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I like the idea of having solar cells that charge up a bank of batteries that could power my house at night. I was recently talking to a Solar City rep and the

I like the idea of having solar cells that charge up a bank of batteries that could power my house at night. I was recently talking to a Solar City rep and they are thinking along those lines. I wonder if this would be a good time to define a standard low voltage plug for house hold use. An awful lot of modern electrical devices don't need 110VAC and end up wasting a lot of power converting AC to DC. I've seen replacements for wall sockets that combine a single AC socket with a few USB power ports. That's convenient, but USB wasn't designed as a power plug, it's just been co-opted for it. A well designed system of 24VDC or 48VDC would be a nice thing to have. Bonus points if it's a world standard. I'd also like a pony.

ph0rque 12y ago
One could bootstrap by using 12V RV appliances, with the exception of big items like the refrigerator, range, and washing/drying machines.
- IgorPartola 12y ago
  Don't forget AC and furnace. In most places where you can efficiently use solar panels, AC is pretty essential.
  - freehunter 12y ago
    It would be nice to re-think the necessity of AC, as well. It's been around for quite a long time and the ineffectiveness are crazy (same thing with whole-house heating). Why heat or cool your house and deal with the insulation problems that come from having doors and windows and walls and exposure to sun or wind on one side? Your house doesn't get hot or cold, it doesn't care. You get hot and cold. Supercomputers run on batteries for an entire day or more in our pockets. Powerful mobile gaming machines can be run from a USB socket. There has to be a way to cool me down in the summer without needing to cool my entire house (and watch as the cold air streams out underneath my door).
    - bkmartin 12y ago
      Easy answer... it's convenient. You show me a people warming/cooling solution as convenient as whole home heating and cooling and then the conversation can begin. It's about creating an environment to live in that is consistent, has nothing to do with a house's feelings.
      - emcrazyone 12y ago
        agree. Also, you need to heat your house here in Michigan if you don't want your water pipes to freeze... or your kid's pet cockatiel to die or suffer.
        33W 12y ago
        I can't speak to cockatiels, but the house should be okay ar 40-45degrees, where people would be uncomfortable.
        emcrazyone 12y ago
        I have a bathroom where the water pipes pass through an outside wall. On nights where the temperature goes below 0 degrees F, I open the cabinet door under the sink so heat can get in there. My thermostat is programmed to drop to 60 degrees F at night but because the thermostat is across the house, our downstairs bathroom gets very cold. It's on a slab too. Pipes always freeze if we forget to prop the door open and the temps get down below or in the single digits. I had been thinking of getting one of those wires you put on the pipe to keep it from freezing but it's behind a wall and very hard to get too...
        IgorPartola 12y ago
        You might be able to use a water circulator to keep hot water in the pipes.
      - freehunter 12y ago
        I honestly thought I was talking to a group of engineering-minded people. This comment? This is where dreams go to die. But I guess there's no room for improvement, which is why heated seats were never invented in cars, why hand warmers were never invented, why heated jackets don't exist, why we don't have ice packs, etc. Those things would be crazy and useless.
JshWright 12y ago
Modern switching transformers are pretty darn efficient. I think it's very unlikely that the losses from converting AC to DC would outweigh the transmission losses you'd get from using low voltage DC (even over the short distances inside a house).
- samatman 12y ago
  I would love to see a Fermi estimate of this, I'm afraid it's outside my bailiwick. The proposal would be 48VDC (pretty standard for panels) to 120VAC 50Hz, back to 5 and 12 volt at the application, versus sending 12 and 5 volt around a house, call it 10x10 meter perimeter and pessimize the layout (some outlets go all the way around the house). My strong sense is that the single-step conversion beats the three-step, but losses transmitting low voltage DC are substantial.
  - adamgravitis 12y ago
    My understanding was that the greater losses in today's tech tend to lie at the VDC->VAC conversion panel-side. Also, I agree that the USB Power Delivery spec is a very good candidate for modern homes/vehicles.
  - wtallis 12y ago
    Sending 12V around a 22' boat leads to voltage drops that are beyond the tolerances of many of the devices that consume 5 and 12 volt DC. Sending it around a whole house would require stupidly thick wires to stay within ATX spec (5%).
- rootbear 12y ago
  Yeah, I wondered about that, but my electronics-fu is not up to analyzing it. Running low voltage DC from one end of a large house to the other might simply not be practical. I'd still like to see a low-voltage plug standard other than USB and cigarette sockets, even if the conversion was being done inside the electrical box in my wall. I see the huge number of wall warts I have as a source of needless duplication and waste. (They are also, I understand, a revenue source for vendors selling replacements at inflated prices, so there is an economic incentive for the status quo.)
samatman 12y ago
The new USB standard supports up to 100 watts per port, which is sufficient to many applications. If we accepted 20 amps as the current rating, a 12v ride-on system would offer 100 / 5 * 12 -> 240 watts, which seems low, except that DC, especially if well filtered, stacks in parallel and series much more composably than AC. The cigarette charger standard plug sucks though, and there's a limited window of opportunity to replace it.
- rootbear 12y ago
  Yeah, we have two standards now, auto cigarette sockets and USB, neither of which is optimal. And I agree, the window of opportunity here is narrow and I'd hate to see us miss it. Oh, and to address the comment on wattage, I should have made clear I don't want to eliminate AC sockets where they are needed. I'm just looking at having DC in the wall as a convenience and efficiency thing and a way to reduce the number of power adaptors I need.
  - m_mueller 12y ago
    USB has the best chance to be successful (since people already get used to it on airplanes etc.) - it's better than nothing.
  - wodenokoto 12y ago
    What could a new standard do that usb can't? Next generation is reversible, there's little to no chance of touching a half plugged in plug and get shocked. It seems pretty good to me.
    - MichaelGG 12y ago
      There's the security downside of plugging in a data capable port when you think you're just getting power. I know this isn't worth consideration for most people, though, and there are "condoms" to deal with it. Still, it'd be nice if we could fully rely on charging devices with no chance of being attacked, like dedicated power systems in use on most laptops today.
TD-Linux 12y ago
Running off-grid solar cell systems has been quite popular in the hobbyist space for a while. There are tons of products and examples out there for DIY installations. These generally use lead-acid batteries and inverters to convert DC up to 110 VAC for your house. There are already DC power standards used for electronics, too. Telecom equipment commonly uses -48 VDC. However, I expect that you will find that the majority of your electricity is used by motors and other appliances that run directly off of 110 VAC.
- diydsp 12y ago
  Exactly. And not even just in hobbyist space. There is a long-established history of running homes off of solar power using lead-acid batteries in professional installations. And not even just in homes; many, many businesses have invested in it. The only barrier is financing... and companies are even forming California to amortize the financing of solar to the home, so home owners can get started with ~$200/month instead of a $20k installation. There, the possibility that a "Tesla" battery could do anything the same or better is not new, redundant and this article is just marketing hype: It's a report of an investor call, for crying out loud, not researched journalism. There is no reason to expect a lithium battery in the home would be cheaper than traditional, established lead-acid batteries. The advantage of lithium in a car is obvious (weight, if you haven't had your coffee). In the home, weight is not a factor. Lithium would save space, but at the expense of lifetime and cost. Since cost is the only factor holding back installation now, I don't expect many people to pay even more for the privilege of a lithium home battery bank. BTW, in reference to your expectation, a motors expert I work with says that 50% of all electricity consumed is consumed by motors. The refrigerator's compressor motor is generally the heaviest electricity consumer in the home.
  - IgorPartola 12y ago
    The barrier is batteries and the cost of them. I briefly looked into this. To run my house's essentials: heat, water, fridge, and 1-2 outlets for electronics I currently use a 5KW generator when the power goes out. I have a transfer switch that shows me my peak current: roughly 2.5-3 KW when the well and fridge are running. A deep cycle marine batter that you can readily buy from Amazon costs $100 or so and gives you 12 Volt 35AH. That's 420 Watt hours. Thus to run just the bare essentials in my house for 1 hour, I'd need 7 of these (assuming perfect DC to AC conversion). To run for 24 hours, I'd need 168 of them. So I am investing $16,800 in just batteries. But don't forget, that there will be periods of cloudy days, so you want enough capacity to get through those. I haven't seen the sun here in CT for about a week now... Oh, and in the summer, I do like my AC which itself pulls 5kW and has a relatively high starting current. I'd have to quadruple the capacity to run it. My basement is simply not large enough to contain all these batteries + inverter system. Doing all this to save under $200/month on the electric bill will never pay for itself. A low cost space saving battery with high energy density would be pretty game changing here.
higherpurpose 12y ago
Europe uses 220-240V.
- walshemj 12y ago
  Which is safer in terms of fires than 110
  - toomuchtodo 12y ago
    220-240V is much more likely to arc then 110V.
    - walshemj 12y ago
      its the old wiring getting hot and setting fire than the arcs
ChuckMcM 12y ago
I've often wondered if someone would make a DC outlet strip. As the typical one has a half dozen "wall wart" type power supplies plugged into it, doing the conversion to say 24VDC and then down converting from there seem to be more convenient. But efficiency wise its something of a wash. And from a whole house perspective, I keep hoping for a capacitor (storing charge directly rather than in chemical bonds) which would give me back most of the energy I had stored.
- reportingsjr 12y ago
  That is sort of becoming a thing with USB outlets. It is starting to become quite ubiquitous. I wouldn't be surprised to see an outlet that had 4+ USB ports and a standard outlet maybe.
  - jimktrains2 12y ago
    Laptops, speakers, and many other devices require more than USB2 can deliver (though Type-C might change that). Also, USB outlets still down convert 120V AC. It'd be much better to do it in bulk at once place in the house and let devices use that
    - JoshTriplett 12y ago
      > Also, USB outlets still down convert 120V AC. It'd be much better to do it in bulk at once place in the house and let devices use that That's not entirely clear. Low-voltage DC has higher transmission losses, so converting to USB-level voltage in one central location might do quite a bit worse. Plus, you still need logic at the plug to detect how much power to supply.
      - ChuckMcM 12y ago
        This is my opinion as one. Switching supplies are 90+ efficient, at nominal load and they are less efficient below and above that nominal load. So your 48VDC converter might by 87% efficient because its rated for 500W and you're only drawing 50. And your 5V regulator may be only 92% efficient while your device is charging but 88% when your device is 'idling'.
krschultz 12y ago
We had 110VAC & 12V DC wall plugs on our boat. It wasn't exactly fool proof (there was just a label above each that said AC or DC), but it totally worked if you knew what you were doing. We had a bunch of devices that could plug into 12V DC directly and avoid the inverter penalty. Phone chargers, lamps, laptop chargers, etc.
- emcrazyone 12y ago
  my Chrysler Town & Country van has 110v outlets in the rear of the van. Occasionally, we trip the breaker but for the most part it works rather well too.
emcrazyone 12y ago
Curious... I live in suburbia where putting solar panels on one's domicile would most likely be met with an order to remove or fines. I had an experimental panel in my backyard to provide power to a work shop shed. The shed was there when I purchased the property & house. About 6 months after planting a pole in the ground, behind the shed, but in view to my neighbors garnered a letter from the township where I live that basically said to remove it for being an eye sore. Has anyone else ran into this problem?
- blacksmith_tb 12y ago
  That's crazy. What, they hate tax credits? I'm glad I live in middle of a smallish city, where the 20 panels on my roof don't raise any eyebrows whatsoever.
- saraid216 12y ago
  Maybe decorate it with flowers? Or talk with your neighbors? =/
- driverdan 12y ago
  Do you mean an HOA is regulating this or the town itself?
  - emcrazyone 12y ago
    there is no HOA. The township sent me a letter saying it violated some ordinance about affixing stuff to the ground like a flag pole. It was affixed to the ground with a solar panel on top of the pole. I've contemplated moving the panel to the roof of the shed where I think they wouldn't have an argument then.
- bdcs 12y ago
  >Has anyone else ran into this problem? So many people did that this very practice is now banned in the state of California.
  - toomuchtodo 12y ago
spacecowboy_lon 12y ago
There are problems with using DC in a consumer environment incresaed losses and nore fires ( problem in Amrica with its use of wood as abuiding material) Talk to any telecoms workers and they will tell you amusing stories about acidents with the DC supply - the Painters shorting out the bussbars whilst decorating an Echange (Central Office) was one I remeber. 48 V might be posble but that means 2 Diferent sets of wireing.
todd8 12y ago
The problem with low voltage power is power loss during transmission. Power in a circuit is voltage times current: Watts = Volts * Amps Power lost in transmission is current through the wire times the voltage drop across the wire. The voltage drop is easy to figure out with Ohms law: Volts = Amps * Ohms Rewriting these with V = voltage, I = current in amps, R = resistance in ohms and P = power in Watts and simplifying one gets: P = V * I P = (I * R) * I P = I**2 * R So power losses are proportional to the square of the current flowing through any given piece of wire (that will have a resistance independent of the voltage or current). My house has 20 Amp circuits at 120 Volts. The same power transmitted at 5 volts needs 24 times the current (i.e. 480 Amps) and 24^2 times the copper in the transmission wire to have the same power losses. So I would basically need a wire with 576 times as much copper to have the same power loss in that one low voltage circuit. This is why it isn't practical to run the whole house on low voltage. High efficiency transformers can step up or down a voltage while losing only a few percent of the power. When their output voltage is 10 times higher their output current will be 10 times smaller and can be transmitted over the same wire with only 1 percent of the original voltage's transmission power loss. This is the reason that power transmission lines run at 120,000 volts--a million times lower transmission line losses. (It actually is a bit more complicated due to the alternating current interactions, but it's the basic idea.) Power transformers can be 99% efficient. I have no idea of the power losses that would occur between DC current from solar panels to 120 VAC and then back to 5 VDC for USB, but you definitely don't want to transmit 5VDC over long distances.
- deleted 12y ago
  [deleted]
- CucumberLime 12y ago
  I think the idea is use these only for low wattage applications, way below 2400 Watts. 48V at, say, 10A is plenty of power for many uses. Also the transmission distances should be relatively short if coming from a battery in the home.
  - jws 12y ago
    The cross over is surprisingly early. I care for a cabin that uses a 24VDC battery for its solar power storage. I run that in #6 copper to the cabin (pencil thick conductors). I regularly see a >2 volt drop on that run when the tiny high efficiency fridge kicks on, on top of the ~40watts that the telemetry and comm gear takes. You wouldn't notice that on a 120v line, but that's 10% of my power gone to heating the earth. Given a do-over on infrastructure, with today's equipment costs, it would save up front capital and power to use a small inverter at the batteries and run those items off of AC using smaller copper lines for the long run. Keep in mind that you still need DC-DC converters at the loads, since nothing is going to want to run off of your varying DC socket voltage. (Batteries closer to the cabin is not a win, the solar panels are off that direction and those lines need to be kept short too. I do have a large inverter in the battery shed and send 120v to the cabin for big loads, but its idle current is too high to keep up for the base loads. The most expensive part of this spring's wind turbine installation (and heaviest) is the copper wire. Low voltage DC is not an answer.)

ph0rque 12y ago

One could bootstrap by using 12V RV appliances, with the exception of big items like the refrigerator, range, and washing/drying machines.

IgorPartola 12y ago
Don't forget AC and furnace. In most places where you can efficiently use solar panels, AC is pretty essential.
- freehunter 12y ago
  It would be nice to re-think the necessity of AC, as well. It's been around for quite a long time and the ineffectiveness are crazy (same thing with whole-house heating). Why heat or cool your house and deal with the insulation problems that come from having doors and windows and walls and exposure to sun or wind on one side? Your house doesn't get hot or cold, it doesn't care. You get hot and cold. Supercomputers run on batteries for an entire day or more in our pockets. Powerful mobile gaming machines can be run from a USB socket. There has to be a way to cool me down in the summer without needing to cool my entire house (and watch as the cold air streams out underneath my door).
  - bkmartin 12y ago
    Easy answer... it's convenient. You show me a people warming/cooling solution as convenient as whole home heating and cooling and then the conversation can begin. It's about creating an environment to live in that is consistent, has nothing to do with a house's feelings.
    - emcrazyone 12y ago
      agree. Also, you need to heat your house here in Michigan if you don't want your water pipes to freeze... or your kid's pet cockatiel to die or suffer.
      - 33W 12y ago
        I can't speak to cockatiels, but the house should be okay ar 40-45degrees, where people would be uncomfortable.
        emcrazyone 12y ago
        I have a bathroom where the water pipes pass through an outside wall. On nights where the temperature goes below 0 degrees F, I open the cabinet door under the sink so heat can get in there. My thermostat is programmed to drop to 60 degrees F at night but because the thermostat is across the house, our downstairs bathroom gets very cold. It's on a slab too. Pipes always freeze if we forget to prop the door open and the temps get down below or in the single digits. I had been thinking of getting one of those wires you put on the pipe to keep it from freezing but it's behind a wall and very hard to get too...
        IgorPartola 12y ago
        You might be able to use a water circulator to keep hot water in the pipes.
    - freehunter 12y ago
      I honestly thought I was talking to a group of engineering-minded people. This comment? This is where dreams go to die. But I guess there's no room for improvement, which is why heated seats were never invented in cars, why hand warmers were never invented, why heated jackets don't exist, why we don't have ice packs, etc. Those things would be crazy and useless.

JshWright 12y ago

Modern switching transformers are pretty darn efficient. I think it's very unlikely that the losses from converting AC to DC would outweigh the transmission losses you'd get from using low voltage DC (even over the short distances inside a house).

samatman 12y ago
I would love to see a Fermi estimate of this, I'm afraid it's outside my bailiwick. The proposal would be 48VDC (pretty standard for panels) to 120VAC 50Hz, back to 5 and 12 volt at the application, versus sending 12 and 5 volt around a house, call it 10x10 meter perimeter and pessimize the layout (some outlets go all the way around the house). My strong sense is that the single-step conversion beats the three-step, but losses transmitting low voltage DC are substantial.
- adamgravitis 12y ago
  My understanding was that the greater losses in today's tech tend to lie at the VDC->VAC conversion panel-side. Also, I agree that the USB Power Delivery spec is a very good candidate for modern homes/vehicles.
- wtallis 12y ago
  Sending 12V around a 22' boat leads to voltage drops that are beyond the tolerances of many of the devices that consume 5 and 12 volt DC. Sending it around a whole house would require stupidly thick wires to stay within ATX spec (5%).
rootbear 12y ago
Yeah, I wondered about that, but my electronics-fu is not up to analyzing it. Running low voltage DC from one end of a large house to the other might simply not be practical. I'd still like to see a low-voltage plug standard other than USB and cigarette sockets, even if the conversion was being done inside the electrical box in my wall. I see the huge number of wall warts I have as a source of needless duplication and waste. (They are also, I understand, a revenue source for vendors selling replacements at inflated prices, so there is an economic incentive for the status quo.)

samatman 12y ago

The new USB standard supports up to 100 watts per port, which is sufficient to many applications. If we accepted 20 amps as the current rating, a 12v ride-on system would offer 100 / 5 * 12 -> 240 watts, which seems low, except that DC, especially if well filtered, stacks in parallel and series much more composably than AC. The cigarette charger standard plug sucks though, and there's a limited window of opportunity to replace it.

rootbear 12y ago
Yeah, we have two standards now, auto cigarette sockets and USB, neither of which is optimal. And I agree, the window of opportunity here is narrow and I'd hate to see us miss it. Oh, and to address the comment on wattage, I should have made clear I don't want to eliminate AC sockets where they are needed. I'm just looking at having DC in the wall as a convenience and efficiency thing and a way to reduce the number of power adaptors I need.
- m_mueller 12y ago
  USB has the best chance to be successful (since people already get used to it on airplanes etc.) - it's better than nothing.
- wodenokoto 12y ago
  What could a new standard do that usb can't? Next generation is reversible, there's little to no chance of touching a half plugged in plug and get shocked. It seems pretty good to me.
  - MichaelGG 12y ago
    There's the security downside of plugging in a data capable port when you think you're just getting power. I know this isn't worth consideration for most people, though, and there are "condoms" to deal with it. Still, it'd be nice if we could fully rely on charging devices with no chance of being attacked, like dedicated power systems in use on most laptops today.

TD-Linux 12y ago

Running off-grid solar cell systems has been quite popular in the hobbyist space for a while. There are tons of products and examples out there for DIY installations. These generally use lead-acid batteries and inverters to convert DC up to 110 VAC for your house. There are already DC power standards used for electronics, too. Telecom equipment commonly uses -48 VDC. However, I expect that you will find that the majority of your electricity is used by motors and other appliances that run directly off of 110 VAC.

diydsp 12y ago
Exactly. And not even just in hobbyist space. There is a long-established history of running homes off of solar power using lead-acid batteries in professional installations. And not even just in homes; many, many businesses have invested in it. The only barrier is financing... and companies are even forming California to amortize the financing of solar to the home, so home owners can get started with ~$200/month instead of a $20k installation. There, the possibility that a "Tesla" battery could do anything the same or better is not new, redundant and this article is just marketing hype: It's a report of an investor call, for crying out loud, not researched journalism. There is no reason to expect a lithium battery in the home would be cheaper than traditional, established lead-acid batteries. The advantage of lithium in a car is obvious (weight, if you haven't had your coffee). In the home, weight is not a factor. Lithium would save space, but at the expense of lifetime and cost. Since cost is the only factor holding back installation now, I don't expect many people to pay even more for the privilege of a lithium home battery bank. BTW, in reference to your expectation, a motors expert I work with says that 50% of all electricity consumed is consumed by motors. The refrigerator's compressor motor is generally the heaviest electricity consumer in the home.
- IgorPartola 12y ago
  The barrier is batteries and the cost of them. I briefly looked into this. To run my house's essentials: heat, water, fridge, and 1-2 outlets for electronics I currently use a 5KW generator when the power goes out. I have a transfer switch that shows me my peak current: roughly 2.5-3 KW when the well and fridge are running. A deep cycle marine batter that you can readily buy from Amazon costs $100 or so and gives you 12 Volt 35AH. That's 420 Watt hours. Thus to run just the bare essentials in my house for 1 hour, I'd need 7 of these (assuming perfect DC to AC conversion). To run for 24 hours, I'd need 168 of them. So I am investing $16,800 in just batteries. But don't forget, that there will be periods of cloudy days, so you want enough capacity to get through those. I haven't seen the sun here in CT for about a week now... Oh, and in the summer, I do like my AC which itself pulls 5kW and has a relatively high starting current. I'd have to quadruple the capacity to run it. My basement is simply not large enough to contain all these batteries + inverter system. Doing all this to save under $200/month on the electric bill will never pay for itself. A low cost space saving battery with high energy density would be pretty game changing here.

higherpurpose 12y ago

Europe uses 220-240V.

walshemj 12y ago
Which is safer in terms of fires than 110
- toomuchtodo 12y ago
  220-240V is much more likely to arc then 110V.
  - walshemj 12y ago
    its the old wiring getting hot and setting fire than the arcs

ChuckMcM 12y ago

I've often wondered if someone would make a DC outlet strip. As the typical one has a half dozen "wall wart" type power supplies plugged into it, doing the conversion to say 24VDC and then down converting from there seem to be more convenient. But efficiency wise its something of a wash. And from a whole house perspective, I keep hoping for a capacitor (storing charge directly rather than in chemical bonds) which would give me back most of the energy I had stored.

reportingsjr 12y ago
That is sort of becoming a thing with USB outlets. It is starting to become quite ubiquitous. I wouldn't be surprised to see an outlet that had 4+ USB ports and a standard outlet maybe.
- jimktrains2 12y ago
  Laptops, speakers, and many other devices require more than USB2 can deliver (though Type-C might change that). Also, USB outlets still down convert 120V AC. It'd be much better to do it in bulk at once place in the house and let devices use that
  - JoshTriplett 12y ago
    > Also, USB outlets still down convert 120V AC. It'd be much better to do it in bulk at once place in the house and let devices use that That's not entirely clear. Low-voltage DC has higher transmission losses, so converting to USB-level voltage in one central location might do quite a bit worse. Plus, you still need logic at the plug to detect how much power to supply.
    - ChuckMcM 12y ago
      This is my opinion as one. Switching supplies are 90+ efficient, at nominal load and they are less efficient below and above that nominal load. So your 48VDC converter might by 87% efficient because its rated for 500W and you're only drawing 50. And your 5V regulator may be only 92% efficient while your device is charging but 88% when your device is 'idling'.

krschultz 12y ago

We had 110VAC & 12V DC wall plugs on our boat. It wasn't exactly fool proof (there was just a label above each that said AC or DC), but it totally worked if you knew what you were doing. We had a bunch of devices that could plug into 12V DC directly and avoid the inverter penalty. Phone chargers, lamps, laptop chargers, etc.

emcrazyone 12y ago
my Chrysler Town & Country van has 110v outlets in the rear of the van. Occasionally, we trip the breaker but for the most part it works rather well too.

emcrazyone 12y ago

Curious... I live in suburbia where putting solar panels on one's domicile would most likely be met with an order to remove or fines. I had an experimental panel in my backyard to provide power to a work shop shed. The shed was there when I purchased the property & house. About 6 months after planting a pole in the ground, behind the shed, but in view to my neighbors garnered a letter from the township where I live that basically said to remove it for being an eye sore. Has anyone else ran into this problem?

blacksmith_tb 12y ago
That's crazy. What, they hate tax credits? I'm glad I live in middle of a smallish city, where the 20 panels on my roof don't raise any eyebrows whatsoever.
saraid216 12y ago
Maybe decorate it with flowers? Or talk with your neighbors? =/
driverdan 12y ago
Do you mean an HOA is regulating this or the town itself?
- emcrazyone 12y ago
  there is no HOA. The township sent me a letter saying it violated some ordinance about affixing stuff to the ground like a flag pole. It was affixed to the ground with a solar panel on top of the pole. I've contemplated moving the panel to the roof of the shed where I think they wouldn't have an argument then.
bdcs 12y ago
>Has anyone else ran into this problem? So many people did that this very practice is now banned in the state of California.
- toomuchtodo 12y ago

spacecowboy_lon 12y ago

There are problems with using DC in a consumer environment incresaed losses and nore fires ( problem in Amrica with its use of wood as abuiding material) Talk to any telecoms workers and they will tell you amusing stories about acidents with the DC supply - the Painters shorting out the bussbars whilst decorating an Echange (Central Office) was one I remeber. 48 V might be posble but that means 2 Diferent sets of wireing.

todd8 12y ago

The problem with low voltage power is power loss during transmission. Power in a circuit is voltage times current: Watts = Volts * Amps Power lost in transmission is current through the wire times the voltage drop across the wire. The voltage drop is easy to figure out with Ohms law: Volts = Amps * Ohms Rewriting these with V = voltage, I = current in amps, R = resistance in ohms and P = power in Watts and simplifying one gets: P = V * I P = (I * R) * I P = I**2 * R So power losses are proportional to the square of the current flowing through any given piece of wire (that will have a resistance independent of the voltage or current). My house has 20 Amp circuits at 120 Volts. The same power transmitted at 5 volts needs 24 times the current (i.e. 480 Amps) and 24^2 times the copper in the transmission wire to have the same power losses. So I would basically need a wire with 576 times as much copper to have the same power loss in that one low voltage circuit. This is why it isn't practical to run the whole house on low voltage. High efficiency transformers can step up or down a voltage while losing only a few percent of the power. When their output voltage is 10 times higher their output current will be 10 times smaller and can be transmitted over the same wire with only 1 percent of the original voltage's transmission power loss. This is the reason that power transmission lines run at 120,000 volts--a million times lower transmission line losses. (It actually is a bit more complicated due to the alternating current interactions, but it's the basic idea.) Power transformers can be 99% efficient. I have no idea of the power losses that would occur between DC current from solar panels to 120 VAC and then back to 5 VDC for USB, but you definitely don't want to transmit 5VDC over long distances.

deleted 12y ago
[deleted]
CucumberLime 12y ago
I think the idea is use these only for low wattage applications, way below 2400 Watts. 48V at, say, 10A is plenty of power for many uses. Also the transmission distances should be relatively short if coming from a battery in the home.
- jws 12y ago
  The cross over is surprisingly early. I care for a cabin that uses a 24VDC battery for its solar power storage. I run that in #6 copper to the cabin (pencil thick conductors). I regularly see a >2 volt drop on that run when the tiny high efficiency fridge kicks on, on top of the ~40watts that the telemetry and comm gear takes. You wouldn't notice that on a 120v line, but that's 10% of my power gone to heating the earth. Given a do-over on infrastructure, with today's equipment costs, it would save up front capital and power to use a small inverter at the batteries and run those items off of AC using smaller copper lines for the long run. Keep in mind that you still need DC-DC converters at the loads, since nothing is going to want to run off of your varying DC socket voltage. (Batteries closer to the cabin is not a win, the solar panels are off that direction and those lines need to be kept short too. I do have a large inverter in the battery shed and send 120v to the cabin for big loads, but its idle current is too high to keep up for the base loads. The most expensive part of this spring's wind turbine installation (and heaviest) is the copper wire. Low voltage DC is not an answer.)