Project – 20Ah Solar

I've built a portable 20Ah Battery that's keeping my small electronics charged. It makes use of a Victron MPPT charger which can be connected to solar panels and via USB-C to XT-60 to charge the battery.

The setup can also be used mobile to charge devices via USB-C or USB-A. We've used this already for assignments in the field where we needed to charge Laptops, Drones, Phones and other devices. In earlier versions, we've bridged the 12V inputs to a Cigarette Lighter Socket, which kept the battery charged while driving. This is not ideal, but it worked. In the future, I plan to make use of a USB-C to XT-60 cable to charge the battery while driving via the MPPT charger. This should top off the battery via the MMPT charger and make sure the battery is always correctly charged.


  • 125W Solar Panel
  • Victron MPPT 100/20 Solar Charger
  • 20Ah LiFePo4 Battery
  • CoolGear 60W USBC
  • 2x 12V USB/USB-C 30W Outlet
  • Low Voltage Disconnect Switch - CZH-LABS D-1021
  • Rako/Eurobox with Lid - 40x30x12cm
  • XT60 Connectors

A few things are not in the images below as this came in in V1.1+:

  • Raspberry Pi 2
  • Victron VE.Direct > USB Cable



This version featured a Cigarette lighter socket and 2 USB Ports (the rounds ones) As I didn't use the cigarette lighter socket I've removed it in an overhaul and replaced it with a USB-C /USB-A charger.

This version was very basic and field tested as a Balcony Power Supply for a few months during summer.


I've extended the setup and made it possible to hook it up via a cigarette lighter socket to a car. This was not ideal as the battery was not charged, only held at a certain level. What the Board Power supply had as voltage. I was mostly concerned that the battery would be drained by the car, but this didn't happen. At some point I needed to replace the green USB-A Port charger with something newer as the plastic was brittle and started to fall apart.

I even tested this by drawing 120W continuously from the battery while supplying external power via the 12V Car System, and this worked fine.

V2.ish Aka Current State of the Project

Currently, I'm working on overhauling the system a bit. Version 2-ish had now a Raspberry Pi with Victron Venus Image as well as a VE.Direct cable to make the system remotely accessible via APP and the online portal.


I'm thinking about developing the system further to support a few additional features. An idea I had recently been that this would be a good setup to extend my Solar Setup in the Van (should also be documented soonish). Where I could take the 125W solar panel on a Long Cable and still park in the shade. This will need the Recabling and the External MPPT Output, as well as an Input on the VAN side.

  • [ ] External MPPT Battery Output
    This would allow the charge of an external Battery via the MPPT Charger (most likely an Anderson Plug)
  • [ ] Better Solar Input Socket
    I'm using an XT-60 connector to connect the solar panel to the MPPT Charger. This is not ideal as the XT-60 connector is not made for this (but it works)
  • [ ] Recabling
    Replace the speaker wire with a more suitable cable


A few images taken during the build process and some later ones

Inside view during buid of V1 Side vew of V1 Side view of Version 1.1 Inside view of Version 1.1 Last Updated: 2023-06-18

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