Sorry just to go off-topic a bit, cost and ease of using repurposed OEM packs aside, why would you say that LiFePO4 is "nothing but problems"?
The chemistry is delicate in odd ways (can't charge when cold or it's instant death).
But mostly, they're low volume production runs (are DIY EVs their primary market?) that are all plagued with quality problems.
Someone (Duncan?) this last year pointed out an observation, that they can't recall a single LFP build that didn't have at least one cell fail on them at some point. Meanwhile, they couldn't recall a single example of an OEM cell that had failed (other than 1st gen Nissan Leaf cells that got degraded and ruined before time of purchase).
There couldn't be a broader spectrum of quality than every car fails vs. no cars ever failed, to make the LFP vs. OEM Lithium a clear result. Even if that's not technically true (there must be examples of both), it's at least overwhelmingly generally true.
LFP are also far, far more expensive. And lower energy density.
...
The only reason to use LFPs is if you need a high voltage but small pack. OEM cells are generally only 1p, 2p at best, so they're large form factor built for the their host car. You can't chop them in half and have a pack half the size, and you probably can't fit them in a vehicle that wasn't optimized for them (or them for it). Your building blocks are too large to stuff enough series into your build.
But generally that's not an issue because you can run lower voltage just fine, no one needs a car that's still accelerating at 90mph.
I don't think I want to roll my own controller I plan on being busy doing plenty of other things.
There's no rolling your own controller.
It's pretty much plug and play for most models.
His Nissan Leaf adapter board you don't even need to take apart the case.
The Prius Gen3 replacement board is a finished product, you unscrew the original, screw the new one down into the same screw holes, plug the wires back in, done. Built in charger too.
The Lexus, I think the same.
The Prius Gen2 is all through-hole, easy-beginner soldering, but it will soon be replaced with a finished board (Johannes is actually designing a finished board on that one based on his inverter hardware, not the various shortcuts Damien made so that it was beginner kit-friendly).
The Gen2 also has a ~100A DC-DC stepdown converter that you enable with a single switch (ignition). No need to even access the rest of the inverter or replace its brains or even use it as an inverter to turn it on. Couldn't be easier. Even just that alone is a ridiculously cheap 1200w DC-DC converter ($150 inverter), if bulky.
Things are changing pretty quickly. Even the stuff Damien was working on a year ago is obsolete in the new meta. OEM inverters are clearly, clearly the way to go. Nothing else is even comparable.
And, the Open Inverter hardware boards are what almost every single EV shop is using as their engineered solution... usually uncredited because it's open source and they copied the design and threw their own logo on it.