $2

7. 1/2" plywood (or whatever you have lying around) - $10.00

8. Hinges, handles, latches and screws for the box - $15.00

9. Eight zinc plated "L" brackets - $5.00

Step 1: Buy the Parts

I got most of my parts from Kragen Auto. They'll give you a 10% discount if you ask. I had some 1/2" plywood left over from another project to build my box but I saw that RoDuS1488 used a small cooler for his solar generator...that's a great idea, especially if you don't have wood working tools or just can't wait to get the party started. The solar panel comes with a fifteen foot cord that seems long enough to keep the panel out of the shade. Multiple panels can be wired together to get more power. One 15 watt panel barely keeps the battery charged. I think two (at thirty watts) would do a little better.

Step 2: Build a Box

I built my box out of 1/2" plywood and reinforced the inside corners with zinc plated "L" brackets. The sides have heavy duty chest handles to carry the generator and the bottom has four zinc plated metal corners to protect the bottom. The lid is held on with two hinges in the rear and one latch in the front. I made the box 1/2" bigger than my battery around the sides and 2" taller. I also drilled one inch holes in the sides to vent hydrogen gas and allow the battery to cool.

Step 3: Connect the Wires

Put the battery in the box and connect the wires. I cut the ends and used 3/8" ring crimp wire connectors to run the wires to the battery terminal posts. My deep cycle battery has four posts...two are standard car battery type posts and the other two are threaded studs. I used the threaded studs for a more secure connection. Connect the red terminal from the inverter to the positive post and the black to the negative. The solar panel connects to the battery through the charge controller. This keeps the battery from over-charging. The controller shuts off at 14.2 volts and comes on when the voltage drops below 13 volts. I also added a 12 volt outlet directly to the battery for use with cigarette lighter adapters. There's a two amp inline fuse on the positive lead. I bought a cheap digital multimeter and zip tied it to the top of the battery so I can monitor the voltage usage. I cut the leads and again used 3/8" ring crimp connectors to permanently connect them to the battery.

Step 4: Plug in and Enjoy Clean, Silent Power!

I'll use the generator in my dome to run white LED Christmas lights, satellite radio and to charge batteries for my camera and ham radios. )'(

Update: The generator worked great. It never ran out of power. I use it every day at home now.

Comments

[musicman79]

Does anybody know a site or what information I would need to gather to figure how much battery and watts I would need to run a selection of things? I am wanting to build something similar to this for my own family camping needs and would like to run a couple small tent fans, a small 12v mini fridge, and maybe a cell phone charger or two. I can get the power requirements for the items just want to know how to judge the size of my requirements.

[AkiraD2]

Once you have converted doc to ac then use killawatt to measure your real time ac wattage.

[bushb1]

Figure out each item's power load in amps and judge that total against your battery's amphour rating.

[Texas1845]

Wattage of Common Household Appliances/Tools
Appliances

Resistive Load

Reactive Load
Blender
375 watts 500 watts
Clock Radio
5 watts ---
Coffee Maker
1,700 watts ---
Computer - PC
300 watts ---
Cuisinart
450 watts 650 watts
Deep Fryer
1,800 watts ---
Electric Blanket
400 watts ---
Electric Curlers
300 watts ---
Frying Pan
1,250 watts ---
Hair Dryer
1,875 watts ---
Iron
1,200 watts ---
Light Bulbs
see marking on bulb
Microwave
1,050-2,500 watts ---
Washing Machine
1,150 watts 2,200 watts
Water Heater
4,000 watts ---
TV - Color
300 watts ---
Common Tools

Resistive Load

Reactive Load
Air Compressor (1hp)
1,500 watts 4,500 watts
Cultivator
700 watts 1,400 watts
Freezer
800 watts 2,100 watts
Furnace Fan
875-1,200 watts 2,200 watts
Garage Door Opener (1/4 hp)
550 watts 1,000 watts
Grinder, Bench
1,400 watts 2,450 watts
Heater, Kerosene (90,000 BTU)
500 watts 725 watts
Sump Pump (1/3 hp)
800 watts 1,250 watts
Well Pump (1/2 hp)
150 watts 1,950 watts
Saw, Band
1,100 watts 1,350 watts
Table Saw (10 inch)
1,750 watts 4,250 watts

the chart is on http://www.askthebuilder.com/B178_Common_Wattage_of_Household_Appliances.shtml

[NightLord]

Isn't 800W inverter too powerful? I mean, 15W solar panel produces much too little for powering anything in the range of 800W. While you are not able to power big devices, you power small devices at higher losses - high power inverter means higher no-load current, which can take a lot of energy over time. So I would suggest to use smaller, say 300W inverter or even less :)

[AkiraD2]

And I would suggest using Kill-a-watt to help with your addition so that you can ensure the math is right before buying an inverter- count up how many watts you plan on using on all your devices and get an inverter that will cover a continuous load for that rating.

[tk1314]

There are inline fuses. You can see one in the pictures. The solar panels are pretty cheap. They aren't very powerful, since the time of the project, the prices have gone down for better panels.

[AkiraD2]

I recognize that multimeter from harbor freight. Nice- because with a coupon they are free. I have Harbor Freight's 45w kit and a 7a charge controller. The problem ai have is that it is not water resistant. I never would have thought to tie in the multimeter to be used as a digital gauge. Genius!

[flazcoeidc]

I think you need to take some time and go to inplix website to learn how to make it.

[daenergymon]

Not bad. I would have used a larger solar panel to power more things. And for safetys sake add an inline fuse between each part. Cheaper to replace a fuse than anything else

[SIRJAMES09]

Cool!

My first Questions is, Where did you get that dome tent? 8 )

I love it(the dome)!

I also love the idea of how simple & easy it is to build this thing...

I don;t know why, but I always thought that these were a very complicated thing/project....

Obviously I was wrong.

TY for sharing!! : )

[JPcreo]

http://www.harborfreight.com/solar-panel-kit-45-watt-68751.htmlI have found this set at harborfreight.com they also sell a deep cycle battery for about $60 to $80 depends on the sale.

[bsouth]

How many hours did it run the lights, radios and camera battery chargers?

[tk1314]

It would run them all night and have plenty of power left before the sun came up to re-charge the battery. I used LED Christmas lights that only used a few watts and I don't think the battery charger used too much power.

[bsouth]

Awesome, thanks for the info. I am looking for something to power my laptop, a box fan and small refrigerator. Would I have to modify yours much in order to power all that?

[tk1314]

I think it could handle all that. My friend has a 12 volt refrigerator/freezer in his FJ Cruiser running off a deep cycle battery. It doesn't seem to use too much power. He has a dual battery system, one deep cycle for accessories and one regular battery for starting the car. The laptop and fan shouldn't drain the battery either. If you can get them all to run off of 12 volts instead of using the inverter, you would probably use less power.

[Fujo]

I'm not great at electronics but I think it depends on the laptop.. Mine has an adapter that outputs 19v therefore I think I'm correct in assuming it would need more than this setup to run it. Could be wrong though!

[ElectricMan1]

Just because it charges at 19v dosen't mean that a DCDC converter wont work, i bet if you check your BATTERY, it should say like 10.2 or 10.8v.

[tsunami78]

Great post!!  I have been looking at setting something like this up for a while.  I know this is an old one, but I was wondering if there was a way to add a battery charge indicator to quickly see how much life is left between charges.

[ElectricMan1]

Hey, i couldnt help but read your comment, but i just recently found a PV charge controller for 80 dollars.
It can handle up to 50 volts and or 12 amps of current.
Its a Prostar 12.