Anyone else's leisure battery draining overnight with the fridge on?

Yeah, same issue here. Had a 100Ah lithium setup in my van and the fridge was absolutely killing it — losing about 15-20% overnight with just the compressor running. Nightmare.

Turned out a few things were stacking up:

The fridge itself — those cheap portable units are proper power-hungry. Mine was drawing 40-50W continuously. Switched to a Dometic or Waeco and it made a real difference. Compressor cycles rather than running constant.

Battery size — if you're running a small lead-acid bank, you're fighting a losing battle. A fridge needs consistent 12V ideally above 12.5V, and traditional batteries sag quick. That's when they work hardest and drain fastest. Went to a 200Ah lithium setup and honestly, game changer.

Undersized solar/alternator charging — if you can't recharge what the fridge uses during the day, you're always depleting. Worth looking at your charge sources.

What's your battery setup? And is the fridge a compressor type or absorption? That matters loads. Also check what voltage you're sitting at overnight — if it's dropping below 12V the fridge compensates by running more.

Some people swear by a separate leisure battery just for the fridge, which you can trickle-charge independently. Bit of faff but it works.

Curious what others are running that actually doesn't tank their batteries. Might be worth a proper audit if you're losing loads overnight.

Yeah, fridges are brutal. Mine was doing similar on the boat—absolutely hammering the battery even when barely running.

Few things I'd check:

Fridge efficiency - older compressor models are shocking. Switched to a Vitrifrigo and it made a difference, though not cheap. What model you got?

Phantom draws - sorted loads of parasitic drain on mine. Microwave, habitation relay, even the water heater standby was pulling amps constantly. Kill switches help.

Battery size vs usage - 100Ah sounds decent but depends what else you're running. Cabin setup made me realise I needed roughly double to comfortably run a compressor fridge plus other stuff overnight.

What's your actual SOC dropping to? And are you measuring with a proper monitor or just guessing? Makes a difference knowing if it's the fridge or something else bleeding you dry.

Had exactly this problem in the shepherd's hut a couple years back. Installed a cheap portable compressor fridge thinking it'd be fine on a modest 200Ah lithium bank—absolute disaster. Was pulling 40-50W continuously, and the parasitic drain from the controller and bits added another 15W on top.

The real killer was I wasn't monitoring actual consumption properly. Got a Victron BMV-712 fitted and suddenly could see what was happening in real time.

Ended up swapping to a 12V absorption fridge instead—Dometic CF40. Uses maybe 8-10W average over 24 hours. Completely transformed the setup.

Worth checking if your fridge is actually sized right for your battery capacity. A lot of people underestimate the daily throughput required. What size is your leisure battery and how long are you running the fridge between charges?

Had this exact problem in the conversion back in 2019. The real kicker isn't the fridge itself—it's the idle drain. Most cheap compressor units pull 30-40W just sat there between cycles, which absolutely tanks a 100Ah pack overnight.

Sorted mine by switching to a proper leisure-rated unit (Dometic CRX50, not cheap but worth it) and wiring it through a Victron MPPT with load shedding enabled. That way the fridge shuts down if the battery drops below 50%, rather than killing everything else in the van.

If you're stuck with what you've got, timer switch on a 12-hour cycle is the bodge solution—fridge only runs 6 hours a day. Not ideal in summer, but keeps your batteries alive.

What size battery are you running? That'll determine whether you actually need to replace the unit or just manage it differently.

Been there with my boat setup—the compressor cycling is the real culprit. Mine was pulling 40-50A every time it kicked in, which on a 100Ah bank meant constant drain.

Have you checked what type of fridge you're running? Absorption fridges are gentler than compressor models, but if you're stuck with what you've got, a few things helped me:

Proper insulation around the unit made a massive difference—reduced how often the compressor fired up. Also invested in a Victron battery monitor so I could actually see what was happening in real time rather than guessing.

The other option is splitting the load—run the fridge on solar during the day, switch it off at night if possible. Not ideal, but beats waking up to a flat battery.

What size is your leisure battery? Might be undersized for your fridge's duty cycle.

Had the same grief with my static caravan setup. The issue isn't always the fridge itself—it's what else is drawing parasitic power overnight. Check your leisure battery monitor isn't constantly backlit, and make sure your solar controller isn't bleeding charge through an inverter that's left running.

One thing @12V_King mentioned about compressor cycling is spot on. My Dometic was cycling every couple of hours, pulling the battery down fast. Upgrading to a smaller absorption fridge (used one from a Fogstar unit) actually solved it—less efficient on paper, but way more stable overnight since it doesn't cycle.

If you're set on keeping the compressor fridge, consider a dedicated small lithium pack just for it, or a proper relay setup so it only runs when you've got decent solar input. Saves the main battery getting hammered.

What size leisure battery are you running?

@WonkyMender my static caravan bled out a full 200Ah Fogstar bank overnight and turned out the culprit was a cheap PWM controller keeping the charge circuit "awake" and draining 3-4A constantly — fridge was basically innocent the whole time, poor thing.

Stick a clamp meter on each circuit individually before you go pointing fingers at the compressor 🔍