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Regeneration will make a difference

Basically coasting > regen > braking. So when you cannot safely coast to a stop, regen > braking.

Drive mode is a little more difficult to judge, as I don't know the actual settings that are changed. The electric motor can't be changed, but the pedal response curve can and indirectly it can impact your driving efficiency. And again, I'm not saying the car's efficiency, but your driving.

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Yep, that's about the size of it. Also, unless you have to stop really sharply, the brake pedal will be using regen to slow, up to as much as pulling the left paddle can do (about 0.24g according to the regen curves I've seen).

Regeneration will make a differenceifyou are doing a lot of stop-starting that you cannot predict. If you always let off the accelerator when coming up to a roundabout or traffic light such that you glide to a near stop anyway, regen won't help. If you're cruising on the motorway for hours, regen won't affect your range noticeably either. However, if you have to stop more suddenly (e.g. car in front decides late that they want to make a right turn), doing more braking with regen instead of traditional brakes will waste less energy. Same if you're driving through town and there are just junctions and roundabouts every 100m: it's impossible to drive through these conditions without using brakes without infuriating those behind you.

Basically coasting > regen > braking. So when you cannot safely coast to a stop, regen > braking.

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Agreed, as regards regen level, it's a case of whatever floats your boat. Even in level 3 you can spend just as much time hovering around 0 power. The drive modes have progressively steeper torque curves that also top out above each other, but again it's all under the control of your right foot. I suspect the fact that the car won't default to SPORT mode is Kia's attempt to stop you caning the battery too often.

Drive mode is a little more difficult to judge, as I don't know the actual settings that are changed. The electric motor can't be changed, but the pedal response curve can and indirectly it can impact your driving efficiency. And again, I'm not saying the car's efficiency, but your driving.

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As I said at the beginning, other things being equal .... Obviously, there is a temptation in SPORT mode to get more of a wriggle on, but if you drive the same as usual, the energy required is the same.

I agree with everything else, but not this. the battery losses (and other resistive losses) are proportional to current squared.Also, partly because there are no gears, slow vs fast acceleration doesn't make much difference either.

Let's say you need 10kW for normal driving (a current of about 28A) and you choose to accelerate as here:

Case (a) - Accelerate quickly, let's say in 5s, with 60kW power

Current ~ 60,000/356 = 168A

Losses are proportional to 168^2 x 5s + 28^2 x 5s ~ 145040

Case (b) - Accelerate slowly, let's say 10s at 30kW

Current ~ 30,000/356 = 84A

Losses proportional to 84^2 x 10s = 70560

So the losses in the rapid acceleration case are 2.05 times greater. So you would arrive a bit quicker, reducing aerodynamic losses and rolling friction, but only 5s quicker (if you only did it once ) , so roughly speaking the losses are twice as big.

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It's a bit more complicated.Let's say you need 10kW for normal driving (a current of about 28A) and you choose to accelerate as here:

Case (a) - Accelerate quickly, let's say in 5s, with 60kW power

Current ~ 60,000/356 = 168A

Losses are proportional to 168^2 x 5s + 28^2 x 5s ~ 145040

Case (b) - Accelerate slowly, let's say 10s at 30kW

Current ~ 30,000/356 = 84A

Losses proportional to 84^2 x 10s = 70560

So the losses in the rapid acceleration case are 2.05 times greater. So you would arrive a bit quicker, reducing aerodynamic losses and rolling friction, but only 5s quicker (if you only did it once ) , so roughly speaking the losses are twice as big.

Resistive losses in watts (W) in the battery are equal to the battery current (I), squared, multiplied by the battery's internal resistance (R)

I^2R = W

Resistive losses in watts (W) in the motor are equal to the motor current (I), squared, multiplied by the motor's internal resistance (R)

I^2R = W

What makes it more complicated are the majority of resistive losses occur in the motor, not the battery (blue line, bottom middle chart), and the motor current is nearly always significantly higher than the battery current.

Motor Current (I) = (Battery Voltage (V) * Duty Cycle (D)) - Back EMF Voltage (B)) / Motor Winding Resistance (R)

Battery Current (I Bat)= (Motor Current (I) * (Battery Voltage (V) * Duty Cycle (D))) / Battery Voltage (V)

^When the battery current is constant (red line top left chart 25mph and above), the resistive losses in the motor (blue line bottom middle chart) and motor current (blue line, top left chart) decrease with increasing velocity.

Whilst it's undoutedly more complex than I said, I would stand by the fact that it will be better to accelerate more slowly; for one, the charts show that ohmic losses in the motor depend on the range over which you are accelerating, so if we were talking about main road driving I guess the answer would be subtlety different to urban driving, but also whilst accelerating slowly means that you spend less time in the inefficient motor region, you end up spending more time at higher speed with higher aerodynamic losses and they appear to be higher than the motor ohmic losses in the middle top chart, but I'll happily let you interpret that for me as they are a bit difficult to get your head round!

But in the real world it isn't always the case, as sometimes you can't roll/coast due to traffic or a hill being so steep you'd be out of control/breaking limits.

For example, I have a trip to my parents whereby there is a long drag of about a 1.5 miles of gradual descent. If you coast in a 38kwh Ioniq with that you'd be over the limit. I adjust the regen to level 1 and it is just enough to bring it below 60mph. Following that descent is a further 0.5 miles of steep descent. Moving the regen to level 3 for that claims almost 2kwh back in the battery over 2 miles.

So regen where you need to, but aim to coast.

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With the "rubber band" effect in Level 3 it's easy to be fooled into thinking that accelerating and regening are both the same energy-wise, but regen losses can add up quickly if that is frequently used.

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I'll stick to practical observations, and leave the theorising to you!

Whilst it's undoutedly more complex than I said, I would stand by the fact that it will be better to accelerate more slowly; for one, the charts show that ohmic losses in the motor depend on the range over which you are accelerating, so if we were talking about main road driving I guess the answer would be subtlety different to urban driving, but also whilst accelerating slowly means that you spend less time in the inefficient motor region, you end up spending more time at higher speed with higher aerodynamic losses and they appear to be higher than the motor ohmic losses in the middle top chart, but I'll happily let you interpret that for me as they are a bit difficult to get your head round!

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The brake pedal will only use friction brakes after it has called up the maximum amount of regenerative braking available at the current speed.Doesn't the brake pedal only do regen if you use it lightly anyway?

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