Electric cars question

DrEskimo

50Twuncle wrote: »

Yes - if the range is so poor that it needs plugging in every day ?

Doesn't necessarily mean the range is poor if you connect everyday. You may have a high daily commute. It makes little difference if you charge it little and often, or a large amount rarely. Except that some every tariffs offer cheap rates for a set amount of hours, so it would be better to do it little and often. As above, you can also heat it using the mains, so can conserve battery energy if needed too.

bob_a_builder

Think I saw a simple rule of thumb saying with regard to Electric cars

ABC = "Always Be Charging"

AnotherJoe

50Twuncle wrote: »

How is the range of Electric cars affected by continual use of aircon and heaters ?

It depends on the difference between external and internal temps. But worst case tends to be about 8% on my car, and the next one should be better because it has a heat pump that scavenges heat from the motif and battery. OTOH i happened to notice a few months back it was 24 outside and I set air con to 23 and the shown range didn't drop at all when switched on.

The biggest hit by far is the winter where irrespective of losing range due to heater, the cold makes a bigger difference. My car again for example, it's gone from 135 a few months ago to just over 100 now when it's freezing.

AnotherJoe

50Twuncle wrote: »

So using, say a Hyundai Kona - what would the TRUE range be in cold weather ?

If we say it's 280 and it's a 30% drop then that's about 200.

50Twuncle wrote: »

Also - when does the "memory effect" start to kick in - in terms of battery charge ?

There is no "memory effect". That was NiMh batteries there is a degradation. Worse on older cars with less sophisticated battery management. I saw reports of. Tesla few month ago, 400,000km and about 90% of original capacity left. Leafs tend to have much worse degradation than others and it tends to be noticed as well since they hada low range to start with.

Herzlos

bob_a_builder wrote: »

Think I saw a simple rule of thumb saying with regard to Electric cars

ABC = "Always Be Charging"

If you could trickle fill a petrol car by plugging it into a wall you'd do it at every opportunity too.

NigeWick

50Twuncle wrote: »

How is the range of Electric cars affected by continual use of aircon and heaters ?

Depends on the vehicle. Gen 1 Nissan Leaf, a good 5%. My Hyundai Kona, less than 2% as a rule.

uknick

Herzlos wrote: »

If you could trickle fill a petrol car by plugging it into a wall you'd do it at every opportunity too.

Note sure it was fully explained why you should leave an electric car charging whenever possible. When plugged in the car's battery management system balances the charge across all the 96 batteries in the battery pack so they are all charged to the same level.

If you don't balance the batteries, during charging the strongest cell will reach full capacity first, leaving the weakest short of charge. Therefore, during use the weakest will discharge first meaning the strongest will never be fully discharged. This reduces the overall battery pack capacity. Without balancing, as time goes by the stored voltage gets less and less, thus having a significant impact on range. A fully balanced pack takes time to achieve, hence the mantra, Always Be Charging.

AnotherJoe

I"m going to disagree with that.
Yes in the past it was good advice to occasionally charge up to 100% to enable the batteries to be balanced but i think that is outdated advice now with much better battery management that does that anyway, you'll often see manufacturers recommend you charge to 80-85% only and on fast chargers theres usually an auto cut off at that point.
I believe ABC is there because of pragmatism, basically the charging network is still inadequate in many places (unless you have a Tesla) so grab a charge when you can.

almillar

How is the range of Electric cars affected by continual use of aircon and heaters ?

Depends a bit on the car. Many these days have a heat pump, some use an electric element to heat the air - this is less efficient, and has more effect on battery.
For a literal answer, I've had a Renault Zoe and Kia Soul EV - these both show, at the start of a cold morning, 2kW going to the heating system. That will of course tail off when up to temperature. These cars both have heat pumps.

But you're onto a myth. The amount of energy used to heat the car, is dwarfed but the amount used to move it. And the loss of range in winter (I say sort of one third less - 66miles instead of 100 in summer, in the UK, safely), is mostly caused by... the cold weather, as DrEskimo points out. An Eskimo should know! When the batteries are cold, they have less capacity. Same with your phone, laptop, tablet. The chemistry just works far better above, say, 10 deg than below.

A strong case for garageing these cars then? It's a pity everyone in Britain has felt the need to convert their garage into a spare room!

A strong case for pre-heating. If you charge overnight, almost any EV can be programmed to be 'warm' at a certain time. This means you're not taking range to heat the cabin of the car, and depending on the car, the batteries might also get a nice heating to a more ideal temperature, helping range again.

So using, say a Hyundai Kona - what would the TRUE range be in cold weather ?

Depends on where you drive it! What kWh is the battery? Goto the speakEV forums to see what actual drivers are getting. What size is the battery?

Also - when does the "memory effect" start to kick in - in terms of battery charge ?

No such thing. I think you're thinking on NiMH batteries. These are Lithium Ion amd there is no memory effect.

Yes - if the range is so poor that it needs plugging in every day ?

Another misconception. You don't have to wait until a car is empty to plug it in. You can plug it in whenever you like. You can set a charge timer on most cars, so that it DOESN'T charge when you plug in, only beteween certain hours. If you know it's cold, and you want to pre-heat your car for the morning, plug it in. Nothing to do with charging and range, everything to do with comfort and convenience.

50Twuncle

almillar wrote: »

Depends a bit on the car. Many these days have a heat pump, some use an electric element to heat the air - this is less efficient, and has more effect on battery.
For a literal answer, I've had a Renault Zoe and Kia Soul EV - these both show, at the start of a cold morning, 2kW going to the heating system. That will of course tail off when up to temperature. These cars both have heat pumps.

But you're onto a myth. The amount of energy used to heat the car, is dwarfed but the amount used to move it. And the loss of range in winter (I say sort of one third less - 66miles instead of 100 in summer, in the UK, safely), is mostly caused by... the cold weather, as DrEskimo points out. An Eskimo should know! When the batteries are cold, they have less capacity. Same with your phone, laptop, tablet. The chemistry just works far better above, say, 10 deg than below.



A strong case for pre-heating. If you charge overnight, almost any EV can be programmed to be 'warm' at a certain time. This means you're not taking range to heat the cabin of the car, and depending on the car, the batteries might also get a nice heating to a more ideal temperature, helping range again.


Depends on where you drive it! What kWh is the battery? Goto the speakEV forums to see what actual drivers are getting. What size is the battery?

No such thing. I think you're thinking on NiMH batteries. These are Lithium Ion amd there is no memory effect.



Another misconception. You don't have to wait until a car is empty to plug it in. You can plug it in whenever you like. You can set a charge timer on most cars, so that it DOESN'T charge when you plug in, only beteween certain hours. If you know it's cold, and you want to pre-heat your car for the morning, plug it in. Nothing to do with charging and range, everything to do with comfort and convenience.

But running any car in frosty/icy weather will require its heating to be run constantly - not just to de-ice the screen first thing in the morning
This will clearly decimate the range ?