Pink7

12 minutes ago, Muhendis said:

Those figures work out to just under 29kWh at 40% dod.

Looks like you have things running at optimum best for a good long life.

I use Lead Carbon 36kWh at 30% dod which in theory will give me over ten years longevity.

 

Yes that was a important part of my whole plan for batteries, inverters and BMS  etc to run everything on moderate capacity and not push any limits for longest possible life of the setup. My guess is that my mid level brands equipment do not have same ability  to run near limits over same time as more costly brands.

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15 minutes ago, Muhendis said:

Yes the position of the sun in the sky does vary a bit doesn't it.

What chemistry batteries do you have and what is your normal nightly depth of discharge (dod)?

I have Lifep04 280a 3.2v cells. From the numbers on JK BMS i see i average have around 60%/150-160A capacity left in morning per battery. I have 2 batteries with 16 cells each.

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26 minutes ago, Muhendis said:

My panels are on a flat (and leaky) carport roof so access is easy from the house balcony without a ladder.  I also have a walkway between the two rows of panels.

I gave them a good clean only this morning which is both good news and bad news.

I noticed some flaws in three of the panels. They were cheap from China ten years ago so they're moving up my todo list for replacement next year.

The good news is, they still get my 36kWh battery charged by lunchtime.

 

Forgot to mention. I use a drop of car wash 'n wax liquid in with the water. 

Yes your panels do look easy to clean. Charged before lunchtime is great. This time i have 80% or so of the capacity i had some months back before sun turned more to the other side here but still doing ok. So now fully charged an hour or two after lunch time on a average day.

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12 hours ago, Muhendis said:

 

This works so well for me

 

The material of this type cleaner seems to be gentle and very suited for solar cleaning. We cleaning from a ladder so i need  it 4-5meter or so. So a diy extender could be the solution.

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23 hours ago, 007 RED said:

Congratulations on your DIY solar project.  It looks a really good job and hopefully it will pay its way in a relatively short time frame.

 

Regarding cleaning your panels:  Its not really a good idea to use soap to clean them, for a couple of reasons: -

 

Firstly, you never know what chemicals the manufacturer has put into the soap to give it that ‘extra’ cleaning boost.  There is a danger that these chemicals may cause the seal between the glass and the frame to break down over time and allow water to get onto the photovoltaic cells, which will cause the panel to fail.

 

Definitely do not use standard window cleaning solutions to clean your panels as these contain alcohol-based substances which will cause the panels seal to degrade fairly quickly.

 

Secondly, even if you flush the panels off with water after soaping them, the soap will still leave a very fine film on the glass which tends to attract dust, so you will be back in the same situation of having to clean the panels again soon.

 

The best solution for cleaning solar panels is rainwater, as opposed to tap water.  Tap water inevitably contains calcium and when the panels dry off, the calcium sticks to the panel’s glass.  Initially this will have little, or no, effect on your array’s output, however, each time you clean the panels this calcium film gradually builds up and will eventually reduce the amount of sun light that strikes the photovoltaic cells of your panels, hence, reduced output.

 

The small-scale system on my carport roof (4 x 415W panels) tends to get dirty fairly quickly due to the fact that we live in an area where there are a several food producing factories nearby which are far from pollution free.  See photo below of my panels after about a month during the ‘dry season’.

 

The best solution for cleaning the panels is rainwater.  During the ‘rainy season’ my panels get a good regular clean without any input from me, which is great, and there is always a noticeable slight increase in the array's output following a good shower.  I collect rainwater in a 1k Liter tank (very basic filtering to eliminate any large particles) which I use specifically for cleaning the panels.

 

Initially I used a hose and soft brush to clean the panels. This was followed by a squeegee to remove any surplus water, and then a cloth to dry them off.  This was hard work, especially at my age. 

 

 

So, I decided to invest in a commercial solar panel cleaning brush.  It was a bit expensive, and some would consider it ‘over the top’, but it has made cleaning the panels a lot easier.  The brush cleaner comes with its own small pump, which is connected to the rainwater tank.  Once the panels have been washed, I now use a small battery powered garden blower to remove any surplus water.  It now only takes about 10 minutes to set up and clean my 4 panels.

 

I’ve attached below some photos of the brush kit and a short video of me using it.

 

 

FYI…. I’ve attached a PDF of the brush spec.   Solar Panel Cleaning Brush Cleaning Equipment Solar Panel Cleaning Rotating Brush For Customized - Buy Solar Panel Cleaning Rotating Brush For Customized,Solar Panel Cleaning Brush,Solar Panel Cleaning Equipment Product on Alibaba.com.pdf

 

Hope this helps and gives you some ideas.

Thanks allot.. exactly the kind of feedback i hoped for. Where did you buy your cleaner?

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15 hours ago, lom said:

^

Solar panel cleaning brush, Google is your friend

Yes google is a great tool for anything. I still think its interesting to get suggestions and views from the forum members here and also try contribute with some content here. My Solar project would never been a reality to get up an such a successfully way if it was not for this forum and its members. When Im thinking about, it my project is quite big as fist timer solar DIY for someone who not even been near a solar panel before.

So let me use this opportunity to THANK to all forum members who contributed with advises. info and help to this project.

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Cleaning day today of may panels. They started to look dusty so we just try trow some soap water from the ladder the shower of the soap with the garden hose. I guess there is better tools for this like a tool to to swipe the panels?

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On 11/23/2023 at 2:22 PM, Pink7 said:

Got my first full month electric bill after going solar: Billed for 1 unit ( +fee) 38 bath.

 

Btw very goos to see aseanow back online.

 

 

 

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Just so it will be correct and same as posted other places: Total was just under 31thb

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My first fully billed month ended up at just under 31thb. It was one utit electric the rest was fee.

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Some days ago I fully charged both batteries then I calibrated my both JK BMS voltages and I Temporary edited the over voltage protection to a lower value so it be triged and to "help" the BMS to understand this wast the 100% left capasity level. After that the 2 BMS been as in sync and all good.

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11 hours ago, MangoKorat said:

I'm going to have to have an alternative for hot water in any case and whilst 50,000 for a heat pump might sound a lot, the alternative is 3 x electric showers + 1 under sink heater (they have to be very high powered to be of any use) and that would still leave the hand basins with only cold water.  My current heat pump supplies the entire hot water system - 3 showers, 3 basins + the kitchen sink. I have the overall temperature set fairly high but the showers are thermostatic valve types. The pump itself has a built in expansion tank and copes well without an additonal one.

Be aware that 3 x electric showers might not be able to be used in same time from a inverter capacity of for example 10kwh. I have 2 x 4500w showers but we not use in same time and i not run them on very high power(heat) If I had redo it I had built a sun heated solution. One alternative could to connect your showers to grid and not to the inverter.

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Got both batteries charged up today and noticed:

Both batteries complete charge in same time ( one with 99% and the other with 97% state of charge)

Batteries have exact same voltage when checking with multi-meter. Some differences on the values with BMS. Then inverters show 0.4v more than multi-meter. So all in all not to bad at all but i will do some calibrating of voltage and try reset/recalculate state of charge on the 97% battery.

19 minutes ago, MangoKorat said:

I will be installing solar whatever, I'm aiming for a 10kw system but I want to but quality equipment so if the cost of that is above what I want to spend at the moment, I'll add to it later.  That said, I really hope I can install a full 10kw system form the start. I've learned in other fields though, that the most expensive isn't necessarily the best quailty - some companies live off their names

I used long time to choose my inverters and ended up with 2 x Growatt spf5000es at 27k or so each delivered on my door. You can save a few thousand going cheaper but for me Growatt was the best value deal from my research. I planed this for last long time so i not push any limits and have a bit more capacity than needed. My solar input is 270v and my near 10kwh panels at it most does 7kwh.

First i had the idea to do in 2 or 3 steps but then I conclude that for me much better to get it all ups in one project. All In all I spent more or less exactly 300k for all ( 30 kwh batteries included)

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3 minutes ago, Crossy said:

It's the voltage difference between the packs (effectively state of charge) that drives any current between them.

 

But slight differences in pack/BMS internal resistance will affect just how much of the total charge current ends up in each pack. 

 

At the end of the day both packs will have the same voltage and state of charge, how they get there is outside our control, "You cannae change the laws of physics Jim".

 

Thanks for the info. I will just get both batteries charged back up to full status if the weather hold up.

Pink

9 minutes ago, Pink7 said:

Yes they are in parallel with wires between the 2 breakers.

 

Pink

Is it voltage or the Current (Ah) level who make the parallel connection to transfer current between the packs?

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8 minutes ago, Crossy said:

 

Your BMS can't regulate current, it's a purely on-off device, "charge" or "not charge" only.

 

I admit that I'd never thought about the inverter actually controlling the BMS, I've always assumed it was a purely one-way (BMS to inverter) message.

 

Are your batteries completely separate on the DC side? I'd assumed your packs were in parallel which I understand is the normal connection even with multiple inverters.

Yes they are in parallel with wires between the 2 breakers.

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Update: Just come to my main that the 2 JK BMS do not communicate with each other so then that part of my idea will not help, but the inverters do communicate but does they do anything related to manage how much current to charge/de charge each battery/inverter pair? ( INV1/Bat1 vs INV2/Bat2)

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So I have do some more checking and 2 times switch to charge the one battery only to balance the current between the 2 batteries. What happen next is the bms will reverse my operation by less charge current to the battery I just charged up to same level. I also noticed that voltage on the battery who BMS now give less charge have a slight higher voltage so i gues thats maybe why this happens. My first thought is to get both batteries back to fully charged and then I guess or hope there is a voltage calibrate option on the BMS.

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17 minutes ago, Crossy said:

Are your cables approximately equal length??

 

You can expect some variation as the packs charge / discharge even if everything is "identical".

 

Thanks for that input Crossy. I just switched to charge the one battery with both inverters to close the gap (30Ah), and was able to see in app that the current made sense at least on lower current. Yes cables are quite equal in length.

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Last day I got quite allot of difference Amp level of my to batteries and i wondering if my parallel cables between the 2 breakers not doing the job as i should. Today i tested to close down the battery with most Amp to get more Amp on the one with less, but I see much less Amp on the parallel cables than I wold expect. I will try investigate this and try collect some more details on this. My setup use cables between the breakers instead of busbar.

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First month on solar completed. The whole month home was 100% run offgrid and produced 701Kwh. Im very happy with the level of power production even in cloudy days. Last days with much rainy weather I have been able to keep it going with good power management but last nigh not so this morning the ATS flipped at 06 or so. Then 2 hours later when battery voltage over over 50v it flipped back to solar power. So now that part of the system tested also. I use a external ATS from my inverters, I dont feed grid power to my inverters. I was happy to see my PC did not needed to restart when the ATS flipped.

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39 minutes ago, Bandersnatch said:

 

There is rain and there is rain!

 

 

I was thinking same when i writed the reply. last week there was rainy/claudy days but still some sun at times and i was able to produce some power and even charge batteries. But right now im producing 0 watt. Im surprised how much power i can produce in a cloudy day without much sunny weather. If I had managed my power usage a bit better i guess I could manage a day or 2 more with my 2 x 280A (30kh)

A funny thing i noted. I see my wife checking battery capacity on here phone and adjust usage after the capacity.

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18 hours ago, Bandersnatch said:

I designed my house to be off-grid powered by solar. I have a grid connection but it has been switched off at the breaker for over a year now. 
 

Im on 30 days off grid since switched over, but now its raining and Im on 66% battery so lets see if I can "survive" this day and next  before need to switch over to grid. I use ATS and expect to do the switching manually. I will save some battery for emergency if ever on grid and grid down in the bad weather. How much battery capacity you have? How many rainy days can you "survive" ?

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