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Most “will it run a fridge?” articles skip the only question that matters: how many watt-hours (Wh) do your actual loads need, after inverter losses?
This is a practical sizing guide for the three loads people ask about most — fridge, Wi‑Fi (router/modem), and CPAP-class overnight devices — plus phones and lights so the math matches real blackouts and camping nights.
CPAP note (read this): Draws vary widely. Humidifiers and heated hoses can dominate. Check your device’s labeled wattage and talk to the manufacturer about approved DC cables and power options. A portable power station is only a battery + inverter. We make no medical claims and do not recommend devices for clinical use.
Quick answer
| Goal | Rough usable tank | Typical station class |
|---|---|---|
| Router + phones overnight | ~100–400 Wh | RIVER / ~300–800 Wh |
| Router + phones + careful mini-fridge ~12 h | ~700–1,200 Wh | ~1 kWh LFP |
| Full-size fridge ~24 h (no solar) | often 1,500–3,000+ Wh | 1 kWh + solar, or 2 kWh class |
| Fridge + Wi‑Fi + CPAP overnight | add CPAP Wh from the label | usually ~1 kWh+ |
Soft picks once you know the number: best under $1,000 · apartment blackout kits · camping brand compare.
The only formula you need
Wh needed ≈ (device watts × hours) ÷ inverter efficiency
Then add 10–30% buffer for heat, aging, fan draw, and “I opened the fridge too much.”
Inverter efficiency (~85–90%)
AC outlets convert DC battery energy through an inverter. Budget ~85–90% usable for planning:
| Battery capacity (rated Wh) | Usable at ~87% | Usable at ~90% |
|---|---|---|
| 768 Wh (RIVER 2 Pro class) | ~668 Wh | ~691 Wh |
| 1,024 Wh (Anker / DELTA 3) | ~891 Wh | ~922 Wh |
| 1,070 Wh (Jackery 1000 v2) | ~931 Wh | ~963 Wh |
| 1,152 Wh (Bluetti AC180) | ~1,002 Wh | ~1,037 Wh |
| 2,042 Wh (Jackery 2000 v2) | ~1,777 Wh | ~1,838 Wh |
DC outputs (12V car port, some USB-C paths) often waste less than full AC inversion — use them when the device supports it (fridge 12V cable, manufacturer CPAP DC option).
Step 1 — List loads (example watts)
Use your nameplate or a kill-a-watt style meter when you can. These are example planning ranges, not guarantees:
| Load | Example watts | Notes |
|---|---|---|
| Wi‑Fi router | 10–20 W | Modem + mesh nodes add more |
| Cable / fiber modem | 10–15 W | Often separate from router |
| Phone / tablet charge | 5–15 W avg | Bursts higher; average over the day |
| LED lamp / string lights | 5–15 W | Easy win vs old bulbs |
| Laptop (AC brick) | 45–100 W | USB-C PD 60–140 W can be cleaner |
| 12V compressor fridge | 30–60 W average | Peaks higher when compressor kicks |
| Mini fridge (AC) | 50–100 W average | Duty cycle rises in heat |
| Full-size fridge (AC) | 100–200 W average* | Nameplate 300–800 W is not average |
| CPAP (base, no humidifier) | check label | Often tens of watts — verify |
| CPAP + humidifier / heated hose | check label | Can be much higher — verify |
\*Compressors cycle. Ambient heat, dirty coils, and door openings raise average watts.
Step 2 — Multiply by hours
Example A — Communications-only night (apartment)
| Load | W | Hours | Wh |
|---|---|---|---|
| Router | 15 | 12 | 180 |
| Modem | 12 | 12 | 144 |
| Phones (avg) | 10 | 12 | 120 |
| LED lamp | 10 | 6 | 60 |
| Subtotal | 504 | ||
| ÷ 0.87 inverter | ~580 Wh from battery | ||
| +20% buffer | ~700 Wh tank |
Station class: EcoFlow RIVER 2 Pro (768 Wh) is in range. See EcoFlow RIVER 2 Pro.
Example B — Mini-fridge + Wi‑Fi for 24 hours
| Load | W avg | Hours | Wh |
|---|---|---|---|
| Mini fridge | 70 | 24 | 1,680 |
| Router + modem | 25 | 24 | 600 |
| Phones | 8 | 24 | 192 |
| Subtotal | 2,472 | ||
| ÷ 0.87 | ~2,840 Wh from battery |
Reality check: A single ~1 kWh station cannot do aggressive mini-fridge + network for a full day without solar or shedding. Options:
- Run fridge fewer hours / keep doors closed / pre-chill
- Add solar recovery midday
- Step up to ~2 kWh (e.g. Jackery Explorer 2000 v2 when under budget) or expandable EcoFlow + extra battery
For a 12-hour mini-fridge stretch at 70 W avg + light network:
| Load | Wh |
|---|---|
| Fridge 70 W × 12 | 840 |
| Network 25 W × 12 | 300 |
| Phones | ~100 |
| Subtotal | ~1,240 |
| ÷ 0.87 + 20% buffer | ~1,700 Wh ideal / ~1,000–1,150 Wh if you shed hard |
~1 kWh class picks (honest: careful fridge hours, not magic): Anker SOLIX C1000 Gen 2 · Jackery Explorer 1000 v2 · Bluetti AC180 · EcoFlow DELTA 3
Example C — 12V compressor camping fridge weekend
| Load | W avg | Hours | Wh |
|---|---|---|---|
| 12V compressor fridge | 45 | 48 | 2,160 |
| Phones / lights | 15 | 48 | 720 |
| Subtotal | 2,880 |
On DC (if your station’s 12V path is efficient), you may skip the worst AC inverter tax — still plan a large buffer. Many campers cover this with ~1 kWh + solar or disciplined daytime sun, not a naked 1 kWh brick for 48 hours of heat-wave fridge duty. Brand trade-offs: Jackery vs EcoFlow vs Bluetti camping.
Example D — Fridge + Wi‑Fi + CPAP overnight (template only)
Do not copy folklore wattages. Fill from labels:
| Load | Your watts | Hours | Wh |
|---|---|---|---|
| Fridge (avg) | ____ | 8–12 | ____ |
| Router / modem | ____ | 8–12 | ____ |
| CPAP (mode you actually use) | ____ | 8 | ____ |
| Phones / lights | ____ | 8 | ____ |
| Subtotal | ____ | ||
| ÷ 0.85–0.90 | ____ | ||
| +20–30% buffer | = target Wh |
Humidifier warning: If you sleep with humidifier + heated hose, measure or read the combined draw. That number alone can exceed the base CPAP. Ask the manufacturer whether a DC cable is approved — DC can cut inverter losses and sometimes avoid AC brick inefficiency.
Again: no medical claims; confirm setup with your equipment maker.
Step 3 — Match a station (under-$1k class cheat sheet)
Verified capacities (Sep 2026) from our under-$1k set:
| Model | Rated Wh | ~87% usable | Continuous AC | Weight | Street band (Sep 2026) |
|---|---|---|---|---|---|
| EcoFlow RIVER 2 Pro | 768 | ~668 | 800 W | 18.2 lb | ~$349 sale |
| Anker SOLIX C1000 Gen 2 | 1,024 | ~891 | 2,000 W | 24.9 lb | ~$430–$530 sale |
| EcoFlow DELTA 3 | 1,024 | ~891 | 1,800 W | 27.6 lb | ~$599–$699 |
| Jackery Explorer 1000 v2 | 1,070 | ~931 | 1,500 W | 23.8 lb | ~$499–$559 |
| Bluetti AC180 | 1,152 | ~1,002 | 1,800 W | 35.3 lb | ~$450–$500 |
| Jackery Explorer 2000 v2 | 2,042 | ~1,777 | 2,200 W | 39.5 lb | ~$799–$899 (live-check under $1k) |
How to choose after the math:
- Target Wh ≤ ~87% of rated Wh for your outage window
- Continuous watts must clear the hungriest AC device (fridge surge matters too)
- Prefer LiFePO4 for a kit that sits between storms
- Apartment UPS needs → Anker 10 ms / DELTA 3 <10 ms (apartment guide)
- Carry weight → Jackery 1000 v2 (23.8 lb) or RIVER 2 Pro (18.2 lb)
Full buying criteria and CTAs: Best portable power stations under $1,000.
Anker SOLIX C1000 Gen 2 · Jackery Explorer 1000 v2 · Bluetti AC180 · EcoFlow DELTA 3 · EcoFlow RIVER 2 Pro · Jackery Explorer 2000 v2
Fridge math that people get wrong
Nameplate ≠ average
A fridge that lists 400 W on the sticker might average 80–150 W over a day because the compressor cycles. Plan with average watts (meter them for a day if you can).
Door openings and ambient heat
Summer blackouts destroy “fridge for 24 hours” claims. Every open door dumps cold; hot apartments raise duty cycle. Pre-freeze water jugs, keep the door shut, and shed non-food loads first.
Mini vs full-size
Mini-fridges are not automatically thrifty — some cheap units are inefficient. Still, they are often the only fridge that fits a ~1 kWh overnight plan.
12V compressor vs AC fridge
Camping compressor fridges on 12V are usually the efficient path. Apartment full-size units are stuck on AC unless you like bad ideas involving transfer switches (out of scope here).
Wi‑Fi / work-from-home math
Routers are small Wh consumers; desktops and monitors are not.
| Setup | Rough draw | 8 hours |
|---|---|---|
| Modem + router | 20–35 W | 160–280 Wh |
| Laptop only | 45–100 W | 360–800 Wh |
| Gaming desktop + monitor | 200–500 W+ | 1,600–4,000 Wh |
For blackouts, kill the desktop; keep modem + laptop + phone. That is how a 768–1,070 Wh station still feels useful. UPS timing helps the modem stay up through the switch — see the apartment blackout guide.
CPAP sizing (non-medical, label-driven)
- Read the device wattage (and humidifier / hose if used)
- Multiply by sleep hours
- Prefer manufacturer-approved DC options when available
- Add fridge/network on top if those run the same night
- Confirm everything with the manufacturer — not a blog comment thread
If the combined night exceeds ~80–90% of your station’s usable Wh, you need a bigger tank, solar, or load cuts (fridge first is the usual trade).
Solar as a Wh multiplier (not a free lunch)
Panels do not increase battery capacity; they refill it.
- Brochure 200 W panel → often ~120–160 W average in real sun
- 5 good sun hours × 140 W ≈ 700 Wh recovered (before charge losses)
- Apartment balconies: assume worse (balcony limits)
- Camping: one panel can turn a marginal 1 kWh weekend into a workable one
Station solar caps (for kit planning): Anker C1000 Gen 2 600 W, DELTA 3 500 W (Plus 1,000 W), AC180 500 W, Jackery 1000 v2 400 W, RIVER 2 Pro 220 W.
Jackery SolarSaga 200W · EcoFlow foldable solar · Bluetti PV200
Decision tree
- Only router + phones + lights? → ~300–800 Wh (RIVER 2 Pro class)
- Add careful mini-fridge ≤12 h? → ~1,000–1,150 Wh class
- Full-size fridge 24 h, no solar? → often 2 kWh+ or “don’t believe the TikTok”
- Add CPAP overnight? → add label Wh, then re-check
- Need UPS for modem? → Anker C1000 Gen 2 or DELTA 3
- Stairs / elevator carry? → Jackery 1000 v2 or RIVER before AC180
- Might expand later? → DELTA 3 path to 5 kWh
Worked “buy this” map
| Your math lands near… | Start here | Skip if… |
|---|---|---|
| ≤700 Wh usable | EcoFlow RIVER 2 Pro | You insist on full-size fridge overnight |
| ~900–1,000 Wh usable | Anker SOLIX C1000 Gen 2 or Jackery Explorer 1000 v2 | You need native expansion |
| Max Wh per dollar ~1 kWh | Bluetti AC180 | You have a 4th-floor walk-up |
| Expandable core | EcoFlow DELTA 3 | You will never buy an extra battery |
| ~1,700+ Wh usable | Jackery Explorer 2000 v2 (if still under budget) or DELTA 3 + extra | Price climbs back over your cap |
FAQ
How many Wh to run a fridge for 24 hours?
Often 1,200–4,800 Wh of energy drawn depending on average watts — then divide by ~0.87 and add buffer. Meter your fridge; do not trust “runs a fridge” ads.
How many Wh for a router overnight?
A 15 W router × 12 h = 180 Wh before inverter losses — small. Modems and mesh nodes add up; desktops dominate if left on.
How many Wh for CPAP?
Whatever your label says × hours, plus humidifier if used. Ask the manufacturer about DC options. No medical claims here.
Is 1,000 Wh enough for fridge + Wi‑Fi + CPAP?
Sometimes for a short night with a efficient fridge and a modest CPAP mode — often not for 24 h fridge + humidified CPAP. Do the table; believe the arithmetic.
Should I size continuous watts or Wh first?
Both. Wh = runtime. Continuous (and surge) watts = whether the fridge/compressor or kettle can start. A huge battery with a tiny inverter still fails hard loads.
Why do you use 85–90% efficiency?
Inverters are not 100% efficient; stations also use power for displays and fans. 85–90% is a practical planning band, not a lab certificate for every SKU.
Bottom line
- Write watts × hours for each load
- Divide by ~0.87 (or use DC where appropriate)
- Add 20–30% buffer
- Buy the smallest station that clears the number — then stop
- Most ~1 kWh apartments / weekends: Anker SOLIX C1000 Gen 2 or Jackery Explorer 1000 v2
- Max Wh/$ in class: Bluetti AC180
- Expand later: EcoFlow DELTA 3
- Light network kit: EcoFlow RIVER 2 Pro
Continue: Apartment & condo blackout power stations · Best under $1,000 · Jackery vs EcoFlow vs Bluetti camping
Capacity and street figures aligned with manufacturer pages / WattList SPEC-UPDATE 5 Sep 2026. Prices move weekly — re-check before publish.
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