One Year Later: My DIY Field Charger

The Build

At the heart of this charger are 120 Samsung 5000mAh lithium-ion cells, grouped into six clusters of 30 cells each. The final configuration came out to 6s5P x4, giving me plenty of capacity and flexibility for charging multiple packs in the field.

This wasn’t just about raw power, it was about building something safe, portable, and reliable. I carefully designed the clusters to balance easily, keep heat under control, and handle the current demands without stress. For anyone who builds with lithium cells, you know how much attention goes into layout, wiring, and protective measures.

Performance Over the Past Year

Fast-forward a year, and I can confidently say: this thing has worked flawlessly. No hiccups, no unexpected issues, and no scary surprises. The cells have stayed well-balanced, the wiring has held up under heavy use, and the output has delivered exactly what I needed every single time.

It has powered countless charge cycles in the field, sometimes topping off packs between flights, other times recharging full sets after long sessions. The convenience of not being tethered to wall power has completely changed how I approach flying days. Instead of worrying about running out of juice, I just focus on flying.

Lessons Learned

What I’ve learned over the past year is that when you design something with care, it pays you back in reliability. Using quality cells, taking the time to build with precision, and not cutting corners on safety has meant I can simply trust the system to work every time I need it.

And honestly, that peace of mind is worth more than the charger itself.

Huge shout-out!

I could never have built this without help from my pal Birger.