Balena Fin POE with Netgear switch (Safe?)

balenaFin
#1

Have a Fin v1.1.1 (thanks @mpous !) and a Netgear GS108PE-300NAS that delivers 15.3 watts per port.
Was about to wire the Fin up to get power & data from the Netgear, but figured I’d check here before risking frying it.

I know the Fin can take 6-24 volts safely, but I’m uncertain how that related to 15.3 watts from the Netgear ports. How do I make the calculation to 1) make sure I get enough power and 2) make sure I don’t get too much power.

FWIW, I’m also running the RAK2245 via the Fin’s HAT which adds a bit to the power requirements.

Any suggestions?

#4

Hi barry,

the balena Fin needs about 3 Watts alone under heavy load ( Why is the balenaFin right for fleet owners? Part 2: Power ). I don’t know how much the RAK2245 will be drawing, but I guess it would be enough. However, to use PoE you will need to add a PoE Hat as well, so that the PoE functionality on the Fin can be used. Please be advised of the clearance issues handeld here: Fin v1.1 PoE hat clearance issues - #15 by mycroes

There is also a way to passively gain access to PoE by using an intelligent PoE splitter, attaching this to the Netgear Switch and inserting the “only data” ethernet into the Fin and the power via e.g. the phoenix connector, but its a bit more fidly, adds to more bulk and cabling and maybe not as safe as just using a PoE hat :slight_smile:

Cheers

Nico

#6

Hello Barry,

As Nico said you can’t power the Fin using POE directly without a HAT. You need to pick one of the POE HATs availble in the market. Any raspberry Pi 3 or 4 POE HAT can do the job.
You can check these videos/articles for more information about how to power the Fin/pi using POE

#8

Thanks for the advice guys. Unfortunately I’m HAT’d out with the Lora HAT and a tight enclosure.
Might need to look into feeding via the phoenix and do my own connector.

Didnt I see somewhere that you can pull power from those onboard pins and send to the phoenix assuming you’re sending the right voltage? I believe I saw it on the flight tracker blog post.

#9

Hello @barryjump ,

That’s correct, you could use 24V passive PoE without a HAT by connecting the PoE pin headers as described here. You just need to be absolutely sure that you’re using a passive PoE injector and that it outputs 24V or less.

Passive PoE is non-standard, so it requires an extra degree of caution when developing and especially when deploying units.

Hope this helps.
Cheers,
Nico.

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