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Forum Index : Microcontroller and PC projects : HMI monitoring solar charging based on arduino

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Mason
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Joined: 02/07/2021
Location: United States
Posts: 20
Posted: 02:24am 09 Jul 2021
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Solar energy is the energy generated by the continuous nuclear fusion reaction process inside the sun, while solar power generation panel is the tool to convert solar energy into electricity. During the conversion process, we generally focus on the following parameters:

A. Output voltage of solar panels

B. The output voltage of the circuit protection device, that is, the real output voltage of the output terminal

C. Conversion efficiency

According to the above information, we can use the UART touch screen of STONE to make a human-machine interface to display the power generation of solar panels and charging of lithium batteries in real-time.

The HMI display is as follows

1. Display the power generation voltage of the solar charging panel through the STONE display module

2. Display lithium battery voltage through the STONE display module

3. The charging efficiency is shown by the STONE display module

In practical application, there may be more parameters to pay attention to, but since I am not from this major, I only pay attention to the above three parameters.

The hardware modules that I have:

1. Solar charging panel


2. STONE serial touch screen

3. Arduino UNO

4. Lithium battery charging board

5. Lithium battery
 
Mason
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Joined: 02/07/2021
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Posts: 20
Posted: 02:28am 09 Jul 2021
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Now I have learned how to connect the Arduino to the display.



Does anyone perhaps have a good suggestion about solar charging or how to put them together?
What all do I need to look for in this process?
 
Volhout
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Joined: 05/03/2018
Location: Netherlands
Posts: 1808
Posted: 06:38am 09 Jul 2021
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look here: FID=4https://www.thebackshed.com/forum/ViewForum.php?FID=4
If nothing goes right ... turn left
 
Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 3139
Posted: 06:47am 09 Jul 2021
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The output voltage of the charger must never exceed the maximum charging voltage of the battery and the output current of the charger must never exceed the maximum charging current of the battery. Those are fixed limits, it doesn't matter what your solar panel generates - anything exceeding these limits has to be throttled back in some way. That has nothing to do with charging efficiency.

If you are looking for efficiency calculations then you are looking at Watts generated and Watts feeding the battery. Between these is the charger module - and it is that which you are calculating the efficiency of. You can't calculate the efficiency of the solar panel without knowing the light intensity and Watts output. You can't calculate the efficiency of the battery as you (apparently) aren't measuring its output into a known load.

There are two sorts of charger modules.
.  A switching type accepts a wide range of input voltages from the solar panel and generates a charging output for the battery by using PWM techniques to reduce losses. The output remains more or less constant while the panel is illuminated.
.  A linear type (much cheaper) does almost the same thing but all excess power from the panel is dissipated in the charger module as heat. Obviously, this heat is the loss of efficiency.

You'll notice that I've been referring to Watts. That's what you need to get your calculations as the output voltage and current from the panel may not be the same as the input voltage and current to the battery - depending on the type and efficiency of the charger module. To get Watts you will need to measure current in both positions as well as voltage. I would suggest getting high-side current sensors to simplify things. Your Arduino will then have analogue inputs for voltage and current on both sides of the charger. After that it's up to you. :)
Edited 2021-07-09 16:49 by Mixtel90
Mick

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Preliminary MMBasic docs & my PCB designs
 
phil99

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Joined: 11/02/2018
Location: Australia
Posts: 754
Posted: 08:30am 09 Jul 2021
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Efficiency of the solar panel is maximized by constantly adjusting the switching regulator to keep the panel at it's optimum combination of voltage and current, for the solar intensity. The switcher is doing double duty as a charger and peak power tracker.
The efficiency of the batteries is related to the difference between charging and discharging voltages. There isn't much you can do to change it.
 
Mixtel90

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Posted: 09:15am 09 Jul 2021
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I'm not sure that Mason is using a proper solar charger board, Phil. The (Russian) page in his link is only to generic lithuim cell chargers as far as I can see (I can't read it but I recognise several of the boards). Not the best way to do it.
Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs
 
lizby
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Joined: 17/05/2016
Location: United States
Posts: 2367
Posted: 11:53am 09 Jul 2021
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I've just started experimenting with this Banggood $18 "100W" solar panel and charger (price may vary depending on when and from where you click the link).

"100W" can only mean that you might get 100 Watts out of it in a full day of good sun, but the panel is quite sensitive--you can get charging current out of it even when overcast and through mottled leaf shade.

The charger is lead-acid, not lithium. I'm working on Mixtel90's suggestion of monitoring current in from the panel and current out to a 12V "48W" 16LED Work Light, which is actually a pretty good light for the price, though not 48W by any conventional measurement (at the local auto-supply store, a similar-looking LED goes for 4 times the price--it might or might not be better, but it's not 4 times better).

For the purpose of experimenting, this size panel is easier to work with than full-sized solar panels.

Note that 100W would easily give you an evening's worth of good-enough-to-read light from that 16-LED module (throttled down with this dimmer), and many more hours of emergency walking-around-without-tripping light.

~
Edited 2021-07-09 22:05 by lizby
PicoMite on fruitoftheshed
 
Mixtel90

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Location: United Kingdom
Posts: 3139
Posted: 12:03pm 09 Jul 2021
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That looks good fun, lizby. Probably a selected sample that managed 95W for 15mins in the middle of a Chinese field in midsummer so they rounded it up a bit. :) I bet they are quite good for something like a caravan if you only need a small battery though.
Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs
 
CircuitGizmos

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Joined: 08/09/2011
Location: United States
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Posted: 08:19pm 09 Jul 2021
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Nevermind. Something failed...
Edited 2021-07-10 06:20 by CircuitGizmos
Micromites and Maximites! - Beginning Maximite
 
CircuitGizmos

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Posted: 08:21pm 09 Jul 2021
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That was strange. My quoted post format was clobbered.

I just thought the panel was very small for 100W. I have a panel 6 times that size that manages 100W.
Edited 2021-07-10 06:23 by CircuitGizmos
Micromites and Maximites! - Beginning Maximite
 
lizby
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Posted: 08:32pm 09 Jul 2021
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  CircuitGizmos said  I just thought the panel was very small for 100W. I have a panel 6 times that size that manages 100W.

It is small, and I also have a much larger 100 watt panel. This one is much easier to position, and the principles of what I want to try are the same, greater or lessor output.
PicoMite on fruitoftheshed
 
phil99

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Joined: 11/02/2018
Location: Australia
Posts: 754
Posted: 01:37am 10 Jul 2021
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Re BangGood panel output.
When you calculate the area x max. solar input x efficiency = 15 to 20W max.
If it seems like a super bargain it is usually bogus.
 
lizby
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Posted: 02:16am 10 Jul 2021
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  phil99 said  Re BangGood panel output.
When you calculate the area x max. solar input x efficiency = 15 to 20W max.
If it seems like a super bargain it is usually bogus.

I did not expect it to be 100W (I have two real 100W panels). If I get 20W, I'll be happy. If I get 15W, then I'll figure that on a good day, it's a 100W per day panel. In any case, it's adequate for playing, and it does charge my 5Ah battery.
PicoMite on fruitoftheshed
 
Davo99
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Joined: 03/06/2019
Location: Australia
Posts: 1551
Posted: 04:00am 10 Jul 2021
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  CircuitGizmos said  

I just thought the panel was very small for 100W. I have a panel 6 times that size that manages 100W.


The panel you have is probably a real 100W panel, The other is probably sucker bait.
I Still don't know what the fascination Americans have with 100W Panels  though? There are so much bigger available now and have been for decades that I have no idea why anyone would even look at 100W panels to begin with.  At the other end of the scale they are Building 600W panels now although they are monsters so I can see why people wouldn't want them to play with.  250's are cheap and available everywhere used. I don't even bother picking up anything under 250W now and I could get loads of them for nothing. Too small to bother with these days.

There are a LOT of these stupidly over rated panels on these sites That are not what they seem other than to pull the money out of the pockets of the unsuspecting and Gullible. Many look at price only and don't query specs or question any ridiculous numbers they are given. That's why they seemed small, because they are.

The efficiency in panels varys very little even from 10 years back so any claims of " High efficiency"  is  BS. Bit like they advertise 10 AH 18650 Cells and 8W individual  LED's. Just numbers to pull in the ignorant who don't know any better or have the smarts to do some homework.

 It's easy to count the number of cells and work out what the real output is.  In typical Chyneese style, these are more often than not given BS ratings like a lot of other things. They are not cheap if they only deliver a portion of what their rating is and you cost them out at their True rather than the sucker rating.

Panels are one of many things I wouldn't buy online like this unless I was getting a known brand or could would out the output. Looking at Reviews on YT is a good way to sort the  crap from the real deal. There are a number of Channels where they buy these things and test them. The results are sometimes surprising in some of them do actually perform as stated.

Just search the name and the type of panel in YT and you might find a review that tells you if they are good or just sucker bait. :0)
 
Solar Mike
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Joined: 08/02/2015
Location: New Zealand
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Posted: 08:47am 10 Jul 2021
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If you read their description of the panel specifications, it quite clearly says 30 watts. The "100" value will be some daily amount.





Mike
 
lizby
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Posted: 11:09am 10 Jul 2021
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30W would be excellent.

I just bought it to play--if $18 is a total loss, it's not much of one. And so far, it isn't--I can charge a 5Ah battery and get useful current out of it, useful 12V lighting, and I can charge a power bank to get 5V with the USB ports. In past times, I'd have found the controller itself worth the price, though I know they're now cheap as chips.

Re inexpensive panels, not in North America, and try finding them used. A scroll through Amazon shows $100USD about the minimum for a 100W solar panel (and a not-well-known brand). The 200W kits have two 100W panels.

In any case, in Nova Scotia, there's not much I can do with solar except play at it in the summertime.

There are some medium-sized solar farms being put in well north of me, along the Northumberland Straight shore--it will be interesting to see in a couple of years what kind of stats they have.
PicoMite on fruitoftheshed
 
Davo99
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Posted: 01:45am 11 Jul 2021
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  Solar Mike said  

The "100" value will be some daily amount.


The Chyneese fleabay sellers like to Invent their own ratings and fantasy Numbers.
NEVER seen any real rating on a panel other than the standard Max rating which is BS anyway. Bit like car Mileage. Yes, If Driven on rock hard tyres like a Pensioner on Downers measured only going down a mountain, the numbers might be relevant but otherwise, they are rarely achievable except in my experience during  brief cloud edge effects. And that's with proper household panels, I guarantee these cheap crap panels that are made inevitably from 2nd or 5th grade cells are even worse.

I have used this to my advantage several times.

It can be useful if you KNOW what you are getting.
I have bought a boatload of those 48W LED driving/ Flood Lights and some light bars. They advertise them with all sorts of BS ratings, usually laughable. Yeah sure that light bar is 652W or whatever. Do these scammers even stop and think how many amps that would be @12V?

They have claimed that they are " Equivalent" to 48W lights but as they don't say that or what type of light they are equivalent to ( Halogen, mercury vape, Tungsten etc) that does not get them far in a dispute.

Making their lies more laughable is they often specify some contradictory factor like they have a 10A fuse. They tend to not specify amps and are getting away from ratings now as well. I'm beginning to suspect it is because some friends and I have called them on it so many times they are waking up. If they spec 3 or 5 or now I see 8W LED ratings, that's another shot in their own foot.

I order these lights fully well knowing what they are. When they arrive I video unboxing them showing the label and the box clearly then open them up and put them on a battery with a Couple of Multimeters showing the amps and volts.  When they fail to meet spec as I know they will, I put in a claim for goods not as described and ask for a refund. I send some pics straight up of the volts and amps and ask if they would like me to put the video on YT with all the details on it so they can see the unboxing and testing. If they hesitate I link them to the vid with all their details.  That generally gets a satisfactory outcome but some are too stubborn for their own good.

They will offer some $5 refund or something but then I mention I am not satisfied, the things are not what I wanted or as described and if we cannot reach an agreement I'll ask ebay to referee the outcome.  They have always sided with me ( amazingly) mainly because I have the evidence they can't argue with and 95% of the sellers don't know jack about what they sell either as they are all just doing store fronts from the suppliers and are selling everything from Marital aids, to generators to egg timers. Usually just the Ebay Bot will issue the refund especially if you call them " Counterfeit" goods.

I know they are buying the lights cheap as chips so they rarely ask for their return and if they do, it's pretty easy to get round that as well.
Yes, I take great pleasure in scamming the scammers and would like to think it deters this soert of crap but I'm not that stupid. The amount of scam items and didgy sellers on fleabag is exploding and Fleabay really don't give a rats. They will give refunds when they get a complaint but do nothing to make the seller change the listing for future sales.  It's really fun to buy off the same seller Multiple times. 4 is the record so far and that was within a fortnight. They then banned my account so I just created another one and got another 3 orders out of them.

One of the best arguments was when they said you bought these before and complained, why did you buy them again if you knew they weren't right? I said because after I alerted you to it I thought you would get proper rated lights and I wanted to give you the business. I said ebay refunded me before, should I ask them or you want to do it yourself and avoid the bad seller rating?  Didn't get a response, just the notice of the refund.  

Only trick is not to buy too many at a time. If you do that then there is more value in getting them back. That said. I did get 6 in one lot and had no problems getting a refund on that.  Buying from China is a help as THEY have to pay return shipping on faulty or not as described goods ( much as they will tell you it's going to be at your cost) but if you call them out on it clearly it's not worth them doing it.  If they baulk, Fleabay won't.

I must have got about 26 Odd of these lights now for nothing. I bought a Light bar for the truck and although way short of rating, It's been great. Kinda happy it was not as rated because the thing is so damn bright particularly when reflecting off road signs, any brighter would be a detriment. I did get a couple of others and several of the emitters failed pretty quick so glad I didn't pay anything for them.

The 48w Lights are about 21W in reality and not bad lights. They do throw a LOT of light and are very useful. Really need the cover's popped off and the LED board pulled back and some heat compound put on them because the heat sinking is actually terrible. Done that with a few that might see long hours of use.

ANY of these cheaper non branded lights ar 1.2-1.5W LEDS ONLY. don't matter what they say about size or being osram or whatever LED's they are the basic output ONLY.  Easy to count the emitters in a light and work out what it's really going to be and compare that to spec.  Worst thing for me is an HONEST seller but not too many of them without brick and mortar shops as well.  Also the price is pretty much a giveaway.


I am using the lights mainly as yard lights mounted on the eaves and as Christmas Lights for the big tree out the front. The 240V LEDS I bought when I got here for the yard have all crapped out with bugger all hours and these pretend 48W types ( also seen them advertised as 96W many times which are even easier to get a "Not as described" refund on) are smaller and more effective especially when I can run multiple along the back  to really light up the yard. Going to set some up on the shed with a Radio remote so I can switch them remotely.
They are also useful to put on a stand and use when working on cars, tractors etc.

These BS ratings can be very handy if you know how to use them against the crooks flogging them and ripping people off. Wouldn't waste my time with these dodgy panels that will probably fall over in no time anyway.

Some of this crap isn't worth having even for free.
 
Davo99
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Posted: 02:23am 11 Jul 2021
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  lizby said  

Re inexpensive panels, not in North America, and try finding them used. A scroll through Amazon shows $100USD about the minimum for a 100W solar panel (and a not-well-known brand).


I read that a lot. And laugh at it as well.
A quick look on Fleabay as well as other sites proves it is complete and utter parroted bullchit. How surprising. Not.

Right now on flebay US with the simplest of Searches I can see 300W panels for $120.  I can see 190's for 55, 49 in lots of 10. I can see 355's for 100.  
I can't remember seeing 355's here any cheaper and most times are far more exy.
Again, shows this fascination for 100w panels is illogical and the realm of the ignorant on price.

There ARE Clearly much larger panels available at very affordable prices so this "not available mentality is just an excuse and an unsubstantiated sook.

Ebay here tends to be at the higher end of the price range for used goods. I assume much the same would be in the states especially as they have Craigslist, Facewaste and endless other local trading sites which would no doubt have even cheaper panels available same as here.

I guess people will believe whatever they feel like and want to whinge about no matter how flawed and demonstrably untrue the argument.
 
lizby
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Posted: 10:40am 11 Jul 2021
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  Davo99 said  Right now on flebay US with the simplest of Searches I can see 300W panels for $120.  I can see 190's for 55, 49 in lots of 10. I can see 355's for 100.


Can you provide some links? Perhaps I'm not searching correctly.

I scrolled through the first two pages, and all the ones I saw appeared to be the same type (or bigger or smaller) as the $18 Banggood one I bought which you described as "sucker bait" (and not incorrectly, if someone expected to get a continuous 100W in good sun, which I didn't).

They all seem to be "RV, Boat, Car" types, flexible and small for the claimed rating. I'd be happy to see correctly rated ones in the price range you quote if you can show me how to search.

Even with "solar panel -rv -caravan -boat -camping" I don't see anything that appears to be legit.
PicoMite on fruitoftheshed
 
Mason
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Posted: 07:47am 12 Jul 2021
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Thank you for your enthusiastic replies, I am the first time involved in the field of solar energy, if I have incorrect questions please point them out, if you have a recommendation for suitable solar panels can also give me a link, thank you!

I've got a few things figured out now, so if I make any progress I'll update here!
 
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