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40aH LiFePo4 Battery Box (w/Solar)

Parts List

  • 2x ECI Power 12V 20Ah LiFePO4 (parallel)
  • Victron Energy SmartSolar MPPT 100v/15a Solar Charge Controller
  • 2x USB A (2.4a ea)
  • 1x USB A QC 3.0
  • 1x USB C PD (power delivery for charging laptops)
  • 1x 12v Accy Port (Cigg Lighter)
  • 2x Andersons Powerpole (Bi-Directional)
  • 1x Andersons Powerpole (direct to batt)
  • 1x Andersons Powerpole (direct to MPPT)
  • Inline Shunt Power meter (voltage & current)


The case got beat up a bit when installing the parts due to my dremel taking a dump on me mid-project. All parts are individually fused & switched. Andersons Powerpole inputs for external DC charging & solar panel input (up to 100v/15a). Both of the battries have built a built in BMS so all you have to do is shove 14.6v for absorption charge and 12.8v (or 13.8v) for float. The max charge rate (DC in or solar) is 10a but it's much safer/easier to do 5a input. It takes roughly 6-7hrs to charge from 0% to 100% when using a 14.6v 5a smart charger. The load output on the Victron is not used due to a 20a max throughput (I wanted 40a max load).

This box pairs well with my ROCKPALS SP003 100W Portable Solar Panel. Here in the SF Bay Area we havent gotten much sun so I haven't tested it's solar charging capabilities. If you are interested in building somthing like this, check out my parts list here. You can scale it up/down based on the box size & battery capacity.

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