RPi4 standalone wifi

 

The RPi4/Bookworm12 offers a hotspot option from wiithin the GUI. That works but there are issues.

I ran across a more direct method using nmcli from a SSH headless session. The RPi4 remains online if the router/modem is shut down. My notes follow:

How do I set up networkng on Raspberry Pi OS - Bookworm

Not the same as an access point.

December 26, 2025

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Google AI:

raspberry pi 4, bookworm, turn on hot spot from cli

# 1. Stop NetworkManager if needed (sometimes helps)

sudo systemctl stop NetworkManager

(-RPi shutdown, reboot needed., this step probably not needed.)

# 2. Create the hotspot (replace values):

sudo nmcli device wifi hotspot ifname wlan0 ssid "RPi4-Spot2" password "raspberry"

{-RPi4 is now on 192.168.0.193)

"Windows can't get thhe network settings from the router"

"Enter security key instaead" : 'raspberry'

Mobaxterm closes

Now using 10.42.0.1 / 'RPi4-Spot2' SSID and logged in.

The RPi4-Spot2 hot spot may or may not boot and run without the router/modem.

This remains to be seen. 

Turned off router/modem and let the RPi4 run all night. Everythings good.

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Unused option for internet sharing:

# 3. (Optional) If sharing internet, ensure ipv4.method=shared on the hotspot profile

# This might need manual editing of the connection file or specific nmcli commands.

# Example for setting up internet sharing (requires dnsmasq/bridge setup):

sudo nano /etc/NetworkManager/NetworkManager.conf

# Add [main] dhcp=internal to disable NetworkManager's DHCP, and set ipv4.method=shared on the hotspot connection.

# 4. Start NetworkManager

sudo systemctl start NetworkManager

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# 5. Verify hotspot is up

nmcli con show

nmcli connection show

NAME                UUID                                  TYPE      DEVICE

Hotspot*             3cd3ec9d-0bcd-4b40-a630-52e0bf267c4e  wifi      wlan0

Wired connection 1  34d66ff1-2341-3e52-9a95-a4ecb8758e18  ethernet  eth0

lo                  67bfa196-29c6-4ce0-9f54-7bab05f610a9  loopback  lo

preconfigured       8611a411-98af-4d8c-9148-f6a0389f8b75  wifi      --

* Note name of hotspot, 'RPi4-Spot',

 is not used, as when GUI version is set up.

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Deletion process:

nmcli connection show

sudo nmcli connection delete "HotspotName"

nmcli radio wifi off

nmcli radio wifi on

The hotspot may be deletable from the GUI as well but nmcli is probalby more consistent.

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/

USB SSD RPi boot update

 I have settled on a new and more efficient way to get the RPi to boot from a SSD on a USB3 port.

-Install Bookworm 12 - Desktop, on an SD card. Remember to check options in Raspberry Pi Imager.

-Run the RPi with the SD card.

-Run Rasp-config 

    set Interface/VNC on.

    set Advanced/Bootloader to latest

    set Advanced/Boot order to NvME/USB firat

-Finish and reboot

-Copy all files to the RPi and get the final system up and running.

-Open VNC on a PC

-Open the Chromium Accessories menu and run the "SD Card Copier" with the SSD attached to a USB3 port.

-Reboot the RPi fromShutdown the RPi and remove the SD card a CMD and check the SSD is root

-Optional: Use Win32 Imager to make an image of the SD card. Such an image cannot be made of the SSD which would be 500Gb.

More needed upgrades

 

A recent spell of rainy weathewr highlighted the need for more battery power. I had to turn off the refrigerator for a couple of days and the system still shutdown at a low voltage. Granted I'm using mor epower on a daily basis, but the extra power is always welcome.

This includes an increase in solar panel power too. Currently, I've one kilowatt. I need two, minimum, to runappliances such as the microwave and a 1/2HP water pump (to replace the 3/4HP pump).

.Current power usage:

Porch lights dusk to dawn

Refrigerator 24/7

RPi system 24/7

Internet modem and WiFi 24/7

In a shortage, the first to be shut off is the internet system.

Next the porch lights.

Last, the refrigerator.

The RPi system uses so little energy, shutting that down would have a negligible effect.

Four more 120Ahr/12VDC Group 24 batteries from WattCycle are needed.

More/different solar panels are needed. A move to 500W panels may be needed as would a move of the panel array to the garden area. Up to three arrays, side by side, may be placed in the garden area,

Major update

 

A lot has been done since the last post.

Previously, I had 580 watts of solar panel power. One of the panels, on examination, had lost a significant amount of power. That panel was replaced by a new 100 watt panel, making the system 600 watts.

More power was needed. I ordered two Renogy 100 watt panels from ebay and added them. A few weeks later I decided to buy a couple of HQST 100 watt panels and add them.  That's ten panels in all.

The current power total is 1000 watts, or 1 kw (kilowatt). There is a noticeable difference in the charge rate of the LiFePo4 batteries. I run the mini-fridge and the internet connection more often now, and, dependiing on the weather, overnight.

The second half of the upgrade was the mounting hardware for the additional panels. Steel struts used in electrical construction in factories and institutions is the framework I chose. The necessary additional pieces along with nuts, bolts, washers, lock nuts, couplers, and strut nuts were purchased.

I believe I have reached the maximum array size for the strut framework. I'm uisng half channel Superstrut. Full channel struts would approximately double the capacity, but the physical size of the array is starting to become awkward. I need to be able to single-handedly move and manage the array. A single array that size could become potentialy dangerous.

A second array is in order. Or upgrading the ten 100 watt panels to something like ten 500 watt panels.

Another option: fiberglass struts. The load bearing characteristics would have to be examined and comppared to the array loads and to the steel strut characteristics.

I neglected to add an image of my revised webpage for the solar array monitor.

In case the link on the new charts page is not working, here is that image:

RPi4b storage memory: SD to SSD conversion

 Ordinarally, the RPi uses an SD card for memory storage. Those cards have gained a reputation for unreliability. My suspicion is oxidation of the contacts.

The RPi is now capable of USB drive storage. I setup an SD card and an SSD hard drive with the RPI operating system. I followed the instructions for use of a USB memory device and now use a 250Gb SSD for memory storage and operating system installation. The SSD is much faster than an SD card and has enough space to contain the operating system and any programs I wish to install.

New webpage and chart(s)

 

The new web page, for monitoring the solar power station activity, has two charts, one above the other. There are links to a copy of my old website, a more touchscreen friendly version of the page, and a sunpath chart web-app by Dr. A.J. Marsh.

The new chart software was more difficult than I imagined, still, I got the work done.

The charts are synchronized with a vertical crosshair. A vertical line appears wherever the mouse is over the charts. A similar line occurs, simultaneously, over the second chart and is synchronized with the first. The page is updated, approximately, every 30 seconds.

The top chart shows panel array and battery bank, volts and amps. The bottom chart shows panel array power output and battery bank  power input. The solar elevation (altitude) and azimuth (heading) are charted too.

There are two solar path chart images at the bottom. One in Cartesian format, the other in Polar format. These predict the sun's elevation and azimuth for any day throughout the year. The images are large and can be downloaded for easier and more accurate reference.

           The new charts - live 

February 2025 update

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

Only the panels were spared, except for one which had a leaking diode, which I replaced. The lightning came into the house over the aircraft cable guy wire carrying signal and power cables from the panel array and into the station inside the house.

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

I replaced the inverter with a Xantrex Freedom X 1200. The thing I like about that product is the auto switch off when the presence of an external power source is detected. If  I connect a generator to house electrical system, the inverter automatically disconnects.

My lead-acid batteries had a much shorter lifetime or were destroyed outright. The battery bank went through a major upgrade. LiFePO4 batteries had become affordable, and were, therefore replacements for the Duracell Ultra Marine lead-acid batteries. Each of four batteries is a 12VDC/108Ahr battery. Three are made by WattCycle, and one is a LiTime product.

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 (Debian 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 to get the driver running but without any interaction. The 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, for each use. 

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, installed a service to run at boot, and that solved the Exar driver problem.

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

I have been using HTML, PHP and D3. The new software is Dygraph 2.2.1. That software seems so much easier than D3. And more versatile, but not without problems.

The queue also includes a new array support 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., spell check April 06, 2025.