Electric Car Batteries

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Everyone's talking about electric cars these days and the various ranges and pulling ability.
But nobodies talking about battery temperatures.
Batteriy ratings are at a certain temperature usually 20oC and depending on the battery the ratings go up and down for higher and lower temperatures.So when a range of say 250 miles is quoted this will be at 20oC and could be a lot lower for a lower temperature.
Note,when battery manufacturers talk about temperature they mean electrolyte temperature not air ambient temperature
 
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The same is true for WLTP mileage for ICE cars, but no-one talks about that either. However for EVs there is a great resource with real-world ranges in both cold and warm weather in different driving conditions. It's pretty accurate, and far more useful than manufacturer claimed range or economy for ICE or BEV. I would say that EV manufactures are a bit more transparent though - they generally acknowledge that WLTP range is flawed.
 
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Hello bertiboy

This is partly true. EV's do suffer a drop in range when the weather is colder, that is beyond doubt. and typically figures of summer range of 250 might drop to winter of about 200, so that is a real world drop of about 20% - but it's not all down to the battery losing its ability to develop power.

Generally when the weather is cold there are other factors that also sap power, for instance cabin heating, and windscreen de misting. Often wipers are on, and there can be more use of the headlights. Wet road surfaces produce more rolling resistance, becasue they are moving water out of the way of the tyre contact area - it all needs energy.

And as Tobes rightly points out the same factors do affect ICE vehicles, it just they carry such large reserves of fuel most people don't notice the additional wastage.

In practice the actual loss of battery capacity is less than you imply, ist just that other things also need to use more power to overcome the condition.
 
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The beauty is when plugged in at home or on a public charger I can prevent this a bit by preconditioning. I set our car to come on and precon before going out. This either heats or cools the car and warms the battery ready for more efficient use on mains so not wasting the battery. Warms to about 20-22degrees and cools too.
 
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The same is true for WLTP mileage for ICE cars, but no-one talks about that either. However for EVs there is a great resource with real-world ranges in both cold and warm weather in different driving conditions. It's pretty accurate, and far more useful than manufacturer claimed range or economy for ICE or BEV. I would say that EV manufactures are a bit more transparent though - they generally acknowledge that WLTP range is flawed.
All the vehicle manufacturers use WLTP because they have to and aren't allowed to make any other claims for mpg / kw per mile. The original consumption standard included steady speed 120 kph (75 mph) and gave a good guide to motorway consumption but was abandoned when the NEDC test was introduced.

As WLTP is intended as a world standard, the use of 23 degrees to do the test is unrealistic in most of Europe so consumers really need to accept that a 30% correction is needed to get close to real world figures. As noted, it applies to IC and EV cars but the restricted range of EVs makes it more noticeable.

The calculated range of my Touareg is 960 miles, reducing by 30% to get 672 real world is no issue, nor is reducing it by 50% more for towing to give 336 miles - but similar % reductions in EV WLTP range would play havoc with journey planning.
 
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All the vehicle manufacturers use WLTP because they have to and aren't allowed to make any other claims for mpg / kw per mile. The original consumption standard included steady speed 120 kph (75 mph) and gave a good guide to motorway consumption but was abandoned when the NEDC test was introduced.

As WLTP is intended as a world standard, the use of 23 degrees to do the test is unrealistic in most of Europe so consumers really need to accept that a 30% correction is needed to get close to real world figures. As noted, it applies to IC and EV cars but the restricted range of EVs makes it more noticeable.

The calculated range of my Touareg is 960 miles, reducing by 30% to get 672 real world is no issue, nor is reducing it by 50% more for towing to give 336 miles - but similar % reductions in EV WLTP range would play havoc with journey planning.

I think we all recognise that neither WLTP or NEDC produce result that are representative of "normal" driving. But making % reductions to get real range is very usable. Why is it any harder on EV than on ICE (internal combustion engine)? Or do you mean 30% and 50% would produce numbers that were too small? If so - I agree, except that the % numbers are different.

The WLTP range of my Polestar is 295 miles, but that is the base car without paint, leather, towbar and on 19" rims. Mine has leather, towbar, paint and 20"s. I get more like 200 miles out of a charge, do a fair number of short journeys and don't drive for economy. Am I surprised by this? No - not at all, partly because if I look at polestars website they have a calculator here that tells me at 70mph in 5C and with 20''s I will get 199 miles. If I did longer journesy and had a lighter right foot the number would be higher. I average 33 to 34kWh per 100 miles - thats not excellent economy, but like I say I don't drive for economy.

When towing - I started out with the assumption I would do 50% range that I do solo. Using a very nifty route planning tool (ABRP) designed for EVs, I told it I would need 67kWh per 100 miles, that I would have an 1800kg weight penalty and would not driver faster than 60mph. It estimated my 100-0 towing range to be about 100 miles and planned my journey accordingly.

It turns out, (having now done over 900 miles towing) that my average consumption is only 56kWh per 100 miles, and can be as low as 53kWk/100m. That gives me a towing range of more like 120-130miles.

So - my numbers (just to compare to the Touareg) are 292, reduce by 31% to give me 200 real world, reduce by 38% to give me 125 towing. I can work with that just fine.

Of course - thats just me. I don't mind (in fact actively do) take a break from driving every 2 hours (which is about 100 miles) when towing, and recharge while I am at it. If you like to tow for 6 hours straight - a Touareg is a better bet. (y)
 
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As Roger says the figures are required to be at 20c by law. This produces a near equal comparison between models for customer comparison.
 
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I think we all recognise that neither WLTP or NEDC produce result that are representative of "normal" driving. But making % reductions to get real range is very usable. Why is it any harder on EV than on ICE (internal combustion engine)? Or do you mean 30% and 50% would produce numbers that were too small? If so - I agree, except that the % numbers are different.

The WLTP range of my Polestar is 295 miles, but that is the base car without paint, leather, towbar and on 19" rims. Mine has leather, towbar, paint and 20"s. I get more like 200 miles out of a charge, do a fair number of short journeys and don't drive for economy. Am I surprised by this? No - not at all, partly because if I look at polestars website they have a calculator here that tells me at 70mph in 5C and with 20''s I will get 199 miles. If I did longer journesy and had a lighter right foot the number would be higher. I average 33 to 34kWh per 100 miles - thats not excellent economy, but like I say I don't drive for economy.

When towing - I started out with the assumption I would do 50% range that I do solo. Using a very nifty route planning tool (ABRP) designed for EVs, I told it I would need 67kWh per 100 miles, that I would have an 1800kg weight penalty and would not driver faster than 60mph. It estimated my 100-0 towing range to be about 100 miles and planned my journey accordingly.

It turns out, (having now done over 900 miles towing) that my average consumption is only 56kWh per 100 miles, and can be as low as 53kWk/100m. That gives me a towing range of more like 120-130miles.

So - my numbers (just to compare to the Touareg) are 292, reduce by 31% to give me 200 real world, reduce by 38% to give me 125 towing. I can work with that just fine.

Of course - thats just me. I don't mind (in fact actively do) take a break from driving every 2 hours (which is about 100 miles) when towing, and recharge while I am at it. If you like to tow for 6 hours straight - a Touareg is a better bet. (y)

It's reading your real world figures which convince me I'm not ready yet for an EV! I too like to take a break every 2+ hours but just a short comfort stop interspersed with a longer break at meal times - I also have an issue with some of our day trips as they can be up to 400 miles/day but stopping at places without chargers, mostly without mains electricity!

Having read some of the technical articles about not using the top or bottom 20% of battery capacity to preserve the battery longevity, I'd be wary of using 100-0 figures and use a shorter recharge frequency - just as I avoid using the bottom 10% of my diesel tank to avoid pulling debris through.
 
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As Roger says the figures are required to be at 20c by law. This produces a near equal comparison between models for customer comparison.
Yes, the comparison between models is valid but the official figures need a big deduction when planning real world usage.
 
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Its reading real world stuff like this that make me think it is more than viable-130 miles was as much as we ever did without doing an overnight stop in our Dacia Duster because the tank was so small-so we'd be back to that-we never do more than 200 anyway as it isn't nice for us or the dog-so we're looking forward to EV prices coming down and towing with them becoming more mainstream-ie specifically we are waitign for the Rivian to break cover here. But charging is fast too so you could charge with breaks-we're talking 20mins to 80% for some EVS.
With batteries -there is a lot of hype about this but since it doesn;t say this in our manual and it's much vaunted that battery management is key it seems fast charging is the battery killer-and makers have buffers already so there's nothing to be gained from 20 80 % -if we did this our range on our mini would be rediculous-and we're always fully charged ready to go.
 
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It's reading your real world figures which convince me I'm not ready yet for an EV! I too like to take a break every 2+ hours but just a short comfort stop interspersed with a longer break at meal times - I also have an issue with some of our day trips as they can be up to 400 miles/day but stopping at places without chargers, mostly without mains electricity!

What amazed me when we started towing with the EV was just how long "short" stops really are. What I mean is , we would pull up for a planned stop knowing we needed to gain a certain amount of juice to carry on. The 1st task is unhitch and start the charge. Takes about 2-3 mins. Then you get on with the stop. SWMBO goes to the loo, while I watch the van. She comes back - reports on available refreshments. I go to the loo, pick up selected refreshments and come back to the van. Consume coffee and sticky bun. GO and check on the car - its already beyond the level we needed, and the whole exercise has taken about 25 mins so far. Stop charge, re hitch and move off. What I thought used to be a 5-10 min break is actually far longer in practice.

I imagine your 400 mile day trips are not towing, but solo? There are EVs available today that will do 300+ miles on a single charge, making such events absolutely possible, but, it depends as much on you as on the car. Of course a 400 mile day trip will cost >50 or 80 in diesel. Same in an EV is probably about £30 half charged from home, half on the road.

Having read some of the technical articles about not using the top or bottom 20% of battery capacity to preserve the battery longevity, I'd be wary of using 100-0 figures and use a shorter recharge frequency - just as I avoid using the bottom 10% of my diesel tank to avoid pulling debris through.

Thats a fair point, but miss-understood. When you look at the 100% and 0% on an EV - that excludes buffer that is in the battery pack, but never used for that very purpose. My EV has a 78kWh pack, but only between 72-75kWh useable. The rest is hidden. My range numbers are based on usable, not actual. Because I home charge, I charge to 90% (on days that I need to) and very rarely get below 30%. Only when I am on a long trip (mainly towing) will I get close to 10% or less. You can absolutely use all the (available) pack, but you should never leave it for long periods totally full or totally empty. I charge to 100% the night before I am towing, or have a longer journey to do. In practice, my longest tow so far has been 100%-19% and was 95 miles taking just about 2 hours.
 
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Its reading real world stuff like this that make me think it is more than viable-130 miles was as much as we ever did without doing an overnight stop in our Dacia Duster because the tank was so small-so we'd be back to that-we never do more than 200 anyway as it isn't nice for us or the dog-so we're looking forward to EV prices coming down and towing with them becoming more mainstream-ie specifically we are waitign for the Rivian to break cover here. But charging is fast too so you could charge with breaks-we're talking 20mins to 80% for some EVS.
With batteries -there is a lot of hype about this but since it doesn;t say this in our manual and it's much vaunted that battery management is key it seems fast charging is the battery killer-and makers have buffers already so there's nothing to be gained from 20 80 % -if we did this our range on our mini would be rediculous-and we're always fully charged ready to go.
The Kia EV 6 and Hyundai Ioniq 5 look like excellent tow cars. 300mile real world solo range, 1600kg towing limit, possibly 180-200 mile towing range (based on my experience so far) 10 - 80 in 18 mins on an 800v charger.
 
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What amazed me when we started towing with the EV was just how long "short" stops really are. What I mean is , we would pull up for a planned stop knowing we needed to gain a certain amount of juice to carry on. The 1st task is unhitch and start the charge. Takes about 2-3 mins. Then you get on with the stop. SWMBO goes to the loo, while I watch the van. She comes back - reports on available refreshments. I go to the loo, pick up selected refreshments and come back to the van. Consume coffee and sticky bun. GO and check on the car - its already beyond the level we needed, and the whole exercise has taken about 25 mins so far. Stop charge, re hitch and move off. What I thought used to be a 5-10 min break is actually far longer in practice.

I imagine your 400 mile day trips are not towing, but solo? There are EVs available today that will do 300+ miles on a single charge, making such events absolutely possible, but, it depends as much on you as on the car. Of course a 400 mile day trip will cost >50 or 80 in diesel. Same in an EV is probably about £30 half charged from home, half on the road.



Thats a fair point, but miss-understood. When you look at the 100% and 0% on an EV - that excludes buffer that is in the battery pack, but never used for that very purpose. My EV has a 78kWh pack, but only between 72-75kWh useable. The rest is hidden. My range numbers are based on usable, not actual. Because I home charge, I charge to 90% (on days that I need to) and very rarely get below 30%. Only when I am on a long trip (mainly towing) will I get close to 10% or less. You can absolutely use all the (available) pack, but you should never leave it for long periods totally full or totally empty. I charge to 100% the night before I am towing, or have a longer journey to do. In practice, my longest tow so far has been 100%-19% and was 95 miles taking just about 2 hours.
Yes, our 400 mile/day trips are solo* but to nature reserves and similar outdoor places, usually with no mains electricity, certainly no chargers so 300 mile range is simply not enough - without a change of lifestyle - * once / year we tow 400+ miles on our way up to the Highlands, usually overnighting in a Rest Area where there's no chargers and then continuing the next day - such trips would take an extra day each way by stopping somewhere overnight within range of home.

My understanding is that slow charging, as at home, past 80% is fine - it's fast charging over 80% that reduces battery longevity, despite the management system reducing the charge rate once over 80%.

By charging to 100% at home it's possible to get longer range out of that first charge than from subsequent recharges if restricting fast charges to 80% - so using your example you'd get 95 miles from the first charge but only 72 from subsequent charges (80-20%) which at motorway towing speeds is every 1 hour 12 minutes.
 
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Yes, our 400 mile/day trips are solo* but to nature reserves and similar outdoor places, usually with no mains electricity, certainly no chargers so 300 mile range is simply not enough - without a change of lifestyle

Well - if you had charging at the 100 miles from home mark - that would work. You dont _have_ to destination charge - its just easier if you can.

- * once / year we tow 400+ miles on our way up to the Highlands, usually overnighting in a Rest Area where there's no chargers and then continuing the next day - such trips would take an extra day each way by stopping somewhere overnight within range of home.

Towing 200 miles in a day - again - not really an issue (I did that from south Northants to Whitby and had 20% available on arrival - though I did stop twice as my bladder demanded it) . If your rest stop was just near a rapid charger, you can always visit that. No need to add another day...

My understanding is that slow charging, as at home, past 80% is fine - it's fast charging over 80% that reduces battery longevity, despite the management system reducing the charge rate once over 80%.

No - the car will handle that. In fact when you get above 80% it will simply throttle back the charge rate to what is long term safe. The last 10% can take as long as the 1st 80%. Rule of thumb - don't rapid charge above 80% - not because its damaging, but because its slow.

By charging to 100% at home it's possible to get longer range out of that first charge than from subsequent recharges if restricting fast charges to 80% - so using your example you'd get 95 miles from the first charge but only 72 from subsequent charges (80-20%) which at motorway towing speeds is every 1 hour 12 minutes.

But you dont HAVE to save 20% and you CAN charge to above 80%. 10-90 is perfectly possible in 45 mins, and will give you 100 miles again. So 200 miles in a day takes 4 hours of driving and 45 mins of lunch while charging.
 
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At Tobes says that last block percentage charge is slow as charging reduces specifically to protect the batteries. As above the Hyundai and Kia have superfast charging ability-but there aren't many chargers with that power and I think the mindset of battery life will change-EV batteries whether molly coddled or treated harshly seem to be lasting far far longer than the 8 years 100k miles they initially predicted. Likewise at those sorts of miles a diesel vehicle would need a new dpf at over £1000 and probably a clutch too-an ev owner might start thinking of renewing a few cells-and that will very soon be possible-happening on Leafs already.
 
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Yes, our 400 mile/day trips are solo* but to nature reserves and similar outdoor places, usually with no mains electricity, certainly no chargers so 300 mile range is simply not enough - without a change of lifestyle - * once / year we tow 400+ miles on our way up to the Highlands, usually overnighting in a Rest Area where there's no chargers and then continuing the next day - such trips would take an extra day each way by stopping somewhere overnight within range of home.

My understanding is that slow charging, as at home, past 80% is fine - it's fast charging over 80% that reduces battery longevity, despite the management system reducing the charge rate once over 80%.

By charging to 100% at home it's possible to get longer range out of that first charge than from subsequent recharges if restricting fast charges to 80% - so using your example you'd get 95 miles from the first charge but only 72 from subsequent charges (80-20%) which at motorway towing speeds is every 1 hour 12 minutes.
This is an intersection discussion but one thing puzzles me. Your 400 miles return day trips to nature reserves. Surely in that journey there’s somewhere where you might stop, take a break and charge.

Since changing to petrol I was more aware of range restrictions than with diesel. Since 2000 I had always towed with diesels. My general yardstick was that I could journey from home to Penrith and arrive with 25% fuel left. A journey of 274 miles. Yet last November I towed to north Norfolk a distance of 224 miles. To keep within my own comfort zone I fuelled on route. So just changing fuel type turned the clock back 20 years as apart from longer daily drives in France don’t think I ever fuelled a diesel en route in UK apart from the evening when having overnight stops. But we did stop around every two hours wherever we drove so having to charge at one or another stops wouldn’t be a problem.
 
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At Tobes says that last block percentage charge is slow as charging reduces specifically to protect the batteries. As above the Hyundai and Kia have superfast charging ability-but there aren't many chargers with that power and I think the mindset of battery life will change-EV batteries whether molly coddled or treated harshly seem to be lasting far far longer than the 8 years 100k miles they initially predicted. Likewise at those sorts of miles a diesel vehicle would need a new dpf at over £1000 and probably a clutch too-an ev owner might start thinking of renewing a few cells-and that will very soon be possible-happening on Leafs already.

Toyota are now giving up to 15 years, 150000 miles. Once the initial 10 year 100000 mile warranty expires each year you have it serviced extends the battery warranty by 12 months and 10000 miles on their SC and. PHEV models. I understand from a friend in Australia that the same will apply to EV models too. The present Toyota commercial van shares its power train with a PSA vehicle and Toyota give 10 years, 100000 miles battery warranty in Europe. When I had a Sorento it’s warranty here was 3 years, 60k miles and in the US it was 10 years 100k so the same vehicles will be sold with differing warranties in different regions. It could be subsequent owners who will be sensitive to remaining battery life but as the EV, hybrid market matures I’m certain non OEM suppliers will be offering remanufactured batteries for exchange.
 
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Well - if you had charging at the 100 miles from home mark - that would work. You dont _have_ to destination charge - its just easier if you can.



Towing 200 miles in a day - again - not really an issue (I did that from south Northants to Whitby and had 20% available on arrival - though I did stop twice as my bladder demanded it) . If your rest stop was just near a rapid charger, you can always visit that. No need to add another day...



No - the car will handle that. In fact when you get above 80% it will simply throttle back the charge rate to what is long term safe. The last 10% can take as long as the 1st 80%. Rule of thumb - don't rapid charge above 80% - not because its damaging, but because its slow.



But you dont HAVE to save 20% and you CAN charge to above 80%. 10-90 is perfectly possible in 45 mins, and will give you 100 miles again. So 200 miles in a day takes 4 hours of driving and 45 mins of lunch while charging.
Our 400 mile solo days are long enough as it is, without stopping for a recharge.

Our Highlands towing trip is nearly 600 miles, with 400 the first day - at 200 miles/day that's an extra day each way.
 
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This is an intersection discussion but one thing puzzles me. Your 400 miles return day trips to nature reserves. Surely in that journey there’s somewhere where you might stop, take a break and charge.

Since changing to petrol I was more aware of range restrictions than with diesel. Since 2000 I had always towed with diesels. My general yardstick was that I could journey from home to Penrith and arrive with 25% fuel left. A journey of 274 miles. Yet last November I towed to north Norfolk a distance of 224 miles. To keep within my own comfort zone I fuelled on route. So just changing fuel type turned the clock back 20 years as apart from longer daily drives in France don’t think I ever fuelled a diesel en route in UK apart from the evening when having overnight stops. But we did stop around every two hours wherever we drove so having to charge at one or another stops wouldn’t be a problem.
On our 400 mile day trip we stop at several places, none with charging - we obviously pass places with chargers but stopping there would mean hanging around doing nothing while it recharges and extending the already long day.

Any range restriction for petrol/diesel cars is quickly overcome by a few minutes refuelling - when we had a petrol Astra automatic, it could only manage 200 miles towing, but refuelling only delayed us a few minutes.
 
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Eventually I would envisage your stop offs having chargers. However if you are sited and charging overnight at a caravan site ther will be \EVs with this sort of range. some aren;t far off now .Till then you're better off burning dinosaurs but I'd say you are fairly unique in your holiday mileage. A 400 mile day trip wouldn't find me relaxed or in the holiday mode but we're all different and I admire you.
 
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Eventually I would envisage your stop offs having chargers. However if you are sited and charging overnight at a caravan site ther will be \EVs with this sort of range. some aren;t far off now .Till then you're better off burning dinosaurs but I'd say you are fairly unique in your holiday mileage. A 400 mile day trip wouldn't find me relaxed or in the holiday mode but we're all different and I admire you.
The amount of business driving during my working years gradually made me hate driving - but within a year of retirement, the freedom and lack of time pressure soon rekindled my enthusiasm - so now I don't find a full day driving any hardship as I can set off when I want, stop for a break whenever I want and I don't set a target arrival time - and without the time pressure I manage to stick to speed limits (mostly!).
 
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Our 400 mile solo days are long enough as it is, without stopping for a recharge.

Our Highlands towing trip is nearly 600 miles, with 400 the first day - at 200 miles/day that's an extra day each way.
Or 2 300 mile days.
I am not suggesting you change, just that there may be other options in case that’s the way the world goes.
 
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I normally restrict myself to about 300 miles maximum when towing on the continent however in the UK normally about 100 miles or maximum of 150 miles. Driving on British motorways can be quite stressful at times.
 
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