Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

BMW EV achieves 1000km in range using Dual-Chemistry batteries

forbes.com

Post reply on HN
Print view View original

21–30 of 92 posts

Re: BMW EV achieves 1000km in range using Dual-Chemistry batteries

#21

Post by prmoustache »

marcosdumay wrote: post #6
russfink wrote: post #2

How do the charging times compare? That’s the deal maker/breaker for long road trips greater than 500 miles, or shorter trips where you use all the accessories, encounter lots of hills, etc not possible on a dynamometer.

Well, I really think 500 miles is too high of a lower bound, but when you reach 1000 km, it stops mattering again. This is about how long you can travel before stopping to rest.

At this kind of mileage in a day you just really need to question your decision making skills if you are living in a country with a decent railway network.

However that is nice because it means you can do 3 300 miles trips and only charge at home when the price is right. That is the most relevant part to me.

One thing is article doesn't mention is the average speed. I looked at a few EV in the constructors websites and most range in the spec were calculated at ~30kph. This is my average speed in the flat on a bicycle when not even riding hard! While it is pertinent in an urban context where average speed is not much higher it isn't when we are discussing long trips.

Re: BMW EV achieves 1000km in range using Dual-Chemistry batteries

#23

Post by keenmaster »

wongarsu wrote: post #17
keenmaster wrote: post #9

Earlier quoted context omitted.

You need more LFP to carry the weight of the manganese battery though (increasing cost), and all the extra weight can affect driving dynamics. Maybe both the cost and weight increase are minimal but that’s what came to mind. It’s a great idea though.

Yes, to get more range you need more batteries, and those increase your weight meaning you need more batteries. But those increase your weight, so you need even more batteries. The tyranny of the rocket equation. Not really specific to this dual-chemistry though, the same holds true for normal EVs and for gasoline-powered cars.

True, but the difference here is that the second battery isn’t even used most of the time, and if it was it would die quickly.

Re: BMW EV achieves 1000km in range using Dual-Chemistry batteries

#24

Post by _ea1k »

wongarsu wrote: post #17
keenmaster wrote: post #9

Earlier quoted context omitted.

You need more LFP to carry the weight of the manganese battery though (increasing cost), and all the extra weight can affect driving dynamics. Maybe both the cost and weight increase are minimal but that’s what came to mind. It’s a great idea though.

Yes, to get more range you need more batteries, and those increase your weight meaning you need more batteries. But those increase your weight, so you need even more batteries. The tyranny of the rocket equation. Not really specific to this dual-chemistry though, the same holds true for normal EVs and for gasoline-powered cars.

It is a bit different from the rocket equation. The impact of weight on energy consumed per mile in a car is not particularly large. You can add hundreds of pounds and the impact will be negligible.

Re: BMW EV achieves 1000km in range using Dual-Chemistry batteries

#25

Post by bryanlarsen »

russfink wrote: post #2

How do the charging times compare? That’s the deal maker/breaker for long road trips greater than 500 miles, or shorter trips where you use all the accessories, encounter lots of hills, etc not possible on a dynamometer.

This. I've done 4 3000km road trips in an EV. I never went more than 200 miles between charging sessions because my family and I need to eat, sleep and toilet. So more range wouldn't have made the trip any quicker. Faster charging would have.

Add a bit of margin and I believe that 300 miles is the point at which charging speed becomes more important than range.

Re: BMW EV achieves 1000km in range using Dual-Chemistry batteries

#27

Post by keenmaster »

adam_arthur wrote: post #12
keenmaster wrote: post #9

Earlier quoted context omitted.

You need more LFP to carry the weight of the manganese battery though (increasing cost), and all the extra weight can affect driving dynamics. Maybe both the cost and weight increase are minimal but that’s what came to mind. It’s a great idea though.

EVs already have far better driving dynamics than gas cars... doesn't seem like what designers should be optimizing for, or what the average consumer will care most about.

“Far better driving dynamics than gas cars”? No way. Go throw a BMW 3-series around some corners and compare to the Model 3 - you will feel the weight of the batteries. I would have said compare to a Porsche but that’s a different price range.

Note: I’m a big fan of EVs. I’m just saying that handling is one of their weaknesses until battery density gets a lot better.

Re: BMW EV achieves 1000km in range using Dual-Chemistry batteries

#28

Post by adam_arthur »

keenmaster wrote: post #27
adam_arthur wrote: post #12

Earlier quoted context omitted.

EVs already have far better driving dynamics than gas cars... doesn't seem like what designers should be optimizing for, or what the average consumer will care most about.

“Far better driving dynamics than gas cars”? No way. Go throw a BMW 3-series around some corners and compare to the Model 3 - you will feel the weight of the batteries. I would have said compare to a Porsche but that’s a different price range. Note: I’m a big fan of EVs. I’m just saying that handling is one of their weaknesses until battery density gets a lot better.

The average people don't buy BMW or Tesla, they buy Honda CR-V. And they'll appreciate 500mi range far more than being able to take turns fast

Re: BMW EV achieves 1000km in range using Dual-Chemistry batteries

#29

Post by extraduder_ire »

HPsquared wrote: post #7
lallysingh wrote: post #3

This took a few reads to parse. There are two kinds of batteries: (1) a low-density LFP that has a great lifetime, (2) a simulated manganese using Nickel manganese cobalt that has a poor lifetime but great density. The former cycles frequently for short trips, and the latter recharges it during the long ones.

That's pretty clever. It leverages the fact that most people make a large number of short trips, and a smaller number of long trips. Also if it's modular enough, this design could allow replacing one or the other battery if the user does lots of short trips, or lots of long trips. Also could let the manufacturer do market segmentation, e.g. a high performance model with no LFP, and both parts of the "high-performance…

Reminds me of how some SSDs do wear levelling, where they treat cells like they're one bit while the drive's empty and go up to four bits per cell as it fills up, with a speed penalty.

Re: BMW EV achieves 1000km in range using Dual-Chemistry batteries

#30

Post by TheLoafOfBread »

Gravityloss wrote: post #20
TheLoafOfBread wrote: post #16

Earlier quoted context omitted.

But don't forget to make it app only, because we don't want to build charging network which would be actually useful.

https://electrek.co/2023/07/11/europe-passes-two-big-laws-to... > the new rules also mandate simpler charger payments. As-is, some networks require subscriptions or app downloads. But under these rules, customers must be able to pay with cards or contactless devices, and prices must be displayed to the customer.

Five years late.
Post reply on HN