[Battlemesh] Solar panel

[Markus Kittenberger]

> I had a lengthy discussion with the austrian guy with a beard (Markus
> I think) who has changed many voltage regulators on the fonera. He
> also played with the Wisp station "changing the voltage regulators" to
> go down below 1W.

i just checked my results of last year,..
(some of them (unluckily not the latest findings) are published here (and
unfortunaetly in german )-:))

http://wiki.funkfeuer.at/index.php/Arbeitsgruppe_Hardware_Fonera_power

summarized a fonera can imho run with less than 700mW, while beeing
connected to an adhoc network, and have e.g. olsr running (but no lan
connection!)
or it can be used as serial/lan adapter with less than 500mW (10mbit
ethernet), or as a lan/wlan router 900mW should be reachable.

reaching such low power levels, needs at least two efficient dcdc converters
(e.g. > 90% efficiency) providing ~ 1.6V for cpu/radio and ~3.2V for
ethernet,flash,memory,... (up to 0.2V less voltage is better, but your
fonera might get unstable *G)

btw: power consumption of cpu/flash/memory/wifi/lan of 2100 foneras are very
similar as for 2200 foneras (better cpu, worse lan), but the 2200 have at
least on acceptable dcdc switching regulator!

when using even more regulators (the wifi afair is happy with ~ 1.2V, the
ethernet with ~ 2.6V, and so on) you could reduce consumption even further!

but the costs/complexitiy of the setup is rising aswell!

> The table here says that you can go down to 2.30W just by changing the
> bad voltage regulators:

> http://wiki.fon.com/wiki/Energy_consumption

if u look in detail 2,3W is for 100% load, with lan and wlan active, so i
guess THIS fonera doing only wlan and idle would be around 1,3W consumption

but such a dcdc modded fonera 2100 is quite exactly a fonera 2200, which has
an acceptable converter from 6..14V to 3.3V built-in, but still linear
converters to 1.9V and 1.3V,...

> I am gonna work with Pascal at HSB on changing those bad voltage
> regulators, and make the fonera work on 3.3v:

great! i suggest creating an external powerboard for the fonera, providing
as many voltages as reasonable,..
imho old foneras (5V input) are the best to mod, as u can gain the biggest
improvements on them. (as they contain only unuseable linear regulators *G)
if u want to reach absulute minumum with foneras use the never ones (2200)
as their cpu/wifi can be undervolted some percent deeper *G

> Markus also said that you can change the voltage regulator of the
> radio chip below the faraday RF cage, and he made tests to the point
> of unsoldering most of the components and trying them out with lower
> voltages.
I just unsoldered "all" dcdc converter chips, and provided the power
"myself" to the fonera,..

> Maybe Markus can say more about that?

as soon as i find all my fonera measuremeant results of last year *G
unfortunately i did not write a detailed wiki at the end, as the project
stopped somehow very suddenly *G

at the moment my modded foneras are still lying somewhere in a house in the
countryside 1h outside vienna, where we tested them (to verify whether they
still work well on an ~3km link after modifying them,..) (they worked *G)

regards Markus

p.s. currently i`m working on a solar based router for "extreme" alpine
environment #0, (and even got some small funding for this (-;)
http://alpenrouter.xaok.org (unfortunately only german again *G)

we are using/evaluating arm based cpu boards, to couple them with SPI/SDIO
or USB wifis #1 and probably A123 lifepo and a microcontroller doing
solar-cell and battery management (including mpt)

the current (imho realistic) goal is to build a 3 radio device consuming
quite exactly 1 Watt in total (in adhoc mode, without any wifi power save
modes)

if u are interested to participate/cooperate/whatever, just contact me. (-;
#2

#0 but we also try to build a system that contains easy to get (&& with
reasonable prices) parts,..
#1 an usb wifi was not planned at the beginning, but we found there are some
surprisingly power efficient & cheap & easy to get usb sticks around (with
somewhat useable opensource drivers *G) e.g.
http://www.edimax.com/en/produce_detail.php?pd_id=303&pl1_id=1&pl2_id=44(300mW@100%
TX or RX are "reachable" with minor modifications (without 400-500mW))
#2 especially if u are interested in wireless driver develpoment, regarding
efficient power save methods in adhoc mode !!!
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