Thelvanor, PBC · forming in Texas
A data center the size of a keg.
Three Raspberry Pi 5 nodes, one 100 W solar panel, one 256 Wh battery, sealed in a stainless keg painted safety orange. Built for under $1,000. Instrumented so every design claim becomes a measurement, then published.
- 0
- Phase, pre-build
- 0
- Measurements logged
- 10
- Claims under test, graded
- $1,000
- Budget, $0 spent
The thesis
Small on purpose. Cheap on purpose. Instrumented on purpose.
The questions that matter about data centers, how energy becomes computation, how heat leaves a sealed box, how a shared power budget is split among competing loads, are usually studied at the scale of a warehouse. They can be studied at the scale of a keg. Keg-1 is not built for throughput. It is built so that every abstraction in a data-center curriculum ends in a number read on a $25 multimeter.
Vol. I–III · the system
Three domains, each one measured.
- Plausible
Energy
256 Wh · 12.8 V × 20 Ah LiFePO₄, 80% usable
A 100 W panel that is also the sunshade feeds an MPPT controller, then a fused 12 V bus with five branches, one per node, one for the switch, one spare.
- Verified
Compute
3 × Pi 5 · 1 GB each, wired gigabit, no Wi-Fi
A steel keg is a Faraday cage. Nodes talk over a five-port switch; one outdoor Cat6 leaves through an IP68 bulkhead. Node 1 hosts the sensors and the log.
- Speculative
Hall
0.50 m² · stainless shell, fanless
Each SoC conducts into a 3 mm aluminum plate bolted to the keg wall. The shell is the radiator. The bet is that passive conduction is enough for three nodes.
The governing problem
The scheduler, not the panel, is the design.
Over a 14-hour winter night three idle nodes draw about 179 Wh and finish the night with roughly 26 Wh above the reserve. Three nodes at full load would need 366 Wh, which the battery does not hold. Night compute must be scheduled against a 26 Wh margin, about six node-hours of full load. Every input here is a pre-build estimate. The first overnight log redraws the lines.
Battery energy through a 14-hour winter night
The build
Four phases. Four volumes. One gate each.
Parts are bought when their chapter is being studied. A phase ends only when its bench test passes. The curriculum, Poles, Chips, and Halls, climbs five rungs in each domain, from sixth grade to doctoral research questions, and each rung ends on the bench.
01 · Energy
Weeks 1–4 · Vol. I, Poles
$315
Panel, MPPT controller, LiFePO₄ battery, the main fuse, the fused 12 V bus, and the first node as sensor host.
Gate
Node 1 runs from the fused bus; both INA226 monitors report sensible watts in and watts out.
02 · Compute
Weeks 5–8 · Vol. II, Chips
$185
Nodes 2 and 3, the gigabit switch, wired network, and a three-node load test under a stop rule set in advance.
Gate
Three-node load test completes under the pre-set stop rule without a brownout.
03 · Keg
Weeks 9–12 · Vol. III, Halls
$265
Primer and safety-orange paint, IP68 gland and RJ45 bulkhead, the passive heat path to the keg wall, sensors, desiccant.
Gate
Water-only leak test of the empty keg, then a seven-day sealed soak with a flat humidity trend.
04 · Deploy
Weeks 13–16 · Vol. IV, Deployed
$65
Land, tethered water, and a ground-based orbit analog: simulated eclipse power cycles and radiation-only cooling.
Gate
Eclipse cycles logged; radiation-only cooling run completes with SoC below throttle.
Field rules
Four rules on every week.
R.1
Fuse first.
The main fuse goes on the battery's positive terminal before anything else is connected.
R.2
Never pressurize the keg with electronics inside.
The pressure-relief valve is never disabled or painted over. Leak tests use water on the empty keg, never gas.
R.3
Water tests are tethered only.
A pool, a private pond, or a permitted dock. No open water in v1.
R.4
Orbit is a ground analog.
Simulated eclipse power cycles and radiation-only cooling. Nothing launches.
Thelvanor, PBC
Built as an instrument. Published as it is measured.
A public benefit corporation forming in Texas. A sub-$1,000 solar data center in a stainless keg.