My neighbor and I are working on a way to interface the Victron Smart Shunt to our SMA inverters. Smart Shunt is extremely accurate and can be used to keep track of SoC by directly measuring amps in/out. This is good if you have a mix match of BMS units that don't talk to each other. So our goal is to read the serial data from smart shunt once a second (contains voltage, temperature and SoC among other values) and pass that SoC along to the SMA inverter on CANBUS. The processor that does this communication bridging is an $7 ESP32.

So far we've done a proof of concept and gotten numbers from smart shunt and we've sent "canned" messages to the SMA inverters to make them happy. Eventually, we'll include features like forwarding all smart shunt data and all SMA data such as AC power in/out to a database via MQTT and then make a remote display for my kitchen.

CANBUS is pretty interesting... it's like a party line where any device can hear or speak to all other devices. The data structure is pretty rigid. In a system a variable such as voltage is assigned a number. Amps or temperature are assigned numbers as well. So we agree that a packet containing 100 will be voltage, and 101 will be amps, etc. The packet also has a place to store the value being communicated. So we might have a packet off 100=12.8 or 101=10 or 102=72 . That's 12.8v, 10amps and 72F.

the voltage on the CAN-L and CAN-H signals are usually the same. This is the "non active" state of the bus. When a device wants to send a 1 it does nothing and the termination resistors at each end of the line "float" the two lines to the same voltage. But when it wants to send a 0 it "yanks" the CAN-H to 5v and the CAN-L to 0v. Believe it or not this is a part of how the collision control works.

Imagine a room where 2 people stand up and speak at the same time. When one guy hears another speaking he stops talking.

Consider that two devices try to transmit at the same time. Each waits a few milliseconds after the last traffic on the network and each starts to transmit at the same exact moment. Each one sends a 1 or a 0 and looks at the voltage on the line. If one of them is sending a 1 (meaning they aren't actually asserting anything on the line. So as each device starts to send a 1 and it realizes another device is actively asserting a 0 (can L and H are 0 and 5v), that device will actually stop trying to transmit. This means that even if 10 devices tried to transmit, each would drop off as soon as it tried to send a 1 and saw someone else was sending a 0.

By the time a device as transmitted the ID number's last digit, it will be the only device that still "has the floor". It transmits the value such as voltage or temperature.

Continued.

The device also transmits a checksum and leaves a pause at the end of it's still on-going transmission. In this gap, all other listeners will quickly add up the check sum for what they've received and assert a "0" on the line if all is correct. Consider this to be a little applause after a speaker makes a statement. If no one fills that gap with "applause" the device will either think that it is alone or the packet got garbled and send it again.

The transmitter will then conclude the packet with a few 1's and 0's. Think of this as "shave and a haircut", and after a short intermission, each of the devices that yielded to the previous packet will start. Once again, the one with the lowest number packet will prevail.

So for each packet send, all devices play a game of "last man standing". It really is pretty slick. In my ham radio days we'd send an entire packet hoping for the best and often had desctrive collisions. With this method, order comes out of chaos due to the "last man standing" concept. SLICK.

And if all of that glaze ya'll over.... my wife said the rooster in one of our coops bristled up at her yesterday and attacked her leg. She hit it with a piece of PVC pipe and he retreated but bristled at her thru the coop fence. I told her you gotta beat him repeatedly to establish dominace. Like my dad used to say "beat your kids until they stop crying".

SO there.. ha.... one extreme to the other... goats, rabbit chickens, canbus and solar power. All under one roof. A one stop shop! 😁

A young man went to seek an important position at a large printing company. He passed the initial interview and was going to meet the director for the final interview. The director saw his resume, it was excellent. And asked,'

"Have you received a scholarship for school?" The boy replied, "No".
'It was your father who paid for your studies? '' Yes.' He replied.
'Where does your father work? ' 'My father is a Blacksmith'

The Director asked the young man to show him his hands.
The young man showed a pair of hands soft and perfect.
'Have you ever helped your parents at their job? '
'Never, my parents always wanted me to study and read more books. Besides, he can do the job better than me.

The director said: 'I have got a request: When you go home today, go and wash the hands of your father and then come see me tomorrow morning.'

The young man felt his chance to get the job was high.

When he returned to his house he asked his father if he would allow him to wash his hands.

His father felt strange, happy, but with mixed feelings and showed his hands to his son. The young man washed his hands, little by little. It was the first time that he noticed his father's hands were wrinkled and they had so many scars. Some bruises were so painful that his skin shuddered when he touched them.

This was the first time that the young man recognized what it meant for this pair of hands to work every day to be able to pay for his studies. The bruises on the hands were the price that his father paid for his education, his school activities and his future.

After cleaning his father's hands the young man stood in silence and began to tidy and clean up the workshop. That night, father and son talked for a long time.

The next morning, the young man went to the office of the director.
The Director noticed the tears in the eyes of the young man when He asked him,

'Can you tell me what you did and what you learned yesterday at your house?'
The boy replied: 'I washed my father's hands and when I finished I stayed and cleaned his workshop.'

'Now I know what it is to appreciate and recognize that without my parents, I would not be who I am today. By helping my father I now realize how difficult and hard it is to do something on my own. I have come to appreciate the importance and the value in helping my family.

The director said, "This is what I look for in my people. I want to hire someone who can appreciate the help of others, a person who knows the hardship others go through to accomplish things, and a person who realizes that money is not his only goal in life".

'You are hired'.

A child that has been coddled, protected and given everything he or she wants, develops a mentality of "I have the right" and will always put himself or herself first, ignoring the efforts of parents, family and friends. If we are this type of protective parent are we really showing love or are we helping to destroy our children?

You can give your child their own room in a big house, good food, a computer, tablet, cell phone, and a big screen TV, but when you're washing the floor or painting a wall, children need to experience that too.

After eating, have them wash the dishes with their brothers and sisters, let them fold laundry or cook with you, pull weeds or mow the lawn. You are not doing this because you are poor and can't afford help. You are doing this because you love them and want them to understand certain things about life.

Children need to learn to appreciate the amount of effort it takes to do a job right. They need to experience the difficulties in life that people must overcome to be successful and they must learn about failure to be able to succeed.

Children must also learn how to work and play with others and that they will not always win, but they can always work harder to reach their goals. If they've done their best, then they can take pride in all the effort they put forth.

Life is about giving and serving and these qualities are taught in our homes.

Taking a snippet from the above story... "A child that has been coddled, protected and given everything he or she wants, develops a mentality of "I have the right" and will always put himself or herself first, ignoring the efforts of parents, family and friends. If we are this type of protective parent are we really showing love or are we helping to destroy our children?"

I'm not much of a bible beater, but 2 Timothy 3 sure says alot about many in our current youth.

2 Timothy 3
But mark this: There will be terrible times in the last days. 2 People will be lovers of themselves, lovers of money, boastful, proud, abusive, disobedient to their parents, ungrateful, unholy, 3 without love, unforgiving, slanderous, without self-control, brutal, not lovers of the good, 4 treacherous, rash, conceited, lovers of pleasure rather than lovers of God— 5 having a form of godliness but denying its power. Have nothing to do with such people.

6 They are the kind who worm their way into homes and gain control over gullible women, who are loaded down with sins and are swayed by all kinds of evil desires, 7 always learning but never able to come to a knowledge of the truth.

If anything I think boomers and gen-x are guilty of spoiling their children.... and I am gen-x.

https://www.youtube.com/watch?v=tg-3dOfTeb4 price seems to be down on shipping containers.....

https://youtu.be/LwdSwU3cmpU nice solar (except he's using lead acid batteries) and nice outside insulation.

https://youtu.be/AkzXfNzUNlU
A serious solar system for a summer camp. They use SMA inverters like me and my neighbor do. I’m working my way to 100kwh battery and they have 200kwh.