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Hello,
I would like to build several sensor boxes with a PiZero. This should be operated via a solar panel, which is connected to a 12 V motorhome battery. The reason for this is that, in addition to the 5 V PiZero, other 24 V consumers are to be connected that are controlled via the Pi. The plan so far has been to bring the incoming current for the Pi to 5V with a step down, and to set a step up with a relay circuit in parallel for the 24V consumers. This set up worked quite well for the Pi3, but there were problems with the external RTC. I now wanted to monitor and schedule the Zero with the Witty Pi mini - I have read similar application examples on the Internet ( https://honey-pi.de/witty-pi/). For the successor version, an external shop (BerryBase) now stated the following: The Witty Pi 4 L3V7 can be operated with all rechargeable lithium-ion or lithium-polymer batteries with a nominal voltage of 3.7 V (and a fully charged voltage of 4.2 V).
This makes me unsure - can I also connect a normal 12 V lead car battery to it? And is the approach with a step-down converter effective, should it be soldered directly to the DC/DC contact points?
Thanks in advance
This topic was modified 1 day ago by Kiwy
Posted : 15/04/2025 8:51 am
Witty Pi 4 L3V7 and Witty Pi 4 Mini are two different products.
Witty Pi 4 L3V7 has built-in DC/DC step-up and it can only accept input voltage below 4.2V. So you can not connect a 12V car battery to Witty Pi 4 L3V7.
Witty Pi 4 Mini doesn't have any built-in DC/DC, so you may connect your own. The 5V output of your DC/DC should connect to the 5V pin in the unpopulated P2 header. If you want to monitor the car battery voltage, you also need to connect the "+" of battery to VIN pin in P2 header. The "-" of battery connects to the GND in P2 header.
Soldering is always a better way for connection, if the configuration is not temporary.
Posted : 15/04/2025 10:25 am
Topic starter
Posted : 15/04/2025 11:42 am