Source of small LiFePO4 cells?

Hardware diyBMS
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Does anyone know a UK supplier of small ‘raw’ LiFePO4 cells?

I am thinking about making a 48v LiFePO4 pack to power a few low voltage electronic devices that are always-on in my house. I am on Octopus Agile, so it would be good to be able to power them reliably for long periods of higher energy prices.

But the smallest prismatic cells I can find seem to be 3.2v / 280 Ah, which is massive and too expensive for my needs. And the best cylindrical cells I could find are too expensive:

(that works out at about £800 per kWh!)

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Hey Nicolas, I order mine from china slim pickings in the UK, and the USA

Gotion has a set of cylindrical cells that are reasonable and available

I’ll post some pricing and a contact person you can buy from shortly and see if that gets you what you’re after

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https://docs.google.com/file/d/14WfSvV4Mm66WNJzz3VOTFWpiFrCbsZwa/edit?usp=docslist_api&filetype=msexcel

See if any of those are good, these are prices in china so still need to add shipping and tariffs if applicable

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Yeah, finding small Coremax LiFePO4 cells in the UK is pretty hard these days. Most sellers have pretty much moved to the big prismatic stuff — 280Ah, 304Ah, 320Ah, 300Ah, etc. Anything smaller is either crazy overpriced or just not stocked.

I was looking for the same thing not long ago because I wanted a small 48V pack for some always-on devices (also on Octopus Agile, so I get the idea). But yeah… the smallest “real” prismatic cells I could find were 3.2V 300Ah, which is waaay more capacity and cost than I needed too.

Honestly, unless you really want to build it from scratch, it might be cheaper to just buy a prebuilt 48V battery. I came across an EGbatt 48V 300Ah LiFePO4 pack for about $1480, which surprised me because the price per kWh is stupidly low. By the time you buy cells + BMS + case + busbars + shipping, a DIY pack can easily cost more.

So yeah — small loose cells in the UK? Pretty much unicorns.
But grabbing a complete 48V pack might be the easiest (and weirdly cheaper) route if you just want something to run small loads during high Agile prices.

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What I decided to do in the end was to get an Eco-worthy 24V 100Ah LiFePO4 Lithium battery pack - with built-in BMS in the January 2025 sales for £308.

I am running some things like my home server off it directly (which has a wide voltage input DC-DC converter). And then have a 12v DC-DC converter for other small devices. I am then also powering a PoE network switch off it, which I am using a 24v → 48v DC-DC converter to bring it up to the right voltage. I also have a USB-C adaptor, that works with 24v. So 24v has worked out quite well as an in-between voltage.

I have a couple of solar panels connected to a Victron MPPT, to charge the battery during the day. And then a Victron 24v charger, which tops the battery up using cheap electricity overnight, when there isn’t enough sun. And it is of course all tracked using EmonCMS :heart:

It was really cool to be able to play with some of this technology without spending thousands. And all working really well - need to write a blog post about it!