Autonomous wifi bridge

Schema/distances

---------------                                                     ---------------
|             |-||                           ||-| |-||           ||-|             |
|             |                                 | |                 |             |
| Location1   |                                 | |                 | Location 2  |
|             |                                 | |                 |             |
_______________                                 ___                 _______________
                <-----------815m-------------->      <-----763m--->

Note: no osbtacles

|| WiFi antenna

Power needs estimation

• 2 Ubiquiti Nanostation LocoM 5 24v, 5,5W each, so approx 12W
• 1 Ubiquiti ToughSwitch 5PoE 24v, 1,5W
• TOTAL => So to have some margin, 15W

The estimation is voluntary "high". If we assume that the setup is used 24 hours a day at 100% of its capacity, it means 15*24=360Wh per dey. The solar panel have to produce at least 360Wh per day. The maximum debited current from the batteries to the WiFi installation is 15/24 = 0.625.

Solar panel

At the Goutailloux, the solar power is 1,46kWh/m**2/d, so we can take large : 1,40. If we take a 300Wc solar panel, the average power delivered a day is 300*1,4=420Wh per day, for the worst case (the december month). https://www.myshop-solaire.com/panneau-solaire-300w-mono-solarworld-_r_676_i_1560.html : 305€

Regulator

The setup has to be robust, with low temperature and humidity. So we have to take great hardware. The MPPT 100/15 seems to be great, it can take 400w under 24v solar panels. https://www.myshop-solaire.com/regulateur-solaire-victron-energy-mppt-75-15a-_r_370_i_10.html : 91.80€

Battery setup

Lead/acid

We want to have native 24v because we don't need DC/DC converter for the PoE. We can take 4 batteries of 80Ah each. We can assemble 2 batteries in series to make a pack of 24v/80Ah, then do the same with the 2 others. Finally, we can assemble this 2 packs (connected in series) in parallel to obtain 24v/160Ah.

AGM

The adopted choice is to have 2 AGM batteries of 25Ah in series. We will have to use this battery at 60%, so approximately 700 cycles, which is sufficient.

https://www.myshop-solaire.com/batterie-agm-12v-25ah-super-cycle-victron-energy-_r_572_i_1994.html

These batteries are not so expansive and seems to fit our needs.

WiFi relay prices

WiFi antennas will be loan.

Docs

• https://www.myshop-solaire.com/quel-regulateur-solaire-choisir-pwm-ou-mppt--_r_80_a_183.html
• https://ragedecamp.eu.org/
• https://www.ffdn.org/wiki/doku.php?id=formations:wifi
• https://www.ffdn.org/wiki/doku.php?id=memo_wifi_ubiquiti
• https://www.ffdn.org/wiki/doku.php?id=documentation:wifi_federes

What do we need

We can buy some stuff, but we would like to recover as mush as possible from motivated people :)