80% charge in one hour?

Batteries, Chargers, and Battery Management Systems.
James Broadhurst   1 W

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80% charge in one hour?

Post by James Broadhurst » Feb 14 2019 7:46am

The only way I can get an 80% charge into a Li battery is if I start with the battery fully discharged or near enough. Within +5/0 minutes (it's never faster than 60 minutes) I can hit 80% which presupposes I've towed the car to a charger as there isn't a BMS car system around that will allow a battery to be discharged completely. With a 10% residual charge, although you can reach 80% in less than an hour, you will not reach 90% for 90 minutes or so. This means that under any normal condition you can not put 80% into a battery within an hour.

The problem is that irrespective of what value of constant current I start with, as soon as the voltage reaches 4.2 the current rapidly drops off. You can move that transition point backwards or forwards but what you gain in one charging phase, you lose in another.

The batteries I tested were Samsung 30Q & 35E, LG MJ1; all of which performed as per their data sheets although an 80% charge becomes a difficult to achieve target the more cycles you put it through. The 35E is alone in having a maximum charge current considerably less than 1C.

I ask this because here in Europe many governments, even down to the lowest parish council, are wanting to ban combustion engines in 10 or 20 years time and in the 10 years that I've been involved in this, the rate of technical progress (as measured in energy capacity) has been miserable. All good virtue signalling to the voters but it isn't going to end well at this rate.

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izeman   10 GW

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Re: 80% charge in one hour?

Post by izeman » Feb 14 2019 8:09am

The only question i see is in the topic :)
So what IS your question? If it is possible to charge a battery to 80% in less than an hour.
Simple answer: Yes. It just depends on the chemistry if they will survive it or not. I got graphene rc-lipo that can be charged @4C. So it's full in 15min.
You write that the charge current gets less very quickly as soon as the battery reaches 4.2V. Sure. It's full by then. Charging happens as CC/CV. Which means that in the beginning you see a Constant Current, and as soon as the charger's output voltage and the battery's voltage start to match (near the end of charge) the current will drop (even to zero amps).
Did that answer your question?

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Re: 80% charge in one hour?

Post by john61ct » Feb 14 2019 8:15am

The key is defining YOUR version of 100%, not going by the absolute top voltage possible according to the batt maker who wants a short cycle life.

Drop your Ah expectation a little, back the finish voltage down a lttle.

Peace of mind, fast charge now possible, bank lasts much longer and really not giving up much range.

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Re: 80% charge in one hour?

Post by iOn <-+-> uOil » Feb 14 2019 8:17am

izeman wrote:
Feb 14 2019 8:09am
I got graphene rc-lipo that can be charged @4C. So it's full in 15min.
But its still not a true graphene battery. it would have much more whr/kg and could be charged in 5 minutes to 90%.
Truth hurts

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izeman   10 GW

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Re: 80% charge in one hour?

Post by izeman » Feb 14 2019 8:30am

iOn <-+-> uOil wrote:
Feb 14 2019 8:17am
izeman wrote:
Feb 14 2019 8:09am
I got graphene rc-lipo that can be charged @4C. So it's full in 15min.
But its still not a true graphene battery. it would have much more whr/kg and could be charged in 5 minutes to 90%.
Sure, but "Turnigy Graphene" is the product name i was refering to. And those are GREAT batteries. The best i've every used regarding charging times and voltage sag.

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Re: 80% charge in one hour?

Post by iOn <-+-> uOil » Feb 14 2019 8:38am

izeman wrote:
Feb 14 2019 8:30am
iOn <-+-> uOil wrote:
Feb 14 2019 8:17am
izeman wrote:
Feb 14 2019 8:09am
I got graphene rc-lipo that can be charged @4C. So it's full in 15min.
But its still not a true graphene battery. it would have much more whr/kg and could be charged in 5 minutes to 90%.
Sure, but "Turnigy Graphene" is the product name i was refering to. And those are GREAT batteries. The best i've every used regarding charging times and voltage sag.
Yep its called graphene enhanced Lipoly battery is the right name of it.
There internal resistance is best.

Do you know how they perform in cycle life against other not enhanced Lipoly ?
Truth hurts

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spinningmagnets   100 GW

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Re: 80% charge in one hour?

Post by spinningmagnets » Feb 14 2019 9:50am

The higher the discharge capabilities of a given lithium battery, the faster it can be charged. Monitor the heat, and slowly raise the amps you are charging with. As the cell gets closer to being full, you must lower the charging amps. Again, continuously monitor the heat...

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Re: 80% charge in one hour?

Post by iOn <-+-> uOil » Feb 14 2019 10:15am

Thats only partly true.
Each Lithium chemistry has its own parameter for fast discharge and fast charge to yield a reasonable cycle life.
Watch in the specification of your buy. and only charge fast when needed.
Truth hurts

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Re: 80% charge in one hour?

Post by billvon » Feb 14 2019 12:53pm

James Broadhurst wrote:
Feb 14 2019 7:46am
The only way I can get an 80% charge into a Li battery is if I start with the battery fully discharged or near enough.
Sounds like you are saying that if you start with a battery charged to 50% you can't get another 80% worth of charge in it. Yes, that's true - but sorta obvious.
With a 10% residual charge, although you can reach 80% in less than an hour, you will not reach 90% for 90 minutes or so. This means that under any normal condition you can not put 80% into a battery within an hour.
See above.
The problem is that irrespective of what value of constant current I start with, as soon as the voltage reaches 4.2 the current rapidly drops off.
Yes. That's how lithium ion batteries charge - CC/CV.
You can move that transition point backwards or forwards but what you gain in one charging phase, you lose in another.
No. If you charge at a higher C rate you do not "lose" the ability to charge in the CV section. You just can't accelerate the CV section any faster than voltage allows.
I ask this because here in Europe many governments, even down to the lowest parish council, are wanting to ban combustion engines in 10 or 20 years time and in the 10 years that I've been involved in this, the rate of technical progress (as measured in energy capacity) has been miserable. All good virtue signalling to the voters but it isn't going to end well at this rate.
Hard to tell what that statement has to do with anything in the rest of the post. Tesla now has cars that will hit 335 miles, so I think there has been quite a bit of progress on that front. Now the challenge is getting the cost down.
--bill von

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Re: 80% charge in one hour?

Post by flat tire » Feb 14 2019 1:21pm

Well, you can accelerate (or get around) the CV charging section especially if your termination is significantly under 4.2. You do it by understanding the charge profile, shooting past your CV section in CC mode by setting a higher terminating voltage than normal, and terminating manually or by power transferred around the point where the resting voltage will be what you want.

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Re: 80% charge in one hour?

Post by john61ct » Feb 14 2019 1:41pm

LI of any chemistry will **accept** (pull, demand) a rate higher than is good for it wrt longevity.

Up to you what you want the max rate to be allowed, "made available" by the charge source.

From the batt health POV, no Absorb / CV stage at all is needed, can just charge **to** a termination voltage and stop.

The Bulk/CC to Absorb/CV transition will happen at a much higher/later SoC% with low current than with a high rate.

You can maintain a bit higher charging voltage safely with a high charge rate, just means the settling to a lower resting voltage will be a greater drop, and SoC will not be as high

compared to low currents say overnight.

You do not actually want to get LI to **maximum** Full in normal cycling, unless you really need every last bit of range/Ah capacity for your use case.

Lower volts, lower amps and stopping sooner are all conducive to greater longevity.


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izeman   10 GW

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Re: 80% charge in one hour?

Post by izeman » Feb 14 2019 3:38pm

TBH is have NO idea where this discussion is heading, and the TS hasn't given a clue what this thread is about. I think we should wait for him to reply and tell us what his question really is?!
What do you think?

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Re: 80% charge in one hour?

Post by john61ct » Feb 14 2019 5:56pm

TS? Is that the OP?

I think his statement of his (perceived) problem is perfectly clear, and the response are accurate and targeted toward clearing up his misunderstandings, with constructive suggestions for adjusting his expectations and behaviours so as not to cause other problems of which he seems to not be aware.

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Re: 80% charge in one hour?

Post by izeman » Feb 15 2019 3:19am

john61ct wrote:
Feb 14 2019 5:56pm
TS? Is that the OP?
Yes, Thread Starter. :)

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Re: 80% charge in one hour?

Post by Warren » Feb 15 2019 10:13am

James Broadhurst wrote:
Feb 14 2019 7:46am
I ask this because here in Europe many governments, even down to the lowest parish council, are wanting to ban combustion engines in 10 or 20 years time and in the 10 years that I've been involved in this, the rate of technical progress (as measured in energy capacity) has been miserable. All good virtue signalling to the voters but it isn't going to end well at this rate.
I think I understand the question. Some cars with liquid cooling are now pulling up to 1.7C for a small portion of the charge cycle. None are doing a full charge in an hour. However, some can definitely do 80% in under an hour, as seen in this video.

https://youtu.be/VABvS9zfuiI?t=115

We have been driving a Chevy Bolt for 19 months, and while the fast charge rate is an annoyance when on trips beyond its 200+ mile range, this is not a big deal.

The real issues are lack of fast charging infrastructure, and the high cost of batteries.

Both of these problems can be solved a lot easier than many of the other challenges of dealing with climate change, over population, resource depletion, etc. I don't think politicians, or most of us, can get our heads around the exponential nature of our problem.

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Re: 80% charge in one hour?

Post by James Broadhurst » Feb 15 2019 7:21pm

Warren wrote:
Feb 15 2019 10:13am
I think I understand the question. Some cars with liquid cooling are now pulling up to 1.7C for a small portion of the charge cycle. None are doing a full charge in an hour. However, some can definitely do 80% in under an hour, as seen in this video.

The real issues are lack of fast charging infrastructure, and the high cost of batteries.

Both of these problems can be solved a lot easier than many of the other challenges of dealing with climate change, over population, resource depletion, etc. I don't think politicians, or most of us, can get our heads around the exponential nature of our problem.
Agreed and thank you. I don’t own a Tesla but I disagree with the conclusion you draw from the video. The actual capacity of that 75kw battery will be greater by about 10% or even more. It is a sensible cushion for Tesla and not criticism by me. If I were to do the same, I would get the same result. Quite how the owner of the car in the video dragged his car to the charging point with a fully discharged battery is not known and that is one issue I have.

My criticism of the EV manufacturers is that the claims that are made about charging are fanciful. We have politicians who believe that if they say something often enough, eg affordable and with charging infrastructure, then it happens as if by magic and anyone who makes them isn’t going to disagree.

The observation by bill von that a 335 mile battery is progress isn’t surely due to any technological breakthrough but simply by packing more batteries in? You can only go so far with that before the weight of the battery begins to impact the performance of the vehicle.

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Re: 80% charge in one hour?

Post by Warren » Feb 16 2019 11:26am

James Broadhurst wrote:
Feb 15 2019 7:21pm
The actual capacity of that 75kw battery will be greater by about 10% or even more. It is a sensible cushion for Tesla and not criticism by me. If I were to do the same, I would get the same result. Quite how the owner of the car in the video dragged his car to the charging point with a fully discharged battery is not known and that is one issue I have.

My criticism of the EV manufacturers is that the claims that are made about charging are fanciful. We have politicians who believe that if they say something often enough, eg affordable and with charging infrastructure, then it happens as if by magic and anyone who makes them isn’t going to disagree.

The observation by bill von that a 335 mile battery is progress isn’t surely due to any technological breakthrough but simply by packing more batteries in? You can only go so far with that before the weight of the battery begins to impact the performance of the vehicle.
I can't say how much cushion a Model 3 has. I can say that our Bolt has 4-5%. When I pull into the garage with 1.6% remaining, I still have about 4% cushion. GM won't tell me this, but Torque Pro and some hacked PIDs give me the information.

While there has definitely been some incremental progress in lithium ion batteries from 2011 to today, I personally doubt batteries will ever be cheap enough to match petrol prices, since fighting wars isn't factored into the price.

I think that requiring that every vehicle be a hybrid has been the logical thing to do for a decade, at least. But it has been fought by auto, and oil interests. Of course, consumers don't want the added up-front expense either.

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Re: 80% charge in one hour?

Post by billvon » Feb 16 2019 12:33pm

James Broadhurst wrote:
Feb 15 2019 7:21pm
The actual capacity of that 75kw battery will be greater by about 10% or even more.
To be more accurate, the car will only let you use about 90% of that 75kw. It behooves manufacturers to advertise the highest capacity battery they can, so they do. Software then prevents 100% discharge.
My criticism of the EV manufacturers is that the claims that are made about charging are fanciful. We have politicians who believe that if they say something often enough, eg affordable and with charging infrastructure, then it happens as if by magic and anyone who makes them isn’t going to disagree.
My first EV was a Leaf. The 80% claim was certainly accurate when the car was new. Since it was a 24kwhr pack, a 50kw charger could get it to 80% in about half an hour. After five years ESR increased and the car could barely reach 80% in an hour.
The observation by bill von that a 335 mile battery is progress isn’t surely due to any technological breakthrough but simply by packing more batteries in? You can only go so far with that before the weight of the battery begins to impact the performance of the vehicle.
Exactly.

That 335 mile range is, of course, to EV manufacturers packing lots of batteries in. If they did not have a high energy density battery to start with the weight would make the design impossible.

I used one of the first 18650 batteries in a satellite phone I designed back around 2000. It was 1300mah and was the best we could get at that point. Now the same size/weight cell is more than twice that - due to slow, incremental improvements in cell technology.
--bill von

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Re: 80% charge in one hour?

Post by billvon » Feb 16 2019 12:40pm

Warren wrote:
Feb 16 2019 11:26am
I think that requiring that every vehicle be a hybrid has been the logical thing to do for a decade, at least.
I think a better thing to do is require cars to average a certain fuel economy, and gradually increase that fuel economy. In 20 years, gas powered hybrids may seem like gas guzzlers.
--bill von

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Re: 80% charge in one hour?

Post by Chalo » Feb 16 2019 12:45pm

Warren wrote:
Feb 16 2019 11:26am
I think that requiring that every vehicle be a hybrid has been the logical thing to do for a decade, at least. But it has been fought by auto, and oil interests. Of course, consumers don't want the added up-front expense either.
That makes no sense. We have fuel economy requirements; we only need to keep them updated. And they need to apply to every single new vehicle instead of entire production fleets. How you meet economy, emissions, and safety requirements should be irrelevant.

Cars have been getting faster, heavier, and more powerful continuously since the political will to keep tightening fuel economy standards was lost decades ago. That's not only the result of corruption in government and industry-- it's the moral failure of a people who have decided that driving personal cars is acceptable no matter what damage it does.

I hope I live long enough to see that no longer be the default assumption. But I'm not waiting; I'm living another way already.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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Re: 80% charge in one hour?

Post by john61ct » Feb 16 2019 1:04pm


Chalo wrote: That's not only the result of corruption in government and industry-- it's the moral failure of a people who have decided that driving personal cars is acceptable no matter what damage it does.
A lot of that moral failure is due to billions of dollars spent by FF on decades of skilled propaganda subverting the truth, making it easy for a critical mass of naturally lazy and gullible people to rationalize, "maybe it really isn't true".

But then maybe even without that, enough people just don't care if our habitat won't support the species, long as the real crises are after their own personal death.

Older people have the power, the young wear the consequences.


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Re: 80% charge in one hour?

Post by billvon » Feb 16 2019 1:04pm

Chalo wrote:
Feb 16 2019 12:45pm
That makes no sense. We have fuel economy requirements; we only need to keep them updated. And they need to apply to every single new vehicle instead of entire production fleets. How you meet economy, emissions, and safety requirements should be irrelevant.
Would be impractical to meet them for things like ambulances, 18 wheelers, tow trucks, farm trucks, snowplows, school buses etc. In fact the effort would result in more, rather than less, fuel consumption. (Think about WalMart using 20 small hybrid trucks instead of 1 18 wheeler to get their goods.)

The reason I like the CAFE approach is that it drives what's important (average vehicle fuel economy) while putting all the burden on the manufacturer. They can do whatever they like, as long as their average fleet fuel economy is X.
--bill von

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Re: 80% charge in one hour?

Post by Warren » Feb 16 2019 1:40pm

billvon wrote:
Feb 16 2019 1:04pm
Would be impractical to meet them for things like ambulances, 18 wheelers, tow trucks, farm trucks, snowplows, school buses etc. In fact the effort would result in more, rather than less, fuel consumption. (Think about WalMart using 20 small hybrid trucks instead of 1 18 wheeler to get their goods.)

The reason I like the CAFE approach is that it drives what's important (average vehicle fuel economy) while putting all the burden on the manufacturer. They can do whatever they like, as long as their average fleet fuel economy is X.
I agree that raising fuel standards would result in the same thing. One form of hybrid, or another, would likely be the result anyway.

I am curious what makes you think an 18 wheeler can't be a hybrid, since diesel locomotives have been from the beginning?

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Re: 80% charge in one hour?

Post by Chalo » Feb 16 2019 3:01pm

billvon wrote:
Feb 16 2019 1:04pm
Chalo wrote:
Feb 16 2019 12:45pm
We have fuel economy requirements; we only need to keep them updated. And they need to apply to every single new vehicle instead of entire production fleets.
Would be impractical to meet them for things like ambulances, 18 wheelers, tow trucks, farm trucks, snowplows, school buses etc. In fact the effort would result in more, rather than less, fuel consumption. (Think about WalMart using 20 small hybrid trucks instead of 1 18 wheeler to get their goods.)

The reason I like the CAFE approach is that it drives what's important (average vehicle fuel economy) while putting all the burden on the manufacturer. They can do whatever they like, as long as their average fleet fuel economy is X.
So have a different per-vehicle economy standard for commercial trucks and industrial vehicles, and exempt emergency vehicles from the requirements. The point is to make all, not just some, of the vehicles within a given class conform to standards. Imagine a system that allowed fleet average crash safety ratings.

Why should we have (for example) city buses that weigh 30,000 pounds empty? That's normal these days, and it's stupid.

With cars, the presence of a few huge gas guzzlers not only drives demand for more of them, but it makes people regard small, efficient vehicles as impractical or unsafe. If every personal vehicle is only allowed say 4 liters per 100km, then we would see the tradeoffs inherent in using an excessive vehicle. Sure-- have your three row SUV, but you're gonna go slow. The incentive would be to use the smallest and lightest vehicle that works for the job.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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Re: 80% charge in one hour?

Post by billvon » Feb 16 2019 6:31pm

Warren wrote:
Feb 16 2019 1:40pm
I am curious what makes you think an 18 wheeler can't be a hybrid, since diesel locomotives have been from the beginning?
No reason at all. I was saying that it would counterproductive to require 18 wheelers to get the same MPG as a car (i.e. I was arguing against applying one standard to "every single vehicle.")
--bill von

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