Author Topic: Any interest in solar panel group buy? 06-2018  (Read 530 times)

John Galt 1

Re: Any interest in solar panel group buy? 06-2018
« Reply #15 on: July 10, 2018, 03:20:53 PM »
General knowlage FYI...   Inverter based motors that run compressors for refridgerators and AC units don't have the termindus start up energy surge most motors we use here in the US use.       Instead inverter powered motors can start slowly (lot less amperage required) and run the motor at a variable rate.       Anybody who has sat by a window air conditioner has heard the compressor cycle on and off, there is no middle speed.      Inverter based compressors instead slowly ramp the compressor speed up and down so you get just the right amount of cooling/heating.      Most compressors here in the US just turn on or off.

Why is this important?     Because when any regular electric motor first starts up there is a huge increase in required power for about 1/10th of a second.       A 1 hp motor that draws 1100 watts while running will require about 3300 watts for 1/10th of a second when it first cuts on.      That means a 1500 watt inverter can't start a 1hp motor because the 1500 watt inverter can't produce the 3300 watts required for the starting surge.

Most inverters have some ability to ramp up well above their power rating for a few seconds to help with a starting surge but usually not enough unless the inverter is a lot larger than the load.     For a 1hp motor that draws 1100 watts I'd want at least a 2500 watt inverter        But if you instead have a inverter based compressor you can start that 1 hp motor with a smaller 1500 watt inverter.

Since inverter controlled compressors don't just turn on and off but instead keep the compressor running and varying the speed they are more efficient.

Here in the US electricity is inexpensive compared to much of the world.       US national average price is 11 cents per kwh (kilowatt hour).       Here in GA residential electricity is only about 8 cents per kwh with electricity sold to a business at about 12 cents per kwh.

Inverter based refridgerators are rare in the US.       I've heard of some people ordering Panasonic inverter based refridgerors from Mexico (they're made in Mexico) for use in solar powered homes.



John Galt 1

Re: Any interest in solar panel group buy? 06-2018
« Reply #16 on: July 10, 2018, 03:35:43 PM »
One thing I fell in love with in the inverter vein, and now on the verge of falling out of love with is mini split climate control.

I was seeing systems approaching 30 SEER, which is crazy. But then in a "pros and cons" article, I saw that a "con" is humidity control. That's not a con. That's a dealbreaker in Georgia. Yes I could supplement it with a dehumidifier, but wouldn't that kill the savings relative to a high SEER conventional system?

Mini-Splits do remove humidity.       My 22 seer LG minisplit even allows you to use it as a dehumidifier without using it for cooling if desired.       When you run the Freon lines for a minisplit you also must run a water drain line so the water it pulls from the air goes outside.        It drips all the time when using the minisplit in cooling mode.     

We used to heat 100% with wood which sometime was a pain when it only goes down to 48 at night and the woodstove puts out too much heat.        Now we use the  minisplit and burn a lot less.        Playing around with the minisplit during the winter to see how it heated my less than well insulated house and it does a fine job when it's 20-25 outside.      When the outside temperature gets below 20 my admittedly undersized 18,000 btu mini-split can't keep up but it will still produce heat down to about 8 degrees.

Asia_Off_Grid

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Re: Any interest in solar panel group buy? 06-2018
« Reply #17 on: July 11, 2018, 12:46:50 AM »
Since inverter controlled compressors don't just turn on and off but instead keep the compressor running and varying the speed they are more efficient.

No doubt. I have measured one of my inverter refrigerators drawing as little as 2 watts.

Another plus to the technology is, there is much less variance in temperatures, inside the refrigerator / freezer, due to the compressors "always on". Old style compressors, allow the temperatures to drop several degrees inside, prior to starting.

Inverter based refridgerators are rare in the US.       I've heard of some people ordering Panasonic inverter based refridgerors from Mexico (they're made in Mexico) for use in solar powered homes.

If you are living off-grid, using wind, sun, or hydro to generate your power, no doubt, these are the refrigerators to buy.

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Great reply, regarding the technology. Thanks for posting it.
Paul

RWS

Re: Any interest in solar panel group buy? 06-2018
« Reply #18 on: July 11, 2018, 08:03:27 AM »
27 to 30 years ago when I was trying to decide what thye of system to have, I only knew of two.  Back then I knew of a house that had a 12VDC system.  I decided to use 120/240Vac.  Back then you had to take two 120 volt inverters and "series stack" them 180 deg out of phase to get 140 volt ac just like the power company.  The problem then was the the inverters available did not have much surge capacity.  They would not start a 240 volt submercible pump which has tremendous start up current requirements.   I upgraded from 2.5kw stacked pair to a 4000 watt stacked pair that advertized surge capacity and my pump worked. 
When Schneider bought out part of Zantrex the came out with the XW6048 inverter that puts out 240 vac right out of the box.  I ordered one.  The problem was they were not available yet.  The marketing was out ahead of the product availability.  After 3 months wait it finally arrived.  I fell in love with it as it does everything I wanted and more.  I now use a stacked pair of them for 12Kw interactive with the grid.  I have to current limit them to keep from going over 10KW power company limit.  It's all available off grid.  The problem now becomes the 400AH 48VDC battery bank is a little small.
All of this rambling to say all of my appliances are standard and available at any appliance store.

RWS

Re: Any interest in solar panel group buy? 06-2018
« Reply #19 on: July 13, 2018, 05:52:41 PM »
My phone rang yesterday.  A guy down the road wanted help with his solar system.  He had a grid tied system installed and twisted their arm to sell him 5 extra panels.  He wants an off grid system also.  Well the panels are Chinese, Jinco JKM325PP-72V.  In English they are 325 Watt Poly 72 cell panels with open circuit voltage of 46VDC and max load voltage 37VDC.  He wanted to get some more matching panels and asked me how much.  I guessed 325 Watt maybe $300.00 ea?  So today I got a quote because I was concerned with trade war tariffs.  I thought panels need to be secured now.  I found them advertised on the web for $217 ea.  min order 4.  I got a quote for $165.75 ea plus freight.  I had the salesman check freight for 4, 6 and 8.  Sometimes I can get more shipped for the same freight.  Not this time.  I expect to order in the next week or so.