From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-x22d.google.com (mail-it0-x22d.google.com [IPv6:2607:f8b0:4001:c0b::22d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 10E1B3B2A4 for ; Mon, 5 Jun 2017 14:53:40 -0400 (EDT) Received: by mail-it0-x22d.google.com with SMTP id r63so86869951itc.1 for ; Mon, 05 Jun 2017 11:53:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=X41XdosMvNVHaLL6RkxlYWIkjlt4+tFX4IQrOMzgqmg=; b=XV2bsloiNMYMiCAwhq/B07JNpbDqB1m3JidopFvcRfCdoK1qXlALiYxEZQyqYwpKzl zOW2SA4JHUHLM5e+IZvGuD30D/yLYbBaQi3TQ+30IKF81i1b+txch1mJbM2QFDrkFSzp 147gvybihZSESUzZifmaSZMn05ua+7uCUVTvy6lQ9PoTRIAvhfXQAIVNk81v3BYtEB6m lcg6lnCz3TS/rcaZZPpKZx74nMhd4bUF99SeoJnyEf8qwYurGcrlXUg3k5LQzAnTZo5d Vw38WLy8KSIEMdGZYi9jX9EmuLfDtk9wxU1J3U5VYQt6ImV2mhrGT6d+pSjkF5MaMa66 is5Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=X41XdosMvNVHaLL6RkxlYWIkjlt4+tFX4IQrOMzgqmg=; b=uhLTgkhcXPd/E5joTatyb14gMLCsGU7mNXbYhfRyTsjAeuFVWKXQXcNUSrHzoBoifJ QtXd5PeiiRNgzQxO61GU3idf7YPnhchPnekqBoFVuHdGw+Yk38uECMIRdDKcP1ZK19YH XpsFug7cLI9Kt1wDAPfUxFdQj83cAjKXSUH18T9M4cdZoNVsS3S8Wahy9RokpV7uk7MF LEprczRlH48xlsPnq8/uzFHcAsogtsnOg5jlIQAJiPgeBT+0ildaYb4EDQ7LuPltklrG ltQk1XY4s0pYrekZoGNG1Y8I3NeIldhbM4zVHk+wJU26irig38UWRi+ZF8yMbICX8Ld5 +oTw== X-Gm-Message-State: AODbwcDd/dgiPlqLWcs6zV+RHgiVC/E6Q8p6Q1LCm9f+i5F1nP9n0Myk AF46IPgAYCJ3XE95//q1rNKy+fXXHw== X-Received: by 10.107.162.132 with SMTP id l126mr22187584ioe.91.1496688820434; Mon, 05 Jun 2017 11:53:40 -0700 (PDT) MIME-Version: 1.0 References: <2d60e776-2a4f-de66-0d2f-a36568562f96@gmail.com> <1496685154.544113991@apps.rackspace.com> <1496685671.564811498@apps.rackspace.com> In-Reply-To: From: Aaron Wood Date: Mon, 05 Jun 2017 18:53:29 +0000 Message-ID: To: Jim Gettys , David P Reed Cc: "cerowrt-devel@lists.bufferbloat.net" Content-Type: multipart/alternative; boundary="001a1140fd1a7b75db05513b051e" Subject: Re: [Cerowrt-devel] solar wifi ap designs? X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 05 Jun 2017 18:53:41 -0000 --001a1140fd1a7b75db05513b051e Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable As for why 12V: it's a common standard regulator that allows all the various internal voltages to be derived from (5, 3.3, 1.8, etc). So that's why a lot of designs use that. Especially since the 5v for USB can be isolated corrected against being pulled too low by devices that are plugged in. That's harder with a 5v supply (although I tend to see designs using those simply let an overloaded USB bus reset the whole device) IIRC, a 5354g took about 1 watt, pretty much regardless of what it was doing. But I haven't looked at any of the current APs. Measure, and measure under full load on all interfaces. And measure a 24 hour cycle to see the watt hours used. -Aaron On Mon, Jun 5, 2017 at 11:22 Jim Gettys wrote: > On Mon, Jun 5, 2017 at 2:01 PM, wrote: > >> It doesn't jump to mind, but a radio carrying bits near the edge probabl= y >> won't be used near capacity most of the 24 hours it is operating. Just a= s >> Iridium was designed to quiesce most of its electronics on the dark side= of >> the earth, extending its battery life, you can probably assume that a ra= dio >> in a tree won't be heavily used most of the hours of a 24 hour cycle. >> > > =E2=80=8BTurns out that (at least in OLPC days), the signal processing in= the WiFi > module dominated power consumption (relative to the radios themselves). A= t > the time, power consumption was of order 1 watt and the radios themselves > consuming only a fraction of that. > > I don't know what the current chips/modules consume, however. > > Another big consumer turns out to sometimes be ethernet chips; gigabit > nic's often take/took a watt of power. > > So your mileage varies, and you cannot easily presume its one thing or th= e > other, but need to measure (which we did extensively for OLPC, to get its > power consumption down to where it is) and fix lots of software. > > Linux itself is pretty decent for power management these days: but all it > takes is a single chip/subsystem or stupid applications to blow that up. > So the whole bus structure has to be understood and properly done, and so= me > technologies are pretty hopeless. > > The details matter. Unfortunately, home routers have generally been plug > in devices, and the vendors haven't paid much attention. > - Jim > > > =E2=80=8B > >> >> >> >> On Monday, June 5, 2017 1:52pm, dpreed@reed.com said: >> >> > "Deep discharge" batteries work in LEO satellites for such >> applications. But they >> > are extraordinarily expensive, because the designs are specialized, an= d >> that use >> > case doesn't have the 2-3 day solar outage problem. >> > >> > You are not going to put a good enough system for an AP up in a tree. >> Maybe on an >> > antenna mast structure with solid base and guy wires. Roofs and ground >> are better >> > choices. >> > >> > But I would wonder whether redesigning the AP itself to be >> power-conserving would >> > be the place to start. They are not designed to be "low power" - they >> are designed >> > to be inexpensive. >> > >> > So, for example: why 12V??? No logic needs 12V. Integrate the battery >> into the AP >> > and run it at 3V, eliminating multiple conversion losses. >> > >> > You can use 12/20 V off the solar panel to charge the 3V battery syste= m >> (high >> > current only while charging). >> > >> > Pay lots of attention to the duty cycle of the radio. If you really >> expect the >> > radio to be on 100% of the time, you may have to power it all the time= . >> Otherwise, >> > minimize uptime. Similarly, the processor need not be on most of the >> time if it >> > is mostly idle while accepting and sending packets from memory. (ARM >> BIG.little >> > might be helpful). >> > >> > Get rid of Linux if possible. Linux is not a low-power OS - needs a lo= t >> of work in >> > configuring or rewriting drivers to cut power. (there's a need for an >> LP Linux, >> > but like Desktop Linux, Linus, and his coterie, isn't terribly >> interested in >> > fixing his server OS to optimize for non-servers, so "server power >> saving" is the >> > only design point for power). >> > >> > >> > >> > >> > On Monday, June 5, 2017 12:01pm, "Richard Smith" >> said: >> > >> >> On 06/04/2017 08:49 PM, Dave Taht wrote: >> >>> I keep finding nicely integrated solar/battery/camera/wifi designs >> >>> >> >>> >> https://www.amazon.com/s/ref=3Dnb_sb_noss_2?url=3Dsearch-alias%3Delectro= nics&field-keywords=3Dsolar+wifi&rh=3Dn%3A172282%2Ck%3Asolar+wifi >> >>> >> >>> But what I want is merely an solar/battery/AP design well supported = by >> >>> lede... and either the ath9k or ath10k chipset - or mt72 - that I ca= n >> >>> hang off a couple trees. I've not worked with solar much in the past >> >>> years, and picking the right inverter/panel/etc seems like a pita, b= ut >> >>> perhaps there are ideas out there? >> >> >> >> This is something I was up against constantly when I worked for OLPC. >> >> There's a big gap for products that use more power than a cell phone >> but >> >> less than an RV or a off-grid cabin. >> >> >> >> For the XO itself we worked around it by designing the front end of t= he >> >> XO to be able to handle the range of output voltages from "12V" panel= s >> >> (open circuit voltages up to 20V) and to implement an MPPT algorithim >> in >> >> the EC firmware. You can plug up any solar panel with a Voc of 20V o= r >> >> less to an XO-1.5 to XO-4 and it will DTRT. >> >> >> >> Figuring out what to do with the deployment's APs though was always a >> >> struggle. >> >> >> >> Solutions exist but you need to get a good estimate of what sort of >> >> power budget you need. It makes a big difference in what equipment y= ou >> >> need. >> >> >> >> Unless its a really low power device the numbers can get large fast. >> >> >> >> My WNDR 3700v2 power supply is rated at 12V 2.5A which is a peak of >> 30W. >> >> >> >> Lets assume your average is 30% of peak. That's 9W. Your 24h energy >> >> requirement is 216Wh. A reasonable input to usable efficiency for a = PV >> >> system is 70%. Given average 5 hour window of full sun you need a PV >> >> output of at least 62W. It only goes up from there. >> >> >> >> Realistically you need to survive a 2-3 day period of terrible solar >> >> output. So your storage requirements should be at least 2-3x that. >> >> When you do get sun again you need excess PV capacity to be able to >> >> recharge your batteries. You would probably need a PV output in the >> >> 100W-150W range to make a system you could count on to have 100% >> >> availability 24/7. >> >> >> >> That's going to be a pretty big chunk of hardware up in a tree. >> >> >> >> If the average power draw is more in the 3W or 1W range then things >> look >> >> a lot better. That starts to get down into the 40 and 20W range. >> >> >> >>> so am I the only one left that likes edison batteries? you don't nee= d >> >>> a charge controller... they last for a hundred years.... >> >>> _______________________________________________ >> >> >> >> I've never used this battery type but it looks like the resistant to >> >> overcharge assumes you replace the electrolyte. All the cells I've >> >> looked at on a few sites seem to be flooded which means maintenance. >> >> Are there sealed maintenance free versions? >> >> >> >> For discharge nominal is 1.2V but charging is listed as ~1.6V/cell so >> >> you are going to need 16V to charge. I don't really see how you can >> >> build a workable system with out some sort of setup that can isolate >> >> your 12V loads from a 16V charge. >> >> >> >> Perhaps undercharge them at a lower voltage and live with the capacit= y >> >> loss? >> >> >> >> -- >> >> Richard A. Smith >> >> _______________________________________________ >> >> Cerowrt-devel mailing list >> >> Cerowrt-devel@lists.bufferbloat.net >> >> https://lists.bufferbloat.net/listinfo/cerowrt-devel >> >> >> > >> > >> > _______________________________________________ >> > Cerowrt-devel mailing list >> > Cerowrt-devel@lists.bufferbloat.net >> > https://lists.bufferbloat.net/listinfo/cerowrt-devel >> > >> >> >> _______________________________________________ >> Cerowrt-devel mailing list >> Cerowrt-devel@lists.bufferbloat.net >> https://lists.bufferbloat.net/listinfo/cerowrt-devel >> > _______________________________________________ > Cerowrt-devel mailing list > Cerowrt-devel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cerowrt-devel > --001a1140fd1a7b75db05513b051e Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable As for why 12V: it's a common standard regulator that allows all the = various internal voltages to be derived from (5, 3.3, 1.8, etc). So that= 9;s why a lot of designs use that. Especially since the 5v for USB can be = isolated corrected against being pulled too low by devices that are plugged= in.

That's harder with a 5v supply (although I tend to see desi= gns using those simply let an overloaded USB bus reset the whole device)
IIRC, a 5354g took about 1 watt, pretty much regardless of what it was= doing. But I haven't looked at any of the current APs.

Measure= , and measure under full load on all interfaces. And measure a 24 hour cyc= le to see the watt hours used.

-Aaron
=
On Mon, Jun 5, 2017 at 11:22 Jim Gettys <jg@freedesktop.org> wrote:
On Mon, Jun 5, 2017 at 2:01 PM, <<= a href=3D"mailto:dpreed@reed.com" target=3D"_blank">dpreed@reed.com>= wrote:
It doesn't jump to min= d, but a radio carrying bits near the edge probably won't be used near = capacity most of the 24 hours it is operating. Just as Iridium was designed= to quiesce most of its electronics on the dark side of the earth, extendin= g its battery life, you can probably assume that a radio in a tree won'= t be heavily used most of the hours of a 24 hour cycle.

<= div class=3D"gmail_quote">
=E2=80=8BTurns out that (at least in OLPC days), the signal processin= g in the WiFi module dominated power consumption (relative to the radios th= emselves). At the time, power consumption was of order 1 watt and the radio= s themselves consuming only a fraction of that.=C2=A0

I don't know what the current chips/module= s consume, however.

Anoth= er big consumer turns out to sometimes be ethernet chips; gigabit nic's= often take/took a watt of power.

So your mileage varies, and you cannot easily presume its one th= ing or the other, but need to measure (which we did extensively for OLPC, t= o get its power consumption down to where it is) and fix lots of software.<= /div>

Linux itself is pretty de= cent for power management these days: but all it takes is a single chip/sub= system or stupid applications to blow that up.=C2=A0 So the whole bus struc= ture has to be understood and properly done, and some technologies are pret= ty hopeless.
The details = matter.=C2=A0 Unfortunately, home routers have generally been plug in devic= es, and the vendors haven't paid much attention.
=C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 - Jim


=E2=80=8B



On Monday, June 5, 2017 1:52pm, dpreed@reed.com said:

> "Deep discharge" batteries work in LEO satellites for such a= pplications. But they
> are extraordinarily expensive, because the designs are specialized, an= d that use
> case doesn't have the 2-3 day solar outage problem.
>
> You are not going to put a good enough system for an AP up in a tree. = Maybe on an
> antenna mast structure with solid base and guy wires. Roofs and ground= are better
> choices.
>
> But I would wonder whether redesigning the AP itself to be power-conse= rving would
> be the place to start. They are not designed to be "low power&quo= t; - they are designed
> to be inexpensive.
>
> So, for example: why 12V??? No logic needs 12V. Integrate the battery = into the AP
> and run it at 3V, eliminating multiple conversion losses.
>
> You can use 12/20 V off the solar panel to charge the 3V battery syste= m (high
> current only while charging).
>
> Pay lots of attention to the duty cycle of the radio. If you really ex= pect the
> radio to be on 100% of the time, you may have to power it all the time= . Otherwise,
> minimize uptime.=C2=A0 Similarly, the processor need not be on most of= the time if it
> is mostly idle while accepting and sending packets from memory. (ARM B= IG.little
> might be helpful).
>
> Get rid of Linux if possible. Linux is not a low-power OS - needs a lo= t of work in
> configuring or rewriting drivers to cut power. (there's a need for= an LP Linux,
> but like Desktop Linux, Linus, and his coterie, isn't terribly int= erested in
> fixing his server OS to optimize for non-servers, so "server powe= r saving" is the
> only design point for power).
>
>
>
>
> On Monday, June 5, 2017 12:01pm, "Richard Smith" <smithbone@gmail.com&g= t; said:
>
>> On 06/04/2017 08:49 PM, Dave Taht wrote:
>>> I keep finding nicely integrated solar/battery/camera/wifi des= igns
>>>
>>> https://www.amazo= n.com/s/ref=3Dnb_sb_noss_2?url=3Dsearch-alias%3Delectronics&field-keywo= rds=3Dsolar+wifi&rh=3Dn%3A172282%2Ck%3Asolar+wifi
>>>
>>> But what I want is merely an solar/battery/AP design well supp= orted by
>>> lede... and either the ath9k or ath10k chipset - or mt72 - tha= t I can
>>> hang off a couple trees. I've not worked with solar much i= n the past
>>> years, and picking the right inverter/panel/etc seems like a p= ita, but
>>> perhaps there are ideas out there?
>>
>> This is something I was up against constantly when I worked for OL= PC.
>> There's a big gap for products that use more power than a cell= phone but
>> less than an RV or a off-grid cabin.
>>
>> For the XO itself we worked around it by designing the front end o= f the
>> XO to be able to handle the range of output voltages from "12= V" panels
>> (open circuit voltages up to 20V) and to implement an MPPT algorit= him in
>> the EC firmware.=C2=A0 You can plug up any solar panel with a Voc = of 20V or
>> less to an XO-1.5 to XO-4 and it will DTRT.
>>
>> Figuring out what to do with the deployment's APs though was a= lways a
>> struggle.
>>
>> Solutions exist but you need to get a good estimate of what sort o= f
>> power budget you need.=C2=A0 It makes a big difference in what equ= ipment you
>> need.
>>
>> Unless its a really low power device the numbers can get large fas= t.
>>
>> My WNDR 3700v2 power supply is rated at 12V 2.5A which is a peak o= f 30W.
>>
>> Lets assume your average is 30% of peak.=C2=A0 That's 9W.=C2= =A0 Your 24h energy
>> requirement is 216Wh.=C2=A0 A reasonable input to usable efficienc= y for a PV
>> system is 70%.=C2=A0 Given average 5 hour window of full sun you n= eed a PV
>> output of at least 62W.=C2=A0 It only goes up from there.
>>
>> Realistically you need to survive a 2-3 day period of terrible sol= ar
>> output.=C2=A0 So your storage requirements should be at least 2-3x= that.
>> When you do get sun again you need excess PV capacity to be able t= o
>> recharge your batteries.=C2=A0 You would probably need a PV output= in the
>> 100W-150W range to make a system you could count on to have 100% >> availability 24/7.
>>
>> That's going to be a pretty big chunk of hardware up in a tree= .
>>
>> If the average power draw is more in the 3W or 1W range then thing= s look
>> a lot better.=C2=A0 =C2=A0That starts to get down into the 40 and = 20W range.
>>
>>> so am I the only one left that likes edison batteries? you don= 't need
>>> a charge controller... they last for a hundred years....
>>> _______________________________________________
>>
>> I've never used this battery type but it looks like the resist= ant to
>> overcharge assumes you replace the electrolyte.=C2=A0 All the cell= s I've
>> looked at on a few sites seem to be flooded which means maintenanc= e.
>> Are there sealed maintenance free versions?
>>
>> For discharge nominal is 1.2V but charging is listed as ~1.6V/cell= so
>> you are going to need 16V to charge.=C2=A0 I don't really see = how you can
>> build a workable system with out some sort of setup that can isola= te
>> your 12V loads from a 16V charge.
>>
>> Perhaps undercharge them at a lower voltage and live with the capa= city
>> loss?
>>
>> --
>> Richard A. Smith
>> _______________________________________________
>> Cerowrt-devel mailing list
>> Cerowrt-devel@lists.bufferbloat.net
>> https://lists.bufferbloat.net/listinfo/= cerowrt-devel
>>
>
>
> _______________________________________________
> Cerowrt-devel mailing list
> Cerowrt-devel@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/ce= rowrt-devel
>


_______________________________________________
Cerowrt-devel mailing list
Ce= rowrt-devel@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/cerowrt-d= evel
_______________________________________________
Cerowrt-devel mailing list
Ce= rowrt-devel@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/cerowrt-d= evel
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