Battery Charging

[Hopkirk]

Does it take more power to charge an electric car from 90% to 100% than from 10% to 20%?

[barry1010]

No, I don't know why you think it could. It is the same measure at both ends of that scale.

[bhg481]

The charging could be less efficient as the battery becomes full, so you might waste more power. I understand from a friend who has an electric car that you shouldn't charge to 100% as a matter of routine as long-term battery life is affected.

[davebro]

Estimating the Charging Profile of Individual Charge Sessions https://www.mdpi.com › pdf

[davebro]

they battery monitoring app for mobile phones recommends only charging to 80% for best battery life.

[davebro]

link not as intended - google "electric car charge profile"

[ZebuSanctuary]

Could this be analogous to pumping up a tyre? It requires more energy as you approach full inflation since the compressed air inside the tire, puts up more and more resistance to the incoming air being pumped in.

[Hopkirk]

The car is leased so battery life isn't high on my list of worries. For range I sometimes charge to 100% but was worried I was paying more to squeeze the last bit in.

[bhg481]

You're better off squeezing as much as possible at home as commercial chargers have got expensive; as expensive as petrol, I've heard.

[Hymie]

Your vehicle battery will be storing energy in kWh, since you will be paying for the electricity used to charge the battery in kWh, the state of battery charge should have no effect on the cost of charging.

But heating losses during fast charge could result in an increase in kWh used to charge the battery versus a slower charging rate with less heat loss.

[Hopkirk]

Oh I do it all at home. 5% VAT at home as well.

[Hopkirk]

I also do it very slowly with a three pin plug.

[Zacs-Master]

‘Your vehicle battery will be storing energy in kWh’

Erm, no. Your battery will be storing energy, the use of which can be measured in kWh. Bit of a difference.

[bhg481]

Nor does it follow that feeding a quantity of electricity into an empty battery results in the same increase in stored power of the battery as does feeding the same quantity into a nearly-full battery.

[sunny-dave]

Check your settings - if you can find one that limits 'routine maximum charge' to 90% then that will extend the number of charge-cycles that the battery will manage before the maximum charge level starts to decline. You can then override this setting if a 100% charge is going to be needed for a longer trip.

[sunny-dave]

Oh .... feckit

Have just read that this is a lease car, so my typing is irrelevant to you, but may help others

[bhg481]

dave - not necessarily irrelevant; reduced capacity results in reduced range even if it doesn't increase the risk of needing a replacement battery.

[Hopkirk]

I think it's the rapid charging that causes most 'wear'. I do the opposite, very slow charging.

[sunny-dave]

Not quite the same, but I've been 100% charging my PHEV for the last three and a half years - from a standard home wallbox - and the predicted range is still identical with that when new.

Excellent car (KIA Niro PHEV) for my purposes - virtually all local trips on the electric power (up to 35 miles), then switch to hybrid (or even pure petrol) mode for longer trips.

35 electric miles for about €2 (was €1 until latest rise in prices) then about 70mpg once the pure electric range is finished.

[Hopkirk]

Thanks Dave.

That's my next question.
As the battery degrades, does the displayed predicted range drop? Alternatively it might still claim the same range, but not achieve it.

[Hopkirk]

(I don't know why I'm worrying about that. I've only leased it for four years)