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Joined 2 years ago
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Cake day: July 24th, 2023

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  • Extended family “IT Guy” here. Have replaced 30ish laptops batteries. The cheap ones on Amazon/eBay you have a ~30% chance of them being DOA, and 99% chance of them being dead within a year.

    “Brands” like Duracell GreenCell I’ve had better luck with but I’ve been sent batteries from GreenCell which only lasted a year because they were sitting on a shelf for 3 years before they were sent to me.

    OEM batteries tend to last longer than the originals as most BIOSs from Dell, Lenovo etc. now include battery optimisation which extends the life of cells.

    It all come down to what you need, and how much you value your time compared to money. My personal stuff I always go OEM as I rarely replace my laptops. Current one from 2015 is still going strong. If you are willing to put up with returns and rapid replacements a £20 cheapie can look good when the OEM is £100

    EDIT: Sorry just re-read your question. The OEM at 75% health is dead already. The cheap no-name ones are probably just random used cells thrown together.

    You’d probably be better off with the no-name but for this use case just get the cheapest thing with a 1year warranty and cross your fingers.












  • With current technology yes it’s impossible, although those doughnut motors are next level, so you are spot on with tweaking the definition of efficiency. Things we can do now are as you mentioned wind resistance, Lucid have achieved over 5mi/kWh in a large luxury vehicle focusing on that.

    You can focus on rolling resistance of the tyres, or my making an ultra-efficient smooth self-driving system.

    Next is weight, making the car and batteries as light as possible. Although this would reduce the regenerative braking, the inefficiencies in that system would also be reduced.

    Ancillary power, most cars have reasonably efficient heat-pump and electrical systems but shaving a few milliwatts from each system and cutting out a few truly unneeded systems will cut down on wasted power and weight. I like the Ami and it’s, ‘you already have a screen, entertainment system, and sat nav on your phone’ philosophy.

    Now we get to the tweaking of the efficiency definition… how about we say you can have as many kWh as you like as long as it’s no bigger and no heavier than the origin leaf 22kWh pack?

    Maybe adding solar or other micro-generation with an assumption on % of day/night driving and average power achieved by micro generation.