EV Driving Questions and Tips

[swoop5511]

40 minutes ago, Malop said:

I don’t know the full details behind it but from what I have been able to understand it’s to do with how the battery charge is spread out across the batteries as battery life is measured by charge and discharge cycles. 

Apparently Rapid Charging affects the lifecycle whilst Fast (home charging) allows a more controlled distribution of the charge. 

I believe Toyota have made the decision to control rapid DC charging more strongly than competitors to focus on the battery lifetime. 

Two quick notes. VW did this at launch for all cars on the MEB platform. They limited the fast charging originally to 105kw (I think) after about 6 -8 months increased to 135kw

Need to find the article, i remember reading  thatToyota is limiting the ability to fast charge beyond 80%. Which is what you should do anyway when on the road. Which in return is limiting the range if you work of 100% charged Battery range

[W id]

9 minutes ago, swoop5511 said:

Two quick notes. VW did this at launch for all cars on the MEB platform. They limited the fast charging originally to 105kw (I think) after about 6 -8 months increased to 135kw

Need to find the article, i remember reading  thatToyota is limiting the ability to fast charge beyond 80%. Which is what you should do anyway when on the road. Which in return is limiting the range if you work of 100% charged battery range

But I still don’t understand. 80% is 80 even if charging at home or fast charge. I don’t get why the range would go down. 

[philip42h]

24 minutes ago, W id said:

But I still don’t understand. 80% is 80 even if charging at home or fast charge. I don’t get why the range would go down. 

At home you would charge the Battery over ten hours or more to it's full 71.4 kWh (i.e. 100%)

At a rapid charge stop you would quickly charge the Battery to around 80% (so around 57 kWh) and be on your way again.

The estimated range is based on the charge / fuel in the Battery / tank and your recent consumption rate. So, hypothetically, if you have been achieving 4 miles / kWh when you set out from home with a full tank it would show an estimated range of 285 miles (say). When you recharge to 80% on the motorway the estimated range would be around 230 miles. You then dash off down the motorway and recharge to 80% again, but in your recent usage you have been burning juice at a rather higher rate so the car now perceives you as doing 3 miles / kWh (say) - so at this point your estimated range might be a mere 170 miles. Your actual range will always be dependent on how you drive 'today' rather than how you drove 'yesterday' and when you get 'home' and slow charge back to 100% everything will be normal again.

(Note the 3 and 4 miles / kWh are mostly "plucked out of the air" for effect rather than true estimates of what might happen. 🙂 )

 

[W id]

5 minutes ago, philip42h said:

At home you would charge the battery over ten hours or more to it's full 71.4 kWh (i.e. 100%)

At a rapid charge stop you would quickly charge the battery to around 80% (so around 57 kWh) and be on your way again.

The estimated range is based on the charge / fuel in the battery / tank and your recent consumption rate. So, hypothetically, if you have been achieving 4 miles / kWh when you set out from home with a full tank it would show an estimated range of 285 miles (say). When you recharge to 80% on the motorway the estimated range would be around 230 miles. You then dash off down the motorway and recharge to 80% again, but in your recent usage you have been burning juice at a rather higher rate so the car now perceives you as doing 3 miles / kWh (say) - so at this point your estimated range might be a mere 170 miles. Your actual range will always be dependent on how you drive 'today' rather than how you drove 'yesterday' and when you get 'home' and slow charge back to 100% everything will be normal again.

(Note the 3 and 4 miles / kWh are mostly "plucked out of the air" for effect rather than true estimates of what might happen. 🙂 )

 

Ok. But it would be the same if I charged at 80 percent at home everyday. So that would have nothing to do with fast charging. 80 percent is always 80 percent. 

[philip42h]

9 minutes ago, W id said:

Ok. But it would be the same if I charged at 80 percent at home everyday. So that would have nothing to do with fast charging. 80 percent is always 80 percent. 

Yes, 80% is always 80%. A sensible person would always charge to 100% rather than stop at 80% at home. Rapid charging stops at 80%, largely to protect the Battery, so it does have something to do with the nature of rapid charging.

Just to make things more 'fun' there's nothing stopping you from using an [ultra] rapid charger to charge the Battery all the way to 100% - but it won't top-up the last 20% (80% - 100%) rapidly because the car will reduce the rate that it accepts charge to protect the Battery and you'll then be at the charge stop for hours.

Rapid charging is 'tuned' to give you the fastest possible burst of charge and then get you on your way again. And multiple 70% charges (from 10% to 80%) entail a lot less down time that fewer 90% charges (from 10% to 100%).

[W id]

1 minute ago, philip42h said:

Yes, 80% is always 80%. A sensible person would always charge to 100% rather than stop at 80% at home. Rapid charging stops at 80%, largely to protect the battery, so it does have something to do with the nature of rapid charging.

Just to make things more 'fun' there's nothing stopping you from using an [ultra] rapid charger to charge the battery all the way to 100% - but it won't top-up the last 20% (80% - 100%) rapidly because the car will reduce the rate that it accepts charge to protect the battery and you'll then be at the charge stop for hours.

Rapid charging is 'tuned' to give you the fastest possible burst of charge and then get you on your way again. And multiple 70% charges (from 10% to 80%) entail a lot less down time that fewer 90% charges (from 10% to 100%).

Ok I get it. So basically what Toyota warns for is so people don’t get angry when only charging to 80% shows less range then if charging to 100% 🤷🏼‍♂️

[Malop]

From todays Zap-Map newsletter 

the UK has officially passed a new milestone. There are now over 35,000 public charging devices across the country.

[Cyker]

The warning for the rapid charging is because the faster you try and stuff electrons into the Battery the more damage it takes. This is something that gets brushed under the carpet, but doing only DC rapid+ charging will shorten the life of a Battery pack significantly faster than slower charging.

Anyone who's played with battery-powered RC cars as a kid will know how fast charging shortens the life of the Battery pack, and it's no different with EVs; That's why it's almost essential to be able to charge it at home as you have time to charge the battery slowly which will give it the longest life.

The odd rapid charge will not make a significant difference, but always rapid charging exclusively will deplete the life and capacity of the battery pack noticeably. There've been known cases where Tesla have disabled Superchargers for cars that have used them too much to stop the battery degrading further.

As for the 80% thing, it's the same reason the Toyota hybrids keep the charge between 20% and 80% as much as possible - That's where the lifespan of the battery will be extended the most, especially when sat for a while.

Lithium cells don't like being at 100% and actually resist being pushed up to it, which is why you can't rapid charge at high current up to 100%, as it will cause the battery cells to heat up much faster as they resist the charge, and that also causes them to be damaged more, so slow charging the rest is much safer and better for battery health.

 

It's one of the un-intuitive things about taking an EV on a long journey - You're better of doing more frequent stops and shortish runs from 80 to 20% SoC to get maximum charge speed (EVs generally charge slowest below 20% and above 80%, depending on their hidden 'buffers'), rather than charging from 0 to 100% and trying to maximise the distance between charge stops, as that actually extends journey time far more than the shorter stops because the charging takes so much longer.

 

[Malop]

Great summary 

[lightboxcar]

39 minutes ago, Malop said:

From todays Zap-Map newsletter 

the UK has officially passed a new milestone. There are now over 35,000 public charging devices across the country.

That is interesting as it suggests there will soon be more EV chargers than petrol pumps in the UK:

https://www.statista.com/statistics/312331/number-of-petrol-stations-in-the-united-kingdom-uk/

But maybe not for more rural areas , thay may be missing out looking at soem of the EV charging station maps....

[lightboxcar]

25 minutes ago, Cyker said:

will shorten the life of a battery pack

Thanks for the really helpful post.

However, for those of us new to EV / PHEV, there remains many questions about liON batteries.

For example at one time, many suggested that for these batteries inside laptops , phones, tablets etc. , it was bad to leave them on the charger all the time.

And when the Battery was new, it was best to cycle them from 100% to zero , twice, to 'train' the Battery and get maximum run time and Battery lifetime.

Also it was 'good/life extending' to let them flatten now and then , and then charge up to full in ONE SINGLE charging session.

Another one was not to for example go 80% to 50%  , repeatedly, i.e. frequent top up charges as the battery 'forgets' it full capacity.

Of course much of this may be myth and nonsense, but it would be hugely helpful to have an informative guide to proper care, maintenance and best practice to achieve two important goals;

1.  Achieve longest serviceable lifetime of the battery unit ( not least for resale purposes )

2.  Maintain the best range for the battery

 

 

[Cyker]

36 minutes ago, lightboxcar said:

That is interesting as it suggests there will soon be more EV chargers than petrol pumps in the UK:

https://www.statista.com/statistics/312331/number-of-petrol-stations-in-the-united-kingdom-uk/

But maybe not for more rural areas , thay may be missing out looking at soem of the EV charging station maps....

There needs to be - Charge times are measured in tens of minutes vs single minutes for refuelling, and even then there are often queues at petrol stations at busy times, so with some unscientific maths you'd ostensibly need 10 times more charging stations than fuel stations.

Add to that almost all charging stations are unmanned and apparently unmonitored, you need even more to counter the relatively high failure rate to stop people getting stranded.

One of the biggest problems with an EV is if the Battery gets depleted, you can't just get a lift to a petrol station, fill up a jerry can, and then take it back to the car. Teslabjorn tried to do the EV equivalent of that scenario recently with an ID Buzz and a £2000 portable lithium Battery 'jerry can' and it didn't even put 1% of charge back in the Battery when he ran it out.

So having masses of reliable charging stations is going to be much more important, esp. outside of cities where you can't bum a charge from some friendly samaritan's house socket.

I'm still of the opinion that dedicated charging hubs like the Braintree one are a terrible idea, and they should be focusing on filling supermarket and retail park carparks with chargers - If you charge at Braintree, you're effectively trapped and forced to spend e.g. half an hour drinking over-priced coffee and wandering through WH Smiths and generally being unproductive.

If they'd done it on the car parks at e.g. Bluewater or Lakeside or Harlequin or even a supermarket then you could charge and go for a proper shop instead of wasting time just waiting for the charging.

 

16 minutes ago, lightboxcar said:

Thanks for the really helpful post.

However, for those of us new to EV / PHEV, there remains many questions about liON batteries.

For example at one time, many suggested that for these batteries inside laptops , phones, tablets etc. , it was bad to leave them on the charger all the time.

And when the battery was new, it was best to cycle them from 100% to zero , twice, to 'train' the battery and get maximum run time and battery lifetime.

Also it was 'good/life extending' to let them flatten now and then , and then charge up to full in ONE SINGLE charging session.

Another one was not to for example go 80% to 50%  , repeatedly, i.e. frequent top up charges as the battery 'forgets' it full capacity.

Of course much of this may be myth and nonsense, but it would be hugely helpful to have an informative guide to proper care, maintenance and best practice to achieve two important goals;

1.  Achieve longest serviceable lifetime of the battery unit ( not least for resale purposes )

2.  Maintain the best range for the battery

 

TBH that advice is mostly carry-over from the NiMH laptop battery days; They needed to be babied more to avoid e.g. the 'memory effect', and doing a fully charge-discharge cycle was one of the strategies to stop that happen, or at least mitigate it.

Lithium cells usually have a monitoring circuit that handles all of that, and they absolutely do not need a charge cycle to 'train' it like NiMH did.

The keeping it plugged in at 100% charge being bad is true - That's not great for them, and is why some higher quality laptops have options to limit the charge to a lower level (My Thinkpad's set to stop charging at 70% and only start charging if plugged in below 50% currently, and the battery has so far lasted 2 more years than the previous one when I left it at 100%!)

The main thing for lithium is the charge cycles - The cell has a limit number of cycles as each one slightly degrades its innards. Each 100 to 0 to 100 is a full charge cycle, but 80-50-80 would be less than half a charge cycle and is actually better for it because of that.

This is partly why almost everyone recommends a maximum charge to 80% unless you really need the extra 20% (e.g. to get a bit of extra range out at the beginning of a road trip). Reducing the cycle count by using partial cycles more often helps extend the battery life, but doing a full 100-0-100 all the time would accelerate wear and capacity loss.

I should note that this is the current wisdom for existing 'wet' lithium cells - Supposedly solid state cells are much more robust and have a longer cycle life, and smeg knows how sodium cells will react, assuming we ever see them before Nuclear Fusion  

 

[lightboxcar]

18 minutes ago, Cyker said:

80-50-80 would be less than half a charge cycle and is actually better for it because

So in a real world scenario, say you have a home charger.  You mainly do round town, school runs, supermarket, and 20 mile return trips a few times a week to work.

In this case then is not good to plugin the charger every night and top up..

and better to let it go down to 50% over a few days, then charge back up to 80 %  ?

 

[lightboxcar]

Toyota are saying "it will take few charges before it gets optimised....."

Does that sound right ?

[Cyker]

Keeping it around 80% will not harm it, and because EVs already have less range than ICE cars I agree with Teslabjorn's philosophy of ABC (Always Be Charging  )

So I think it'd be fine to just plug it in every day (Assuming can charge at home), and letting it top back up to 80%.

It's holding it at 100% that's not so good for it, but 80% would be fine, and then if you have an emergency you don't need to be worried that you only had 50% charge in it or something.

When it boils down to it, it's a car, it's supposed to transport you where you need to go, so you shouldn't have to compromise that functionality for the sake of the Battery.

 

[Malop]

New topic for the EV tips section: One Pedal driving.

I’m a big fan and really love full one pedal where the car comes to a full stop when you lift off the accelerator. I am hoping Toyota bring out a software update that enables it but lots of other manufacturers seem to be going with the Partial Pedal driving with brakes required to full stop (read a theory somewhere that this is to keep the brakes in use as some cars in the past had the brakes rust due to lack of use). 
Disappointed that it’s a button press in the BZ4X rather than a software option you can turn on and off. I’m not sure if the car remembers the last setting each time or if you have to turn it on for every trip. I find this frustrating enough with the auto hold after driving a RAV4 for a couple of years. Honestly believe both should be software switches. 
I know the theory behind one pedal is to regen into the Battery but I actually prefer it as a driving experience, regen is just a bonus. 
Anyone seen any stats on how much regen braking actually adds to a Battery on a “typical” trip.

 

[Cyker]

I think it's very marmite. I only tried it a long time ago briefly in a Leaf (I think?) and hated it.

The thing is I have a very pulsey driving style which just doesn't work with one pedal driving, as you have to hold the pedal constantly at a certain position to keep it going, whereas I like to squirt in some power then lift and coast on the momentum, which also lets my leg have a short rest.

Having to provide a constant input to the pedal made that impossible and I reckon would also give me a leg-ache with extended use, as it's like having to hold a constant speed on the motorway for long periods when you don't have cruise control.

It's one of the things I love about the Mk4 as they've judged the lift-off regen perfectly to simulate light engine braking so I can judge traffic ahead after the 'pulse' and coast down to the back of traffic on the regen as well as I did with my manual cars.

I think people with a constant-input driving style would love the one-pedal driving mode tho'

[Malop]

Originally mentioned by @swoop5511 in another thread. 

One benefit of EVs (and PHEVs) is the ability to pre-heat or pre-cool your car without exhaust fumes going everywhere. And with some cars, including the BZ4X, you can do this on a set schedule or trigger remotely via key fob and app.

Pre-heating in winter fully defrosts your car and warms it up. If you pre-heat while plugged into a charging point at home you’ll also keep the Battery topped up at same time so keep your full mileage. 
 

 
 

[Malop]

On 11/4/2022 at 7:23 AM, swoop5511 said:

Quick note, not something unique to the BZ,  but a great feature on EVs. I work morning shifts and it was 3-4 degrees this morning at 5am. I set up a schedule yesterday to defrost and heat up the car 10min before leaving and it worked like a charm. Car was defrosted and cozy warm, seats warm. It was awesome. 

 

[Malop]

On 11/3/2022 at 7:58 PM, lightboxcar said:

In this case then is not good to plugin the charger every night and top up..

and better to let it go down to 50% over a few days, then charge back up to 80 %  ?

I follow Mr EV on YouTube and he has a very relevant section from a Battery expert in this weeks video. Not sure if the link will place you in the right place but if not it starts around the 4 minute mark.

I know the UK BZ4X has Lithium Iron batteries but not sure if they are LFP.

 

[philip42h]

1 hour ago, Malop said:

I know the UK BZ4X has Lithium Iron batteries but not sure if they are LFP.

That should be Lithium Ion ... 😉 

Google tells me that the bZ4X uses Toshiba’s  Lithium titanium oxide (LTO) Battery technology - aka 20Ah-HP SCiB. So not LFP, but LTO ... though how  true that is I couldn't say ... 

Edit: I should have referenced my sources ... 

https://www.saurenergy.com/solar-energy-news/toyotas-new-e-suv-comes-equipped-with-toshibas-lto-battery-tech

https://www.autoevolution.com/news/toshiba-s-new-li-ion-battery-is-key-to-toyota-s-ev-plans-promises-to-be-indestructible-179595.html

As I say, they may or may not be correct.

Edited November 5, 2022 by philip42h
Add source references

[Malop]

9 minutes ago, philip42h said:

Lithium Ion

I’ll resist going back and editing the autocorrect 😂😂

I’ve seen a lot of online chat about the USA AWD coming with CATL batteries which are maybe LFP.

[Cyker]

I'm hedging my bets, we might be using super cheap sodium fluoride solid state batteries in some years!  

That'd be hilarious, it turns out toothpaste is the ultimate Battery chemistry  

[Rajavina]

On 11/3/2022 at 9:01 PM, Malop said:

New topic for the EV tips section: One Pedal driving.

I’m a big fan and really love full one pedal where the car comes to a full stop when you lift off the accelerator. I am hoping Toyota bring out a software update that enables it but lots of other manufacturers seem to be going with the Partial Pedal driving with brakes required to full stop (read a theory somewhere that this is to keep the brakes in use as some cars in the past had the brakes rust due to lack of use). 
Disappointed that it’s a button press in the BZ4X rather than a software option you can turn on and off. I’m not sure if the car remembers the last setting each time or if you have to turn it on for every trip. I find this frustrating enough with the auto hold after driving a RAV4 for a couple of years. Honestly believe both should be software switches. 
I know the theory behind one pedal is to regen into the battery but I actually prefer it as a driving experience, regen is just a bonus. 
Anyone seen any stats on how much regen braking actually adds to a battery on a “typical” trip.

 

I fully agree with you. I found it difficult when I charged mine to 99% as I could not use one pedal driving. City driving is so easy and comfortable.

[dannyboy413]

One of the things that puts me off an EV is all the talk of 'contactless', 'Apple Pay' etc. Whilst I have a phone capable of using an app to pay for the charging, what about the people who do not have a smart phone? I realise that more and more people now have one, but it seems a bit 'off' if, in order to charge an EV away from home, you need a smart phone. Remember cash? Oh well, that's progress - I suppose.