February 2025 update

 Over a year ago, a lightning strike destroyed or damaged most of my solar power station.

Only the panels were spared. The lignbting came into the house over the aircraft cable guy wire carrying signl and power cables from the panel array.

I replaced the Epever Tracer 3210 charge controller with an Epever Triron 4210.

I replaced the inverter with a 

My lead-acid batteries had a much shorter lifetime or were destroyed. The battery bank went throough a major upgrade. LiFePO4 batteries had become affordable, and were, therefore replacements for the Duracell Ultra Marine lead-acid batteries. 

I also chose to, at this time, upgrade and update my Raspberry Pi and associated software, always a formidable task.

I updated the RPi3b with a RPi4b-2Gb. The prevoius operating system, Debian Buster, was replaced by Bookworm 12. 

PHP and Python programs were both updated to current versions as well.

The Exar driver, always a pain and always taking days, was a pain and took days. However, the programmer of the original driver software, Kasbert on github, provided software to send and receive messages from the Exar driver, now an integral part of Raspberry Pi OS, labeled as 'xr_serial.'

I needed software that would work get the driver running but without any interaction. That work-around lasted for a week or two. I tried everything to use the code, but the minimal use resulted in two failed tries before USB0 would run consistently. 

I tracked down the linux source code and discovered some code in an article on serial rs485  communications. I extracted the code and made minor modifications to get a runnable executable.

I compiled the code in the Raspberry Pi and that solved the Exar driver problem.

Currently, everything is up and running. My next taskk is to change the online graph software. 

I have been using HTML, PHP and D3. The new software is Dynagraph 2.2.1. That software seems so much easier than D3. And more versatile too.

The queue also includes a new array suport system made from 'superstrut.' The old patched aluminum ladder plus 2x6 and 2x12 is gone, as is the large concrete slab used as an anchor for the ladder and array.

February 28, 2025.

RPi update & battery calculations

 The RPi is online and running 24/7 now, but not collecting data or moving the array. 

I decided to bite the bulket and update to Bookworm OS and python's virtual environments.

I still haven't gotten the network set up the way I want and the OS included Exar driver is not working, and while the Maxlinear driver compiles, it is not inserting ('insmod').

More study is needed.

I still need two more batteries.

Battery charge time calculations.

I have 585 watts of solar panels that I will round off to 600w.

I also have 4.2kW of battery storage.

4.2kW/0.6kW=7hr to full charge

But, the charge controller has a ma charge rate of 20A for the configuration.

20A x 12V = 240W=0.24kW

 This results in a charge time of 

4.2kW / 0.24kW = 17.5hrs to full charge from complete discharge.

A complete discharge is not likely since system shutoff is set at 10.5V.