EV Optimum Battery Charging and Real World Range

Is my thinking correct or flawed?  If an EV has an official WLTP range of 300 miles, can we assume in reality an effective range of around 260 miles, especially in cold weather?  If that is the case, and the recommendation is that you charge at around 20% remaining but not more that 80% to prolong the battery life, does that mean that the 300 mile range is really only about 60% of 260 miles, i.e. 156 miles?  Surely that cannot be right?  What am I missing?

All comments welcome, especially from those owning EVs!

Glen

260 miles if you getting only 3.5 miles per kWh would need a 75 kWh battery.   & 75 kWh electric.

if you were just using 50 kWh worth of battery then that would be 175 miles.

or 50 kWh and getting 4 miles a kWh 200 miles. 

70 kWh and 4 miles a kWh 280 miles.

No you can not assume anything.  

If in the coldest and at worst got 2.7 miles a kWh then 75 kWh takes you only 202.5 miles. 

So What size of battery, or car are you looking at?

   Something like an Enyaq 80  (82 kWh,  usable battery is 77 kWh.

Many need to charge to 100%. Do not leave it charged to 100% and sitting. 

Go to 10% or 5% if you know there is a charger and the charging speed will be faster for the first charging period.

Charging to 100% and using the car below 20% isn't an issue, the issues come if you leave the car parked below 20% or above 80% for several hours.

Range will vary dramatically depending on how you drive, drive 'normally' at the NSL (like an ICE) then 3 miles per kWh should be your bench mark to work out your figures especially when it's cold.

On 20%:

The old recommendation was based on unreliable rapid charging network and shorter range EV's. If you only had 100 miles WLTP, 80 miles real world range, at 20% 16 miles there isn't a lot of options left. I've been there.

But these days, if you have 250 miles real world range EV, you can drive it down to 10% and know there's still 20 odd miles if you can't get a charge. However, that's rarely needed nowadays down south where there is typically 10+ charging stalls at hub locations.

On 80%:

The charge to 80% rule only really applies for daily use if you don't need full range every day, simply plug it in every day and know you have 80% (or whatever you've set) range every morning. On road trips, you can still use en-route rapid charge to 100% if you need the extra range, but it's not often done because it's quite slow on a lot of EV's. Less time waiting by stop and charge 3 hours later during another comfort stop.

On longevity:

I would say don't leave it setting outside 20%-80% for days. It's fine for a few hours, such as I'd cheaply charge up to 100% before 5:30 and use the car at 10am. Or get home at 5pm with 15% and wait until midnight to charge it. Li-on battery don't like to be stored at extremes. Going further, if you are OCD about it, you can keep it charged at 50% if don't need the car next day and only dial it up if there's plans, that's what I do.

But end of the day it's meant to be used and a good battery management system (BMS) takes care of it. Example: I've noticed at high state of charge and hot days, Tesla will run fans for a while after parking to cool down battery pack. Or old days at low SoC, compressor would also run for a bit after driving to scavenge remaining heat into the battery.

On 19/05/2024 at 21:29, TheITGuy said:

Is my thinking correct or flawed?  If an EV has an official WLTP range of 300 miles, can we assume in reality an effective range of around 260 miles, especially in cold weather?  If that is the case, and the recommendation is that you charge at around 20% remaining but not more that 80% to prolong the battery life, does that mean that the 300 mile range is really only about 60% of 260 miles, i.e. 156 miles?  Surely that cannot be right?  What am I missing?

 

All comments welcome, especially from those owning EVs!

 

Glen

 

 

AS a Renault Zoe owner, I gather there has been about a third of a million Zoes made, about half a million LEAFs, EV range is something the driver has very much in their control.

the latest iteration of the Zoe, the ZE 50, 52 kWh battery useable, 55 kWh actual  Renault say, has a nominal range of 238 miles with the more powerful 100 kW motor, actually pulls around 111 kWs on the digital instrumentation ie around 150 hp.

I get over 200 miles range in the Zoe depth of winter or height of summer.  Zoe's have heat pumps so keeping toastie is not very energy consumption even in deep winter, plus I am big guy who does not need masses of heat to be comfortable.  18C is usually OK for me, bit of heated seat and I do not need much more.

If one drives with ECO on initially one can get very close to 4 miles per kWh in the Zoe, even in sub zero though it is climbing hills that is a bit of a killer ie going from the Severn valley floor, up passed the Hawthorne football ground which is quite a big climb, sometimes only showing 3.5 miles per kWh but then when I do the Brum to Stoke bit which is on the level it improves a bit and then Stoke to Manchester even better as one drop s down again in height above sea level ie up to 4 Kwh so I can do the over 200 miles from Worcester to Manchester airport and back no bother without charging.  Mostly tootling in eco but with occasional kickdown or removal of ECO to find so clear space etc.

Do the same for Worcester to Heathrow too but I can usually get a charge at work at Heathrow.  About 240 miles round trip.  If cannot get a charge then simply do not use the motorway, pop thru the Cotswolds which is shorter and the route more at closer to optimum speeds is 50/60 on the country roads, 30 mph through the villages and towns and 5 miles per kWh can easily be seen.

A Zoe ZE50 was taken by a bunch of RAF hypermilers and achieved 424 miles or normal tyres and 474 on special tyres I recall round Thuxton, oddly the fastest of UK racetracks, they were averaging about 20 mph I recall, very boring, but if one does chose country roads, go through urban areas rather than taking the bypasses, EVs are very efficient through towns, so crazy ranges from EVs have been achieved.

Few manufacturers have really tried to build a high range EV.  TESLA one of the few to build a car with a low drag coefficient ie 0.22 for the Highland Model 3 I think, and are about to mix the long range battery with the lower energy motor(s) output to deliberately make a 400 mile ranged car.  Many TESLAs can charge at 250 kWs in the lower State of charge and can splash and dash 200 miles of range on a TESLA supercharger, enough time for a waz and getting a coffee and a McMuffin and be on your way.  Not much of an inconvenience and these Superchargers are appearing on a fortnightly bases at motorway service in banks of 8, 12, 16 or so as well as Gridserve ones as well as dedicated Gridserve charge stations like at Norwich, Braintree, Gatwick and hopefully Plymouth soon.

With Octopus EV tariffs so cheap to run an EV on energy, servicing is cheap, I find insurance cost OK too.  Tyre wear a bit higher but then my Zoe only use 16 inch boots so £60 each and sorted.