Offgrid PoE options
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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.
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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.
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@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.
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I would get some of these because you can power these with 12vdc
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The mast - minus the extension and cable management
The AC power
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By far the prettiest setup here,...
But six 18650 cells pulled from laptops running 12v ouput into a 175w inverter for AC power.
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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?
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@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.
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@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?
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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
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@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.
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@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.
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@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.
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Power inverter...
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@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.
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@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...
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@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.
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@JaredBusch with a power conditioner?
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@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.
@gjacobse you may want to looks for a 24v passive PoE injector with a DC input. The UBNT ones are all AC.
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But wouldn't injectors require a ton of plugs to be laid out?
