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Discussion Starter · #1 ·
For arguments sake & to keep it simple:

  • if a 24kwh leaf had SOH of 50%, to 'fully' charge it, would it only take 12kw of electricity?

So it would cost (@10p per kW) £1.20 to drive approx 45-50 miles, or would it still draw 24 kW but still only drive 45-50 miles for £2.40?

Many thanks (and sorry if I've confused my kwh & kW)
 

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Was half asleep at time of posting and realised I missed the point of the question. Others have done a better job of explaining. See their answers below.

Basic answer to the question is yes, but with 50% SOH you probably won't be doing 45-50 miles in a 24kWh LEAF especially in winter.
 

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NISSAN LEAF 62Kwh
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When charging the battery, there will be energy lose to be factored in, from a wall charger this is usually about 10%, for example for every 6.6Kws that leave my charger, only 6Kws arrive in the battery.

The lose from rapid chargers is much greater, but for various reasons, is hardly referred to.
 

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For arguments sake & to keep it simple:

  • if a 24kwh leaf had SOH of 50%, to 'fully' charge it, would it only take 12kw of electricity?

So it would cost (@10p per kW) £1.20 to drive approx 45-50 miles, or would it still draw 24 kW but still only drive 45-50 miles for £2.40?

Many thanks (and sorry if I've confused my kwh & kW)
The basic answer is that, with a SOH of 50% (so 12kwh net capacity) it will only need about 12kwh to fill it.

As mentioned there are charging losses, and one of the things that happens when these batteries degrade is that their internal resistance increases, so losses to heat in the battery are much larger (my leaf internal resistance was over 300 mohm last time I cared to check).

So yes, your fuel tank shrinks.
 
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While there's some excellent info in the previous I'm not sure it answers the ops question. I think they're asking that if a battery has lost half it capacity due to degradation will it still take the same energy to fill but go half the distance - I'm not 100% but my understanding is it would have roughly half the kWhs to fill it (not taking losses into account as mentioned by the previous posters) therefore if it was around 20kWh usable time start it would be roughly 10kWh so around £1 to fill (@ 10pp kWh) not including losses.
 

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Discussion Starter · #6 ·
Thank you for your answers.

You answered my query (I did know about buffers & efficiency, but wanted to keep it simple)

My commute is 25 there & back, so not too bothered about range, was more concerned about the price to 'fill it up' if the battery had degradation - the fuel tank has shrunk - is a great analogy.

Thanks.
 
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