Will Electric Vehicles Be Viable? When?

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Andres125sx
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Re: Will Electric Vehicles Be Viable? When?

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strad wrote:
Thu Oct 29, 2020 9:05 pm
If we want them viable we have to change our pattern.
So.. You are saying we should change our lives to make them viable? I don't think so. They have to make their product fit our lives and life style.
.
As an example, we changed our pattern with smarphones, from phones wich battery could last one whole week, to phones wich need daily charging or almost, and none´s head exploded. Some weeks ago I had to use one of these old phones at work and I couldn´t believe how long the battery last, it was impressive. But I still prefer my smartphone

With EV it´s the same, instead of waiting till the tank is empty and then fill a lot of fuel, we can daily charge it when arriving home and for 80% of people range will never be an issue.

Problem is not changing our patterns, humans get used to anything, good or bad, quite fast, problem is thinking about changing our patterns, that´s what makes people angry. But once the change arrives, they dont even notice they changed their patterns

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strad
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Re: Will Electric Vehicles Be Viable? When?

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Do modern EVs develop battery memory? Is it best to run them down before recharging
and always charging to 100%?
To achieve anything, you must be prepared to dabble on the boundary of disaster.”
Sir Stirling Moss

Brake Horse Power
Brake Horse Power
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Re: Will Electric Vehicles Be Viable? When?

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Nope, no battery memory

Shooty81
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Re: Will Electric Vehicles Be Viable? When?

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strad wrote:
Fri Oct 30, 2020 6:52 pm
Do modern EVs develop battery memory? Is it best to run them down before recharging
and always charging to 100%?
No, that's about the worst thing to do.

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Andres125sx
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Re: Will Electric Vehicles Be Viable? When?

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strad wrote:
Fri Oct 30, 2020 6:52 pm
Do modern EVs develop battery memory? Is it best to run them down before recharging
and always charging to 100%?
Exactly the contrary, it´s much better to keep then around 50% as much as possible, the more deviation from 50% the more degradation it will suffer. Obviously on the long term, nothing will break when you need the full capacity, charge to 100% and use it till it´s empty, but battery lifespan will be longer if you keep it around 50%

Brake Horse Power
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Re: Will Electric Vehicles Be Viable? When?

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Hi Andres, can you prove your point with data or a research paper? I hear this for the first time. As far as I know it doesn't matter much whether you go from 100% to 50% or from 75% to 25%. Or twice from 62.5% to 37.5%..

It's all 0,5 cycle.. Only if you go to very deep depth of discharges battery capacity will reduce quicker..

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subcritical71
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Re: Will Electric Vehicles Be Viable? When?

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Brake Horse Power wrote:
Sat Oct 31, 2020 12:41 pm
Hi Andres, can you prove your point with data or a research paper? I hear this for the first time. As far as I know it doesn't matter much whether you go from 100% to 50% or from 75% to 25%. Or twice from 62.5% to 37.5%..

It's all 0,5 cycle.. Only if you go to very deep depth of discharges battery capacity will reduce quicker..
Here is a paper on the subject with a lot of citations. I believe section 3.2 on State of Charge has what your looking for.

http://css.umich.edu/sites/default/file ... S20-08.pdf

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strad
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Re: Will Electric Vehicles Be Viable? When?

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Only if you go to very deep depth of discharges battery capacity will reduce quicker..
I read the citation and it appears that if you run it to almost flat every time before you recharge or if just plug it in and forget about you kill the battery sooner. Hmmm
To achieve anything, you must be prepared to dabble on the boundary of disaster.”
Sir Stirling Moss

Brake Horse Power
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Re: Will Electric Vehicles Be Viable? When?

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subcritical71 wrote:
Sat Oct 31, 2020 12:56 pm

Here is a paper on the subject with a lot of citations. I believe section 3.2 on State of Charge has what your looking for.

http://css.umich.edu/sites/default/file ... S20-08.pdf
Thanks, interesting paper.
As what Strad concludes. Their best practices regarding charging especially focus on not overcharging (which BMS prevents) and not completely draining the battery (your own responsibility when storing it longer periods. During use it's managed by BMS).

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Andres125sx
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Re: Will Electric Vehicles Be Viable? When?

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Brake Horse Power wrote:
Sat Oct 31, 2020 12:41 pm
Hi Andres, can you prove your point with data or a research paper? I hear this for the first time. As far as I know it doesn't matter much whether you go from 100% to 50% or from 75% to 25%. Or twice from 62.5% to 37.5%..

It's all 0,5 cycle.. Only if you go to very deep depth of discharges battery capacity will reduce quicker..
Sure, this is common for any lithium based battery, some are more delicated in this aspect than others (lipos I use for RC planes and drones are extremelly sensitive), but any lithium battery suffer this

https://batteryuniversity.com/learn/art ... _batteries

Deep Of Discharge, level of charge and storage voltage are the main parameters affecting battery life. Well all those after discharge power as you can ruin a battery just in some discharges if you ask it for more discharge Cs than it´s capable, but with EV, electric tools and anything using LiIon batteries we can´t change discharge power so that´s not a problem for most users

Ferry
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Re: Will Electric Vehicles Be Viable? When?

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strad wrote:
Fri Oct 30, 2020 6:52 pm
Do modern EVs develop battery memory?
No, not at all. You have to go all the way back to NiCd to have that problem. And not really then either. https://batteryuniversity.com/learn/arc ... th_or_fact
I have used NiCd for toys, RC, comm radios etc. since the early 80s. Never had a problem with memory effect. For the past 15 years or so I have used a lot of lipos for RC, e-bikes, tools etc. Keeping them half full between use is a well known practice. I would nearly say common practice. Like not to over-rev a cold engine or similar. Storing full or empty is bad. Using the full range is totally ok, but don't let the lipos stay at 0% or 100% for long. My car (BMW i3) warns me if I park the car in the cold with very low SOC. It's probably a little bit better to use just the mid-range of the battery, say 20-80%. But it's a trade off between usability and long life. And degrading because of aging is there anyways, so no need to go totally crazy about preserving the battery. I want to drive my car too, not just preserve it for the next owner.
At the moment it looks like the batteries will outlast the rest of the car, but it's still early days. No EVs with modern battery tech have reached high age yet. The oldest Nissan Leafs are closing in on 10 years now.

Greg Locock
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Re: Will Electric Vehicles Be Viable? When?

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Reputedly NiMHs also have memory effect. However, it doesn't seem to be a universal occurrence, and changes in geometry and chemistry have a big effect.