Author Topic: Blasphemy..... Solar power.  (Read 33741 times)

glort

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Re: Blasphemy..... Solar power.
« Reply #165 on: October 22, 2017, 06:01:48 AM »

You Got that Right mate! All I need to do is put a Ball in front of her rather than a carrot and she would run all day long. Wouldn't need any engine, just a gen head on the treadmill and we'd be right.
She's a beautiful and intelligent little thing that just lives to chase the ball. I keep telling the Mrs I AM going to have a serious accident one day because If I stop in one place for more than a minute, as soon as I go to move there is at least one tennis ball underfoot. I have almost tripped and twisted my ankle more times than I can remember but I won't get away with being lucky forever.

Funny you say about reflected sun. I was wondering before if putting colourbond in front of the panels but back a bit and tilting them at a correct angle, whatever that may be, could help the output?  I think it's one of those rules I have formulated with solar. The cheapest way to improve efficiency or get more power is just buy more panels. Probably pay $20 for a sheet of colourbond the same size as another panel I can buy for 40. If you could get some for free from a demo or something, might be something to look at?

Been a mixed day here today. Bright sunshine in the morning, overcast and showers, bit more sun now getting murky again.  I checked the inverters, one is under the tilted panels and the other is under the bit of tin you can see in the pic. Since ajusting the tilt of the panels the smaller array is going a little better than the larger flat group. 500W more on the ones lying on the ground.  They are both coming up to 10 Kwh each so worthwhile power despite the less than ideal weather.

Thanks Bruce. I'll be interested to see your design.  As tight arsed as I am I'm going to buy the steel I need, or don't need being over kill, so as to make these things that I can lay in bed on the windiest of nights and know I don't have to worry.
As for councils, the place I left had the slackest most useless and demonstrated corrupt council in the country. I'm not this one is a bit the opposite and sticklers.  Here Solar is not a council supervised development and there is stuff all they can do about it.  Of course they would want to see certification if someone came out and then would put me in to the authority that does look after it.  I have learned though that it's easier to ask for forgiveness than get permission so that's the chance I'll take.

I have had a chat to the neighbour about trimming trees and installing the panels and I think he's like me. The response was " Your trees, do what you like with them." I get on well with him and he does not seem to have liked the previous owner that much.  I think he's the sort of guy that as long as you don't interfere with him, what you do on your side of the fence is your business.  The other owner did apparently do a number of things that interfered with him like building mounds to deflect all the rain run off onto his property and causing him to have to build his own walls. I have also been trimming trees and hedges that were over growing his property and I have got the comment how much better it is, so far as I know, I'm in the good books.
He's obviously seen the panels in my yard and seemed a bit excited when I told him what I was going to do. He'd like to do more himself and add to his 3Kw system but is a bit limited in roof space of the correct orientation that isn't shaded.
Very house proud man. If I can get this place looking like his I'll be well pleased.

Going to do some more Number crunching with the water heating.  Look up how much water I could heat with the amount of solar the spare panels could provide. Going DC just seems to be difficult to do with any efficency and not that cheap anyway. 
I was reading about using a twin element thermostat as a diverter controller. Apparently they have like a double relay so when installed in the top of a tank and they hit the preset temp, they flick over to divert the power to the bottom element.  I'm thinking that I could use this to divert the power back to an inverter to go back to the phase.  I'm then thinking, WTF bother? Just have the pannels going to the phase in the first place and run the thing off the AC and save myself the hassel!

I have a meter here somewhere that has a CT clamp so I might just put that on the water heater and do some measurements for a week as to how much power we are actually using on the thing. If it's close or near enough to what the panels would generate, then I'll just take it off the off peak and run it off the normal power. I'm probably going to have a spare inverter anyway and if not I can probably get one off the net for $150 which is what I'd spend on making a DC controller from what I have seen. There is also the thing that once the water is hot, the power can go back into the mains and spin the meter back a bit faster.

Other thing I was thinking was covering the whole heater with a plastic bag.  It sits where it gets the sun but does not seem all that well insulated and I'm sure has a stack of heat loss.  I was thinking putting a black plastic bag over the thing would probably limit the cooling from the wind and also get the thing plenty warm through the day.  Condensation may be a problem though so I'd have to think of that but then again, it is an outdoor unit and as long as the electricals were ventilated which are right at the bottom.....  I did want to move the thing because it is butt ugly and in a bad place but that would not be as straightforward as I first thought.  For the moment it can stay put and I will think about the bag idea or at very least just painting the thing black. 

Warmer it is on the outside the less attraction for the cold to find the heat.



BruceM

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Re: Blasphemy..... Solar power.
« Reply #166 on: October 22, 2017, 08:24:21 PM »
Here's my neighbor's racks; each as 3 panels (5 for 120V and one 12V which powers his engine room/120VDC power controller/wireless phone and internet.  They are partially cantilevered and one man can easily change the tilt supports, which are 3/4" EMT with smashed flat ends.   The uprights are 3"x3 x3/16 angle.  Each rack is 10 feet long. I split these to make them easier to tilt as the total length is 20 feet.  There is no visible movement or flexing with gusts of 100 MPH.  The panels go all the way to vertical and fully horizontal.  My neighbor and I both do just 2 tilts- one for the summer months and one for winter.  Our priority is for winter gain, we have excess power all other months.

On the next iteration we will go a bit over 16 foot in length for a single 5 PV panel rack with 3 vertical supports, probably 3" round pipe instead of angle depending on steel prices.  I will raise these vertical posts about 6 inches and put the pivot point just above the center of the panel.  The steel above the panel will continue to make it somewhat underbalanced.  We'd like it to be a one man job to tilt the single 5 panel rack. The seasonal angle support vertical posts will be only 12" above ground and perhaps 2x2x1/8 angle.

We need to keep the bottom edge of the panels about 1 foot above ground in winter mode due to snow. It is extremely rare that we would have that much standing snow in winter.

If you look at the commercial rack$, you will quickly see why it makes more sense to have your own custom racks welded up from a local steel source.









BruceM

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Re: Blasphemy..... Solar power.
« Reply #167 on: October 22, 2017, 08:43:47 PM »
Here's my original racks which are a two man job to tilt. When they were built 10 years ago my local steel supplier built them for $150 for steel and welding.  These are smaller 175 watt panels-  in larger panels it would take 3 men.  Thus the change to the split cantilevered design.

My next solar project will be to add an additional 1200-1500 watts of PV. This will provide additional power for my 120VDC inverter for well pumping and washing machine is a 5 panel rack with just 3 supports, and even better balanced.  The inverter will only be used on sunny days (plenty of those here in AZ), as we want to keep our bargain battery banks lightly discharged. The 10 - 110AH  Walmart Marine batteries cost about $1000 to replace, and are lasting  4.5 years. This is a minimalist 120VDC off grid system but it has served me and now my neighbor and our special disability needs very well.

 



glort

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Re: Blasphemy..... Solar power.
« Reply #168 on: October 22, 2017, 10:29:31 PM »

Thanks for that Bruce. Gives me a few ideas.  I like the simple but clever cantilever design. This was one thing on my mind, the weight of the things to  tilt them.  That could reduce the effort significantly.

One thing I have had in my mind as a tilt mechanism is using car scissor jacks. My father throws them out in his wrecking yard because he can't even sell them for $10 ea even if unused.  I was thinking something like you, do the panels in groups of 3-4 on their own rack and have either a heavy bit of steel to support them enough to raise and lower them before attaching struts to hold them or doing a jack at each end but I was worried about them flexing too much unless I went back and forward  each end a couple of times.  Your's are easy, they are on the ground, mine will be on a roof and one that may not have much room either.

I thought if I put the car jacks more to the middle of the panels on a cross beam I'd get a cantilever effect that would allow the limited movement of the jack to be magnified so I got enough travel in the panel to get the angle I wanted. I thought I could set it up for the lowest angle and then could adjust multiple times a year if I was so enthused. I'm also looking at an electric option so I don't have to get up and crank the jacks but then there is the issue of locking them in position.  We don't get 100 MPH winds here ( thank goodness) but I figure there is a lot of lift in the winds we do get acting on the surface area I'm going to have. I might be over thinking it. The string winds are going to come mainly from the side with just a little from the rear. That will also be somewhat sheltered by the roof line itself. 

Still, I don't want to find out I underestimated the wind when a neighbour or cops return a panel and start asking questions.


I have been looking at off grid options just for fun and entertainment. I also came to the conclusion the cheap and not so long lasting option was probably the most cost effective.
There is a place here that does forklift battery packs. They sell 24V, 1500ah packs guaranteed for 3 years for $2400.  Seems to me even if one got 5 years out of the things which they reckon should be much longer as they have no problems with them being used for solar,  that's pretty good value.
There is a kicker though..... Based on the weight of the things, when they were buggered, you'd get almost half the price back as scrap with what lead is going for and has been for a while AND, the trays they are in are worth money for repacks as well.

24V@ 1500 Ah is 36Kwh.  Lets be careful and only go to 50% DOD, that's 18Kwh. That's about 3 Tesla batteries worth (which are $30K here) for $2400 LESS the min $1000 you'd get when you scrapped the things.  That's pretty good value to me and again, another example of where I find the cheap, replace more frequently, option to really be cheaper than the " pay though the nose for the more long lasting option". Yes, maybe a Tesla etc is maintenance free but the day it's too much for me to wander down the shed and put water in batteries ( which can be fitted with a single watering point system), then it's time for me to go to the old folks home because I'm going to need someone to wipe my arse at that point as well.

I reckon atm I'm using about 20KWH a day.  That's with my wife and daughter constantly using the clothes dryer, with 2 Fridges and a freezer thats on it's way out using about 5 KWH a day ( I'm metering it!) electric stove and ovens that also get used a bit too much and a stack of things like ducted AC that I reckon could be economised on to halve the power consumption without living like green washed nutters.
BUT.... I'm making an average of about 20Kwh a day from my solar and I have to have SOME power bill so it's OK.  For an off gridder, that 18KWH would go a long way and if one had a genny for those overcast times, there's still going to be a LOT of money left in the kitty at the end of the year.
Still going to need a genny no matter what storage medium an off gridder uses.

That said, I think panels are Cheap now, it's the storage that costs so I'd be over paneling any setup so I might not go too far backwards on cloudy days.
I have been surprised what my setup produces even when it's quite overcast.  Nothing like what it does in sun but but I would have expected zip on a few of the days and I still got 4-5 Kwh.  :0)


BruceM

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Re: Blasphemy..... Solar power.
« Reply #169 on: October 23, 2017, 12:06:26 AM »
 I also was surprised at fairly good performance of PV on partly cloudy days.  So good, in fact that I abandoned my plans for a DIY windmill.  PV is easier and cheaper.

I have never seen tilting racks on a home's roof.  That certainly adds a serious new twist to the design.  I have 20 acres so ground racks seemed best to me.  I do have a single fixed 12v panel on each on my outbuildings...for those I only make steel brackets.  The largest is on my shop, and powers my one 110ah AGM BATTERY for solar hot water and house heating pumps.  It gets left in winter tilt all year.  That battery lasts more than 8 years. 

Your access to the big fork lift batteries for bargain prices makes them very appealing.  Tesla batteries are presently not competitive for stationary power by my calculations either, even with new wet lead-acid batteries.







glort

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Re: Blasphemy..... Solar power.
« Reply #170 on: October 23, 2017, 01:55:28 AM »
I also was surprised at fairly good performance of PV on partly cloudy days.  So good, in fact that I abandoned my plans for a DIY windmill.  PV is easier and cheaper.

I look at a few DIY power forums and  a couple are wind biased.  The work and effort, expense and time to get what seems a very small amount of power for said investment make me think if there is another way to get your watts, it's probably better! :0)

I have seen the wind blowing here and I think " that's energy going begging" and I think of a small windmill.  Something without too much effort and cost just for funs sake. Next thought is that's still going to be a lot for a return that would bug me as being useless.  So many other more worthwhile things I can put my time into these days.

That said.... I did see a DIY garden ornament windmill on the weekend that was so cool.  Definitely want to make one of those.  Maybe in time I'll hook a DC motor up to it and see if I can generate a few watts to run an LED at night.

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I have never seen tilting racks on a home's roof.
Hmm, maybe this is something I'm missing. getting caught up in the efficency thing again and overlooking the difficulties in making it happen.
More research required I think.


 
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I have 20 acres so ground racks seemed best to me. 
And it looks very clear and unobstructed too!
I only have 1 acre but it's an upmarket estate ( wonder they let me in!) and everything is very presentable.  I only have an area behind the shed that's a bit out of sight and it's no good for panels due to the proximity of the tall border hedges. I am Thinking of another shed up there so that may give me space for another few KW if I need it.  If I do it, will be where the roid and the other engines live so may not need/ want the panels.... but it would be a waste to let that roof go to waste.  :0)

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Your access to the big fork lift batteries for bargain prices makes them very appealing.  Tesla batteries are presently not competitive for stationary power by my calculations either, even with new wet lead-acid batteries.

I can't see any of those type of batteries are are worthwhile for any sort of application.
Looking at the cost and the amount of power they could save in best case scenario ( solar fed, complete charge and discharge every single day) they still are not able to return enough power savings to justify their cost over their ( manufacturer) predicted life time.  People say they are saving money after installing them but I think they are deluded. If the things can only save way less power than what you could buy for their cost, how is that a saving?
Here they would offset about $1.50 worth of power a day but people go on like they are saving Fortunes. You spent a fortune, your returns are minimal at best and in reality represent a significant loss.

There is one testimonial on a local site where a guy with a big family quotes a saving of around $600 a quarter.  Errr, No!
Max your powerwall can hold is 6 KW. ( he has the earlier small version, 5 Kw?) If you are on above average rates of 40c kwh, that's $2.40 a day. x90 = $216 quarter = $864 a year BEST case scenario.
Power wall cost $15K  ( maybe more, this guy was one of the first here to have it) / 864 =  17.5 years payback.
Pretty sure this guy did not have 15K under the bed so add to the price of the tesla the interest, say 5% and you are looking at a 20 yr plus Payback AT BEST. Will be longer because you are not going to get a full charge in the thing every day as my calculation allows.

Given the units life is no where near that, thing is a dead loss and your "saving money" is delusion.

Had the guy the space and put in another say 3 KW of panels, then he'd have something like a 3 yr payback on their cost if he was using lots of the energy in house and if not maybe a 5 yr. It would pay back however unlike the battery.


I put my urn out before and looked at the rating. 1800W which is good because it is half the element in the HWS I have now and I can get an 1800W replacement.  The weather is freaking annoying atm.  Plenty of cloud, some quite dark but very little rain.  I want sun or rain. Need the rain so I'll give up my solar returns for that or I want sun if I can't have the rain. I loose on both accounts with the cloudy weather!

The water was boiling despite the sun not being totally clear. I metered the output from the panels and got 356V open circuit and up to 212 while watching which is great. Still not clear sunshine.
My take now is this will be OK on clear days and useless on cloudy ones with out some sort of PWM/ Mppt controller.

1.5 Kw of panels should net a round 6 Kwh on a good day.  The calculator shows that to raise 250L of water (as is the size of my service) 30oC I will need about 9 Kwh of power. To raise it 20oC will need about 6.
Not going to get 6 Kw when it's direct coupled because the panels will be so far off their power point BUT, they would be OK hooked to an inverter.

Cost wise, I'm paying 30C kwh for normal power and 11C for Off peak. I'd be better offsetting the normal power and just paying for the off peak. I think that perhaps should have been obvious from the start?   :embarassed:

At least now I have crunched some numbers and done the mental arithmetic so I know! 

BruceM

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Re: Blasphemy..... Solar power.
« Reply #171 on: October 23, 2017, 03:33:07 AM »
Yep, the ongoing replacement cost of batteries is a serious issue. 

I had to scale back my solar hot water plans after crunching the numbers.  With a super insulated home, my heating costs were too low to allow for a fancier setup.  What I settled on works great, but I didn't get surplus free heat to heat the shop, which would have been nice.

glort

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Re: Blasphemy..... Solar power.
« Reply #172 on: October 23, 2017, 12:26:32 PM »

Did some more playing around this afternoon and some more learning.

After deciding the direct coupling of the panels to the heater was probably not the best way to go I pondered what to do with the spare Panels?

There are 190W, 45.2V open circuit, 36.6 ideal power point.  I have 8 of them which I bought at the start of the year ( or was it end of last year?) as my first lot to play with.
The 5KW set I bought 6 weeks or so back are 250W, 37.6 open circuit, 30.6 under load.
I wanted to put them with the other panels in an array and looked on the net for info. Everything I could find was about mismatched panels in an array, not mismatched ARRAYS. What I read  said you could do different panels as long as the amps were similar. The 190's are 5.2A and the 250's are 8.17.
Big difference.
I looked at the voltages and thought they would be pulled down anyway.  At max power point the 10 250's in that array would be 306V and the 8 190's would be 293. Not so far away.

In the absence of any data on how mismatched arrays should be wired or what they may do, thought nothing to loose, I'll give it a go.
I wired the 2 arrays together in parallel to my 2 Kw inverter. The 8 panel 190's lying flat on the grass were doing around 880W ( getting around mid afternoon) and the 250's angled correctly were doing around 1500W.
kicked the inverter in on the small array then switched in the bigger one.
Bingo, inverter is maxed out at 2000W+.

I'm happily watching doing the mental arithmetic and thought well it's working but how much better can it work?  I went to the other array and took the 3 Kw inverter off that and put it on this array. It read 1880W, less than the 2Kw inverter was showing.
I thought maybe this one has a different MPPT voltage and maybe the light levels have dropped a bit as well. I put the 2K inverter on the other array and thought I'd wait till tomorrow and see what I get in the morning and around mid day.

I was thinking later  that the 3K inverter is dual input. Only one input is working as I think I blew the other side when I accidently dropped over 1000V on it with my over capped Induction motor generator a while back.  I have a feeling I read in the manual that there is a limit on what each side of the inverter will  take being that the 3K input has to be split across both inputs and the individuals will take more than half each but not the full 3K. Maybe that is 2K and accounts for the near 1900W I'm seeing which I thought would be more?
 I'll have to dig the manual out and verify this but it may explain the difference. Pretty sure I have seen that inverter read over 2K though on one input so I'll wait and see what I find tomorrow in better sun. 

The main thing is that I can couple these panels up and get worthwhile output with mismatched arrays. I'll have to drag my 5 Kw inverter out and see what that produces with this setup. That is dual input as well and I have an idea the arrays do not have to be the same.  Be a waste to only run 5 Kw of panels on that anyway when I can add more cheap panels and get the thing pumping a full 5K a lot longer through the day.

I still might sell the 190's  and buy more 250's though as that would make things a lot easier and more efficient.
It was interesting though that the mismatched arrays could be hooked up together.

Not sure how efficient they are BUT, I am getting a gain that would otherwise be wasted without another inverter so it's a plus from my POV and something else learned.

starfire

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Re: Blasphemy..... Solar power.
« Reply #173 on: October 24, 2017, 03:07:03 AM »
Having a off grid battery bank is a pain, and actually limits what can be reasonably done with solar. A grid tie setup allows greater possibilities.
For me, I use around 2 KWhrs per day. To have a unstressed battery bank, it needs to be roughly 5 times this amount of storage to keep within a small  20 percent Depth of Discharge to make it last a reasonable time. Mine is 1500 Ah lead acid.  To charge the daily losses/use  takes around 2.5 KW hrs charging . To get this at my location with untracked panels requires around 500 watts of panels,  with around  5 hours of useful sun, easily achieved in summer.  On rainy days I see around 5 to 8 amps, worth having but unable to supply demand. More panels would easily increase this, but also supply way too much current in bright sun, they would throttle back via the controller in a very short time , therefore money not well spent.
Where battery banks really shine is with diesel backup, a few hours of generator time is all thats needed to give power 24/7 on demand via inverters.  It matters not to me whether the power is derived from solar or diesel, both are free energy sources for me, but not having to crank the Lister every single day is nice. Some things actually do work out in our favour, the Lister works harder in winter, just when the extra heating is a bonus for an example..
For anyone interested, and even further off topic, have been when time allows, messing with a charge controller that maximises low light  panel output. The concept I have come up with simply uses the panel/s to charge a largish capacitor to whatever voltage the panel can maintain in low light. A very simple differential comparator circuit monitors the delta, or rate of voltage change across that cap,  and dumps that "package" of energy into the bank when no further voltage increase is detected. The faster the delta, (DvDt) the higher the switching rate of the Mosfets. it is basically a high power relaxation oscillator the frequency of which is a product of volatge change and current.
 This reduces the bright sun performance by around half, but nearly doubles the low light performance, even allowing a few amps in average moonlight. I live in a tropical rain forest, so this kind of performance  I think will give me a better long term result  using solar.... as has been  said, panels are cheap, the limitation is now low solar radiation on shitty days.
A fascinating subject for sure..

glort

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Re: Blasphemy..... Solar power.
« Reply #174 on: October 24, 2017, 09:44:02 AM »
For me, I use around 2 KWhrs per day.

Is that a typo? My fridges use more than that! Desktop computer probably would too.
If that's what you are using, that's very Frugal indeed.

I'm afraid I have no such motivation. I reckon I'm around 25-30 Kw a day. Rather than cut down, I just want to ramp up my generation to meet usage close as possible and enjoy the luxuries of life. I'm fortunate in that for the time being, the grid is my battery bank. want to make the most of that I can. :0)

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More panels would easily increase this, but also supply way too much current in bright sun, they would throttle back via the controller in a very short time , therefore money not well spent.

Your call of course but in theory, I disagree.  Even brand new panels can be had for around $150 ea now.  I'm paying $40 ea for used 250's.
Even if you spent $300 on panels, that would offset a lot of the generator use on those marginal days. Solar  will always be cheaper than engine power even if the fuel costs you nothing.  With your very interesting controller, you may never need the genny bar 10 days a year maybe if it will do as you say and work by moonlight.  Which I find hard to believe based on what I have read of the panels needing a " threshold" of light  to work at all but the one thing I have learned in the solar game is that things change fast and maybe the info I have is out of date with the newest panels or something.

If you have more panels and had more power you could relax your no doubt tight controls on what you use every day.  As I say, for me the goal is not to run on the least power possible, but to have the lowest bill while running everything I want.


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Where battery banks really shine is with diesel backup, a few hours of generator time is all thats needed to give power 24/7 on demand via inverters.  It matters not to me whether the power is derived from solar or diesel, both are free energy sources for me,

Don't say this on the boards that think that DIY or alternative energy HAS to be green washed, they will get their knickers in a twist over you burning any fuel in a diesel engine even it it is their save the world Veg or bio.  I see some people going to a LOT of over the top expense with alternative power or living like cave men when the occasional use of a generator would be far more practical and cost as well as resource efficient.
Some just won't accept that sometimes the cleanest and greenest way is to do the very thing they always try to avoid through the stigma they have created with it and that's do what everyone else does and fire up a genny!

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For anyone interested, and even further off topic,
Sounds very interesting and bugger off topic, that's what makes this board so much better than every other I am on, that things like this come up.
Far as i'm concerned the Topic is solar and this is very relevant.

Could you elaborate on your controller?  Is it something an electronics Dilettante could build with a schematic and parts list?
I'd certainly be interested in seeing it.  I have already worked out that the big gains in solar are not when the sun is shining bright, it's the ramp up in the mornings, the fall off in the afternoons and what you get on the cloudy days.

 
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This reduces the bright sun performance by around half, but nearly doubles the low light performance, even allowing a few amps in average moonlight.
Could you not put a controller in front of this one to switch it in and out?  Seems to me it would be real easy to put something like an ACS712 current sensor on an arduino  to control a relay  that switches the " Moonlight " board in and out. Once you get over say 50w or maybe less, the low light controller is bypassed and the regular PWM or MPPT controller is directly fed. Once the output drops below a certain current, the low light board is switched in. Even I could cook that up! :0)
Would seem to be a real easy way to have your cake and eat it too with this.


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I live in a tropical rain forest, so this kind of performance  I think will give me a better long term result  using solar.... as has been  said, panels are cheap, the limitation is now low solar radiation on shitty days.


I don't think there is any substitute for more panels.  You'd get more power from your low light controller as well as having more power available in any sky conditions.
The overcast days are where my flat panels outdo the tilted ones, fairly significantly too!

glort

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Re: Blasphemy..... Solar power.
« Reply #175 on: October 24, 2017, 10:10:44 AM »

Today was another mixed day sun wise, more cloud than clear sky I'd estimate but I got to see how the mismatched arrays worked.

The double input inverter was pegged pretty much every time I looked at it till well into the evening. At that time it was producing a lot more power than the larger single array.
Seems the inverter is pegged at 1880W because that's the highest I saw it and what it did all day pretty much.
I know the second input is blown through over voltage. I wonder if it might be just a fuse I could replace or something else that would at least be a cheap Fix? I'd really like to get the full 3K out of this unit.

I dug out the 5Kw inverter and remembered I don't have the AC connector for it. It's a bosch unit so I have emailed them here asking if they can supply the connector or where a local agent may be that would have one. Bracing myself for the price.   Might be possible to open the thing up and just run cables out and connect in a junction box.

Even though the inverter is well clipping the input, I managed a new ( quite surprising ) high generation today, 28Kwh.  I reckon I'm loosing about 3-500W  with the limited inverters so 30Kwh from what I have may well be possible... and very satisfying.

Given the cloud today, I'm surprised I got what I did but cloud does seem to magnify some band of the spectrum that panels like. Maybe it's a crossover between light intensity and panel temp? A bit of haze certainly does not seem to hurt the generation.
I'm thinking I might look for some mains voltage computer fans. These inverters get hot.  A couple of fans to provide moving air and keep the temps of the things down would be will worth the investment in $ and wattage I think.

Also going to look for remote reporting power meters on ebay. make it easier than going and checking the inverters the several times a day I do as well as the power meter to see how far that's gone back.

Samo

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Re: Blasphemy..... Solar power.
« Reply #176 on: October 24, 2017, 11:11:09 AM »
Glort,

Sounds like 2 steps forward one step backwards but you seem to be making progress  ;D  For my setup I used a serial to Wifi dongle to send the output of my inverter to a computer, it just displayed a line by line update from the inverter, after a while I wrote some software to massage it and send it to a web server, so I had some graphs and history... the Serial to Wifi dongle was called FIREFLY & was pretty powerful with all the options it supports....  took a bit of fiddling to get it configured, but once it was it just worked...

Just an idea if your inverter has a serial port, most of them have some type of port if they don't support BlueTooth.

cheers,
Samo

Lister CS 12/2 & JKSON 10/1 Listeroid

starfire

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Re: Blasphemy..... Solar power.
« Reply #177 on: October 24, 2017, 12:52:43 PM »
Your observations are similar to mine in that some cloud can actually increase panel output. I put this down to cooler panels being more efficient, and this is what got me into a "cloudy day" controller.
My power usage is low in a domestic sense,  lights, my biggest useage, and my electronic workshop.
The other workshop, where I do light engineering and car/motorbike restoration work runs seperately off the Petter, max 5KVa.
Cooking/water heating via gas/oil and wood burner. I have an old fashioned "safe" to keep food cool, refrigeration not really needed with vege garden and meat on the hoof so to speak. This way of living was common a century ago, and for centuries before that. I see no harm in forgoing coffee makers, heated towel rails and all the other crap you city dwellers deem  indispensable....
Would a Lister actually feel comfortable running a heated towel rail?
Clip a high impedance multimeter to one of your solar panels , and monitor the output voltage under varying light conditions. Low light levels effect current dramatically, but the voltage remains fairly constant and when in darkness it will suddenly drop. No commercial controller is designed to work at these levels.
The idea here is to create what effectively is an impedance converter, where the milliohm battery impedance is matched to the high impedance of a light starved solar array. The capacitor passively does this by charging at the highest possible rate, the peak stored energy then dumped into the bank as a series of high current pulses.This is the electrical equivalent of a ram pump, the battery bank being the equivalent of an air over water collector/pressure tank.
Now, connect a largish capacitor across the same panel, and connect a small load, a flashlight bulb will do. You will get a brief flash as the cap  gives up the stored energy. This is the rudimentary concept of current collection over time.
On cloudy days Its better for me to get 16 hours of 22 amps, than 16 hours of 13 amps, the tradeoff is to  take a peak current hit mid summer, but then  nights are shorter and less lightinng time required. 
Im not sure what differences there are in different brand panel performances in low light, I have a very  old mitsubishi 80 watt panel, and 4 similar no name 100 watt Chinese panels that are new, these are what Im working with. As I said, its an experimental setup right now,, lacking any refinements such as over voltage protection for the bank.... purely a proof of concept . The next phase will be to add a voltage up converter to lessen the static battery bank voltage threshold, the equivalent of seriesing more panels.... here it gets tricky, as circuit complexity increases, so too does phantom current draw.
Right now we have a partial moon surrounded by scuddy clouds, Im seeing around 4 pulses a second, with a  4700mfd cap this is around 2 mJ, which is bugger all..... a few hundred mA at most.
 A dull overcast day, this rapidly increases to 120/200 J, there is a  nonlinear relationship between photons and current (Coulomb',s law)
In  bright sun, Im getting around 250/300 J, around 1/2 - 2/3rds of the max, at this point the panels are effectively tied to the battery voltage with a 80/20 pulse ratio.... the cap cannot charge instantaneously.... hence the loss.  measurement  made more difficult as the cap dis/charge rate is logarithmic, so ball park figures  here.
With solar, there are so many variables.
But, as you are on the natiional grid, non of this has any relevance to you.

BruceM

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Re: Blasphemy..... Solar power.
« Reply #178 on: October 24, 2017, 05:05:52 PM »
Some of the mppt controllers are already buck/boost capable- so are capable of doing what Starfire is experimenting with via simpler means.  The losses of running the buck/boost converter will exceed the output for dark/rainy days or moonlit nights.  A tropical rain forest is certainly a climate that would be well suited to a buck/boost mppt charge controller or it's functional equivalent and I applaud his experimentation.

For my high desert climate mppt is unnecessary with my 120vdc system; charging is quite good at low light levels.  With panel costs where they are today,  mppt for most climates is a marketing ploy; as Glort suggests, in almost all cases you are better off putting the money in panels than electronics to try and squeeze the last 20% of power on a semi-dark cloudy day.

In my case, since ultra clean DC was the goal, I used simple analog throttling of PV power via low-side bipolar power transistors.  Today, that design approach is still viable for a higher voltage design.  I used 350V  automotive ignition Darlingtons with a current sensing resistor for each and micropower op amp for each (one is the master and 3 others just match it's current to keep the load spread evenly between the 4 big T0-247 transistors),  but I would now I would likely use the latest linear rated high voltage power Mosfets instead. (They did not exist 12 years ago.)  Regulating the PV on the low side (below the 0v battery connection, with the +PV tied directly to battery +120VDC) keeps my maximum DC voltage to earth less than 148 V; which better than 3x safer than 120VAC.   I would seriously consider high side regulation today, with a maximum of 220VDC, since so many server farms are now running 350 VDC.  Having been zapped by 120VDC many times over the last dozen years, I also have a better appreciation for relative DC safety; it hurts a whole lot less...more like a static shock. For the same RMS voltage, it takes 4x the current to kill you with DC.

I will have to consider my options for increasing the power handling capacity of my series regulator as I add more PV power for my daytime inverter operations. I can just add additional modules in parallel with minor mods or revise the design.  Either way I'll have to add a battery charge current limit since my new PV arrays will be able to exceed my battery charge rate. 

I am amazed that wet lead batteries are STILL best bang for the buck in 2017.  I viewed my original development  as something interim until the new battery technology breakthrough arrived.  A also thought AGM batteries with their higher charge rate and efficiency would have completely eliminated wet lead long ago- but they have not, and their cost remains too high to justify for my system, though it was designed for them, with 10 individual battery shunt regulators. Because of the individual analog battery shunt regulators, I only do mini-equalizations for 3 hours every 2 weeks, and only have to add water every two years. (I do check them annually.) So treating wet lead batteries as if they were AGMs does have advantages.
 
My night time power consumption in winter is about 1.5 KWH.  Lighting and computer/projector use are my night loads. 
My daytime loads include computer plus low wattage electric cooking (300w rice cooker, crock pot, immersion heater, 500W hot plate), but only on sunny days (the norm here).  My refrigerator/freezer is propane which dramatically reduces the load on my batteries (and thus my ongoing battery replacement cost of $220/yr) and I do enjoy the soundless operation.  The "waste" heat does heat the separate gas kitchen in the winter, as does the "waste" heat of my incandescent bulbs for lighting in winter.

My 6/1 CS provides the big loads- AC for pumping water to my 2000 gallon tank (gravity feed), washing machine, and compressed air for my all my woodshop tools.  This runs about $15- $25 a month of diesel depending on what I'm doing in the shop.  My new inverter should be able to take over most of this, as it can run a 2 hp compressor to keep the 500 gallon tank topped up, so the CS would only be used when maximum air is needed (sanders, ripping on table saw, and my air string trimmer for the yard around the house). 






AdeV

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Re: Blasphemy..... Solar power.
« Reply #179 on: October 24, 2017, 08:12:57 PM »
... The calculator shows that to raise 250L of water (as is the size of my service) 30oC I will need about 9 Kwh of power. To raise it 20oC will need about 6...

Just a thought, as this thread is already as far off topic for an engine forum as it's ever likely to be  :o have you considered water solar panels for water (pre-)heating? Rather than convert the sun to electrickery (at ~25% efficiency at best), then convert it back to heat in an urn or other water heater - why not just run the water through a bunch of copper pipe inside of a wooden box (IIRC you paint the inside black) with a glass lid. As with solar PV, you still get heat even on cloudy days (but not at night as with Starfire's system!). Even if the water only picks up 5-10 degrees on its way through the system, that's 5-10 degrees you don't need to find electricity for...

Biggest issue, as I understand it, with direct-to-heat solar panels is boiling them (or "saturating" them as I believe it's called - presumably because something somewhere bursts under the pressure and saturates everything around it ;D), which can be avoided either by dumping the water out of the system before it boils, or having a large heat-sink which can cope with shedding the heat generated in the solar loop. Another problem, which would certainly affect much of the USA and the UK (and Europe) is, of course, freezing - but standard auto anti-freeze can be used if the water circulates through a heat exchanger rather than heating drinking/bathing/etc. water directly.
Cheers!
Ade.
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Back in the UK :) Just need to find a use for the JP now!