OpenCPN Rpi cpu usage and temperature

[AedanC]

I think the red light flickers at 4.6V. Also you won’t see the thunderbolt unless you are using a directly attached screen, it doesn’t appear via VNC etc.

[CapnRon47]

Sorry,

yes I meant 4.6 something volts, the 'red' LED indicates the voltage is low. I am also running this command occasionally,
/opt/vc/bin/vcgencmd get_throttled and every once in awhile it returns a 50005 which indicates the Rpi is undervoltaged and throttled, see here:
https://www.raspberrypi.org/forums/v...art=50#p972790

[conachair]

Originally Posted by CapnRon47

yes I meant 4.6 something volts,

Sounds very low if the buck is actually capable of putting out 3A , a minimum hold voltmeter can be handy across pins 2 & 6 on the Pi and then across the buck output to catch the voltage drop during the spikes and see how much is getting lost in the cable.

[AedanC]

Try it with a really short USB cable if you have one. The shorter and fatter the better.

[CapnRon47]

Thanks for all the input. I went to a better USB cable and it helped. I am monitoring the Rpi voltage across pins on the GPIO strip (+5 to gnd). At startup I have > 5volts, but during the boot process the voltage does drop one time to 4.6 something. Once the Rpi is running with just the boot processes the voltage stays steady at 5.03 volts. This is with a usb gps unit plugged into one of the ports. I started adding processes; xrdp to remote desktop in (I am headless), browser with a window open to internet, signalk-server, a second browser window for Signalk GUI and a third for KIP, start OpenCPN with dashboard. Now the htop window shows all four CPU's pretty busy (> 50%), memory usage is also > 60% . The voltage has now dropped to somewhere between 5.82 and 5.92 it is fluctuating in that range. So this seems acceptable, but I still may try the powered USB hub suggestion. I don't like using a 10 port hub to power one Rpi (it is just big) but I do have room behind my instrument panel. I have a hub I can try using shore power (before I remove the wall wart), so I will do that next.

thanks again.

[skipperearly]

have you tried to set
max_usb_current=1
in the config.txt file?

[conachair]

Originally Posted by skipperearly

have you tried to set
max_usb_current=1
in the config.txt file?

Apparently that does nothing on a. Pi 3, different usb power chip.

Good powered hub is a very good addition with a good power supply, capRon, your voltage still sounds low imho, and cpu very high, I've Opencpn running at the moment over vnc with all cpus down near single figures with a lot of node red in the background and vlc playing some music. Are you running openplotter?

[conachair]

Originally Posted by conachair

I've Opencpn running at the moment over vnc with all cpus down near single figures with a lot of node red in the background and vlc playing some music.

[petter5]

A lot of connected USB devices can bring the RPI close to the limit and make troubel. One approach to solve this is using a powered usb hub. My approach if it is required to connect multiple devices is to use a rs232/422 to rj45 converter and move all connection over to network so the only connection to the RPI is a network cable. It might be a more expensive way but you will never more have any trouble with the stability of the rpi.

Originally Posted by conachair

Apparently that does nothing on a. Pi 3, different usb power chip.

Good powered hub is a very good addition with a good power supply, capRon, your voltage still sounds low imho, and cpu very high, I've Opencpn running at the moment over vnc with all cpus down near single figures with a lot of node red in the background and vlc playing some music. Are you running openplotter?

[verkerkbr]

Originally Posted by Dsanduril

In addition to power supplies, not all USB cables are created equal. 2A is a lot for the tiny wires used in some USB cables. The shorter the better, and the bigger the conductor the better. There are a very few cables that will actually tell you conductor size.

No affiliation, just a satisfied customer, I am happy with Anker products in this role. I have an Anker powered USB hub that uses a 12V wall-wart, chopped of the wart and plugged directly into my 12V system and has so far run for more than a year at 12.3 to 14.5V input voltage. I also use a couple of their 30cm high-power USB cables with larger conductors for the power side of things. Since I started using the hub as the power supply and the cables I haven't had one low voltage warning from the PIs (I run two PI 3's from one 10-port hub).

It is very difficult to find usb cable with a connector for the RPI with thick leads.

My solution is very simple. Take an original RPI 240 volt loader. Cut the cacle in two.

Then you have the right cable for connection to the RPI.

And if you need net supply, simple connect the cable to the original transformer.

Add on both sides crimp pin terminals.

Regards,


Bram

[CapnRon47]

I am not running OpenPlotter on this particular SD card (I have a version of a setup with OpenPlotter). I am running a Signalk-node-server stand alone version as well as OpenCPN. It is interesting that your CPU usage is much lower than mine. I only have 2 usb ports in use, one is an Adafruit GPS and the other is a DigitalYacht NMEA to USB adapter. I had not noticed much change with them in place , but I could try moving them to a hub. I have an old USB hub and tried it yesterday as a power source for the Rpi, but it is not good enough (worse than the DC-DC converter). I put a min/max meter on the voltage last night and over several hours of operation the minimum dropped to 4.693 volts, too low for me to be comfortable also. I will be ordering a better hub today. Meanwhile I found a short USB cable I will give that a try.

thanks everyone for comments and input.