Offgrid PoE options



  • Odd question I suppose,.. but I am looking at some PoE options for an Offgrid project.

    Using a UBNT PowerBridge which needs 24v and a Engenius EAP9550 which comes with a 12v adapter, but the PoE for it uses a 48v injector.



  • Are you looking for a single option that supports everything? Would several wall-warts not work?


  • Service Provider

    @DustinB3403 said in Offgrid PoE options:

    Are you looking for a single option that supports everything? Would several wall-warts not work?

    Do you not understand what off Grid means?

    @gjacobse what is going to be the primary power source? Don't look for an answer until you know what's available to ask the right question



  • Field Day by chance?? I can see what our club's doing this year I'm not part of the wifi project but they are in a similar boat.



  • @JaredBusch

    Ideally I would look into devices that are the same voltage, 24v would be fine and workable. The max cable distance will be less than 20feet of Cat5, so there won't be a huge concern over losses.

    As these may be in the middle of a field with no AC power available - battery/solar/generator are the power options.



  • @jt1001001 said in Offgrid PoE options:

    Field Day by chance?? I can see what our club's doing this year I'm not part of the wifi project but they are in a similar boat.

    Yes - Field day. While the computers and the network can be on AC mains, just trying to simplify the cabling.

    I am perfectly fine with having to use the PoE injectors, but I need DC input. I can manage - with simple DC-DC supply taking 12v (13.8-14.2v) and stepping it up to 24v and 48v.


  • Service Provider

    I would get some of these because you can power these with 12vdc
    0_1493214260123_IMG_6109.PNG



  • The mast - minus the extension and cable management

    0_1493218097599_IMG_1568.JPG

    The AC power

    1_1493218097601_IMG_1570.JPG



  • By far the prettiest setup here,...

    But six 18650 cells pulled from laptops running 12v ouput into a 175w inverter for AC power.

    0_1493220709773_IMG_1571.JPG



  • Was pondering about this lastnight and I discovered that 48v flooded lead acid batteries are a thing. Probably be cheaper to go with 3 12v VRLA batteries like the ones used in a UPS. Do you know what kind of power draw you have right now?



  • @MattSpeller said in Offgrid PoE options:

    Was pondering about this lastnight and I discovered that 48v flooded lead acid batteries are a thing. Probably be cheaper to go with 3 12v VRLA batteries like the ones used in a UPS. Do you know what kind of power draw you have right now?

    UBNT Switching PoE PSU

    • 24v @ 1amp - so 24watts

    EnGenius

    • 18v @ .38amp - so 18.24watts max

    Even if I toss in a 5port Smart switch - 7.5v @ 1 amp I'm below the 175 Inverter.



  • @gjacobse said in Offgrid PoE options:

    @MattSpeller said in Offgrid PoE options:

    Was pondering about this lastnight and I discovered that 48v flooded lead acid batteries are a thing. Probably be cheaper to go with 3 12v VRLA batteries like the ones used in a UPS. Do you know what kind of power draw you have right now?

    UBNT Switching PoE PSU

    • 24v @ 1amp - so 24watts

    EnGenius

    • 18v @ .38amp - so 18.24watts max

    Even if I toss in a 5port Smart switch - 7.5v @ 1 amp I'm below the 175 Inverter.

    18v @ .38a = 7w

    so you're well below 175, which is good

    solar + 18650 pack?

    what kinda panels are you thinking of?



  • So per day you need about 1kwh to run everything at max (a safe assumption)

    So you need to generate 1kwh+ over ~7h of sun

    1000/7=143w

    spec 200w of panels and you're solid

    probably go for 2kwh pack for wiggle room + 50% degradation over time

    I like to massively over build things so YMMV

    Probably don't need near that much solar if I'm being honest - I think your draw will not be more than 0.5kwh/day but you can check that with a kill-a-watt or something



  • @MattSpeller said in Offgrid PoE options:

    So per day you need about 1kwh to run everything at max (a safe assumption)

    So you need to generate 1kwh+ over ~7h of sun

    1000/7=143w

    spec 200w of panels and you're solid

    probably go for 2kwh pack for wiggle room + 50% degradation over time

    I like to massively over build things so YMMV

    Probably don't need near that much solar if I'm being honest - I think your draw will not be more than 0.5kwh/day but you can check that with a kill-a-watt or something

    yea,.. I rather like to over build / complicate things ... so - just like to error on the side of caution also.


  • Service Provider

    @gjacobse said in Offgrid PoE options:

    @MattSpeller said in Offgrid PoE options:

    So per day you need about 1kwh to run everything at max (a safe assumption)

    So you need to generate 1kwh+ over ~7h of sun

    1000/7=143w

    spec 200w of panels and you're solid

    probably go for 2kwh pack for wiggle room + 50% degradation over time

    I like to massively over build things so YMMV

    Probably don't need near that much solar if I'm being honest - I think your draw will not be more than 0.5kwh/day but you can check that with a kill-a-watt or something

    yea,.. I rather like to over build / complicate things ... so - just like to error on the side of caution also.

    Over complicating things is erroring on the side of reckless actually.



  • @scottalanmiller said in Offgrid PoE options:

    @gjacobse said in Offgrid PoE options:

    @MattSpeller said in Offgrid PoE options:

    So per day you need about 1kwh to run everything at max (a safe assumption)

    So you need to generate 1kwh+ over ~7h of sun

    1000/7=143w

    spec 200w of panels and you're solid

    probably go for 2kwh pack for wiggle room + 50% degradation over time

    I like to massively over build things so YMMV

    Probably don't need near that much solar if I'm being honest - I think your draw will not be more than 0.5kwh/day but you can check that with a kill-a-watt or something

    yea,.. I rather like to over build / complicate things ... so - just like to error on the side of caution also.

    Over complicating things is erroring on the side of reckless actually.

    I'm no where near the level of NASA though... but - different reasons there.



  • Power inverter...


  • Service Provider

    @TeleFox said in Offgrid PoE options:

    Power inverter...

    Power inverters are great but inefficient. So for a field day with a DC power source, I would attempt to keep as much DC as possible.



  • @JaredBusch said in Offgrid PoE options:

    @TeleFox said in Offgrid PoE options:

    Power inverter...

    Power inverters are great but inefficient. So for a field day with a DC power source, I would attempt to keep as much DC as possible.

    That would be the preference...


  • Service Provider

    @gjacobse said in Offgrid PoE options:

    @JaredBusch said in Offgrid PoE options:

    @TeleFox said in Offgrid PoE options:

    Power inverter...

    Power inverters are great but inefficient. So for a field day with a DC power source, I would attempt to keep as much DC as possible.

    That would be the preference...

    That is why i recommended the trendnet PoE injector. it uses a 12vdc source with a wall wart normally. so it shoudl be easy to make a connector for.

    The model i linked was gigabit, you probably don't need that one.



  • @JaredBusch with a power conditioner?


  • Service Provider

    @TeleFox said in Offgrid PoE options:

    @JaredBusch with a power conditioner?

    I assume that @gjacobse is handling any DC conditioning needed.

    I was wrong that it was 12vdc input though.
    Here is mine at home.
    0_1493404794088_IMG_6121.JPG

    @gjacobse you may want to looks for a 24v passive PoE injector with a DC input. The UBNT ones are all AC.



  • But wouldn't injectors require a ton of plugs to be laid out?



  • @TeleFox said in Offgrid PoE options:

    But wouldn't injectors require a ton of plugs to be laid out?

    How so?



  • @MattSpeller Because each POE injector requires an outlet to power it and push the power inline to the cable.


  • Service Provider

    @TeleFox said in Offgrid PoE options:

    But wouldn't injectors require a ton of plugs to be laid out?

    That injector is 48VDC input. So, assuming he has 48VDC out of his solar array, he can simply make a standard center positive connector out of the solar array to the injector.



  • @TeleFox

    If you run solely on battery - you should not need a conditioner.

    @JaredBusch

    Thanks for the update on the TPLink.

    Part of the 'ISSUE' is simple voltage.. The included adapter with the EnGenius is 12v. But the PoE injector is 48v. The UBNT uses 24v.

    And while they are just multiples at less than 2AMPs,.. it's that differences and the cabling that makes it a pain.

    The EnGenius has a coax power jack, the UBNT does not.



  • @gjacobse said in Offgrid PoE options:

    hanks for the update on the TP

    I guess if you just need one phone its not a big deal I thought he was trying to lay out more though because he was discussing poe from a switch..


  • Service Provider

    @TeleFox said in Offgrid PoE options:

    @gjacobse said in Offgrid PoE options:

    hanks for the update on the TP

    I guess if you just need one phone its not a big deal I thought he was trying to lay out more though because he was discussing poe from a switch..

    He is doing a point to point wireless bridge to a local access point for wifi if I understand the project correctly.



  • @gjacobse

    The 'Other' issue is that when I lay things out and check with a DVM, the UBNT supply is flat 24v, but when I put the Engenius PoE on,.. the voltage bounces... so it's one of those - triple check and use extreme caution and then check again..

    This is the PoE 802.3af standard

    0_1493405844602_2017-04-28 14_55_45-Power over Ethernet - Wikipedia.png



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