Is rapid charging bad for your car? Learn about battery C-Rate [video] (opens in new tab)

(foxev.io)

3 pointsjanosch_1231y ago6 comments

6 comments

5 comments · 2 top-level

janosch_123OP1y ago· 2 in thread

If you are interested in batteries, the C-rate should interest you. I build my own electric cars, and am now condensing important theory into these 3min - 5min videos. This one is about the c-rate for batteries. Big auto and battery manufacturers like AESC, CATL, BYD and Panasonic spend a lot of time optimising their batteries, and carefully determining the so called C-Rate. In one sentence: It measures the rate at which a battery can be charged or discharged, relative to its capacity.

I make these videos so it can help someone not ruin expensive equipment (like I have done!) and still get the knowledge.

Additionally I am working on "duolingo, but for learning ev tech" and made a little hello world quiz. Answer 10 questions and then get a little breakdown where you are strong and where you are weak: https://foxev.io/academy/

Given that this is HN I expect everyone to be strongest with "Software".

I hope this helps someone, sorry about the influencer glasses, and I am aiming to make as many of these videos as possible to break down complicated and sometimes misrepresented facts as easy as I can, with exactly one concept per video :)

stavros1y ago

This is interesting, thanks! I tried your quiz, and it really isn't obvious whether you got an answer right or not, it just turns blue and it left me wondering. Also, you say that electric vehicles are always more efficient than petrol, but I doubt that's true. It feels like it should be less efficient to put a liter of petrol into a generator, charge a battery with it, then use that battery to move a car, than to just move the car directly. If you mean something else, you're comparing apples to oranges and the question should be reworded.

janosch_123OP1y ago

Thank you for your feedback. I will make the highlighting more obvious, that's easy.

For the questions, maybe I should show supporting sources when the user gave a wrong answer because that's where the learning happens!

For the specific question: if you start with a liter of petrol then yes, burning that to drive the car strikes me as more efficient, like you said (would need to do the maths). You will only be able to use about 30% of the energy as motion, the rest is released as waste heat.

You don't have to start with petrol though, if you start with energy from hydro/nuclear, the same amount of energy will drive an EV further, this is going back to kJ in fuel and kWh in batteries. Maybe I this is a whole new video.

If I can bounce some ideas off you going forward maybe sign up or email me, thank you for taking the time to help.

1 more reply

tubroo51y ago· 1 in thread

The slow charge = longer life axiom is directly contradicted by this Stanford study on EV batteries:

https://news.stanford.edu/stories/2024/12/existing-ev-batter...

yjftsjthsd-h1y ago

Is it? That seems to say that discharging in short bursts is surprisingly good, but I didn't see anything about charging

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