considerations about solar energy

albertsm · Joined: 09 Apr 2004 Posts: 5922 Location: Holland

solar panels are first choice when you have room for them. since we have a roof we have room. the angle is not optimal but with daylight panels you still get energy.
before i started i had little knowledge. i thought ; some panels, a converter connected to the grid and voila. and yes that is true. but with more knowledge come more choices.

we have a stable grid. but since they can not connect new companies to the grid and they are talking about using power in certain hours, i foresee that it will not remain stable.
they connect electric cars and other heavy stuff so it is a question of time before we get interruptions.

a real simple solar option is to use panels with grid inverters like IQ7+ from enphase. they have a good warranty and track record. when you have 1 panel and one IQ7 you can plug this direct into the wall outlet. it is safe since it will only inject power to the grid when it detects a grid. and that is also the problem : when the grid is down you dont have power. because for safety the inverter must shut down.
i never realized that.

there are newer IQ8 which can work off grid with an expensive battery and switch box. that is too much for me. and a downside of IQ8 is that it requires a gateway and the manufacturer to get it going.
i do not really like devices on my network that connect to the net. you never know what they do. and what if the manufacturer goes bankrupt. so for that reason i prefer the IQ7 that does not need the manufacturer to function/unlock.
i can create a separate network but still. i kind of feel taken hostage since they can push updates without my consent.

Then there is the other option : use a hybrid inverter and use an optional battery. but these have less warranty. some inverters allow to use different kind of batteries like lithium, lead acid. and the brand is not important either.
on ali and amazon you can find many inverters. but quality varies.

the downside of hybrid is that you use DC with higher voltage and it can arc when not properly isolated.

the most important thing : check the video from Will https://diysolarforum.com/threads/top-10-mistakes-that-beginners-make.49571/

i did not even discussed the rest : construction on the roof, connect to the mains, insurance, measuring.
watching YT is very helpful since many did this long time ago.

for me : it starts with knowledge of what you consume. so i start with making a simple device that can measure the power. i will also measure separate devices to know what on earth is taking all that power
Very Happy

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JC · Joined: 15 Dec 2007 Posts: 586 Location: Cleveland, OH

What an interesting topic!

I live in northern Ohio, near the "great lakes", and there are not many solar powered homes in our area.

I have a friend who built a new house in town a couple of years ago.
He drives a Tesla all electric car.

He put solar panels on his roof, and installed a "Tesla Powerwall", (rechargeable lithium-ion battery bank), in his garage.
(Wiki has a page on this.)
https://en.wikipedia.org/wiki/Tesla_Powerwall

On sunny days the solar panels recharge the battery bank, and power his house!

He can go through a couple (2 or 3?) cloudy days running his house off of the battery bank.

The battery bank also charges his car, so no $ for gas for his car, and no $ for paying for electricity to charge his car!

The Tesla Powerwall battery banks are expandable, so he can add another bank to the system if he wants the ability to power his house longer without sunny days.

The solar panels are anchored to the roof, so they are not optimally aimed, and they don't track the sun, but the system is efficient enough that it still works well.

The Tesla system, as one might expect, is not cheap, but it is very well engineered, and safe.

He has a computer in his house that tells him how much energy (each panel?) is generating, and the status of the battery bank.

It is a very impressive system, and I am very jealous every time I have to fill my car with gas!

Jay

albertsm · Joined: 09 Apr 2004 Posts: 5922 Location: Holland

yes if i only had money for Tesla it would be great. Energy cost a lot here now and only when they can improve solar cells a lot i could create enough energy during the day.
so i aimed high but to be realistic, the solar energy will not be sufficient. i looked at wind turbines too. great when you have enough terrain. and dito for the solar panels : when you have enough room you can put them in your garden. but here space is limited. Anyway i looked at hybrid inverters but that is also a complete study. most come from china with limited warranty and horror stories on amazon.
so no i doubt if i go that route. maybe better to use inverters and then later create some AC coupled battery backup.

the more i read and understand, the more choices and complexity it adds. i am waiting for some parts so i can measure my energy consumption. that is the first step : know the consumption.

JC · Joined: 15 Dec 2007 Posts: 586 Location: Cleveland, OH

JC · Joined: 15 Dec 2007 Posts: 586 Location: Cleveland, OH

OK, this is more of what I was thinking about:

It is USD: $6.90
It is a coil for one lead, and has a voltage output.
Not much of a data sheet...
It appears that 0-60A -> 0-1V (P-P ???).

So, probably AC couple it into an op-amp to get some gain for a 0-2V PP or 0-3V PP signal.
Then feed that into an ADC.

Unfortunately, it looks like one would still have to disconnect a primary power wire, slip this over the wire, and then reconnect it.
The good thing is that there is no in line resistor or in line PCB trace needed.

The 60 A range ought to be good for a residential house.

JC

albertsm · Joined: 09 Apr 2004 Posts: 5922 Location: Holland

you can open it with a clip then close it. indeed it goes over 1 wire.
this is a good solution but i aiming on something different for now.

my power meter has a LED that gives a pulse. So all i need to do is count the pulses.
it seems simple but... it is a normal red LED so the usual photo diode will not work. you need one in the visible spectrum.
then use the analog comparator of the AVR with a potmeter and you can count the pulses.
Since i need to pay shipping costs i wait with ordering a diode till i need more things.
But in the mean time i also found on ebay a complete pcb that also has a comparator and the proper diode.
LDR is too slow and all the photo diodes i tested did not work. Some red LED emit also near the IR spectrum but not this one.
This situation will be different for everybody. So using a clamp is way better.
60A is indeed the right one since the main fuse is 40A. We have 230 or 240V and 1 phase. Or actual 2 phases. For solar i think for starters 1 phase is simplest.
So in my case i would need 2 clamps.
For the shed i can get an envoy that measures but there i want to use a clamp.

today i read an article in the newspaper that when you have the airco on for 1 night it cost about 10 euro. A normal fan will cost about 25 cents.
but you get why i am busy with this between the other work

Very Happy

Paulvk · Joined: 28 Jul 2006 Posts: 1257 Location: SYDNEY

The PZEM-004T is a cheap way to measure power has a isolated serial port , split core current transformer option.
Interfacing to an AVR would be simple and would be great to have a Bascom library for it.
I have some but not had time to write Bascom code.
Regards Paul

albertsm · Joined: 09 Apr 2004 Posts: 5922 Location: Holland

hi Paul, this seems a great module. especial with the split core. i will get one and make some code for it.

Paulvk · Joined: 28 Jul 2006 Posts: 1257 Location: SYDNEY

Note the wires from the split core can be fairly long if run as a twisted pair as
the impedance is low as the burden resistor is about 30 ohms.
Arduino has already code for them so you will be able to find the registers in the code
descriptions.
One thing to note about the units is they use a capacitor dropper for powering them
and a 100ohm surface mount resistor in series one modification is to replace it with
a larger resistor as its being used at its limits with 230v mains.

albertsm · Joined: 09 Apr 2004 Posts: 5922 Location: Holland

too bad they use a dropper. but thanks for the warning. i will mod it since our range is up to 240V
i got the pdf and it is a simple modbus slave. so you do not really need a lib. it is very simple.
i will probably create a separate topic for it.

JC · Joined: 15 Dec 2007 Posts: 586 Location: Cleveland, OH

albertsm · Joined: 09 Apr 2004 Posts: 5922 Location: Holland

the BPW24R should work too. in the mean time i got some but no time yet to test.
i also looked at ambient sensors with i2c interface for a different project. well i will see what will give the best result.

albertsm · Joined: 09 Apr 2004 Posts: 5922 Location: Holland

here is a small update. using solar panels in our country has all kind of traps. the current situation is that when you have solar panels you can use them to power your home. in the summer when there is a lot of sun you have lot of energy surplus , you deliver this back to the net and you get money for that. in the winter you have less power and the money saved in the summer you can use and this way you save money since you have to buy less. this is subsidized by the government. but now some energy companies charge you for having solar panels. this means the time you need to get your investment paid off is taken longer.
i do not think this will help the energy transition. also the net in our country is full and overloaded.
but that is another story.

What this means for me is that it is better to store all energy in batteries. But the batteries are still expensive.
So this summer i will mount some panels on my balcony. Then i will see what power i get from a panel. the angle is not optimal but my roof is also not optimal.
these are panels i bought cheap to play with. for my roof i probably wait till batteries are good priced. IQ8 series converters can use a battery and can work without the net.
A string with inverter is not a good option for me. the converter per panel are more safe and have longer guarantee.

Alexander-Dan · Joined: 13 Mar 2014 Posts: 111 Location: S.Posad

albertsm · Joined: 09 Apr 2004 Posts: 5922 Location: Holland

that was 2005 that is a long time ago. science advanced and still is.
if you talk about bad for the environment : the war from Russia against Ukraine is way more worse for the environment. Not talking about the nuclear thread from the crazy pathetic Putin.

If you live in a country with no sun then you will not gain much but in our country even with day time panels we have a break even point after just a few years. And the panels will last for 25 years.
We also have many wind mills and they produce a lot of energy.

lithium is bad but it will not take long before other materials are used like sodium or whatever. Sure we can do nothing and keep using gas and oil and heat up the world more but we can also investigate and research in green energy. Sure it will never be totally green.

I know that it will cost time and money to recycle the old panels but it way more doable than clearing all the land mines russia leaves in Ukraine. in Denmark they still are clearing mines from WW2.

edit : i got a complaint about politics are not allowed. that is right but in russia a dictator makes the rules so this should not be new for russians. I got tripped by the negativity of green energy from a country that depends on selling gas and oil. at an old job there were always people that were negative about every possible improvement. only reasons why something would not work but never good ideas to improve.
and i know russia is with a capital letter but IMO only countries with reasonable people deserve that right. yes i take it highly that that EU/world will put billions in weapons , billions that could have been spend way better, just because a mad dictator and friends (does he still have them? ) never has enough and want to rewrite history.
I know there are many good russians too, the ones that believed in free speech and Navalny. so for those russians i hope for a better future. that they can speak and vote without fear of getting poisoned or sent to prison. they are the brave people i respect highly. the others are guilty to genocide of the Ukraine people.there is no place for them here.

no further discussion is possible. it is a pity i had to write this. but as i grew older i understood the world is not a cozy place and some times you have to speak out and break your own rules.