Tag: Electronics

Along with some others I am waiting for Raspberry PIs to become available again (while *not* supporting these overpriced resellers on eBay, Amazon and elsewhere).

Luckily, back in 2016 (or was it 2015?) I bought two Raspberry PI2 Model B Rev. 1.1 with 1 GB RAM and an Edimax EW-7811Un WLAN adapter. At that time the PI did not have built-in WLAN and it was said that the original Wifi dongle Raspberry Pi WLU6331 did not work with all distributions.

We had some plans what to do with the Pi – but they never made it into reality. Instead, they went into the locker.

Fast forward into the future, the whole world experiences stock supply shortages and a Raspberry Pi (now in its 4th generation) is hard to get hold of.

As I am building a couple of batteries mostly with JK-BMS I need a RS-485 connection to my Victron inverters to control charge and discharge currents. Except for the GX versions of the MultiPlus-II and EasySolar-II that _sort of_ support RS-485 (not out-of-the-box, but) in a single box, I always need an additional device like a Cerbo, BBB or: a Raspberry Pi!

But as I already wrote: I did not want to support resellers with their pharmacy pricing, so I had a look at the Venus OS compatibility list and saw that – surprisingly – even a Pi 2 is supported. So, I went looking in my shelves, lockers and other places to find these rusty old Pi 2s – and after a couple of weeks I actually found them (when I was looking for something completely different). Anyway, here they are – but only with a single GB of RAM.

Nostalgic side note: yes, there were times where I would have left out the word “only” …

I was not to sure if Venus OS would run on it. And if – how quick. It was time to find out …

Installation was straight forward: following Getting Started was all it needed. I connected the Pi to my local wired network for that purpose and makes updating and installing software much easier. At the very start I also enabled superuser and SSH access.

Note: There was a minor issue or whatever one might call it. After the install of v3.00 (via the SD card) I had the device check for an update (which at that time should not have been available). But for whatever reason, I was offered to update from v3.00 to v3.00. I did that and it worked and after that no more updates were recommended.

From then on, installing additional packages worked without an issue – but took considerably longer than on a Cerbo, Pi 4 or even the GX in the EasySolar.

One thing just seemed to be missing. Having the Pi to act as a Wifi access point (and router with DNS and DHCP). Why would I want this?

Some of my batteries are just standalone installations in a car, trailer or other machinery. And external network is not always available. And I do appreciate the comfort of wirelessly connecting to the GX – just as I am used to when using my EasySolar-II GX.

And as nearly always: I was not the first one to ask for such a feature:

• “Create Access Point” option missing on Venus OS on Raspberry Pi
• Access point option missing, Venus OS Raspberry Pi B3+

Victron themselves, apparently, have no plans for supporting this feature.

Luckily, pagedo did all the hard work and gave a step-by-step description on how to enable a Wifi access point. And that worked on the Pi 2 as well.

Essentially, we have to enable Wifi, activate tethering and modify the config file:

$> connmanctl enable wifi
$> connmanctl tether wifi on <SsidName> <SsidPassword>
$> connmanctl technologies
$> nano /etc/connman/main.conf
  TetheringTechnologies = wifi
  PersistentTetheringMode = true
  AddressConflictDetection = true

After a reboot, I could successfully connect to the access point and VictronConnect immediately found the “Cerbo”:

After I enabled the access point (or tether option) I could no longer see or access any other SSIDs from the Pi:

Running ifconfig gave me this output:

Certainly, I was interested in the performance or resource consumption of the Pi 2. As it turned out, the UI really took some CPU but the additional network services themselves were not quite as hungry: idle floats between 71% and 92%.

So, this is it. My investment of roughly 35$ in 2016 (even with intereste rate) really paid off. I have a working GX device that does everything I want – plus an access point – all in a single box.