PowerJack grid tied inverters, worth a damn?

[green]

Allow me to explain

I'm not actualy tilting at windmills, but anyways... Like I said to Russ in private, I'm definetly not endorsing these cheap inverters, what I was trying to convey was safe, code compliant installs whatever equiptment is being used. That's all.

NBD
Green

[inetdog]

Wise up and stop tilting windmills -

Tilting against windmills can actually be very entertaining, especially where a bureaucracy is involved, but I can't recommend it to everyone.
Tilting windmills is best done when trying to draw power from vertical winds up the sides of large buildings.

[russ]

You deleted my post? I'm actualy not suprised. All I was saying was that a safe code compliant install is the most important thing when designing a system. My post that was deleted had a link to video that showcased this point. Forums are usually places of OPEN discussions.

Green - I sent you, the other moderators and the forum boss a private message about this - but you seem intent on trying to make some silly point.

Your post was trying to justify your point 1) that the plug and play (plug into a wall socket) types can be done legally if done in a different manner - hardwired and 2) Non UL compliant equipment can be accepted by the utility providing the equipment is tested at your cost (about same thing as UL approval) or if the POCO just accepts the equipment which is not at all likely as they would then assume the liability involved.

Wise up and stop tilting windmills - forums are not for somewhat strange concepts to be promoted as you keep trying.

[green]

You deleted my post? I'm actualy not suprised. All I was saying was that a safe code compliant install is the most important thing when designing a system. My post that was deleted had a link to video that showcased this point. Forums are usually places of OPEN discussions.

[Sunking]

I would qualify that to say that there is no way to get ahead when grid is available.

OK I will give you that one. Point is Battery systems should only be used when there is no other economical choice. Let's not try to fool anyone. Off-grid battery systems are expensive and NOT environmentally friendly as they can never offset emissions. It really Jacks me up when someone puts in a off-grid battery system because they think it is earth friendly. Nothing could be further from the truth.

[inetdog]

Well if you buy the cheap batteries you forget to calculate replacement cost every year. There is no way you can get ahead with solar battery systems. Fact is you will pay 10 to 20 times more for electricity the rest of your life. That is the dirty little secret supporters, activist, and dealers do not want you to know about.

I would qualify that to say that there is no way to get ahead when grid is available. For off-grid and for isolated small loads like gates (or garage doors) the cost stays the same but the alternatives become less attractive in comparison.

[Sunking]

Awesome, TY- that's about what I thought, but I did not have facts, just guesses. I seem to remember reading about a setup where a guy was using a mostly dead 12 volt as a redneck regulator.
back to main topic.
So 1000 watts of panels ~1000.00
MPPT controller 500.00
200~ AH batteries- 4 lets be cheapskates- Sams Club Energizers @ 82.00 each = 328.00
Sanyo mini split 821.00 @ A.J madison.

So we are at 2649.00
Plus wiring
plus fusing- so wound up to 3000.00.

Just for comparison. a "Haier HWF05XCJ 5k BTU, Window AC 9.7EER, Mechanical, 115V" In stock at Target price today is 114.00.

Energy use of this model is approximately 500 watts per hour.

So 3000.00 minus 114.00= 2886 (the cost of the solar vs the cost of the window unit. )

at 500 watts, and an electricity cost of hmm, lets say 20 cents per kilowatt, that means 2 hours for 1 Kw.. and 5Kw to get to 1.00 so 2886 * 10, or 28,860

SO, I will start to break even after running my window unit for 28,860 HOURS. For perspective, there are 8760 hours in a year, so that is running constantly for 3.29 YEARS.

Since you probably only run it for at Most, 1/2 the year, for at most 1/2 the day, probably 1/4 the day that will take over 10 years before you come close to breaking even. at that point, you need another 328.00 in batteries, which will push off break even for another year.

So, as a "practical demonstration" , this is not all that practical.

Well if you buy the cheap batteries you forget to calculate replacement cost every year. There is no way you can get ahead with solar battery systems. Fact is you will pay 10 to 20 times more for electricity the rest of your life. That is the dirty little secret supporters, activist, and dealers do not want you to know about.

[theshadownose]

And also because loads may not draw a constant current and therefore need the battery to supply peak current to load when it exceeds the panel's max current and store current from panels during dips in load.
Some loads, like resistive heating or lighting or some types of motors will try to draw relatively constant current from the source, others like DC-to-DC converters (or Sanyo inverter-based A/C) can have a stepped waveform at some frequency.

As long as the desired instantaneous load current never exceeds the panel output AND the load does not care about voltage spikes from 0 to Voc AND the load will continue to operate at some level or shut down gracefully when the panel output power is less than it would like to have, then you might have a workable system.

Awesome, TY- that's about what I thought, but I did not have facts, just guesses. I seem to remember reading about a setup where a guy was using a mostly dead 12 volt as a redneck regulator.
back to main topic.
So 1000 watts of panels ~1000.00
MPPT controller 500.00
200~ AH batteries- 4 lets be cheapskates- Sams Club Energizers @ 82.00 each = 328.00
Sanyo mini split 821.00 @ A.J madison.

So we are at 2649.00
Plus wiring
plus fusing- so wound up to 3000.00.

Just for comparison. a "Haier HWF05XCJ 5k BTU, Window AC 9.7EER, Mechanical, 115V" In stock at Target price today is 114.00.

Energy use of this model is approximately 500 watts per hour.

So 3000.00 minus 114.00= 2886 (the cost of the solar vs the cost of the window unit. )

at 500 watts, and an electricity cost of hmm, lets say 20 cents per kilowatt, that means 2 hours for 1 Kw.. and 5Kw to get to 1.00 so 2886 * 10, or 28,860

SO, I will start to break even after running my window unit for 28,860 HOURS. For perspective, there are 8760 hours in a year, so that is running constantly for 3.29 YEARS.

Since you probably only run it for at Most, 1/2 the year, for at most 1/2 the day, probably 1/4 the day that will take over 10 years before you come close to breaking even. at that point, you need another 328.00 in batteries, which will push off break even for another year.

So, as a "practical demonstration" , this is not all that practical.

[inetdog]

Because Solar Panels are current sources, not constant voltage sources. The current from a panel varies second by second and you need a batteryto regulate the voltage and make up for shortfalls.

And also because loads may not draw a constant current and therefore need the battery to supply peak current to load when it exceeds the panel's max current and store current from panels during dips in load.
Some loads, like resistive heating or lighting or some types of motors will try to draw relatively constant current from the source, others like DC-to-DC converters (or Sanyo inverter-based A/C) can have a stepped waveform at some frequency.

As long as the desired instantaneous load current never exceeds the panel output AND the load does not care about voltage spikes from 0 to Voc AND the load will continue to operate at some level or shut down gracefully when the panel output power is less than it would like to have, then you might have a workable system.

[Sunking]

Awesome- that is the answer I expected- Now- why?

Because Solar Panels are current sources, not constant voltage sources. The current from a panel varies second by second and you need a batteryto regulate the voltage and make up for shortfalls.

[electricsuperduty]

Pulling power from the panels will have wild, unregulated voltages, the battery's have a steady voltage.
There's more than this issue

[theshadownose]

Absolutely NOT. You will have to have batteries.

Awesome- that is the answer I expected- Now- why?

I have run several fans directly via DC- is it a regulation issue, power spikes? What is the risk of just running off the panels? Not being sarcastic, just clueless.

[Sunking]

I will ask a stupid question, just to get a good answer- with 1000 watts of panels, could I run this during peak hours without batteries?

Absolutely NOT. You will have to have batteries.

[theshadownose]

If you want to do this, give something like this a try:

Sanyo mini-split AC set to a small temp differential (about a 300 watt draw)
Prosine 1000 watt (ok) or 1800 watt (better) inverter (24V)
860 watts PV (4 215-watt Kyocera KD215GX-LPU's)
Blue Sky Energy SB3048 charge controller
200AH / 24V battery bank (4 T105's are a fairly cheap way to go here)
The usual BOS stuff (breakers, cabling etc)

If you monitor such a system carefully and use it only when you have the solar to use it (i.e. don't rely on the battery to do much once the sun goes down) you could have a pretty good demo application for under $5K.

K, instead of back and forth when the law is clear- lets get back to main- Billvon- Sanyo set to low pulls around 300 watts for 3000 BTU of cooling. I agree with you; based on reviews- this is most energy efficient A/C I have ever heard of. It is, unfortunately, an A/C AC pardon the pun.... are there any DC mini-splits? If so, that would eliminate the inverter.

I will ask a stupid question, just to get a good answer- with 1000 watts of panels, could I run this during peak hours without batteries?

[russ]

Doing it is easy - no big deal as a high school kid could manage - probably even some girl scouts.

It is illegal and unsafe in several aspects and if one gets caught with this kind of claptrap installed - by the utility for example - you are in a real mess.

Quit tilting windmills.