One thing we all should learn is quality of an item reviewed years if not months ago bears zero correlation to current quality of products offered today.
The bait and switch is huge with these companies, create demand with perceived quality, keep prices steady, reduce quality, increase profits.
Once the brand is tarnished and sales flatten, trash it and start over, rinse and repeat.
Many of you seem to be missing the point of this thread.
No one is going to argue that you cannot build a higher-quality DIY battery than what you can purchase off-the-shelf.
No one is going to argue that there are huge differences in OTS battery quality and price.
The reason the future of DIY LiFePO4 batteries looks bleak is that the price trend for OTS LiFePO4 battery offerings is decreasing uch faster than the price trend for LiFePO4 cells, meaning that the primary driver for building a DIY LiFePO4 battery is dissapearing.
There will always be those with special battery requirements or a need for the highest quality battery regardless of cost, as well as those who build DIY LiFePO4 batteries because it is a hobby and something they enjoy. For any of those categories of DIY LiFePO4 battery builders, the future does not look bleak at all.
But those are the exception, not the rule. For the vast majority of us who built our own LiFePO4 batteries because we saved a huge amount off money versus what it would have cost us to purchase an OTS LiFePO4 battery, that motivation and that incentive is disappearing and it’s only a matter of time before it’s primarily hobbyists and afficiianados with special requirements who are the only DIYers left.
To track progress towards that bleak future, any OTS battery price reference works equally well. Lowest-quality OTS LiFePO4 batteries on Amazon, highest-quality LiFePO4 batteries on Amazon, any relatively persistent battery offering aimed at the DIY solar community such as the EG4 battery indicate the price trend equally well.
When I started this thread 18 months ago, most were still purchasing their LiFePO4 cells from China and there weren’t really any stable cell offerings through Amazon yet. Totally different world now with a bunch of cell vendor’s shipping cells through Amazon with free shipping.
From a quick scan on Amazon, here is a representative cell offering on Amazon:
https://www.amazon.com/dp/B0BGLHD64...d2lkZ2V0TmFtZT1zcF9waG9uZV9kZXRhaWwp13NParams
$260 for 4 100Ah cells or 1280Wh = $0.23/Wh.
So I’ll start tracking a Representative Cell-offering from Amazon (RCA) as well as Cheapest Off-the-shelf from Amazon (COA), EG4 (Direct and Shipped-to-CA), SOK from Amazon:
RCA: $0.23/Wh
COA: $0.17/Wh (26% cheaper)
EG4D: $0.27/Wh (17% more)
EG4S: $0.33/Wh (43% more)
SOK: $0.40/Wh (74% more)
Especially once factoring in additional costs for BMS, cables, housing, etc… a DIY LiFePO4 is going to cost at least another ~20% in material cost (to say nothing of the value of labor or the expected cost of an accident during assembly).
So we can debate whether a DIY LiFePO4 battery is already going to cost you as much as picking up an EG4 in Texas or not, but I’d say we are safely ‘close enough for jazz.’
For reference, when I built my LiFePO4 battery in 2020, my cell cost all-in shipped from China was less than 25% of what any OTS battery would have cost me…
So let’s wave our hands and say that OTS LiFePO4 batteries have dropped in price by 75% over 3 years relative to the market price of LiFePO4 cells over that same period (and to be clear, the grey-market cells available from Chinese resellers in the early days likely did not have the same quality as cell offerings through Amazon today, so it is not a direct Apples-to-Apples comparison).
That remarkable trend has certainly slowed way down but is continuing.
So while today there may be some who would say: ‘EG4 does not deliver the quality I need and I can save 74% by building an SOK-quality DIY battery from cells myself’, by tomorrow (whether 6 months from now or 12 months from now or 2 years from now…) we are going to see SOK batteries priced at only 20% more than the cost of LiFePO4 cells on Amazon (or SOK will go out of business).
Again, those motivated by special requirements of love of the hobby have a bright future building DIY LiFePO4 batteries. It is the future of those like me who just need basic storage capacity at a cost approaching what we’d get by using lead-acid batteries who will see less and less reason to dive into the world of building our own LiFePO4 batteries from cells.
Personally, an EG4 battery would suit my needs perfectly and I would jump on one of those for a 25% premium over the cost of cells in a heartbeat rather than build another DIY LiFePO4 battery from cells, so I am done with this ‘hobby’.
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