WE HAVE POWER!!! Lots has been going on the past couple weeks and I'm excited to share the news. After completing the roof and building the interior walls for the utility closet bathroom, we got to planning our electrical wiring and power. We probably exchanged something like 50 emails between my brother, Kevin, and friend, Seth. They live in Montana and are electrical engineers - so they pretty much saw this project and freaked out with excitement.
Just to start off, we decided to run the house on 24v DC. What that means: electricity is generated in DC. But many of our appliances run off of AC, so there is an inverter in all our homes that changes the DC to AC. All our homes run off of AC (to give you a frame of reference). However, there are still many devices we use that run off DC (phone chargers, camera battery chargers, laptops, etc), so then what happens is the DC changes to AC and then back to DC again. This inversion process creates a loss of power, which we want to avoid. This is why we want to run as much of the house as possible on DC. This way, we don't need to buy a big inverter for the whole house and we retain most of the power we generate. This means that our fridge will be DC, our laptop will be our "TV", and we will be packing away our toaster oven, blender, and other AC appliances that will not be used in the tiny house.
Kevin's Comment to this section: Today, electricity is generated at AC and then transformed to high voltage and transmitted over long distances. Edison's original Pearl Street generation plant was a DC plant; however, at the time they had no way of transforming the voltage. This meant that the customer at the end of the line saw lower voltage than the customer at the beginning of the line due to voltage drop (losses) through the line. Then Tesla came along and made AC generation possible. Again the advantage to AC generation is that it can be transformed to high voltage and then transmitted, which results in considerably less losses and therefore the customer at the beginning and end of the line have similar voltage. Like you mentioned many appliances actually run on DC, so once the power comes into our homes some of it is rectified to DC. That rectifier is a power electronic device and has some losses. Solar panels generate at DC, this is different from the traditional thermal generators (coal, gas, nuclear) that generate at AC, so it makes sense not to invert to AC and then rectify back to DC to run your loads.
Side note: I have a desktop computer, which runs off AC. We will have one outlet in the whole house that has an inverter to run AC electricity to that desktop. When the computer is not in use, it will be turned completely off.
Here are some of our electrical specs:
-We have Four 100 Watt solar panels, giving us total of 400 Watts of power (yes, I can do math). We purchased them from a company called Windy Nation. We were thinking of purchasing all the different components we need from different companies or sellers in order to save on price. However, we decided that even if it cost us $50-$100 more in the end, it would save time and mental energy if we got everything from the same company. This way, we could be assured that everything would connect with each other, and all the correct components for those particular panels would be purchased. Each solar panel runs at 12v but we connected two panels in series and then the two pair in parallel, giving us 24v of electricity. Here is a link to the package that we bought: 400 Watt MPPT Monocrystalline Solar Kit
Included in the kit is:
(4) 100 Watt solar panels
(1) 40 amp, 12v/24v MPPT charge controller
(4) Bracket mounts
(40 ft) solar extension cable
(3 pairs) MC4 branch connectors
(1) Wiring diagram
-We have two deep cycle marine batteries. We purchased these from our local auto parts store. I basically took their catalog and they ordered the ones I wanted - free shipping that way! These batteries are heavy and shipping can be costly. The deep cycle batteries are very important to get because they last MUCH longer and can be run down more than your regular car battery without much loss of life to the battery. Here is what we got: Optima YellowTop Battery
**Each battery is 12V but we ran them in series to create a 24V system in the house
-We purchased about 10 24v LED lightbulbs to put in our light fixtures (these were not easy to find, but eBay is a wonderful thing). We purchased more bulbs than we needed, since we installed 8 lights in the whole house. Two in the living room, two in the dining room, two in the loft, one in the bathroom, and one outside next to the front door.
-We purchased a Dickinson propane heater. This was a tough decision! We were so set on going with the wood burning stove, but after a lot of discussion with close friends we decided against it. We had to accept the fact that maintaining the heat from the wood burning stove (day and night in the winter months) might be a chore we won't enjoy for too long. This added a lot more cost to our total expenditures, but we coughed up the $700 for the heater.
We then went ahead and bought an exhaust pipe extension so that it would go straight through the roof. That added another $100-$150. We figure it will give off some more heat with a longer exhaust pipe. Here is the heater we purchased: Dickinson Heater. Buying this thing new off the manufacturer's website will cost you much more as opposed to searching around for a cheaper option. I believe we got ours off some marine website.
-We are using light fixtures purchased from Home Depot. We got these $15 pendant light fixture kits for the living room and kitchen, and then you just buy the glass shade that you want to put on it. It was a pretty cheap option and they were new and easy to install. Buying new is great when it's affordable because there are no missing parts and no ghetto rigging necessary! here are the pendant kits: Oil Rubbed Bronze Mini Pendant Kit
-We have a switch panel that allows us to completely shut off power to different areas of the house (this would never have been a reality had it not been for Kevin and Seth geeking out on all these doo-dads). We purchased them from WestMarine.com and here is a link: DC Electrical Panels The one we bought is the one with four switches and two DC outlets on the bottom (AKA car cigarette lighter outlets).
-This is going to be confusing, but most of the outlets we installed in the house are 12v DC outlets. This is made possible by wiring a very small converter at each of these outlets to change the current from 24v DC to 12v DC. 12v DC outlets are the same outlets we all use in our cars to charge our phones, ipads, etc. So we have a lot of these in the house now. There are two or three "regular" three-prong outlets for the 24v fridge, an offshore line (in the rare occasion we could run an extension chord from a regular on-grid house and get 120v AC from it), and for the desktop computer. My brother purchased these and I think he got many of them from Lowes.
-We also have switches at each outlet to make it functioning or not. Again, this is just another little "geek moment" on the part of Kevin and Seth to conserve as much power as possible and not have the tiniest bit of power lost from the outlets being connected but not used. Engineering grad students....can't live with em, can't live without em.
-We installed a battery volt meter on the wall so we can see how drained our batteries our. This will help us to know when to conserve power, and when to REALLY conserve power (for those cloudy days). Basically, is the meter reads 24.0v, the batteries are about 50% depleted, and for the health of the batteries it should not be depleted any more than that. So at 24.0v we need to start shutting everything off and living by candle light. But we hope this doesn't happen. Despite the house running on 24v, it will always be slightly above that as long as power is being generated. Today it was at 26.7 I believe. We got a toggle switch to activate the thing. Oh, and it's really cheap: Volt Battery Meter
-Finally, we have not purchased the fridge yet, but we will be buying the Sundanzer rf134 (24v DC). It is 4.7 cubic feet and it kills out wallets to buy this thing, but its the most power efficient refrigerator we found and it runs on DC! For the one appliance that will be running 24/7 in the house, we had to make sure it was as efficient as possible. Here it is: Sundanzer rf134
I am probably forgetting something, but I think this covers all the basics!
The proof is in the pudding
Just to start off, we decided to run the house on 24v DC. What that means: electricity is generated in DC. But many of our appliances run off of AC, so there is an inverter in all our homes that changes the DC to AC. All our homes run off of AC (to give you a frame of reference). However, there are still many devices we use that run off DC (phone chargers, camera battery chargers, laptops, etc), so then what happens is the DC changes to AC and then back to DC again. This inversion process creates a loss of power, which we want to avoid. This is why we want to run as much of the house as possible on DC. This way, we don't need to buy a big inverter for the whole house and we retain most of the power we generate. This means that our fridge will be DC, our laptop will be our "TV", and we will be packing away our toaster oven, blender, and other AC appliances that will not be used in the tiny house.
Kevin's Comment to this section: Today, electricity is generated at AC and then transformed to high voltage and transmitted over long distances. Edison's original Pearl Street generation plant was a DC plant; however, at the time they had no way of transforming the voltage. This meant that the customer at the end of the line saw lower voltage than the customer at the beginning of the line due to voltage drop (losses) through the line. Then Tesla came along and made AC generation possible. Again the advantage to AC generation is that it can be transformed to high voltage and then transmitted, which results in considerably less losses and therefore the customer at the beginning and end of the line have similar voltage. Like you mentioned many appliances actually run on DC, so once the power comes into our homes some of it is rectified to DC. That rectifier is a power electronic device and has some losses. Solar panels generate at DC, this is different from the traditional thermal generators (coal, gas, nuclear) that generate at AC, so it makes sense not to invert to AC and then rectify back to DC to run your loads.
Side note: I have a desktop computer, which runs off AC. We will have one outlet in the whole house that has an inverter to run AC electricity to that desktop. When the computer is not in use, it will be turned completely off.
Saturday morning discussion of the electrical wiring game plan. Kevin and Seth might have boners if you look close enough.
Wiring Schematic. Artistic Credit: Kevin Marchese
Another wring schematic of the battery. Artistic credit: Kevin Marchese
Here are some of our electrical specs:
-We have Four 100 Watt solar panels, giving us total of 400 Watts of power (yes, I can do math). We purchased them from a company called Windy Nation. We were thinking of purchasing all the different components we need from different companies or sellers in order to save on price. However, we decided that even if it cost us $50-$100 more in the end, it would save time and mental energy if we got everything from the same company. This way, we could be assured that everything would connect with each other, and all the correct components for those particular panels would be purchased. Each solar panel runs at 12v but we connected two panels in series and then the two pair in parallel, giving us 24v of electricity. Here is a link to the package that we bought: 400 Watt MPPT Monocrystalline Solar Kit
Included in the kit is:
(4) 100 Watt solar panels
(1) 40 amp, 12v/24v MPPT charge controller
(4) Bracket mounts
(40 ft) solar extension cable
(3 pairs) MC4 branch connectors
(1) Wiring diagram
It's electric! doo doo doo da-doo da doo, doo doo.....
-We have two deep cycle marine batteries. We purchased these from our local auto parts store. I basically took their catalog and they ordered the ones I wanted - free shipping that way! These batteries are heavy and shipping can be costly. The deep cycle batteries are very important to get because they last MUCH longer and can be run down more than your regular car battery without much loss of life to the battery. Here is what we got: Optima YellowTop Battery
**Each battery is 12V but we ran them in series to create a 24V system in the house
-We purchased about 10 24v LED lightbulbs to put in our light fixtures (these were not easy to find, but eBay is a wonderful thing). We purchased more bulbs than we needed, since we installed 8 lights in the whole house. Two in the living room, two in the dining room, two in the loft, one in the bathroom, and one outside next to the front door.
-We purchased a Dickinson propane heater. This was a tough decision! We were so set on going with the wood burning stove, but after a lot of discussion with close friends we decided against it. We had to accept the fact that maintaining the heat from the wood burning stove (day and night in the winter months) might be a chore we won't enjoy for too long. This added a lot more cost to our total expenditures, but we coughed up the $700 for the heater.
We then went ahead and bought an exhaust pipe extension so that it would go straight through the roof. That added another $100-$150. We figure it will give off some more heat with a longer exhaust pipe. Here is the heater we purchased: Dickinson Heater. Buying this thing new off the manufacturer's website will cost you much more as opposed to searching around for a cheaper option. I believe we got ours off some marine website.
-We are using light fixtures purchased from Home Depot. We got these $15 pendant light fixture kits for the living room and kitchen, and then you just buy the glass shade that you want to put on it. It was a pretty cheap option and they were new and easy to install. Buying new is great when it's affordable because there are no missing parts and no ghetto rigging necessary! here are the pendant kits: Oil Rubbed Bronze Mini Pendant Kit
Left to right: outdoor light next to front door, bathroom light, hanging pendant lights for kitchen and living room, the tall light on the very right will be returned (bought from local thrift...decided not to use it), and finally the lights in front will be mounted to the wall in the loft on either side of the bed.
-We have a switch panel that allows us to completely shut off power to different areas of the house (this would never have been a reality had it not been for Kevin and Seth geeking out on all these doo-dads). We purchased them from WestMarine.com and here is a link: DC Electrical Panels The one we bought is the one with four switches and two DC outlets on the bottom (AKA car cigarette lighter outlets).
-This is going to be confusing, but most of the outlets we installed in the house are 12v DC outlets. This is made possible by wiring a very small converter at each of these outlets to change the current from 24v DC to 12v DC. 12v DC outlets are the same outlets we all use in our cars to charge our phones, ipads, etc. So we have a lot of these in the house now. There are two or three "regular" three-prong outlets for the 24v fridge, an offshore line (in the rare occasion we could run an extension chord from a regular on-grid house and get 120v AC from it), and for the desktop computer. My brother purchased these and I think he got many of them from Lowes.
My head hurts from just typing all that gibberish. Let's look at a picture now. MEN AT WORK!!
-We also have switches at each outlet to make it functioning or not. Again, this is just another little "geek moment" on the part of Kevin and Seth to conserve as much power as possible and not have the tiniest bit of power lost from the outlets being connected but not used. Engineering grad students....can't live with em, can't live without em.
Kevin's comment on this section: You should make some points about energy efficiency and general electrical safety. Anything that is plugged into the wall that doesn't have a switch is consuming energy whether you use it or not (the common vernacular for this is phantom voltage although I don't know where that came from). Putting the DC/DC converters on switches allows you to turn them off when you don't need them, as you mentioned. Also, it's just good practice to unplug things that aren't being used because appliances can short out. Every girl has probably had a hair dryer short out, so you're familiar. If that happened while you weren't there it can cause a fire.
-We installed a battery volt meter on the wall so we can see how drained our batteries our. This will help us to know when to conserve power, and when to REALLY conserve power (for those cloudy days). Basically, is the meter reads 24.0v, the batteries are about 50% depleted, and for the health of the batteries it should not be depleted any more than that. So at 24.0v we need to start shutting everything off and living by candle light. But we hope this doesn't happen. Despite the house running on 24v, it will always be slightly above that as long as power is being generated. Today it was at 26.7 I believe. We got a toggle switch to activate the thing. Oh, and it's really cheap: Volt Battery Meter
-Finally, we have not purchased the fridge yet, but we will be buying the Sundanzer rf134 (24v DC). It is 4.7 cubic feet and it kills out wallets to buy this thing, but its the most power efficient refrigerator we found and it runs on DC! For the one appliance that will be running 24/7 in the house, we had to make sure it was as efficient as possible. Here it is: Sundanzer rf134
I am probably forgetting something, but I think this covers all the basics!
We took this picture into the Paint program and sent these details to Kev and Seth so that they could come up with a wiring map...or something like that. Helps everyone else understand the layout as well!
More deets!
No comments:
Post a Comment