Anyone else running a cheap 100Ah lithium on a budget solar setup — how are you getting on long-term?

Picked up a no-name 100Ah LiFePO4 from a seller on eBay about eight months ago — paid £89 delivered, which felt almost too good to be true. Paired it with a 175W panel off a Facebook Marketplace job lot and a Renogy Wanderer 30A PWM controller I already had kicking about. Total spend was probably £140 all in. It runs my lights, a 12V compressor fridge, and charges phones/laptops in my Transit conversion.

Honestly, the battery has surprised me. BMS seems to cut in correctly, resting voltage looks right, and I haven't noticed any worrying capacity drop yet. That said, I've got no way to actually verify the true capacity — I don't own a proper battery tester, so I'm going a bit on feel and watching how long the fridge runs overnight.

My main worry is longevity. I've read a fair bit about dodgy cells being mismatched or having inflated capacity labels, and I'm aware I might just be getting lucky so far. Winter's been the real test — we've had a few grey weeks in a row here in the East Midlands and I've had to be careful not to pull it too low.

Has anyone else been running budget lithiums for a year or more? Did they hold up, or did you end up wishing you'd saved up for a Battleborn or a decent Fogstar? Curious whether the gamble tends to pay off or bite you eventually.

@BatteryDoug £89 for a LiFePO4 is either a bargain or a ticking drama — my shepherd's hut taught me that lesson when a suspiciously cheap cell decided to celebrate New Year with its own fireworks display.

@BatteryDoug eight months in is roughly when mine started pretending it was still 100Ah whilst quietly only delivering about 60 — like a politician, all the promises, none of the capacity.

Great thread this. I'm about 14 months into a similar setup — picked up a cheap 100Ah from AliExpress rather than eBay, so similar territory.

One thing worth doing @BatteryDoug is a proper capacity test if you haven't already. Charge it fully, then discharge through a known load and time it. Mine claimed 100Ah on the label but actual usable capacity tested out closer to 78Ah from day one. Still functional, still running my shed setup fine, but knowing the real number means I plan accordingly rather than getting caught out.

@Taffy42 makes a fair point about that eight-month window — worth logging your actual resting voltages after a full charge. If you're seeing anything below 13.5V on a "full" charge with an LFP that's a BMS conversation worth having before it becomes a replacement conversation.