Don't Fast Charge your Phone before Watching this Video!

You should continue this experiment maybe a about 300 or 600 or why not 1000 charge cycles, because most people keep their phones around 2-3 years. Then we could see the drop in real life

Would've been nice to see how limiting the max charge to 85% would've affected it since that is adviced for lithium batteries to increase the life span

Interesting study! Only one thing that had to be considered is that the fast charging current is in most cases reduced towards high state of charge. For example charging usually would start with 5A, then maybe 4A at 50% SoC, 3A at 70% and so on. Taking this into account should change a lot. If you additionally limit charging at let’s say 80-90% SoC, I would assume that you measure only minor lifetime difference vs 1A continuous 👍

For the inevitable longer experiment, check heat levels too. I’ve heard (and it feels true) that most of the battery damage comes from the heat caused by faster charging

As an electrical engineer at the start of my career, I can imagine some of the pains you had to go through for this video. Thanks for doing all this for the sake of free education!

Would be nice to use this circuit to also simulate leaving batteries at 100% charge versus 80-90% charge, as some phones now have the option to set a charging capacity limit.

I think it's what most of us expected. I would be interested to see the results comparing the slow and fast charging over many more cycles to show a more realistic phone ownership duration of 3 years.

I work in a battery lab. And i do these measurements. The real information comes from trendlines while charging and discharging. Meaning you have to log all the voltage readings ( 1sec interval). The degredation shows in how the voltage behaves during charge /discharge cycle. To really know the batterys internal stage we measure something called EIS (Elecrochemical Impedance Spectroscopy). That gives good knowlense about the chemichals inside the battery. A EIS measure system would actually be a good electronics project noe that I think of it :)

Interesting video and results! However, I wanna add a thought from my usage pattern. Because fast-charging has significantly changed how I charge my phone. I think we all remember the early smartphone days where you had to charge your phone overnight. That also meant in probably spent a significant amount of time at 100%. For me, that meant I usually significantly drained my battery over the day (near 0%) and then charged it to 100% overnight. Nowadays with fast charging, at least for me, I don't charge overnight any more. I just plug in for half an hour here and half an hour there whenever I go below 20%/30%. And that means that my phone battery (most of the time) stays between 20% and 80% charge, basically never sitting at 100% or being drained to 0%. And from my understanding, modern Li-ion batteries really enjoy being in that 20-80% range instead of being pegged at 100% for hours on end. Maybe that would be something to also consider!

It would be very interesting to see this experiment over the long-term (~12 months or so) with included data for the increased internal resistance measurements over this period (which is probably largest contributing factor to increased capacity degradation over time which increases with respect to higher charge and discharge rates).

Wow. Amazing work. Please continue documenting charges over time (every 100 charge cycles) to track that sliding scale... would be really interesting to see how bad it gets over time. You have build something that is very practical! Great job! Love your videos!

I've not seen a video of yours for years and I'm surprised to see you in front of the camera, and also almost 2 million subscribers! Awesome progress, very proud of you 😊

Hi! Really nice content as always! I would just like to point out that the ageing behaviour of lithium batteries is linear only after a first period of "chemical balancing" inside the cells (which induces a streep drop in capacity). This means that in the first hundred of cycles, the capacity could degrade by even 5%, but then it would stabilize to a much lower (constant) degradation per cycle value.

Very interesting video. Hopefully you let it run for an additional 250 cycles to simulate a year en see if it behavior is linear, exponentially or other. Thanks for sharing!

I like your design for charging and discharging circuit. Although I would recommend using a single atmega328p to achieve 6 charge CV (4.35v) and 6 discharge (1A) using PWM and PFM techniques. The 6 analog pins can be multiplexed for additional 6 analog pins. The voltage and current(need op-amps) sensing can used to detect current and voltage for 6 separate batteries. This can make a single device that can charge and discharge individual cells. This would make the design simpler but it could come at a cost of extensive programing, and manual testing, instead of the purpose built IC. But awesome content and great info on testing batteries. Oh yeah, one more thing, the battery quality and chemistry might be different in commercial phones. Need to test broken phones and test against them.

Awesome that you actually did these tests. I love this video. Agree with some others asking for greater cycle counts, to maybe even see that degradation curve. More importantly for the readers, what he did was tiny compared to what damage some of y'all will inflict. Using your phone while charging(simultaneous charge/discharge), "topping" it off when at 80%, not fully charging before pulling it, etc..

I've always heard that the best way to preserve the battery is to keep the charge between 20-80%. I've often wondered if fast charging when you wake up is better than slow charging overnight. I would be interested to see another test done where you maybe compare fast charging between 20-80% cycles to slow charging cycles where the battery spends 7 hours at 100% per cycle.

Hearing that 3.55V is considered 0% makes me feel a lot better about all the times I let my phone discharge to stone dead flat - even with the slightly higher chemistry that shouldn't be too bad for the battery, and explains why my battery isn't completely dead lol

Great work. I can imagine how much work you put into this. I have wondered about the effect of fast charging and you did a great job of showing the effects. Thank you.

Great video as always! Anytime you post a video, I make sure to watch the whole thing through. One of the best on YT for sure.