Anyone else using their solar setup as a home emergency backup — what's your minimum viable system?

Been thinking about this a lot lately. With all the grid instability chat going on, I've started looking at my existing solar bits differently — less "nice to have" and more "what if the power goes out for 3+ days." Currently running a 400W panel feeding a Victron SmartSolar 100/30 into a 200Ah Fogstar Drift lithium. Enough to keep lights, phone charging, and a 12V fridge ticking over, but I'm wondering if it's actually enough for a genuine emergency.

The bit I keep coming back to is heating. The fridge and lights are sorted, but if it's January and the grid goes down for a week, I'm not going to be very popular with the family. Has anyone integrated something like a diesel heater (Webasto or even a cheap Chinese unit) into their backup thinking? The draw isn't huge but it all adds up on a grey week with limited solar.

What's the bare minimum you'd want — panel wattage, battery capacity, essentials list — to feel genuinely comfortable for a 5–7 day outage in winter?

Dizzy75 | 847 posts | ⭐ Regular

Great thread @PVKing. For me the minimum viable setup came down to three non-negotiables: keeping the fridge cold, charging phones/comms devices, and running a few LED lights after dark.

I've got a modest 400W panel feeding a 200Ah LiFePO4 battery through a Victron MPPT, and honestly that covers those basics comfortably even through a grey November week. The fridge surprised me — it draws far less than I expected averaged over 24 hours.

One thing I'd add that people overlook is the inverter side. Running critical loads directly on 12V where possible massively reduces losses compared to constantly converting to 240V AC.

What's your current storage capacity looking like? That's usually the bottleneck people hit before generation becomes the issue.

PikeAndrea | 312 posts | ⭐ Member

Good shout @PVKing. One thing I'd add that doesn't get mentioned enough — communication. During a prolonged outage your phone becomes absolutely critical, yet it's often an afterthought in these minimum viable conversations.

Even a modest 100W panel with a small LiFePO4 battery (I'm running a 100Ah) will comfortably keep phones, a DAB/FM radio, and a small 12V router ticking over indefinitely. That last one matters if your ISP stays up even when the grid doesn't — which surprisingly often happens here.

The radio specifically is underrated. If mobile networks get congested, BBC local radio on battery power is still how emergency information actually reaches people.

So I'd say: don't just plan for creature comforts or fridges — plan for situational awareness first. Everything else is secondary.

BurnShaun | 1,203 posts | ⭐ Senior Member

Great thread. Something I'd flag that's often overlooked — water. If you're on a mains pressure system, your pump stops when the grid does. I run a small gravity header tank kept topped up by a 12V pump on a timer, powered off a dedicated 100Ah LiFePO4. Costs almost nothing to run normally but means we've got flushing and basic washing sorted indefinitely.

Also worth thinking about your inverter's idle draw. Some cheaper units bleed 20-30W just sitting there — over a 3-day outage that's genuinely significant if you're running a modest battery bank. @Dizzy75 touched on priorities which resonates — knowing what you actually need versus what feels essential is half the battle. Do that audit before you spend anything.

OllieRoss74 | 589 posts | ⭐ Regular

Running my shepherd's hut full-time off-grid gave me an accidental masterclass in this. When everything went in, I had to decide what actually matters when the grid disappears.

For me it boiled down to: lighting, phone charging, and a 12V fan for the wood burner's back boiler circulation pump. That's genuinely it.

My Victron SmartSolar paired with a modest Fogstar Drift 100Ah lithium handles those loads comfortably through two overcast days without breaking a sweat. The entire system cost less than a decent generator and runs silently.

@BurnShaun makes a brilliant point about water — something I learned the hard way when my pump tripped off mid-February.

The psychological comfort of knowing you've got enough rather than everything is honestly underrated. Minimum viable isn't a compromise — it's clarity about priorities.

ExChippie30 | 847 posts | ⭐ Regular

Coming at this from a tiny house angle — my minimum viable ended up being:

• 400W panels
• Fogstar 200Ah LiFePO4
• Victron MultiPlus 500W (small but handles the essentials)

Honestly the EV angle is underrated here too. My Zoe sitting outside is basically a giant battery I can trickle charge the house bank from if needed. Not everyone has that option but worth mentioning.

The thing that changed my thinking was asking what do I actually need vs what am I used to. Fridge, phone charging, a lamp — sorted. Kettle and TV? Luxury.

@OllieRoss74 is right about the accidental masterclass thing. Living small forces good habits before any emergency does.