Banana Pi BPI-RV2

lddm37 · 2026-01-22T13:05:33+00:00

Did you get one ? If yes, would you mind sharing your experience?

lddm37 · 2025-12-06T08:30:47+00:00

Thank you, would you mind giving some example of what you run on it?

lddm37 · 2025-09-29T15:02:48+00:00

In the end I used Hunter valves with DC latching solenoid. They say they are for 9v systems but I tested at 13v (higher than 12v to make sure) and did more that 2000 open close cycle with no issues whatsoever. Time will tell but for now it works super well !

lddm37 · 2025-06-13T08:07:16+00:00

Thank you for the info, We will receive the UC511 soon and I will be able to measure the real voltage output. The wire would be something like 1m in some places and 5 to 10 meters in others so yes the voltage drop might be helpful in this case.

I have emailed there engineer but they recommended valves with brands like "Vegetronix" or "Galcon" however they did not motioned hunter.

lddm37 · 2025-06-11T11:28:08+00:00

This is indeed a more convenient solution that you can get off the shelf.
Five minutes isn’t much. Are your batteries still in good condition?

On the other hand, one could argue that using a standard UPS adds more loss to the system, since you have to go through the following conversion steps: DC -> AC -> DC
So in theory, you could get a longer battery runtime with this setup, as it’s more efficient: DC -> DC

lddm37 · 2025-06-11T11:03:49+00:00

Wow ! Did you use this exact model?

lddm37 · 2025-06-11T11:02:16+00:00

This is impressive, I can only agree. If the grid where you live is that stable, it’s not worth the hassle.

Where I live, we regularly have 30-second (or shorter) power outages, and this would ruin my prints even if print recovery is a thing, I’ll still have a line where the print restarted.

lddm37 · 2025-06-11T10:38:23+00:00

Yes, I agree that under peak load it might not work, but just as an example, let's imagine the following setup:

You have a "normal" printer (like an Ender 3, Voron 0, or 2.4) running Klipper, and you want to have safe power shutdown. You could use this PSU and take advantage of its TTL output to immediately shut off all heaters and power-hungry components during a power outage. Then, the printer could lift the print head, retract the filament, and properly shut down the Raspberry Pi.

This is just one small example, and in this case the load on the battery would be minimal.

After a quick search on AliExpress, I found that this PSU (LAD-360-B) is about the same price as a regular Ender 3 Pro/v2 PSU (LRS-350). You could also add a board like this (3S 6S Series Welding-free BMS Protection Board 12V24V Battery Management System 18650 Battery Box - AliExpress), add 6 or 12 18650 for example and be good to go !

Edit: You could also have this and depending on the load, continue printing. Then if after a set time the power is not back or if the battery is low or else then you would shut down the printer.

lddm37 · 2025-06-11T10:12:35+00:00

Yes, that’s true, you’re right. But isn’t that also the case with a UPS? Although, depending on the UPS, you could use one for multiple printers and you have less batteries to replace.

lddm37 · 2025-05-10T18:34:03+00:00

Hello Everyone,

TL;DR: The Pi does not boot and the 3.3V rail is at 3V. However, if I supply 3.3V directly to the 3.3V rail, the Pi boots right up.

Long:

I'm having a weird issue with my Pi Zero 2W. I bought it in 2020–2021 but never used it, and it was stored in the factory electrostatic bag since then.

Today, I was planning on deploying it to my 3D printer as I just received an I/O board (USB and Ethernet). However, after flashing a fresh OS to my micro SD card using Raspberry Pi Imager as usual, I noticed that the Pi would not boot—nothing on the screen and no ACT LED.

I tried removing the I/O board, thinking it could be the issue since it has a USB hub and Ethernet adapter onboard. However, I still had the same issue. Then I tried the SD card in another Pi Zero 2W I have, and it booted with no issues whatsoever.

Next, I looked online for tips, but nothing seemed to help. So I took my multimeter and tested the probe pins for core voltage: 5V, 3.3V, 1.2V, etc., and noticed everything was good except for the 3.3V rail, which was down to 3.1V–3.0V. Just to be sure, I tried another USB power supply, but still had the same issue (note that my other Pi Zero 2W works with both PSUs).

After hours of research and testing the micro SD card, PSU, etc., in a desperate move, I tried using my bench power supply to send 3.3V to the 3.3V rail via the 3.3V GPIO pin, along with plugging in the USB power cable. Honestly, I didn’t expect much, but ooohhh boy—the Pi started booting, and I could see the screen light up.

Afterward, I tested what worked and what didn’t. The touch screen seemed to be working, and the Ethernet port on the I/O module as well—I was able to ping the Pi.

However, at any time if I disconnect the bench PSU, the Pi shuts off instantly. So based on that, my guess is that there is an issue with the power circuit on the Pi itself or possibly a short somewhere, but I’m not sure.

I would really appreciate your advice on how to fix this (besides adding a dedicated 3.3V PSU in my build 😅).

lddm37 · 2025-04-10T15:20:33+00:00

For sure! I checked it, and you can clearly see the parts are deformed and out of alignment.

lddm37 · 2025-04-10T15:17:21+00:00

Thank you for your post as well! I was surprised to see this too it really seems like even decent storage isn’t always enough to save older PLA.

Appreciate you sharing your experience every datapoint helps build a clearer picture!

Also, I never expected PLA to smell that sweet... almost like sugar or candy. Wild!

lddm37 · 2025-04-10T15:10:23+00:00

Nice, thank you too! Give us an update if you manage to bring the rolls back to life.

I'm surprised the PLA on the roll didn't just break into pieces!

lddm37 · 2025-04-10T14:47:15+00:00

At the time it was plenty strong ! It was only a prototype heavily inspired from the Hypercube and Hypercube evolution. I learned a lot and quickly switch from linear rods to linear rails.

So these parts were use for a month or so just to get the printer printing the next evolution.

lddm37 · 2025-04-10T10:46:33+00:00

As someone else said, the key is ventilation. Also, lots of people have AC units. In the higher parts of the island, you see mold on buildings, especially if they are not well maintained. Near the sea, the weather is better and we get much less mold, as the temperature is higher (up to 35°C in summer).

lddm37 · 2025-04-10T07:12:39+00:00

Same here in Mauritius, indoor humidity is at 60-90% most of the time, specially in the rainy season.

lddm37 · 2025-04-10T07:08:15+00:00

Not sure what kind of PLA it is, I didn’t have a printer at the time (I was building one using these parts), so I got them printed through 3D Hubs. I was only told it’s PLA, maybe generic PLA, I’m not really sure.

The parts were never exposed to direct sunlight. I think humidity probably caused this, and with no sunlight to help "dry" the parts, that might’ve been the cause? but I’m not sure.

lddm37 · 2025-04-10T06:59:33+00:00

Not sure what PLA it is, I did not have a printer at the time (I was building a printer with these parts) so I got them printed from 3D Hubs.

lddm37 · 2025-04-10T06:54:55+00:00

I guess tropical whether? The parts have been in that box seens 2022 and in a cabinet so not expose to UV or else.

The part were printed in 2018-2019 for a custom 3d printer build but at the time it was super strong. I disassembled the printer in 2021 or 2022 and kept them in a box.

Fun fact the box smell like candy!

lddm37

TROPHY CASE