Keine Kühlleistung bei 12V

Had something weirdly similar with my shepherd's hut setup last summer — Dometic absorption fridge running sweet as anything on mains hookup, but the moment I switched to 12V from the panels it basically did nothing. Barely cooler than ambient.

Took a while to track down but turned out to be a voltage drop issue under load. The fridge draws a fair bit on 12V, and by the time the current travelled through my not-ideal cabling, it was seeing something like 11.1V at the fridge terminals. Absorption coolers are really fussy about this — they need a solid 12V, not "roughly 12V".

Few things worth checking if anyone's in the same boat:

• Cable gauge — undersized wire is the usual culprit, especially over longer runs
• Fuse/connection resistance — corroded terminals can rob you of half a volt easily
• What the Victron MPPT is actually outputting — check it via the app, not just assuming
• Battery state — if the bank is low or small, voltage sags the moment something hungry kicks in

Also worth noting — absorption fridges on 12V are notoriously inefficient compared to compressor types. If your solar input isn't generous on cloudy days, you might just not have the amps to sustain it properly.

Switched my hut over to a Waeco compressor fridge eventually, massive improvement. Still use the Dometic on gas when needed.

Anyone else had grief with absorption coolers on 12V? Curious if there's a better solution others have found without replacing the fridge entirely.

Hey @FrostySocket — worth checking your cable run length and gauge before anything else. Absorption fridges on 12V are notoriously hungry, and even a modest voltage drop across undersized cable can kill the heating element's performance stone dead. What gauge are you running and how far is the fridge from your battery bank?

Also, are you seeing the voltage drop at the fridge terminals specifically, or just at the battery? Those two readings can tell very different stories. A decent multimeter at both ends under load will give you a proper picture.

Absorption units genuinely need a solid 13V+ at the element to work properly — anything sagging below that and you'll get barely a whisper of cooling even if the panel output looks fine on paper.

My Victron SmartShunt told me my "12V system" was actually hovering around 11.3V by the time it reached the fridge — absorption units basically sulk below 11.8V and refuse to do anything useful, like a teenager asked to tidy their room.

@NBW_VanLife nailed it — voltage drop is the silent fridge killer, and my Fogstar lithium install taught me that the hard way when my Dometic started throwing a strop mid-August on a 40° day, which is basically a UK heatwave apparently.

@RetiredNurse49 got me thinking — I just zip-tied a Victron Battery Protect right next to the fridge rather than back at the battery bank, which halved my cable run and suddenly my Dometic stopped throwing a tantrum. 🧊