Daily Electrical Consumption Report¶
1. Purpose & Scope¶
The Electrical Report §3.1 budgets energy per print session. This report rolls that up into one full day of daylight operation — multiple prints, the continuous cooling/ventilation load, and the print-wash pumping — and checks it against the battery and the solar recharge. The Brown/Waste tote dump is handled separately (§6): it is a per-resupply servicing event, not a daily one.
Per-session figures come from that per-session budget; the daily roll-up and operational assumptions are derived here.
2. The Operating Day¶
A pinhole exposure uses one film plane at a time, so prints are sequential: load → expose → develop & wash → cleanup, then the next. One cycle is ~182 min (~3 h), of which the exposure is 37.5 min. A realistic daylight field day is therefore ~3 prints (≈ 9 h of cycles + setup/teardown); 4 is achievable when pushing, 2 on a short/poor-light day. The container is cooled once in the morning and the fans + evaporative cooler then run continuously through the operating day.
Standard build is manual (electric actuation was dropped — see Cost Analysis), so Circuit F draws nothing. Per-session energy (incl. the once-daily morning warmup) is ~771 Wh (vs 780 Wh with the optional actuators); the cooler runs through the AC inverter (~97 W on the 12 V bus).
3. Per-Print Energy (from the session budget)¶
| Phase / load | W | Min | Wh |
|---|---|---|---|
| Dark adaptation (fans + cooler + safelight) | 232 | 20 | 77 |
| Load image plane (fans + cooler + safelight) | 232 | 45 | 174 |
| Exposure (fans + cooler) | 217 | 37.5 | 136 |
| Development & wash (fans + cooler + white light) | 277 | 20 | 92 |
| Cleanup (fans + cooler + white light) | 277 | 30 | 138 |
| Wash pump P-01 (Blue, 3× fills) | 90 | 15 | 22.5 |
| Wash pump P-02 (Brown recycled) | 90 | 10 | 15.0 |
| Tray-drain pump P-04 (sump → IBC) | 90 | 5 | 7.5 |
| Per print (manual) | ~663 (excl. one-time morning warmup) |
The continuous fans + evaporative cooler (217 W) dominate — they are on the whole cycle, so most of the energy is climate control, not imaging or pumping. The cooler runs through the 12V→120V inverter (~97 W on the bus).
4. Daily Roll-Up — Representative 3-Print Day¶
| Item | Wh |
|---|---|
| Morning cooling warmup (once: fans + cooler, 30 min) | 108 |
| 3 prints × 663 Wh (cycle + wash/drain pumps) | 1,989 |
| Daily total (3 prints) | ~2,097 Wh |
| Day | Prints | Daily Wh |
|---|---|---|
| Short / poor light | 2 | ~1,434 |
| Representative | 3 | ~2,097 |
| Pushed | 4 | ~2,760 |
5. Print-Washing Load (called out)¶
Each print is washed by P-01 (Blue fresh, 15 min) + P-02 (Brown recycled, 10 min) — 25 min of pumping at 90 W = 37.5 Wh of wash pumping per print (P-04 adds 7.5 Wh of tray-sump drain). Over a 3-print day that is ~112 Wh of wash pumping plus the white light during the wash/develop phase. Pumping is a small fraction (~6%) of the daily energy — the cooling load is the real consumer.
6. Resupply Brown & Waste Pump-Out (per dump run — not daily)¶
The Brown (IBC-3) and Waste (IBC-4) totes are evacuated to the sealed end-wall ports — Brown → X3 via P-05, Waste → X4 via P-03 (Plumbing Report §4.3, Water System Report §6) — only at a resupply / dump run, when the clean-water supply is replenished. That service interval is set by the Blue water (~14 prints ≈ 4.7 days at 3/day, §8.2), so the totes are emptied roughly every ~4.7 days, not every evening — the camera can sit on site for several days between dump runs.
This is gravity-assisted: each tote gravity-drains through its low port, and the pump only lifts the ~120 L residual below the port:
| Pump | Tank | Volume pumped | Min @ 3.5 GPM | Wh @ 90 W |
|---|---|---|---|---|
| P-05 | Brown IBC-3 → X3 | ~120 L residual | ~9 | ~14 |
| P-03 | Waste IBC-4 → X4 | ~120 L residual | ~9 | ~14 |
| + white light for the ~20 min operation | ~10 | |||
| Per-dump-run drain total | ~37 Wh |
Because gravity does the bulk, the pump energy is independent of how full the totes got and is tiny — ~37 Wh per dump run (a fraction of a single operating day's ~2,097 Wh, and incurred only once per resupply, not daily). Worst case — if a tote had to be pumped out entirely with no gravity assist (~600 L) — it would be ~45 min each, ~137 Wh for both; still minor. (Brown is normally recycled through the filter back to Blue rather than dumped; this line covers the case where it is drained off.)
7. Solar Balance & Battery Autonomy¶
| Value | |
|---|---|
| Solar generation (600 W × 5.5 peak-sun-h, Palm Springs) | ~3,300 Wh/day |
| Battery usable (200 Ah × 12 V LiFePO4, 100% DoD) | 2,400 Wh |
| Day | Daily draw | Solar net | Within one battery charge? |
|---|---|---|---|
| 2 prints | ~1,434 | +1,866 | Yes (with wide margin) |
| 3 prints | ~2,097 | +1,203 | Yes — full overnight autonomy |
| 4 prints | ~2,760 | +540 | Exceeds the 2,400 Wh battery by ~360 Wh → covered by daytime solar (which runs during the prints), not battery alone |
Conclusions: - The system is solar-positive at every realistic daily throughput — even a 4-print day generates more than it consumes, so it sustains indefinitely on sun. - A 3-print day fits within a single 2-pack battery charge, giving a full day of operation on a dead-cloudy day from the battery alone. - A 4-print day relies on the panels topping up during the day (the loads run in daylight, so this is normally fine); on a fully overcast day, cap at ~3 prints. The higher-draw AC cooler (~97 W) puts the 4-print battery shortfall at ~360 Wh — still solar-covered, but battery-only 4-print days are off the table. - The dominant load is climate control (fans + evaporative cooler, ~2,050 Wh/day), not imaging or pumping — the biggest lever on daily energy is cooling runtime, not the print workflow.
8. Disconnected Endurance — How Long Off-Grid?¶
The question: with no AC charge (a remote deployment running on solar top-up + the battery alone), how long can the system operate — and does adding the second battery pack extend it? Two limits compete: power and clean water.
8.1 Power is not the limit (with sun)¶
Solar generates ~3,300 Wh/day; a 3-print day draws ~2,097 Wh — a +1,203 Wh/day surplus, so on sunny days the battery never depletes and the system runs indefinitely. The battery's job is to ride out cloudy days, and that reserve is what the pack count changes:
| Battery | Usable | No-sun reserve (at ~2,097 Wh/day) | With sun |
|---|---|---|---|
| 1 pack (1×100 Ah) | 1,200 Wh | ~0.6 day (≈ 2 prints) | Indefinite (solar-positive) |
| 2 packs (2×100 Ah) | 2,400 Wh | ~1.1 day (≈ 3 prints) | Indefinite (solar-positive) |
So the second pack does not lengthen the deployment — it buys a cloudy-day buffer (ride out ~1 fully-overcast day instead of half a day) and the headroom for a 4-print day (which exceeds a single 100 Ah pack). On solar, even one pack sustains operation forever.
8.2 Clean water is the limit¶
Power being effectively unlimited on sun, the binding constraint is the fresh (Blue) water supply. Each print consumes ~32 gal (121 L) of net Blue water even with Brown recycling (Water System Report §3–4), so:
| Constraint | Capacity | Per print | Endurance |
|---|---|---|---|
| Clean water (Blue, in) | 1,800 L (476 gal) | 121 L (32 gal) | ~14 prints ≈ 4.7 days @ 3/day |
| Power, 2 packs + sun | — | ~620 Wh | Indefinite |
| Power, 2 packs, no sun | 2,400 Wh | ~620 Wh | ~3 prints (~1.1 day) |
A disconnected deployment therefore runs ~14 prints (~4.7 days at 3/day) before it needs a resupply run — which is fundamentally a water event (refill Blue), not a charging event.
8.3 Watch the waste side too¶
The endurance is bounded on both ends of the water loop. The Black (waste) tote fills to ~600 L (a 1,000 L tote at its working fill) — a parallel out-flow limit: in fully self-contained field use (no sewer, waste transported for disposal), the waste tank can fill before the Blue tank empties, so a resupply run must empty Black as well as refill Blue. If waste cannot be disposed at all, that — not power or fresh water — becomes the hard stop.
8.4 Verdict¶
- The deployment length is set by clean water (~14 prints / ~4.7 days), not power.
- One vs two battery packs does not change that — both run indefinitely on sun. The second pack buys a ~1-day cloudy-weather reserve (vs ~half a day) and enables 4-print days; for a fresh-water-limited 10-print deployment, a single pack is energetically sufficient on solar, with the second pack a resilience upgrade rather than an endurance one.
9. Source References¶
- Electrical Report §3 — power budget and the per-session itemized energy.
- Water System Report §6 — pump runtimes, wash cycles, and the Brown/Waste drain-out path.
- Plumbing Report §4.3 — P-03 (Waste evac) and P-05 (Brown drain) duties; the ~120 L gravity-drain residual.
- Cost Analysis — the manual-actuation decision (Circuit F unused in the standard build).