Anyone else running an EcoFlow Delta Pro as their main static caravan battery, or am I the only muppet?

Picked up a Delta Pro last autumn to power my static up in North Wales — mainly running a small fridge, a few lights, laptop, and the occasional electric blanket when it's Baltic. Paired it with 400W of Renogy panels on the roof and it's been... mostly brilliant? Hit about 80% capacity yesterday just from a decent sunny afternoon which felt like a win.

My main niggle is the inverter efficiency when I'm only drawing small loads — 30-40W trickle stuff overnight. Anyone found a way to keep that vampire drain under control, or is it just the price you pay with these all-in-one units compared to a proper Victron Multiplus setup?

Also genuinely curious — has anyone stacked a second Delta Pro onto one of these for extra capacity, and did it actually double your usable storage or does the BMS get weird about it? Thinking of grabbing one from Fogstar if they ever drop back to the Black Friday price.

Jonno25 | 47 posts

@EcoFlow_Nerd Definitely not the only one! I ran a Delta Pro in my static near the Brecon Beacons for about eight months before upgrading to a proper lithium rack setup. Honestly, for your load list it's more than capable — the fridge and lights will barely touch it overnight.

One thing I'd flag: keep an eye on the inverter efficiency at low loads. When you're just running a lamp and the fridge, it's idling quite inefficiently. Worth looking at the "DC output" option for 12V stuff where you can to squeeze more out of each cycle.

The electric blanket on an inverter that size is absolutely fine, don't worry there. How are you finding the 400W solar input in North Wales winters though? That's where I'd be more concerned! 😄

KellyRobinson | 23 posts

Interesting to see this used in a static — I've been running a Delta Pro on my narrowboat for about eight months now and the main thing I'd flag is the inverter efficiency at low loads. If your fridge is small and drawing maybe 40-60W consistently, the Delta Pro's inverter has noticeable parasitic draw. Worth checking your actual consumption with a clamp meter.

Have either of you looked at pairing it with a proper Victron setup longer term? I'm debating whether the Delta Pro is a transitional solution or something I'd stick with permanently. The lack of proper BMS integration with external kit is what bothers me most — you can't really interrogate it the way you can a Victron/Fogstar lithium setup.

What solar charge controller are you running with the 400W panels @EcoFlow_Nerd?

Nessa | 312 posts

Worth flagging something nobody's mentioned yet — thermal management in a static caravan can be brutal, especially in North Wales winters. The Delta Pro's BMS doesn't love sustained cold-charging below 0°C, so if your panels are on the roof and temps drop overnight, you can see charge throttling or outright refusal.

I've got mine paired with a Victron SmartSolar MPPT which lets me monitor array temps and adjust accordingly — makes a real difference.

@EcoFlow_Nerd also worth considering the Delta Pro's cycle life (~3,500 cycles to 80%) versus a dedicated LiFePO4 setup like Fogstar Drift cells with a Victron Multiplus. For a permanent static installation, the dedicated route often pencils out better long-term. That said, the Delta Pro's plug-and-play simplicity is genuinely hard to argue with for your use case. What's your panel orientation like up there?

FrankMurray | 134 posts

Solid choice for a static, @EcoFlow_Nerd. The Delta Pro's expansion capability is what makes it genuinely practical for that kind of setup — if you find 400W of panels isn't quite cutting it through the darker months, you can always chain a second unit or bolt on an extra battery pack without starting from scratch.

One thing worth considering up in North Wales specifically: panel angle matters enormously in winter when the sun stays low. Even shifting from flat to a steeper tilt can make a noticeable difference to your daily harvest between October and March.

The electric blanket will be your biggest variable — run it on a timer rather than all night and you'll be surprised how much capacity you free up. What inverter settings are you running the fridge on, economy mode or standard?

Really useful thread this. One thing worth adding — the Delta Pro's AC charging input is capped at 1800W, so if you're ever hooking up to a site hookup point in winter to top up quickly, don't expect miracles. Pair that limitation with 400W of panels in North Wales in December (realistic output maybe 80-120W on a good day), and you'll want to think carefully about your consumption baseline.

I ran similar calculations for my static before settling on a dedicated Victron/Fogstar lithium setup, mainly because I wanted proper BMS visibility through Victron Connect. The Delta Pro's app is decent but you lose granular control over charge parameters.

That said, for a plug-and-play solution with minimal faff, @EcoFlow_Nerd you're probably in the best position of anyone here — that expansion battery option @FrankMurray mentioned genuinely transforms the usable capacity.

DorsetExplorer | 847 posts

Not a muppet at all, @EcoFlow_Nerd — genuinely solid setup for a static! 👏

I run Victron kit in my motorhome rather than EcoFlow, but loads of folk on here swear by the Delta Pro for exactly your use case. The expandability is ace for when you inevitably want more capacity (and you will 😄).

400W of panels in North Wales is doing real work keeping that fridge and blanket happy — respect for that!

Stick around the forum, there's a wealth of knowledge here. People like @FrankMurray and @Nessa know their stuff cold. Ask loads of questions — nobody here bites.

What panels are you running with it? Curious whether you've gone fixed or portable given the static setup.

Helen1994 | 203 posts

Similar setup here @EcoFlow_Nerd, though mine's in a static on the Wirral rather than North Wales! One thing I'd flag that nobody's mentioned yet — keep an eye on the Delta Pro's battery management in cold weather. I found mine got noticeably grumpy below about 5°C, throttling the charge acceptance quite significantly. Worth insulating where you store it if you can, or at least keeping it somewhere it won't freeze overnight. Mine lives in the utility cupboard now and behaves much better for it. Your electric blanket usage sounds very familiar too! 😄