Had a proper nightmare with this a few years back on the narrowboat. Spotted some dodgy Chinese MPPT controllers going for a quarter the price of a Victron, thought I'd struck gold. Lasted exactly fourteen months before the thing stopped charging mid-winter. Turns out the internal components were undersized – it was literally melting itself from the inside.
Cost me a fortune in the end because the battery bank had discharged too far by the time I realised what was happening. Killed two cells trying to revive it. Would've been cheaper to buy the Victron outright, plus I'd still have a working unit now, five years on.
The thing is, on off-grid living you're paying for reliability, not just the hardware. When your system fails in December and you're without power, that's not just an inconvenience – it's genuinely dangerous. A proper Fogstar or Renogy unit might cost more upfront, but you're buying peace of mind and longevity.
That said, I'm not saying you need premium everything. Battery terminals, cabling, breakers – those are places worth buying decent quality because they're critical safety points. But controllers, inverters, charge regulators? Those are your lifeline. Skimp there and you're asking for trouble.
What's everyone else's experience been? Has anyone actually found a genuinely good budget option that didn't bite them, or are we all just learning expensive lessons?