Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
sPuDd Senior Member Joined: 10/07/2007 Location: AustraliaPosts: 251
Posted: 01:46am 11 Mar 2019
Copy link to clipboard
Print this post
Solar Battery Experiment V1.0
I have future plans to setup a large solar PV & battery system on my home. But before doing all that work, I needed to confirm my calculations & field test the proposed equipment. So a test setup was needed. Version 1.0 was to be built.
First I needed a place for the batteries & electronics. I live in the Australian tropics. So we have high temperatures, high rainfall, cyclones, snakes, geckos & insects. Overall its a wonderful place to live... or die. So I allocated a section of my back patio that will eventually be extended & turned into another bedroom & a laundry. This build is temporary and everything will be demolished in about 12-24 months time. Version 2.0 will be part of the new shed to be built soon. So for about $800 I bought the pine framing, ply, fibro sheets, insulation, door & other bits to construct the room & put it together over a weekend.
The pine studs were thinned down on the inside to allow the ply sheets to be recessed into them. Then the fibro sheets went flush over the top. This gives excellent wall strength, something to screw equipment to, and a fire resistant surface. The ceiling is also fibro with insulation on it. The floor & existing walls are concrete.
The lights are standard 10W LED down lights fed by a 12V boost converter from a 12V power supply & battery in a steel casing. This ensures there is light in the room even if the system fails. I installed hydrogen sensors, motion & door sensors & smoke detectors, which are all linked to the house security system which alerts me via the 4G network of any problems. And a CCTV camera is connected to the existing house CCTV system.
Walls were packed with Rockwool, then the outside fibro sheet went on. Makes a big difference in keeping the room cool.
Painted to match the house....
All gaps sealed with fire rated gap sealant. Vents in ceiling travel via duct work to the outside in a constant rising direction to expel the hydrogen & hot air. No it does not vent into the roof space. Even the gap under the door has a silicone seal strip which makes the room as air tight as it could be. This also keeps out insects & reptiles. I like a clean equipment room.
Two vent fans provide positive pressure clean cool air into the room. They use about 30watts total. I considered fitting a split system to the room, but its not worth the short term effort. I will however fit one to the V2.0 room to keep everything cool in our 46C summers. They also bring the air in low across the battery bank and force the hot air up and out. Works well enough.
I used steel speaker box grills for fan covers as they are stronger than the plastic ones that come with the fans. Work a treat.
Battery rack I made years ago from scrap steel & 20mm cement sheet. Weighs almost as much as the batteries. I have to move it with trolleys or a pallet jack.
I drilled & tapped my own copper buss bars to suit. If you ever get the idea to do the same thing, get some other sucker to do it. Copper hates being machined. I had to use cobalt bits & taps with lots of cutting lube & even that took me several hours of careful work. I then lapped the bars smooth on wet & dry paper on a glass sheet. A coating of Lanox was applied to prevent oxidation.
PCM60X 3KW chargers are connected to an east & west panel bank respectively. Each panel bank is rated at 2.4KW (4.8KW total). 12x 200W mono panels bought second hand online. Work 120%. Seriously, I've seen cold winter days peak at 2900W, and summer as well if the panels get rain followed immediately by sunlight. Occasionally it causes the DC breakers to trip, which then sends me an email via the monitoring software that came with the chargers.
I cut out the bottom cable cover to allow more air flow & because its a pain to cable through.
I cut out the top cover to fit 120x38mm 48V fans which are turned on by an Arduino with PWM control. I allowed them to get to their peak of ~60C then turned on the fans. Went down to 35C within 1 minute. Should make them last a long time.
The 5KW MPPSolar inverter. It runs as an inverter only. I've been impressed with these so far. For 9 months my entire house has been running off this inverter with not one failure. 3KW oven, 3KW Mig welder, 3HP power tools, air cons day & night, 3.6KW hot water system booster element, lights, PCs, fans, fridge/freezer, washing machine, clothes dryer etc. Version 2.0 will use a few of these in parallel for the added workshop loads.
The room was designed for more chargers, inverters & batteries to be installed which I will do in the next few months. Hence the abundance of wall space.
The panels are mounted on the old shed which is soon to be demolished. Its an ideal test bed. The panels were arranged to use the maximum roof space with an access gap between rows. Its an east-west configuration which so called experts say won't work. My data shows it works fine. The battery bank reaches absorption voltage by 10am-12pm most days, then floats once that is done. I never run the bank below 25% depth of discharge. If its raining I won't make full power, so I switch back to the grid & top up the bank. The panels make 10% of maximum power in the rain in a worst case. Version 2.0 comprises 84x 250W (21KW) poly panels (which I have stored onsite) across the house roof and about 6-8KW on the new shed roof. By my calculations, even when its raining I'll still have enough to charge & run. When its sunny, I'll have excess to dump into various loads.
Graphed outputs from the chargers. A bit of cloud haze in the morning followed by patchy cloud in the afternoon. The east & west setup compliment each other and form a solid supply during the peak of the day.
Edited by sPuDd 2019-03-12 It should work ...in theory
tinyt Guru Joined: 12/11/2017 Location: United StatesPosts: 438
Posted: 04:14am 11 Mar 2019
Copy link to clipboard
Print this post
Impressive !!
Very neat and professional!Edited by tinyt 2019-03-12
Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814
Posted: 01:48pm 11 Mar 2019
Copy link to clipboard
Print this post
I was also dubious about east/west panels, but we have a gridtie 6kw solar system, 5kw inverter, which was installed at the same time (well 2 weeks apart) as the neighbours system (same company, same panels, same inverter Only difference is ours is 3kw east, 3kw west, the neighbours is all 6kw north
Theory says ours should be less as its a split, neither in the ideal direction.... yet ours is consistently producing more than his, by 2-3kwhrs a day in cloudless conditions, to 5kwhrs a day in overcast.... His has a higher peak true, midday we are about a kw less than his, but ours are already over a kw less than an hour after sunrise, his don't hit that until 2 hours later- he gets a shorter, higher peak, we get a much broader but lower peak, but averaged over the day, we almost always come out ahead on the daily generated Kw/hrs generated
Battery charger systems may differ slightly (we have a 5kw limit to the grid, set by law and the software) but ours rarely actually hits it (the neighbours regularly goes into limiting), but I wonder if that would actually be an issue, most people try to have enough to charge their batteries by midday, in order to have excess for bad weather conditions anyway- and the ability of the panels to generate significant early morning (cuppa coffee time) and late afternoon (dinner time and aircon for that arvo heat) energy would mean hitting the night with fuller batteries I would expect....
thats the east PV wing and the north hws panel(you can see why it had to be a e/w split!)
Love your work btw, very professional looking!Edited by Boppa 2019-03-12
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 08:50pm 11 Mar 2019
Copy link to clipboard
Print this post
Wow sPuDd, that is a really classy installation, extremely professional and very well done.
Have to agree Boppa, east west gives a much more useful and flatter power curve.
A very high mid day power peak may sometimes just not be usable, but steady continuous power over a full day will definitely be better for most applications.Cheers, Tony.
brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548
Posted: 10:54pm 11 Mar 2019
Copy link to clipboard
Print this post
Hi Spud ,
Its a pleasure to view such perfect workmanship---congratulations.
(betcha he was/is an ex telecom installation tech,lol. --everything had to be perfect in my days..
anyhow, so nice to see,Spud.
BruceBushboy
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 11:12pm 11 Mar 2019
Copy link to clipboard
Print this post
Haha yes, been there done that myself. Remember well the balls of waxed string, and lead wiping of the ancient lead covered paper insulated underground cables. Still can remember the blue, orange, green, brown, slate wire colour code. Those were the good days.... Cheers, Tony.
sPuDd Senior Member Joined: 10/07/2007 Location: AustraliaPosts: 251
Posted: 11:31pm 11 Mar 2019
Copy link to clipboard
Print this post
Gday all, thanks for the comments.
You can see in the graph the effect of the sun cresting the horizon at 7am and then going behind the hills at about 5pm. But yes, so far the east/west config has proven effective.
Bruce, close guess. Similar industry. Pics of usual stuff I have to put together. The power room is to be demolished, so its a bit shoddy compared to my usual stuff.
It should work ...in theory
BenandAmber Guru Joined: 16/02/2019 Location: United StatesPosts: 961
Posted: 05:05am 12 Mar 2019
Copy link to clipboard
Print this post
Outstanding!!! U dont see this done in US very often anymore the least that u can get by with instead of taking pride in there work be warned i am good parrot but Dumber than a box of rocks
sPuDd Senior Member Joined: 10/07/2007 Location: AustraliaPosts: 251
Posted: 08:18am 12 Mar 2019
Copy link to clipboard
Print this post
I've noticed a downward trend in US standards across the board. Profit driven as always.
It should work ...in theory
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 09:34pm 12 Mar 2019
Copy link to clipboard
Print this post
Its interesting though, that modern power tools and assembly techniques should make building construction and mechanical assembly faster and much easier than in the old days.
But if you ask anyone that has just had a new home constructed, the workmanship can be conspicuously lacking. Cheers, Tony.
brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548
Posted: 09:55pm 12 Mar 2019
Copy link to clipboard
Print this post
Yes Tony ,
Won,t wander off topic too much ,but I remember the days----- in telecom,actually PMG(thats Postmaster General,s Dept. ) for you young fellas..
Lead wiping , hot twist displacement insulation joining of conductors-that was a failure ,I got a house of of all the overtime they paid me for that stuff up ,so did heaps of my mates,lol..
Oh, those were the days ,, climbing around 600 foot high tv towers ,little or no safety gear ,a pair of sand shoes, yep, still wonder how I'm still alive ??.
into the pub at 12 , stagger out sometime later ,then drive home ,,how the hell did we survive??? dangerous days ,but we survived for another day ,haha.
Back to the workmanship, gee, some of those guys could really make a picture of their work ,, racks that were perfectly installed and all the screws slots lined up vertical ,wiring that was bundled and waxed tied perfectly vertical , some of the stuff was just copybook perfect.
I remember I was very good at running all the copper air tubes in the exchange basement , would spend months lining every 1/4 inch copper air tube up ,no drawings , no instructions, just knew exactly what I was doing.
enough raving on ,,74 now ,so just memories,lol. BruceBushboy
ltopower Regular Member Joined: 08/03/2019 Location: United KingdomPosts: 64
Posted: 01:14am 13 Mar 2019
Copy link to clipboard
Print this post
Nice build, like it.
"I've seen cold winter days peak at 2900W, and summer as well if the panels get rain followed immediately by sunlight"
This is called the "cloud edge effect" and can usually create spikes in output above the panel ratings when the panels are cool and have good light. Brief hail storms usually get the biggest spike when the sun pops out as they cool the panels down the most (increase the efficiency) and the clouds tend to be more compact (edges) giving a greater cloud edge effect.
I was just thinking panels facing "north" (in the UK) crazy, and then remembered when I lived in Sydney...
sPuDd Senior Member Joined: 10/07/2007 Location: AustraliaPosts: 251
Posted: 06:28am 13 Mar 2019
Copy link to clipboard
Print this post
Itopower, I think the cloud edge effect is something else. More likely the response of solar chargers to shade-sun-shade etc. I see that at times with the PCM60X units, where they will drop out & start from scratch if they get bothered by too many fast clouds passing. Something to do with the MPPT algorithm them use.
Reason I say that is the winter power peaks occur as a result of our clear cloudless sunny skies with sub 20 degree temperatures. Which is all the things a solar cell wants, cold air & bright sun. Winter in the tropics means clear cool weather. My favourite time of the year.
Edit: Noted today that we had some very dark clouds pass over for 10-15 minute periods. Once they passed and the strong sun hit the panels, output went 10-15% over label rating. Average temp today over 32C, so I suspect the cooling effect of the shade allowed the panels to take advantage of the full sun.Edited by sPuDd 2019-03-16 It should work ...in theory
Ralph2k6 Senior Member Joined: 24/09/2017 Location: AustraliaPosts: 129
Posted: 12:35am 28 Mar 2019
Copy link to clipboard
Print this post
As has already been said, superb install. So refreshing to see such pride in your workmanship.
I do have a question though, have you heard of any horror stories for your MPP solar inverter? Only asking as there has been a bit floating around on the web with 'that style' or maybe that 'brand' not using up to scratch capacitors in their gear, which then in turn go pop. (Excess heat vs ripple current) Just asking as otherwise they seem to be very good value for money, esp. The parallel output option.
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
Print this post
