Inverter died mid-winter - what's a decent temporary fix while I wait for parts?

Had this exact nightmare last February on the boat — Victron Multiplus gave up the ghost right in the middle of a cold snap and I was stuck at a rural mooring with no shore power hookup.

What got me through was a cheap 1000W pure sine inverter from Amazon (think it was a Giandel). Not elegant, but it ran the kettle and kept the 12V fridge ticking over while I waited on parts. The key thing I'd say is don't bother with modified sine wave even as a temp fix — had a modified sine unit years ago and it did weird things to anything with a motor or switching power supply.

A few things worth considering for a stopgap:

• How long are you waiting? If it's just a week, a small portable unit is fine
• What loads actually matter? On the narrowboat I stripped back to absolute essentials — kettle, phone charging, one light via 12V direct
• Battery state — running a temp inverter with no charge management is a risk if your alternator isn't keeping up

Anyone used one of those Renogy portable power stations as a bridge solution? I've seen a few people recommend them for exactly this kind of situation and they've got their own BMS built in which seems tidier.

Also — what actually failed on yours? Multiplus? Victron Quattro? Curious whether it's worth sourcing second-hand as a longer-term backup unit rather than waiting on new parts.

@DodgyCaptain been there on the cabin side of things. Grabbed a cheap Giandel pure sine from Amazon as a stopgap — not glamorous but it ran the essentials for a few weeks while waiting on parts.

Worth checking if any nearby marina or site has a spare they'd loan out too. People are usually decent about it in a pinch.

One thing I'd say — don't bother with modified sine wave even as a temp fix if you've got anything sensitive. Learnt that the hard way with a battery charger that didn't appreciate it at all.

@Fogstar_Fan the Giandel route works but worth flagging — check your battery bank voltage carefully before just plugging any cheap inverter in. A lot of those units have woefully loose low-voltage cutoffs and will happily drag your cells down past safe limits before tripping.

For a boat situation specifically @DodgyCaptain, if you've got a decent alternator setup, a quality DC-DC charger keeping a small 12V auxiliary bank topped up for critical loads (lighting, heating controls, phone charging) will see you through whilst the Multiplus is away for repair. I ran something similar when my shepherd's hut inverter went — kept a Victron Orion-Tr Smart feeding a separate 100Ah Fogstar Drift LiFePO4 purely for essentials.

Also — what actually failed on the Multiplus? Nine times out of ten it's the transfer switch relay or a blown fuse rather than the inverter board itself. Much cheaper fix.

Good shout from @SolarNotSure on the voltage check — caught me out once on the narrowboat when I nearly plugged a 12V inverter into what was actually configured as a 24V bank after some rewiring. Embarrassing and expensive near-miss.

One thing nobody's mentioned yet: if you're at a rural mooring and the repair wait is going to be more than a few days, it's worth ringing around local chandleries rather than waiting on Amazon. Found a decent secondhand Victron Phoenix at a boatyard near me once — proper pure sine, handled the induction hob without complaint while I waited on warranty parts.

Also — generator + battery charger combo as absolute last resort. Not elegant but keeps you warm and charges the bank overnight. Did exactly that for a week last January on the static. Noisy but saved me.

Really feel this one @DodgyCaptain — I've been paranoid about this exact scenario ever since I started relying more heavily on my setup for EV charging overnight on the narrowboat.

One thing nobody's mentioned yet — have you considered a decent UPS unit as a bridging solution? Something like an APC Back-UPS can run light loads (heating controls, phone charging, basic lighting) while you wait for the Victron parts. Obviously not going to power a kettle, but it kept my critical stuff ticking over during a similar gap last winter.

Also worth checking if your Victron dealer has a loan/demo unit scheme — some UK distributors do this, especially for live-aboard situations. Might be worth a phone call before spending money on a stopgap you'll only use once?