Some additional info and thoughts:
Total cost is $287 not as cheap as I originally thought but still not bad for LTO Battery, with 322Wh usable capacity and with up to 200W charge rate, including in sub-freezing temperatures.
Plus lots of fun designing, building and testing it.
Plus no need to submit ticket to manufacturer if something goes wrong, because I am the "manufacturer", and I can fix it on the fly –
priceless!
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All high power wires in Battery pack are 12AWG, and they are quite difficult to work with, I believe for such a short wires 14AWG would be fine, especially if limit the max current to say 15A and 14AWG wires are much easier to work with.
I also believe now that 6S configuration is better way to go, it works with buck-boost charger and the standard hardwire kit.
All components except BMS are from Amazon, getting them from Aliexpress could considerably reduce the total price.
Building a battery pack for a specific system setup (removing the versatility) will further reduce the overall price by removing certain unnecessary components, such as the 2x5V buck converters and associated switches/connectors if only 12V output is required.
And finally, if the battery size is a concern because the need to hide it, for example, under a seat or in a hidden trunk compartment, then smaller capacity LTO cells may be used or a 4S configuration battery can be built.
That is exactly what I did for my wife’s battery pack and will soon post few videos to show the build process.
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I missed this one in my previous post:
Cigarette Lighter Power Cord - Heavy-Duty 14AWG 20A Male Plug 6ft/1.9m
https://www.amazon.com/gp/B08GFRB8VP