Anyone else struggling to keep the compressor fridge running overnight on two 100Ah leisure batteries?

Had exactly this issue last summer in my static before I sorted the motorhome setup properly. Two 100Ah batteries sounds decent on paper but you're probably only working with ~100Ah usable if they're standard lead-acid — that 50% discharge limit catches everyone out.

Compressor fridges are brilliant but they're sneaky on consumption. Mine pulls around 4-5A when the compressor kicks in, less on standby, but overnight that adds up fast — especially if it's warm and the thing's cycling constantly.

Few things that helped me:

• Switched to lithium (Fogstar Drift 100Ah) — full usable capacity changes everything overnight
• Pre-cool the fridge before you disconnect from hookup
• Keep it well-stocked — thermal mass helps massively
• Check your actual resting voltage in the morning, not just assuming the batteries are "fine"

If you're sticking with lead-acid, honestly two 100Ah batteries just isn't enough for a compressor fridge plus lighting/devices overnight without some solar topping things up during the day. I run a 200W Renogy panel and even on overcast days it makes a real difference.

What fridge have you got and what are your batteries — lead-acid or lithium? Makes a massive difference to the advice really. Others on here will have thoughts too, it's a really common sticking point when people first go off-grid.

@IslandCruiser yeah lead acid will bite you every time — only ~50% usable so you're actually working with 100Ah from two 100Ah batteries, not 200Ah.

Swapped my static caravan over to Fogstar Drift 100Ah LiFePO4 last year and it's night and day. Same footprint, proper 80-90% usable capacity.

Compressor fridges also draw more than people expect at startup — worth checking actual consumption with a Victron Battery Monitor rather than guessing. Mine was pulling way more than the fridge spec sheet suggested.

Also — what's your solar topping them up during the day? If you're not recovering fast enough you're just digging a deeper hole each night.

@OffGridDawn hit the nail on the head — and a compressor fridge typically pulls 4-6Ah average overnight, so you're burning through that 100Ah usable faster than a British summer disappears.

On my narrowboat I run a single Fogstar 100Ah LiFePO4 and it laughs at my compressor fridge all night with capacity to spare — lithium's 80-100% usable depth of discharge is genuinely a game-changer vs lead acid's "well actually it's 50%..." situation.

Quick options for you:

• Upgrade to lithium (Fogstar Drift is cracking value)
• Add a third lead acid as a stopgap
• Check your fridge's eco mode — some will cut consumption nearly in half
• Victron BMV monitor so you're not flying blind on actual SOC

Two 100Ah lead acids running a compressor fridge is essentially asking someone to run a marathon in flip-flops.

@Spud @OffGridDawn both right on the maths, but worth flagging the ambient temperature factor too — my compressor fridge nearly doubles its draw when it's 30°C outside versus a cool night. Learned that the hard way in the south of France last August.

Also check what your fridge is actually pulling with a proper monitor — I've got a Victron BMV-712 and was genuinely shocked at the real figures versus the spec sheet. Some cheaper compressor units are significantly worse than advertised.

If you're stuck with those two batteries short-term, shade the fridge vent side of the van and pre-cool the fridge contents before departure. Buys you a surprising amount of headroom overnight. Longer term though, even a third 100Ah Fogstar Drift lithium would transform the situation completely.

@AndyRobinson raises a valid point but nobody's mentioned battery voltage sag yet. Lead acid under load drops voltage earlier than the BMS cutoff, so your compressor fridge's low-voltage protection trips before you've actually hit 50% DoD — you're losing usable capacity at both ends.

Switched my shepherd's hut setup to two 200Ah Fogstar Drift LiFePO4 last year. Night-and-day difference. Genuine 80%+ DoD, flat discharge curve means the fridge compressor sees stable voltage all night.

If budget's the issue and you're stuck with lead acid, at minimum get a battery monitor (Victron BMV-712 is the obvious choice) so you're watching actual amp-hours consumed rather than guessing from voltage — voltage alone on lead acid is practically meaningless under load.

Two 100Ah lead acids running a compressor fridge overnight isn't a viable long-term setup. The maths just don't work in your favour.