5kw from a 250 watt solar panel?
5kw from a 250 watt solar panel?
(OP)
I have a local electrical shop that is selling a solar panel setup. It consists of a 250 w solar panel, inverter, 1/2 hp 3 phase 220 vac motor , VFD 3 phase motor controller, 5- 20 amp windmill generators. The way they have it set up in their display room is:
Typical grid tie solar panel setup but with the addition of 220vac (2 sigle 110vac lines) going from breaker to VFD - 3 phase 220 vac out to 1/2 hp 3 phase motor.
Motor is belted to 5 - 48 volt 20 amp gen motors. Gen motors are wired to input bus bar of inverter along with solar panel. Inverter reading on digital display shows amps / power going into grid. (almost 5 kw) I know it is apparent power but does the grid know that? Does the power company know that? Are these guys getting paid for apparent power?
When all is done and the bill comes from the power company would we see a reduced cost ?
the motor runs as no load, generators output 20 amps each.
I verified it with a DC meter and confirmed it on the inverter.
They are putting out 20 amps each at 48 volts.
The motor consumes less than 500 watts.
When loaded it all changes of course. But the question is does the grid metering devices know this?
There is no load when grid tied. according to the inverter it is sending 5 kw an hour into the grid.
Do you think the metering device see's it as 5kw.??
The shop says yes.
Typical grid tie solar panel setup but with the addition of 220vac (2 sigle 110vac lines) going from breaker to VFD - 3 phase 220 vac out to 1/2 hp 3 phase motor.
Motor is belted to 5 - 48 volt 20 amp gen motors. Gen motors are wired to input bus bar of inverter along with solar panel. Inverter reading on digital display shows amps / power going into grid. (almost 5 kw) I know it is apparent power but does the grid know that? Does the power company know that? Are these guys getting paid for apparent power?
When all is done and the bill comes from the power company would we see a reduced cost ?
the motor runs as no load, generators output 20 amps each.
I verified it with a DC meter and confirmed it on the inverter.
They are putting out 20 amps each at 48 volts.
The motor consumes less than 500 watts.
When loaded it all changes of course. But the question is does the grid metering devices know this?
There is no load when grid tied. according to the inverter it is sending 5 kw an hour into the grid.
Do you think the metering device see's it as 5kw.??
The shop says yes.





RE: 5kw from a 250 watt solar panel?
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RE: 5kw from a 250 watt solar panel?
Cheers
Greg Locock
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RE: 5kw from a 250 watt solar panel?
As for saving money, as long as your load is less than the output of the generators you will be paying less. How much less depends on your tariff.
Excess power, utilities typically pay a lot less to buy power than to sell it. Remember they supply and maintain the lines and transformers.
The default setting for many electronic KWHr meters is to sum return power to incoming power. I know of a case where an owner connected a 60 KW wind turbine to the grid without the power companies sanction. At the end of the month he was billed for all the power he had used from the grid as well as all the power he had returned to the grid.
And, many wind generators average output over a 365 day period is about 15% of the rating of the generator.
The wind doesn't always blow and sometimes that sucks.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: 5kw from a 250 watt solar panel?
The grid is the load.
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RE: 5kw from a 250 watt solar panel?
I'm going to split my home's electric power service into two. One will be a 200A 'Time Of Day' service, so that I can buy grid power at night for half price. The other will be a reversible 200A 'Net' meter so I can push my locally-generated (assumed-renewable) power back into the grid at full price. With a 50kw motor-generator in the basement running all night, I think that I could earn about $100k per year between the two meters.
Maybe stick a wee decorative solar panel on the roof to confuse the inspectors. Tell them it's the latest super efficient type that even works at night.
Apologies for the thread interruption.
RE: 5kw from a 250 watt solar panel?
"Great! You've invented free money!"
I havent done anything, It is the electrical shop were I seen it. If your going to be a smart ass you should do it in context.
RE: 5kw from a 250 watt solar panel?
When they do that the 1/2 hp motor draws more amps. So the grid load doesnt really load the generators as the resistor does.
Maybe your to smart to understand the common sense stuff?
RE: 5kw from a 250 watt solar panel?
Maybe you're too smart...
Don't take it too seriously.
RE: 5kw from a 250 watt solar panel?
There is always the
- guy who changes what is clearly written in text into something different,
- guy who tries to find something wrong with what you are saying..even if it doesnt apply to the question
- guy who just likes to insult people
- and of course the guy who knows everything when in his own words proves differently.
Why do forums bring out the wierdo's oh ya cause they dont have to face people and get their ass kicked.
RE: 5kw from a 250 watt solar panel?
To somewhat answer your question. The utility company is smart enough to have a meter that measures true power for billing purposes and not the VA.
RE: 5kw from a 250 watt solar panel?
I assumed that the shop was using a motor to drive 5 small generators to simulate an installation of 5 windmills of similar power.
That way they can demonstrate their equipment even when the wind isn't blowing.
Also they can avoid demonstrating that the wind will not produce anywhere near full power most of the time.
Utilities Kilo-Watt-Hour meters: The old memchanical meters with the spinning disk would rotate in the reverse direction when the power flow reversed and power was delivered back into the grid.
The new electronic KWHr meters measure four quadrants and save the measurements to four registers. The registers are:
Real power (KWHr), Reverse power (KWHr), Leading KVARHr and Lagging KVARHr.
The KVARHr registers are not read unless there is a power factor penalty.
The meters, as a default, display the sum of the forward power and the reverse power. This defeats one of the common ways to steal power.
You must have sanction from the power company to deliver power to the grid. If the power company sanctions local generation, they will send a technician out to re-program the meter to show real power and reverse power separately, and start reading the reverse power register as well as the real power register.
If you are using more power than you are generating, you will see a reduction in your power bill. If you generate more power than you are using, and your connection is not sanctioned by the utility, you may expect to be billed for the power that you delivered to the grid as well as the power that you used from the grid.
These fora are for professionals. We cut a little more slack in the hobbies forum, but the personal comments are not welcome from either established posters or new posters.
If we don't all play together nicely, this thread may disappear. Bill/moderator/owner
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: 5kw from a 250 watt solar panel?
When all is done and the bill comes from the power company would we see a reduced cost ?
the motor runs as no load, generators output 20 amps each.
I verified it with a DC meter and confirmed it on the inverter.
They are putting out 20 amps each at 48 volts.
The motor consumes less than 500 watts."
Perhaps the OP could post a picture, but what I read was 500W in, 5kW out.
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RE: 5kw from a 250 watt solar panel?
From your description, I can't tell for certain which side of the meter the motor is connected to. It would also be good to know in more detail how the < 500W draw on the motor is being measured.
A.
RE: 5kw from a 250 watt solar panel?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: 5kw from a 250 watt solar panel?
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RE: 5kw from a 250 watt solar panel?
There is definitely something wrong with these readings.
However this is not hvmicromotor's equipment. He also is concerned with the honesty of the display/demonstration.
I can think of a lot of ways that a display such as this may be set up with misleading readings.
I don't have a problem with a display drawing energy to run a motor and then returning the energy to the grid. However it would need a 5 kW motor. I am wondering; possibly the motor is 5kW rather than 0.5 HP, changed shunts on the DC ammeters, extra turns on the CT.
The generators may be outputting much less than the rated 48 Volts.
Without seeing the display it is just speculation.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: 5kw from a 250 watt solar panel?
RE: 5kw from a 250 watt solar panel?
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RE: 5kw from a 250 watt solar panel?
Best to you,
Goober Dave
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RE: 5kw from a 250 watt solar panel?
RE: 5kw from a 250 watt solar panel?
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RE: 5kw from a 250 watt solar panel?
RE: 5kw from a 250 watt solar panel?
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RE: 5kw from a 250 watt solar panel?
I have a similar problem in that our KWH meter is showing 1600 KWH for the month for my 300 sf 5th wheel, which is a crock, since we heat and cook with propane. I am looking further into that meter... Probably made in China. Kinda reminds me of marking women's shoe sizes smaller than what they are to make the client feel better.
Mike McCann, PE, SE (WA)
RE: 5kw from a 250 watt solar panel?
Have you checked to see if the refrigerator has been inadvertently switched from propane to 120 Volt operation?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: 5kw from a 250 watt solar panel?
The propane side does not work, so it's always 120v electric. It's not a big refer, and is a newer side by side RV model.
I have to figure out why the propane is not getting to the burner (no odor at the burner) and the propane tanks are not empty. Hopefully not a computer module at $150 to $400.00.
My hot water tank propane does not work either, so that is electric right now - could be a similar problem.
Luckily, the propane heat is working.
I am going to invest in a good KWH meter and check the monthly usage. Something is just not right.
I do have two RV's on one 30 amp circuit, but the second is my office and that only has the refer running on electric. Heat there is propane too. Rarely any lights used.
I know the 30A is low, but we make it work. Just have to watch it or we take too many "trips".
Anyway, I still think the OP has a faulty meter to deal with.
Mike McCann, PE, SE (WA)
RE: 5kw from a 250 watt solar panel?
Of course, your controller could just be broken, too.
The electric heater in most of these refrigerators is just 150 watts.