Author Topic: Blasphemy..... Solar power.  (Read 61656 times)

BruceM

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Re: Blasphemy..... Solar power.
« Reply #450 on: January 29, 2018, 01:43:41 AM »
The simple solution to power co./political malfeasance annoyance is to simply switch over your home to PV-battery-generator.

The trick it to do so without shooting yourself in the foot financially; you must minimize battery power consumption so that battery size and cost (or generator fuel cost) is reasonable...since batteries have a finite life and must be replaced.  PV only loses roughly 1 percent per year.

I know a lady with a big off grid system who uses an 1800 watt ELECTRIC water distiller for all her drinking and cooking water, plus has a gas stove with ELECTRIC glow bar and monster refrigerator with all electronic bells and whistles and auto defrost (resistive heating).  It eats Trojan batteries.  I'd bet her battery bill is bigger than many people's on grid power bills.


glort

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Re: Blasphemy..... Solar power.
« Reply #451 on: January 29, 2018, 02:31:39 AM »

Over the last few weeks I have bought  3 and a 4 KW used systems to add to the 5.5 and 1.5 Systems I have had running a few months now.

I have had a bit on and the heat hasn't exactly inspired me to tackle the steeply sloping roof to get this stuff up and running.  Yesterday I got to thinking and crunching some numbers and decided to look at adding more panels to the shed roof.  It's pretty much covered now, ( have to get up and take some pics!)
And the remaining area was facing south so the opposite of what I want here. Given the shed has a gently sloping roof of 5o, I crunched some numbers and the generation wasn't so bad and certainly better than them sitting leaning agaisnt the shed in a stack so I decided to look at putting them up.

First thing was the problem of the overhanging tree which would shade the area a lot of the day. I have been keeping an eye on it when out the back the last week or so and the shading was significant.  The offending branches had to go for the solar reasons as well as the fact the tree is decidious  and made a hell of a mess of the roof and gutters when it dropped it's bundle last Autum and I wanted it at least somewhat clear of the shed roof.

Being the environmentally conscious and tress hugging type I am, I removed 2 Big limbs off the tree but did it with an environmentally friendly and responsible battery powered electric pole saw which is charged directly off my solar panels.  Makes all the difference when you use a an electric rather than a fossil fuel chainsaw.   ::)

There are a string of 8 190W panels on the top roof of the shed ( barn style) which were my first set of what I call " Play" panels.  The last set I bought are 185W panels and the voltages for open circuit ( Voc) and optimum working voltage ( Vmp) are within .5 of a volt of each other.  Not going to matter a damn in reality. I would need to run this string in parallel to the existing 190's because to simply add them in series would give me an over volt situation with the inverter and cause it to shut down either in protection mode or through letting out the magic smoke that we all know everything electrical runs on.

I knew I was short of cable  having burnt through a reel with the last set-ups and some other wiring I did round the place running more and bigger floodlights but then got a brainwave.... and didn't even have to fall off the shed roof to get it!
If I laid the new string along side the existing one, I could tap into the same ( well oversized) return cable and then also tap off the other end straight to the existing lead that ran down to the inverter.  I had a 3 point junction cable I bought back when I was doing the battery/ inverter setup so I used that to connect the 2 arrays together in parallel.
No extra cabling was required at all.  Beautiful!  Screwed down every 2nd panel by removing a roof screw, inserting the hold down brackets I found in the dumpster at Christmas and job done.

This gave me 3 KW on this array. The other 5.5 kw I spit into 2 strings to again avoid over voltage and over powering the dodgy shed wiring which hasn't been carrying the load if should.  I presently have a 5KW inverter and a 2KW inverter. I have 2 2 KW inverters which are playing up which is a bummer and won't track on the Mppt properly.  Also have another 5KW and bought a 1.5 on the weekend.

I decided to feed the 5 KW with the 3kw small panel array, add one string of the 5.5 string and put the other 2.75 on the 2KW inverter.
For some reason the circuit the 5KW inverter is on seems to have come good and is flowing much more current.  The problem has been excessive voltage due to resistance at the inverter end causing it to trip out. With everything connected the 5KW inverter sat there happily shoving 4.8X kw back down the line.  The 2KW was pushing 1900W+ and all was right with the world.

I still have a bit of space left on the shed oof and depending waht panels I pick up in the future I might throw another 1.5 Kw of panels up ther to overdrive the 5KW inverter.
Putting excess panels is not a problem at all, the inverter will simply run to it's capacity and ignore the rest of the input. The benifit it the thing will come to that max output a lot earlier and hold it longer as the sun comes up and then fades off. I have learned it's not the peak power you want to pay attention to, it's the average over the course of the day, particularly morning ramp up and evening wind down.

My goal for my panels was initially 10 KW. I now have 8.5 on the shed roof and thinking about it, putting another 1.5 up there to make it 10 would be satisfying in being a nice round number. Still only 7 KW potential though I spose but I can keep an eye out for another 5KW inverter and already made an offer on one.  That said, can't do much anyway till I upgrade the wiring up there because I'm at the limit of what I want to do with the wire size I have.

Nezxt will be put panels on the house.
The steep incline will make that job fun then there is the question of where to mount the inverter and controls to they don't stand out like sore thumbs.

glort

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Re: Blasphemy..... Solar power.
« Reply #452 on: January 30, 2018, 08:49:39 AM »

New generation Record today.
All up I managed 47Kwh.  Starting to get up to some serious power.

Also got another 1.5 kw of panels up on the roof of the pergola over the back veranda.  This faces west  so won't be a huge power generator but I'm reserving the north side for the 4kw of 240W panels I have. Putting these up gave me a bit of insight as to what I'll have to deal with getting the other panels on the steep roof.

At least this will be a cheap array. $125 for the panels, $26 for the inverter I got to run them.
Calculator says the array with it's size, orientation and tilt will generate $500 a year.  That's just over 1 quarter to pay for itself.
Got to be happy with that.

Where it is situated it can also easy connect it up to an array on the other end of the house and run it all out of one inverter if I want.
That will also be handy for diverting power to the hot water heater.

Just waiting on a few things to arrive to build that.

Hopefully tomorrow is sunny not just cloudy and hot and I can really make some power and crack 50 Kw.

BruceM

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Re: Blasphemy..... Solar power.
« Reply #453 on: January 30, 2018, 05:39:08 PM »
Wow, that is some serious power generation.  And done for a shockingly low cost.

 I found that with my added 1500W of panels I must now upgrade my charge controller to the newer design I did for my neighbors.  My older design switched to a fixed net 2.5 amp absorption charge rate after batteries hit the bulk charge voltage (formerly at a max 5.2 A).  The new design maintains the max current the batteries can take limited only by a maximum variation between batteries of 3A while providing just enough current to all 12V batteries to hold them at the temperature compensated bulk charge voltage.  I can see the advantage of AGM batteries for higher current charging- my cheap 110AH marine batteries can't really take even 10.3 amps when DOD is only 10%.

For offsetting your own daytime power use, west orientation (near vertical) can be helpful for late in the day power. 
My neighbor's want to add a vertical "fence gate" array which can be seasonally aimed at a near sundown. That would be a boon for electric supper cooking and would extend water pumping hours for irrigation in the summer.

buickanddeere

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Re: Blasphemy..... Solar power.
« Reply #454 on: January 30, 2018, 07:38:55 PM »
Snow load from the last storm bent the stamped galvanized steel fromwork supporting the neighbour’s 10Kw ground mount system. Will obtain some images and post .

glort

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Re: Blasphemy..... Solar power.
« Reply #455 on: January 31, 2018, 03:20:58 AM »
For offsetting your own daytime power use, west orientation (near vertical) can be helpful for late in the day power. 

Geez, that's a simple Idea I have never heard or thought of before but i bet is done a load of times by people so much smarter than I !!   :-[

I was wandering around yesterday thinking of a ground mount system but there is no where really to put it without destroying the look of the yard.
last night I was surfing looking for solar ideas and setups for brilliant things people have done but it seems the majority of people are mucking around building some diminutive setup to charge a phone  or a car or smaller battery.
I'm looking for inspiration from people whom can attach leads to the output of their arrays and weld 1/2" plate straight off the panels!  :0)

Hooked up the panels I installed yesterday to the used inverter I bought. It's faulty and does not work.  Emailed the seller to see if they will refund or I should leave appropriate feedback.  luckily on ly $26 so not the end of the world either way.
Got onto another inverter for $50 so try my luck with that.
I have another inverter that came with the panels so I'll see how the labtronics works. Might have to go buy the anderson connector for it. Have 5 here and all of them are too small. I'll try something to jam the wires in first till I verify it works.

Very overcast day here today so no record breaking generation going to happen.  Almost 2:30 and I don't think I have cracked 10 Kw yet.
At least it's cool. First sub 30oC day we have had in weeks.

mikenash

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Re: Blasphemy..... Solar power.
« Reply #456 on: January 31, 2018, 08:09:55 AM »
Snow load from the last storm bent the stamped galvanized steel fromwork supporting the neighbour’s 10Kw ground mount system. Will obtain some images and post .

Nothing made from that stamped, punched galv tin is worth having if there is real work to be done . . .

BruceM

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Re: Blasphemy..... Solar power.
« Reply #457 on: January 31, 2018, 05:01:45 PM »
The commercial ground mount racks that I've seen are a farce- pathetic fixed tilt, high price, weak. 
We have wicked spring winds here so site welded steel and concrete are the only way to go.

I was very pleased with the 2" thin wall (1/16th inch thick) square tube I used for my new big tilting rack- very good rigidity vs weight for a nearly 17 foot length of rack.  About $90 for the three 17 foot lengths. Everything else was angle iron.  A local area fence store has pretty good steel stock and prices, and cuts pieces to length via bandsaw at no charge.  We only had to drill mounting holes and weld it together.

Ground mounting is easier here- few trees to worry about and plenty of space.  Different game altogether for city folks.




glort

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Re: Blasphemy..... Solar power.
« Reply #458 on: January 31, 2018, 09:54:18 PM »

I have got a good bit of solar racking off the setups I have recently bought.  Been mucking wound with it a few times and it seems complicated and annoying stuff. Guess it's something you have to have the mindset and experience to use. I'm thankful I have tin roofs. Just remove an existing screw, slip one of the solar z type brackets I found a box of through the screw and tighten it back down.  Quick, easy and very secure.

Emailed the seller of the Dud inverter and he was quick to offer a refund. I think the guy got dudded by the installer. He was adamant the inverter got changed because it was noisy but the unit I got from him has no fan or anything else to make any sound.  He seems to have had some sort of dispute with the guy that put in the new inverter so I think  the guy may have taken the old working inverter and left a blown one in it's place.  Probably going to do the same as I was, just change the fan.

I opened up the other inverter and just connected a cable straight into the terminal block of that one same as I did the other.  this one has a hulking great transformer which I think I read you can use an inverter to make the things start and then use them as stand alone.
I put the cable in with a couple of Mc4 connectors and buttoned it back up and then realised I couldn't use it for this job.  It's limited to only 200V output or about 4 panels per string. I have 8 on this setup and don't want to double wire them into 2 strings.

Still waiting on the other seller to let me know when and where I can pick this other inverter up. 
There is a Good brand 5KW unit for sale for $200 and wondering If I should get that? Would be good to have as a spare if nothing else.

glort

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Re: Blasphemy..... Solar power.
« Reply #459 on: February 02, 2018, 01:40:32 PM »

Did Some Number crunching today on the panels I currently have.

Basically for the moment there will be 4 arrays. Still have to put 4Kw worth up on the house.  The arrays will be 5.5Kw, 4, 3 and 1.5.
Looking at the direction and tilt of each array I came up with a total of 18465 Kwh per year. That equates to 50.5 Kw day Average.

The numbers the calculator I used spat out seem quite accurate and well reflect the sort of numbers I actually see from my different arrays. I have started logging each inverters output on the various arrays just for curiosity but will be interesting to compare actual and calculated inputs.


glort

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Re: Blasphemy..... Solar power.
« Reply #460 on: February 08, 2018, 09:30:02 AM »


After some more tinkering and mucking about, I did a new generation record today. 50.6 Kwh.
The best part was I backed one inverter off mid afternoon.

I checked my meters and I was 23KWH in credit on one and still dropping at over 3.5KWH.  The other meter is about +120KWH.

I think I'll let that run down to about 100 Kwh tomorrow and then pull the plug and that one. The meter read is due next week so I sure don't want to be in credit.

I am having problems with the back feeding from the shed. Clearly the cable size I have up there is not sufficient so I'm going to have to upgrade.
Plan is to run 6mm 3 phase up there. If I split feed the phases as I am doing now, I should be able to run 2x 4KW inverters and Not have the high impedance/ voltage rise problems.

I'm a bit wary of the 4kw array I bought. Have a bunch of the panels sitting on the lawn but they seem to be doing lower outputs than I would expect for the amount I have there especially considering the bright sunny weather of late. Think I'll have to test each one to make sure they are up to scratch before I go to the trouble of putting them on the roof.  Perhaps some have faulty Diodes or something. Have to look up how to test them and what to look for. Always something more to learn and increase one's knowledge!

I'm impatiently waiting on my voltage sensing switches so I can Divert the hot water. Thinking about it, I don't need them. I just have to change the phase  the heater is on to the analogue metered phases I am back feeding. Given I'm using the grid like a battery, Doesn't really matter when the power comes out but I want to try this as a Cheap way around diverting power for other peoples benefit and to show them how it can be done without complicated electronics or expensive pre built devises.

I was playing with the 3 phase rotary Switches I got today trying to work out the Connections as I had no hope of understanding the instructions in Chinese or their weird Diagrams with letters that did not correspond to the numerical markings.
The switches I got are 3 pole, 3 position, 12 terminal.  They are not what I wanted.  They are  1,0, 2 position. 
They act as 2 , 3phase  switches. One group of 3 terminals connects to one other group in either position.

 What I wanted was a common input with a selectable output with zero connection in the middle .
  I can bridge these switches but that does not seem good engineering.  Maybe what I need is a  switch with a set of 3 terminals  instead of the 4 terminal group I have?

glort

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Re: Blasphemy..... Solar power.
« Reply #461 on: February 13, 2018, 07:08:08 AM »

Sun has been shining here and I have pushed the solar generation High up to 55.5 KWh for the day. Starting to get to some serious power now.
I was talking to my nephew who has been developing a solar power system for developing countries and he was amazed.  they are puting 150W panels on peoples roof and still have a bit of left over with their lights, small TVS, and radios.  He said we could power several villages with that kind of output!

I actually had to turn the solar off on the weekend. I was getting in credit on my power meters and I can't have that without raising attention from the power co.  I have discovered what I am doing is not illegal, they just would spit the dummy at not being able to stiff me for power aand probably change my meters.  I actually saw the meter reader come today as I was expecting, a day early.  Waited till he was out the street and turned it all back on and am in credit already even though the day was pretty overcast and I was running the AC.

Still haven't got everything properly hooked up panel wise.  Still standing around every day looking up at my 34o pitched tin roof wondering how the best way to go about getting the things up there is?  The 35oC weather hasn't exactly motivated me to get the thing up ther either. That's going to have to be an early morning/ late afternoon job I reckon.  I do have some proper scaffold, maybe setting some of that up and working across the roof with some of the panel hooks in place first might be the way to go.  I am sure there is one right way and 1000 wrong ones so I am trying to find the needle in the haystack.

My Voltage monitoring relays arrived today and I just found them in the mailbox. These are what I want to use to switch on the hot water heater by sensing when the panels are making power by monitoring the line voltage increase. There are a lot of complicated and expensive little control boxes one can buy but thanks to Bruce for putting me onto these, I think they will offer the simpliest, easiest and certainly LEAST expensive way of accomplishing this than anything else I have seen and will do entirely as good a job.

That thing about reading instructions is right. Only do it as a matter of last resort ESPECIALLY if they are for something from a Chinese company.
Confused the guts out of me.  It was even in English, as in proper english but just the waffle and wiring diagrams that had things going back into one another that made no sense at all.  had I wired the thing up the way they show, the load would be permanantly on and the controller completely obselete in the circuit.
Had a look online, found something similar and more straightforward, Hooked the thing up and it's not 10/th as confusing as the instructions had me wondering HTF it all went.  Programming was a heap easier as well. Thankfully.

Will hook that up with the control box I have been working on that has the meter and the PWM controller so I can limit the amount of current I feed the water heater. initially I'll be feeding from a power outlet so don't want to be trying to feed a 3800W element off a circuit with a max current of 3600W with other things on it.  I'll turn the PWM down to about 2KW and ajust the Voltage monitor from there. When I run the heavier cable, I'll do one off the power circuit so I can go full tilt. That will require another relay as the voltage switch is only 6A but I have a couple of 40A SSR's already so all good. I also want to have a rotary switch so I can select to run the heater off off peak or the solar fed mains. Not sure why I would want that option or if I'll actually need it but thought it may be handy for something I have yet to anticipate. Running off the mains means an overcast day won't matter with the solar, it will just not make excess power that day.  Can't rain forever and in fact we have received less than 1/4 of our annual rainfall over the last 9 months.

As usual I ordered a couple of these Volate relays and have a use for the 2nd one I didn't know I'd have when I ordered it.
The sun (Untill today) has been very bright and the skys clear resulting in very hight solar generation.  Unfortunately with my evidently undersized wiring, I am getting too much resistance which is causing the voltage at the inverter to go high and the inverter trip out. Takes about 90 sec to reset then generates for 3 sec as the MPPT ramps up, hits over voltage again and goes into another minute and a half of reset. End result is didmial generation for the day as it is only working for a few hours in the morning and a couple at night and all the peak generation times it's spending resetting.

The solution has been to either switch off one array lowering the output from a possible 4.5+ Kw to just over 2 KW.
Kind of grates my nerves doing that. Other thing I tried was running a 500W light immediately where the inverter output is.  Takes the edge off the voltage and although still annoys me as being wasteful, I can have the inverter doing 4KW and the light pulling 500W so I am still 1.5KW better off than taking out the other string.

Problem is, I have to be there and watch it. If clouds pass by or the generation falls off later in the afternoon ( although I have been surprised to be still getting over 2K after 6pm) I'm unnecessarily wasting power when I could be making use of it all.

What I realised I can do is set the voltage monitor relay to kick in the light at about 263V, 2V under it's over voltage trip out.  This should drop the line voltage to about 259-260 and keep the inverter running full tilt.  When the generation goes down and the load is no longer needed, the switch will kick off and I'll get full power for the morning ramp up and the afternoon tail off. I should be able to set the turn off at about 255V which will allow headroom for the voltage increase again.
This will be a temp soloution till I run heavier cable up the back so I can run full tilt plus all the time.  I wish there was something useful I could kick in with the extra power. having the hot water running off the regular power will help a bit and I'll put it on that same main circuit.

Today I realised if I take the broken panels off I'm using to power the radiator fans for ventilation, I have room for about 4 more panels so I may cover the roof in it's absolute entirety and add another KW of panels. That will give one string of 5.5KW and another of 4KW.  I have a 5 KW inverter already there and a couple of new 4KW inverters on order so will match well.

Another ting I put together is a controller for the fan on the 5KW inverter. It's is a passive cooled which I don't like. There is nothing as good as active cooling.  I got a small 40oC temp switch, an SSR relay and a tiny little 240/9v transformer. the switch does 3A but I like to keep everything standard at 10A or better.  I used the transformer to power the switch which turns the 15A relay on and off. I lengthened the wires on the Switch with some light cable ( another reason NOT to have 240V running through it)  and I'll stick that on the inverter with a bit of silver paste and hold it tight with something technical like Duct tape.  When the inverter heats up, the fan will come on which keeps the thing MUCH cooler. when the generation drops off or at night, fan shuts off.

Yes, I could have bought a pre made temp controller for not much more than this cost I spose but what's the fun in that?   ;D