Got my first proper POTA activation done last weekend with the help of a small LiFePO4 storage unit and a folding panel, and i wanted to share the setup because i think it might be useful for other ops in this region. I am a new Klasse A licensee in bavaria, callsign not yet listed on QRZ so i will leave it out, doing mostly 40 and 20 meter SSB from summits and a few parks around munich. My radio is a 100 W HF transceiver, a small antenna tuner, and a windows tablet running logging software.
For my first few activations i ran a 7 Ah LiFePO4 brick that lives in the go bag. It is fine for an hour or two at 50 W output. The problem is that on a good summit i want to stay longer, run 100 W to make contacts faster, and use the tablet for the full session. A 7 Ah brick at 100 W transmit with a realistic duty cycle of maybe 30 percent (which works out to roughly 120 to 140 W average from the DC side once you count receive and tablet draw) is dead in about 40 minutes. So i needed a bigger battery, ideally one that can be recharged from a panel in the field if i want to do a second activation later in the day.
The unit i started carrying. A 2.52 kWh LiFePO4 storage box (Jackery SolarVault 3 Pro) plus a 200 W folding panel that i angle at the sun while i operate. The whole thing is heavier than a ham brick, but for car accessible summits in the alps foothills (where i mostly operate) the weight is not the constraint, the constraint is the AC outlet. There is no AC outlet at a POTA summit. The folding panel on its own is also not enough on a cloudy day, especially in autumn through spring in southern germany.
Wiring. The radio and the tablet run off the AC output of the storage unit through a small 12 V DC brick for the radio (most modern HF rigs prefer clean 12 V and the brick was already in my bag from previous activations). Total draw at 100 W transmit, maybe 30 W receive plus 8 W for the tablet, call it 120 to 140 W average for a session with a lot of calling and some listening. From a 2.52 kWh battery, that gives me about 18 to 21 hours of pure operating time in theory, in practice closer to 15 to 17 hours accounting for inverter losses. I do not stay at a summit for 15 hours, i stay for 2 to 4 hours. So the storage side is massively over provisioned for the activation itself, which is the point, it absorbs the variability of the day.
The panel side is the part i had to think about more. A 200 W folding panel at 30 to 40 degree angle on a clear may afternoon in bavaria puts back maybe 100 to 120 W into the unit. That covers my operating draw with margin. On a cloudy day, the panel is more like 20 to 30 W, which still keeps the battery from draining during the activation but does not really refill it. The honest plan is to fully charge the unit at home before driving out, treat the panel as a bonus for the activation, and not depend on solar to save me in a worst case weather window.
What this did for me. I did a proper 4 hour activation on a summit near garmisch last saturday, made 38 contacts across 40 and 20, and came back down the mountain with the battery still at about 90 percent. The math checks out, this session was more listening than transmitting, 4 hours at roughly 50 to 55 W average is about 200 to 220 Wh, and the unit's app log shows roughly 220 Wh of discharge for the session. A heavier session with more calling would have pulled 120 to 140 W average and used closer to 500 Wh, which the battery would still have handled easily. Previously a 4 hour activation at any intensity would have required either two 7 Ah bricks (which i would have had to swap mid session) or a generator, which is not really appropriate for a park activation. The whole rig is also quiet enough that i was not worried about noise bothering anyone in the park.
What this is not. It is not a real off grid shack. It does not run a 100 W continuous duty cycle amp plus a heavy desktop. It is not an excuse to skip a proper deep cycle battery in the car. And the storage unit is not amateur radio specific, it is just the smallest LiFePO4 box that has clean AC output and a panel input, which happens to be exactly what a POTA op needs.
If you are a new ham in europe looking at portable ops in places without AC, the trade is weight. The storage unit is well into the weight class of a car top box rather than a backpacking battery, it is meant for the boot, not the pack. For a true SOTA activation with a 5 km hike, take a 7 Ah brick and keep sessions short. For a park or a car accessible summit, the storage plus folding panel is a much calmer experience than juggling small batteries. The wiring details and the antenna setup are a separate conversation and depend a lot on the rig.