12V camping fridge on a portable power station
A Dometic or Engel compressor fridge in the back of the van, a power station on the floor, and a long weekend at a DOC site with no power. Will it keep the milk cold until Monday? These fridges run on 12 V and only draw full current while the compressor is running. Dometic rates the CFX3 45 at 1.03 Ah an hour at 32 °C, about 297 Wh a day, with a maximum of 8.2 A. That fits a station’s 10 A car socket, and a 1 kWh station lasts about 3 days on a hot summer weekend. QuietWatt’s answer uses the ratings Dometic, Engel and NZ retailers publish.
Step 1: what a 12V compressor fridge actually draws
There are two numbers on the spec sheet, and they’re easy to mix up. Rated current is the most the fridge will ever pull, and you use it for wiring and fuses. Energy consumption (Ah per hour) is the average over a day as the compressor cycles on and off. Dometic says so itself: divide usable battery Ah by the Ah/h figure for hours of runtime. Never multiply the rated current by 24.
Figures below are from the maker or an NZ retailer (checked 4 Nov 2026). QuietWatt hasn’t measured them:
- Dometic CFX3 45 (46 L): energy consumption 1.03 Ah/h at 12 V (32 °C outside, 4 °C inside); rated DC current 8.2 A; AC 52 W; 18.7 kg; works in ambient temperatures of 16–43 °C. NZ price NZ$1,778.99 (regular price at RV Mega, Mount Maunganui); other NZ retailers list it for less. Sources: Dometic product page and RV Mega NZ listing.
- Dometic CFX3 35 (36 L): 0.98 Ah/h at 32 °C and 0.47 Ah/h at 20 °C (both with 4 °C inside); rated 7.5 A at 12 V; 81 kWh a year in the manual’s technical table. Sources: Dometic US product page, Dometic CFX3 manual, and the Camping Bergler (AT) retailer listing for the 20 °C figure.
- Engel 40 L MT-V (MT45F-G4D-V): DC draw “variable from 0.5–2.6 amps” (the same page also says 0.5–3.0 A max); Sawafuji swing-motor compressor; 24 kg; NZ$1,650 at Engel New Zealand. Engel’s technical factsheet explains the range: the low figure is the minimum fridge setting, and the high figure is the freezer setting with the compressor running continuously. Engel doesn’t publish an Ah/h daily figure.
Step 2: does the fridge fit the station’s 12 V socket?
Rule used here: the fridge’s rated (maximum) current must fit under the 12 V port’s rated amps. Unlike a diesel heater’s glow plug, there’s no big start-up spike to worry about on these fridges. The Dometic’s 8.2 A is already its maximum.
| Station (official listing) | Wh | 12 V output (per listing) | Dometic CFX3 45 · 8.2 A max | Dometic CFX3 35 · 7.5 A max | Engel 40 L MT-V · up to 3.0 A |
|---|---|---|---|---|---|
| EcoFlow DELTA 3 Plus (NZ store) | 1,024 | Car socket 12.6 V 10 A, 126 W max | Yes (1.8 A spare) | Yes | Yes, lots of room |
| Jackery Explorer 1000 v2 | 1,070 | Car port 12 V 10 A | Yes | Yes | Yes |
| Anker SOLIX C1000 Gen 2 | 1,024 | Car outlet 12 V 10 A, 120 W | Yes | Yes | Yes |
| BLUETTI Elite 100 V2 (AU) | 1,024 | Car outlet 12 V 10 A (shared DC budget) | Yes, if other DC loads are light | Yes | Yes |
| EcoFlow DELTA Pro 3 (230 V EU listing) | 4,096 | 12.6 V 30 A, 378 W total via Anderson port | Yes | Yes | Yes |
The station 12 V specs come from the linked official listings, as checked for our tyre inflator and diesel heater pages; listings were reachable on 4 Nov 2026. Jackery’s and Anker’s car-port figures are from their US listings, so confirm them on the NZ/AU listing. Headroom is our own arithmetic. Check the label or listing.
Use the 12 V port, not the AC socket. Both Dometic and Engel fridges take 230 V too, but running them from the station’s AC outlet keeps the big inverter switched on all day and night, and the inverter burns energy just by being on. Plug the fridge’s DC lead into the car socket, or use a fused lead from an Anderson-style output; see Anderson vs XT60 and 12 V car charging. Check that your station’s DC output doesn’t auto-switch off when the compressor pauses and the draw drops to almost nothing.
Step 3: how many days per charge (estimate)
Wh per day ≈ Ah/h × 12 V × 24 h. Days ≈ (station Wh × ~0.85) ÷ Wh per day. The ~0.85 is a planning allowance for conversion losses, not a spec. A 1,024 Wh station gives about 870 Wh to plan with, and a 4,096 Wh DELTA Pro 3 about 3,480 Wh.
| Fridge and conditions (rated figure) | Average draw | Wh per day | 1 kWh station | 4 kWh station |
|---|---|---|---|---|
| CFX3 45 · 32 °C outside (1.03 Ah/h) | ~12.4 W | ~297 | ~2.9 days | ~11.7 days |
| CFX3 35 · 32 °C outside (0.98 Ah/h) | ~11.8 W | ~282 | ~3.1 days | ~12.3 days |
| CFX3 35 · 20 °C outside (0.47 Ah/h) | ~5.6 W | ~135 | ~6.4 days | ~26 days |
| Engel 40 L · assumed 50% compressor time at 2.6 A | ~15.6 W | ~374 | ~2.3 days | ~9.3 days |
| Engel 40 L · worst case, freezer running non-stop at 2.6 A | ~31 W | ~749 | ~1.2 days | ~4.6 days |
All arithmetic only (12 V nominal). Dometic’s Ah/h figures are its own test conditions; they don’t say whether the lid was opened. The 50% Engel row is our assumption because Engel publishes a range, not a daily average. Lid openings, warm drinks going in, freezer mode and a van parked in the sun all push draw up. Cooler weather brings it down: Dometic’s CFX3 35 uses about half as much at 20 °C as at 32 °C.
Summer long weekend
Fridge + lights + phones
A week or more off-grid
Keeping up with solar
To run the fridge indefinitely, the station has to take in what the fridge uses each day. For the CFX3 45 at 32 °C that’s about 297 Wh. If a panel gives about 4 hours of full-sun-equivalent output a day (our assumption for a clear NZ summer day; check your location and season), you need roughly 75 W of panel output, before losses and cloud. That’s why a 100–200 W folding panel is the usual pairing (arithmetic only). Short winter days need more panel, but in winter the fridge also draws far less. More: how many solar panels and MPPT vs PWM.
Why a 12 V fridge and not a small 230 V bar fridge
A household mini-fridge runs on AC through the station’s inverter, so you pay for the inverter being on as well as the fridge. Its compressor also has a start-up surge. The numbers are on our mini-fridge Wh page and fridge runtime page. A 12 V compressor cooler is built for battery use: it runs on DC, the cabinet is well insulated, and Dometic’s battery protection cuts out before a car battery goes flat. On a portable power station it’s the most efficient way to keep food cold.
Practical notes
- Leave the fridge the air gap its manual asks for. A fridge jammed into a hot cupboard runs its compressor much more.
- Dometic recommends 12 AWG wire for DIY 12 V setups. If your lead is long, use a heavier cable so the fridge doesn’t see low voltage.
- Dometic’s three-stage battery protection may switch the fridge off at a low voltage setting. A station’s regulated 12 V port should stay above it until the station is nearly empty, but check the setting in the app.
- Not electrical advice. Check the label or listing.
Where to buy a station (affiliate placeholders)
Tracked affiliate links will replace these placeholders once QuietWatt is enrolled in each program. Until then, use the official station URLs above, and confirm the 12 V port’s amp rating and Wh on the live NZ/AU listing. QuietWatt doesn’t earn from fridge sales, so fridge sources are listed as plain text.
Placeholder anchors: #aff-ecoflow, #aff-bluetti,
#aff-anker, #aff-jackery, #aff-amazon.
Sources (checked 4 Nov 2026)
- Dometic CFX3 45 product page (dometic.com/en/product/dometic-cfx3-45-9600025318): energy consumption 1.03 Ah/h at 12 V DC (32 °C ambient, 4 °C internal); rated DC current 8.2 A; AC 52 W; 18.7 kg; Dometic’s FAQ on rated current vs energy consumption and 12 AWG wiring
- Dometic CFX3 35 product page (dometic.com/en-us/product/dometic-cfx3-35-9600024617): 0.98 Ah/h at 32 °C / 4 °C; rated 7.5 A at 12 V
- Dometic CFX3 25/35 operating manual (media.dometic.com/externalassets/dometic-cfx3-35_76686.pdf): CFX3 35 rated 7.5 A at 12 V, 81 kWh/annum; ambient 16–43 °C
- Camping Bergler, Austria (campingbergler.at): CFX3 35 listing, 0.47 / 0.98 Ah/h at 20 / 32 °C ambient, 4 °C internal
- RV Mega NZ (rvmega.co.nz): Dometic CFX3 45, regular price NZ$1,778.99
- Engel New Zealand (engelnewzealand.co.nz): Engel 40 Litre MT-V MT45F-G4D-V, DC draw variable from 0.5–2.6 A (page also says 0.5–3.0 A max), 24 kg, NZ$1,650
- Engel technical factsheet (marinewarehouse.net/images/engel/Technical-factsheet.pdf): range is the minimum fridge setting to freezer setting with the compressor running continuously
- Station listings as linked in the table above (EcoFlow NZ, Jackery, Anker SOLIX, BLUETTI AU, EcoFlow EU)