Power Systems and Battery Chemistries Used in Electric Vehicles

[Andy-Mat]

This may prove interesting to any Techies here:-

Taken from here:-

All About circuits. A website that I myself find very informative and interesting at the same time!

Power Systems and Battery Chemistries Used in Electric Vehicles

I was particularly impressed with the following sentence from the article, that I have thought about as being possible, but apparently its more true than even I believed! I do believe many here may be "suffering" from such bad quality batteries!

I myself built an electric bike with a nominal 840Wh battery made of 18650 cells. Annoyingly I’m somewhat concerned that the cells are factory rejects that were resold under false pretenses. It certainly makes some sense of the price even though I ordered straight from China.
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I, too, built a 700 Wh electric bike battery but used Panasonic NCR18650B cells (same cells used in the Tesla Model 3 cars) that I acquired new at high cost from a Swedish source rather than risking used batteries from China. The Chinese gov’t really should crack down on their country’s happy selling of rebranded factory rejects as that really hurts their reputation around the world. The bike gets a consistent 30 mile range in level terrain depending on how much pedaling I do.

I hope many of you enjoy the article.
regards
Andy

 

[Woosh]

have you thought of testing the capacity of your battery?
it is simple to do and will put your mind at rest.

 

[wheeliepete]

The problem is that not all Chinese cells are bad, but if you buy a cheap battery pack made with unspecified cells, you have no way of knowing. It's quite interesting that in the 2nd paragragh the person sounds like he has done some research, but has still not chosen very wisely with his cell sellection. If he made his decision based on the fact that if Tesla use them in their cars, they must be fine for my bike, he has failed to realise that car packs are made up of 1000's of cells and your av. 36v bike only has 40. The cell he chose has a max. 6.7 amp discharge rate, so is working pretty hard on his bike and is likely to loose capacity fairly quickly, which goes to show that even top branded cells are not all equal.

 

[flecc]

If he made his decision based on the fact that if Tesla use them in their cars, they must be fine for my bike, he has failed to realise that car packs are made up of 1000's of cells and your av. 36v bike only has 40. The cell he chose has a max. 6.7 amp discharge rate, so is working pretty hard on his bike and is likely to loose capacity fairly quickly, which goes to show that even top branded cells are not all equal.

The cells in e-car batteries can have a surprisingly easy time, hence such as 8 year warranties. My 2018 Leaf with it's 40 kWh battery driven in the congested south east is most of the time just taking a trickle from the battery. That's in stark contrast to my e-bikes batteries which have worked so hard so they've struggled to reach a two year life on the most powerful bikes.
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[Nealh]

Spot on there WP, people don't think about it enough.
Cars have the advantage of a large floor area for 1000's of cells, the parallels alone are a huge number compared to e-bikes that often only have 4 or 5.