Two or more chargecontroller 1 PV

[fivewin]

Like this guy installed in his shed:


MiWi Wireless Networking Protocol Stack is a simple protocol designed for low data rate, short distance, low-cost networks. Fundamentally based on IEEE 802.15.4 for Wireless Personal Area Networks (WPANs), it was later expanded to support Microchip's proprietary RF transceiver

https://www.edn.com/design/led/4436903/Designing---building-a-homemade-12VDC-LED-lighting-system

[Sunking]

But, I disagree that 100% dc is ineffective

Then you are mistaken and do not understand basic fundamentals. DC is not even the issue, so I have no clue what you are talking about, and neither do you. So how can you make such claims when you do not know what you are talking about.

The issue is LOW VOLTAGE is inefficient for power transmission. Exact reason why utilities do not use low voltage. Even the USA 240/120 is inefficient, we got stuck with it because of Edison's ignorance and did not listen to Tesla. JP Morgan listened and bought Tesla and Westinghouse. Edison's Light bulb used 110 volt DC and was a decision made out of pure greed and ignorance. The USA was the first to electrify, and we got stuck with 240/120. Europe did something smarter, they went with 240 volts and thus are 400% more efficient.

So what is the issue with low voltage. Well it is extremely simple, low voltage means high current. With respect to power (watt or heat energy), voltage and heat are inversely proportional which is clearly evident in the formula Watt = Voltage x Current. As a practical matter in a proper electrical design you want to limit losses to 3% of voltage and power. Very simple to understand 3% of 12 volts = 0.36 volts and 3% of 120 volts = 3.6 volts.

Example if you have a very small 100 watt load say 50 feet; what is required using 12 or 120 volts and limit power loss to 3%. At 12 volts DC 100 watts / 12 volts = 8.33 amps and by code the minimum required conductor would have to be 14 AWG with a 10 amp breaker. Just one problem, at 50 feet distance you would loose 2.9 volts and incur a 25% voltage drop. You device would not even work. To get down to 3% would require 4 AWG. Well 14 AWG conductor cost 9-cents per foot and 4 AWG cost 90-cents per foot and at 100 feet $9 vs $90.

Do this at 120 volts still requires the code minimum 14 AWG and you could use a 20 amp breaker to have something much more useful and economical. That same 100 watt load you had to use a very expensive dedicated circuit for a single 100 watt gizmo, at 120 volts uses .83 amps and you only loose 0.2% of your power and you now can run up to 1400 watts (14 gizmos on a single circuit) on a single circuit up to 50 feet on 14 AWG wire AC or DC.

That is why utilities use high voltage, and Edison low voltage DC system is history , and the world uses Tesla high voltage AC system. So you can do it your way, or......

[Mike90250]

Like this guy installed in his shed:


MiWi Wireless Networking Protocol Stack is a simple protocol designed for low data rate, short distance, low-cost networks. Fundamentally based on IEEE 802.15.4 for Wireless Personal Area Networks (WPANs), it was later expanded to support Microchip's proprietary RF transceiver

https://www.edn.com/design/led/44369...ighting-system

Wireless Controlled lighting system. For a minute, I thought you had wireless lighting.

[fivewin]

Wireless electricity like tesla coil? Awaiting further development. I think its coming.

Sunking,

Quote: The Google boys, Sergei and Larry, think this is dumb too. Engineers at Google, tired of running tens of thousands of computers with inefficient power supplies, have proposed a new standard for "high efficiency power supplies for home computers and servers" based on everything running on 12 volts only.

https://www.treehugger.com/sustainable-product-design/big-steps-in-building-change-our-wiring-to-12-volt-dc.html

[Sunking]

Google cannot change Ohms Law. Nor can they change the price of copper. Example of how ignorant the article is.

Revise our current wiring codes to reduce the number of 110V outlets and circuits required. Now most electrical codes demand outlets every 12 feet, in every ceiling, duplex outlets in kitchens. Copper is expensive and its mining is destructive; if there is 12VDC wiring then an outlet per room for the vacuum cleaner is all that is needed.

Ohms Law gets in the way. 1/10 the voltage (12 volts vs 120 volts) takes 100 times more copper for a given power and distance. Tree huggers forget about science and reality. Talk about horrible for the environment and resources. The last city and really the only city that used Edison's DC system was Manhattan Island NYC NY. The last of it was decommissioned 11 years ago in 2007.

Amps = Watts / Voltage

A 20 amp 120 volt circuit can deliver 16 amps continuous for a total of 1920 watt suing 12 AWG conductor up to 75-feet @ 3% loss. To do the same thing at 12 volt DC requires a 200 amp circuit running 160 amps on 750 MCM cable.

12 AWG cost $09/ft and weighs .023 pounds per foot.
750 MCM cost $9.95/ft and weighs 2.4 pounds per foot.

Do the math 100 times more expensive and weight...

Goggle boys and Tree Huggers need to go back to school and learn Physics Environmental Impact, and Economics. DC is not the main issue, it is low voltage. The Reason DC is not used in Generation, Transmission, and Distribution is it is much more difficult and expensive to generate, regulate, (raise and lower voltages), and control. Circuits that raise and lower voltages are very prone and sensitive to outages and transients.

Put as simple as it can be said, Google cannot change the law of physics. It is like saying and believing you can run fast enough to jump into orbit or jump onto the moon.

[fivewin]

All of us can now generate their own electricity and its about time that with one standard wiring circuits (one type of cable) we can run appliances ac or dc. Companies will develop their products ac/dc and @ home its your choice to run these appliances ac or dc . Me, dc ofcourse.

I can imagine that soon or without my knowledge already existing: quality home appliances with high efficiency thus low power consumption like fridge freezers, waterpumps, aircons etc..most likely DC and even low voltage.

A yacht owner run his ac/dc tv with efficient inverters with different capacities , no other loads and no battery charging. He measures the amps. Then he turns on the TV directly from his 12v battery. All with proper cables, same distance etc.... About the amps, guess?

Once again, Edison smiles relaxed @home while Tesla works hard in factories only and hopefully in the neae future no more electric cables under the ground or above our heads to housing areas.

[fivewin]

And let Tesla do more research on harmless wireless electricity so we all can say: kiss goodbye to awg's and perhaps Edison can do a research on cheap long lasting storage of electricity so that the smell of Herr Peukert is history.

[SunEagle]

And let Tesla do more research on harmless wireless electricity so we all can say: kiss goodbye to awg's and perhaps Edison can do a research on cheap long lasting storage of electricity so that the smell of Herr Peukert is history.

While I admire Tesla, you do understand that one of his experiments dealt with "natural resonance" which he determined would create a harmonic frequency that could be deadly to the human physiology.

Just saying be careful of what you ask for.

[Sunking]

All of us can now generate their own electricity and its about time that with one standard wiring circuits (one type of cable) we can run appliances ac or dc.

Yep and it is done with Grid Tied System. USA made the same mistake and limited voltage to 600 volts DC initially, Europe went with 1000 volts and now going up to 2000 volts, and the USA dragging its feet going up to 1000 volts. Commercial battery systems like the Telsa Power Wall operate at 350 volts DC and commercial system up to 600 volts. Electric vehicles started at low voltage of 400 volts DC which is to low and now moving up to 1000 volts. But all the motors are AC.

Reason is simple Ohms Law which you seem to ignore and cannot accept facts.

Once again, Edison smiles relaxed @home while Tesla works hard in factories only and hopefully in the neae future no more electric cables under the ground or above our heads to housing areas.

That idea is as dead as Edison and Tesla. If you had read Tesla's work for wireless electricity was not to transmit power to homes for use. It was to be used as a WEAPON of MASS DESRTUCTION. The lab was located near Colorado Spring by Manitou. FWIW Tesla Wireless power transmission experiments aka Weapon was very high frequency high voltage AC.

This you will you will not like one little bit to the point you will not accept or believe it. All those super high efficiency gizomos you speak of like Air Conditioning, Vacuums, electric vehicles or anything electrical that requires motors all use Induction Motors. An Induction Motor is AC. DC motors are pretty much history because they are too inefficient. Sure you can use DC to run them, but everyone of those items have what is called VFD (varible frequency drive) Inverter. It takes DC and converts it to AC of variable frequency, 3-phase in fact. The speed of the motor is controlled by the Frequency of the AC. I know you do not believe that, but it is the gospel truth.

One thing you do not understand is the basic fundamentals of electric power in particular Ohm's Law. Until you understand it you are being lead astray into fairy tales and make believe. If you understood that then you would know 12 volt AC or DC is pretty much worthless for any meaningful power and pretty much limited to toys. Take you Google post. I build Data Centers for a living. A server is a very power hungry computer much like a desktop tower. They use a PSU that takes AC power and converts 208 VAC into 12, 5 and 3.3 volts. That PSU is inside and the distance the low voltages have to travel is less than 1-foor. In a Data Center you may have up to 4 Servirs in 1 Equipment Rack. Each server PSU is 1500 to 2000 watts each and most of that power is used at 12 volts. Here is what you are missing Amps = Watts / Volts, that is Ohms Law and you cannot get around it. 2000 watts / 12 volts = 167 amps of current.

The minimum size conductor required to pass 167 amps without melting and catching on fire is 1/0 copper cable. But there is is another catch 1/0 with 167 amps operating at 12 volts is only good up to 5 feet 1-way distance. That would not even get you from the floor to the top of the equipment rack let alone a 100,000 ft/2 data center with hundreds of Servers. There is not enough copper in the world to do that.

No problem at say 208 volts that Data Centers use. Each server requires 2000 watts /208 volts = 10 amps which only requires a 14 AWG conductor and can be 75 feet from the Distribution Cabinet. Run that to the PDU which is a Switch Mode DC Power Supply is 95% efficient at converting AC to DC. Not only is using high voltage AC the most economical and environmentally friendly, it is also the most efficient way to get the job done. It is win-win.

Think of it another way. Lets say you want to use a 2000 wat solar panel system. What battery voltage would you use and how would you configure the panels? First I will tel it it would be dam foolish to even consider 12 volts and wire your panels in parallel. Only a ignorant fool would do that. Even if you used MPPT controllers would take 2 very expensive 80 amp MPPT Controllers because 2000 watts @ 12 volts is 167 amps. You could do 24 volts but still foolish because that still requires one very expensive 80 amp controller. Smart money and most efficient is 48 volt battery with a 40 Amp Controller. As for the panel configuration smart money again is using a high voltage MPPT Controller say 600 volts. That allows you to wire a lot of panels all the panels in series using very inexpensive 14 AWG wire up to 100 feet away. Example 8 inexpensive 250 watt grid tied panels. No expensive combiners or fuses needed or required. It is the least expensive and most efficient way to get the job done. Why do you think Grid Tied Systems use high voltage up to 2000 volts if 12 volts was the cats meow? Why do you think utilities run voltage up to just over 1,000,000 volts?

The answer is simple, Ohm's Law, Efficiency, Environment, and Economics. Low voltage throws all that away. 12 volts is fine for Toys and RV's with very low power requirements. Even if you used solar for all your home power would not use low voltage. It is too expensive, limited, and inefficient.

[NorthRick]

Well, I think we have another case of "alternate facts" on our hands. I doubt anything you type will make him change his mind. Give me 12 DC or give me death!

[Sunking]

Well, I think we have another case of "alternate facts" on our hands. I doubt anything you type will make him change his mind. Give me 12 DC or give me death!

You are probable right. I tried to get through.

[ButchDeal]

Give me 12 DC or give me death!

Death it could be....

[Mike90250]

.... The Google boys, Sergei and Larry, think this is dumb too. Engineers at Google, tired of running tens of thousands of computers with inefficient power supplies, have proposed a new standard for "high efficiency power supplies for home computers and servers" based on everything running on 12 volts only.

https://www.treehugger.com/sustainable-product-design/big-steps-in-building-change-our-wiring-to-12-volt-dc.html

How about from the horses mouth:

http://www.datacenterdynamics.com/content-tracks/design-build/dc-distribution-is-not-just-for-the-giants/95037.fullarticle

data center uses 208VAC to each rack, and then a single 12V supply for each rack. Another case of selective factoids from treehuggers.

The next step may be using 500VDC internal distribution. https://www.eetimes.com/document.asp?doc_id=1273186

[ButchDeal]

Another case of selective factoids from treehuggers.

I think it is a case of total miss understanding and latching onto one term like DC and totally miss construing all the facts around it.

[Sunking]

How about from the horses mouth:

http://www.datacenterdynamics.com/content-tracks/design-build/dc-distribution-is-not-just-for-the-giants/95037.fullarticle

data center uses 208VAC to each rack, and then a single 12V supply for each rack. Another case of selective factoids from treehuggers.

The next step may be using 500VDC internal distribution. https://www.eetimes.com/document.asp?doc_id=1273186

Yeah I tried to tell him that, but he wants no parts of facts.

A data center uses a UPS using anywhere from 200 to 500 volt batteries with 100 Kw to 4 Mw Inverters operating at 480 VAC Delta 3-phase. From the UPS goes to what is called PDU's, and fancy name for 208 Y breaker panels with alarming and telemetry located strategically out on the raised floor in the equipment line-ups. Each PDU depending on size will have 24 to 66 20-amp circuits with a 20 VAC circuit serving each equipment rack Most have 2 circuits for the two UPS for redundancy in the event 1 UPS fails. Exactly what Google or any data center uses. Google is not even the biggest, not even close.

The power for the equipment is enormous. But only half the power requirement. A 4 MW UPS loaded generates 4 MW of heat. Everything is on raised floors for a reason, very good reason because the raided floor is used as a Plenum to pump umpteen tons of Refrigerated Air up through the floors and forced through the equipment racks. Today a modern home is designed for 15 watts per square foot of living space. A Data Center or Phone office is 350 watts per square foot. So you can imagine even a tiny 10,000 square foot bank data room is using a lot of power. Imagine a large 100,000 ft/2 data center.

Reminds me a bit of Dan K. He worked for Google and was the lead code writer for Chrome. So we know what Google knows about power. NOTTA a dang thing or even a clue what it is. Just imagine a 35 MW load on 12 volts. Not enough copper in the world or a building big enough to hold and support that much weight. How would you cool it?

So fivewin here is how it is really done. The utility brings in power at 13.2 Kv 3-phase, a mini substation. That gets stepped down to 480 v 3-phase and distributed to various sub feeders like lighting, cooling, and equipment. Air conditioning and lighting is all done at 480/277 volt wye systems. UPS are run at 480 volt Delta and stepped down to 208 wye systems. the equipment rack servers take 208 Y 20 amp circuit to power the servers 2000 watt power supply and distribute 12 volt power for about 1-foot distance. It is the only way it can be done. If you take the time and learn you will understand.