General Raspberry Pi stuff

[shane]

I’ve done a bit of mental number-crunching. From what I can gather, a Raspberry Pi 4b needs about 750mA to run this sort of application, which equates to 90W/hrs over a 24-hour period. Assuming that in winter there’s only eight hours of daylight, then it’s going to need 11.25W to charge the battery enough to last overnight. If I then assume that on a wet January day I’m not going to get more than about 20% of full output from a solar panel then it’s going to need a 55W panel to do the job, which becomes 60w when you actually look at what’s available.

Does that make sense?

[Nick]

I don't know if you cant shut down bits of the Pi that you don't need to reduce the power consumption?

This has some ideas:

https://blues.io/blog/tips-tricks-optim ... -pi-power/
https://forums.raspberrypi.com/viewtopic.php?t=257144

But you can google just as well as I can so I am not adding much new.

[ed]

Hi Shane

even though I did all the calcs for panel efficiency over the year at our latitudes and nailed the panel angle etc I still found there was a learning curve. I recommend a period of testing.

My rigs average 200ma. This is obtained as the prcessors don't require this current but the cellular modem requires high current for a ms or so. My first rig used a 90ah battery with a 25 watt panel. This worked for the summer months but consistently browned out after October and failed completely at the back end of November. Lesson learned I switched to 120ah leisure batteries with 100watt panels.

As Nick has suggested it is worth investigating cutting all necessary functions and also considering some planned off time(like overnight). I considered off-time in the beginning but managed to solve the issues before resorting to that. The upload frequecy and length of time might be your most crucial parameter...it certainly dictates my current draw.

When I first started there was scant info for this kind of thing and the caravan community were in the dark in regards to the tech(pun intended). I think there is more info out there now.

My lesson learned was that the panels don't supply the power advertised and the modems don't suck power at consistent or advertised values.

[shane]

Thanks Ed, that’s useful stuff. I don’t know at this point how much data he’ll be downloading or how often. I’ve sent him a link to this thread though so he can see your findings.

[jack]

Been a while...

Updated Pi-hole (and the Pi it is on) to the latest FTL and in the process switched it from just using upstream DNS (Cloudflare) to a validating, recursive, caching DNS resolver, i.e. unbound with DNSSEC.

It's a bit slower, but far more secure.

[ed]

it's timely that this thread has awakened......today I have been heartily swearing at a pi4 installation which I use for web testing with a lamp stack....
I also have a number of wordpress installations on it which I use from time to time and today I thought I'd set one up for Seb to play with web design....

problem number 1:

the wordpress admin locked me out with a message 'critical error'...couldn't get in to find out what the error was
the live web server reported the same thing.

it transpires there was a bug in one of the add-ons which was auto updated....Fortunately softaculous picked it up and sent me an email explaining how to get in the back door......I'm not sure what the critical users might have thought about this.

problem 2:

The wordpress admin reported that the php version was out of date.
I updated php from v7.something to v8.1 but apache won't pick it up and steadfastly instists on coming up with v7
I haven't sorted this one yet. Annoyingly this is the same on my live web server but that's a problem for the web server admin...I'm keen to see if it gets resolved.

[jack]

Ignore

[jack]

The lamp configuration should set the PHP version for Apache...

[ed]

I'm beginning to understand....
although I have updated the system to php v8.1 wordpress doesn't see it....

seems to be that phpmyadmin holds the answer...

phpmyadmin needs updating, but things have changed here in the last 12 months...

many web entries saying unless you have a very good reason for going to php8.1 then dont!
if it aint broke don't fix it!

this may be why my live web host hasn't changed it...

[jack]

I'm beginning to understand....
although I have updated the system to php v8.1 wordpress doesn't see it....

seems to be that phpmyadmin holds the answer...

phpmyadmin needs updating, but things have changed here in the last 12 months...

many web entries saying unless you have a very good reason for going to php8.1 then dont!
if it aint broke don't fix it!

this may be why my live web host hasn't changed it...

Most of my hosted services are still on 7.x by default. And, yes phpMyAdmin is pretty PHP -version sensitive.

[jack]

Refactored the Comms cabinet using a UDM Pro as my old USG router died.

Much tidier now. Can see the Pi-hole lurking on the right too ... Red is PoE and yellow 1 Gb UTP. The top right white cable is the FTTP delivery (140Mb down/30Mb up), the white cable in the middle is also PoE to the APin the gym - I ran out of suitably coloured CAT5e cables ... So 4 x APs in the house. There's one in the office at the other end of the UBB (building to building 6GHz bridge) and one in the sauna somewhere in the gardens.

The PoE is for the house access points and the UBB.

I just have to add the Synology SAN mirror and that's it.

PXL_20221223_120848242_copy_756x1008.jpg (185.22 KiB) Viewed 1863 times

[shane]

Makes me wonder how I manage with just an EE router plugged into an Openreach ONT!

[IslandPink]

Are you running a secret call-centre at home, Nick ?

[pre65]

Are you running a secret call-centre at home, Nick ?

Perhaps he is "secret Santa" ?

[ed]

UDM, PoE, UTP, FTTP, AP, UBB, SAN, ONT

thank the lord I've got a bottle of scotch....

have to fess up though, I do have an unbadged ONT, s'all a chap needs really