Offgrid PoE options
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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?
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@TeleFox said in Offgrid PoE options:
But wouldn't injectors require a ton of plugs to be laid out?
How so?
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@MattSpeller Because each POE injector requires an outlet to power it and push the power inline to the cable.
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@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.
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If you run solely on battery - you should not need a conditioner.
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.
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@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..
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@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.
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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
