Piso Wi-Fi and vending machines on solar

A piso Wi-Fi box or a small vending machine is a small, steady 12 V load, which makes it the easiest thing in the Philippines to run on solar, and the easiest to undersize for cloudy days. The bench runs the panel through a day of sun, drains the battery through the night and tells you the hours left, so you can pick the panel and the battery before buying them.

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What you can do

• Measure what the box draws (a router and a coin acceptor are under 0.5 A at 12 V) and turn it into Ah per day.
• Pick the battery for two cloudy days, not one sunny one; see what a 12 Ah battery does after a night.
• Add a DC UPS or a grid charger as the fallback, and a low-voltage cutoff so the battery is never flattened.
• Everything else a vendo needs is on the bench: coin acceptors, relays, PoE, routers, DC-DC converters.

Builds (6)

Piso Wi-Fi on solar: how big a panel and battery for a router and coin box

100 W panel, a 10 A MPPT charge controller, a 12 V 30 Ah LiFePO4 battery and the box: router plus coin acceptor on the…

Router DC UPS

Keeps a 12 V router running through a power cut.

12 V low-voltage battery cutoff

Disconnects the load before the battery is damaged.

Solar phone charger

Panel to USB with a buck converter.

Solar garden light with dusk switch

Charges by day, lights at night.

12,000 mAh LiFePO4 power bank · 2 × 32700

12,000 mAh, 5 V 2.4 A USB out, 2 A USB charging, full protection.

Questions answered

• How big a solar panel and battery for a piso Wi-Fi?
• What keeps the Wi-Fi router up in a brownout?

Calculators

Also on the lab

Solar PV simulator · Battery and BMS simulator · ESP32 simulator · Arduino simulator · Breadboard simulator · House wiring simulator · PCB layout and perfboard · Brownout backup: UPS, batteries, inverters and generators