KERS clarification on mixed roads

[Dekkerb]

Hi all. 500 miles in and loving my SR. I know there are various KERS related posts but was there a definitive view specifically around the best (i.e. most economical) setting on motorways and fast flowing
duel carriageways? My new job in January involves an 88 mile round trip mostly on such roads. I tend to go on eco setting from the start when setting off generally but should I keep on KERS 3 for the whole journey or switch to 1 or 2 once I leave the local roads and move to faster roads? Appreciate any advice from experienced owners.

 

[smokie]

I'd just leave it in 3. I'm not sure it makes any difference while you are going forwards but every time you slow for something you'll get a little boost. And save a bit of wear on your physical brakes.

I'm less clear on ECO setting really, though hooning round in any setting will soon gobble your electrons. I think (maybe amongst other things) that ECO accelerates more gently. However that could be like comparing a slow and a fast boiling kettle - they both take the same amount of power to bring the water to the same temp (other than miniscule differences maybe to do with heat loss on the slower one).

 

[Dekkerb]

Thanks for the helpful response as always Smokie. I do sometimes feel I need to 'shift up' from Eco/Kers 3 if going uphill to get some acceleration.

 

[Alb]

I think KERS3 can be the most economical but it has to be controlled very precisely for that to happen.

 

[Dekkerb]

Ooh interesting Alb. Could you expand on what that looks like in practical terms please? Thanks

 

[Jomarkh]

Eco and Kers3 all the way if you want power just press the accelerator more. It is like a scalextric controller don't take your foot off just feather the pedal.

 

[Dekkerb]

Thanks for the useful tip Jomarkh

 

[Petriix]

Kers 3 isn't more economical in any way. It just gives you stronger regen when you come off the power. In many situations that could waste more energy. It does the same job as applying a little pressure to the brake pedal, nothing more.

The kers setting is just about making the car respond how you want it to - feel rather than anything else.

I personally find level 3 too strong for any kind of normal driving where I hope to maintain a relatively constant speed so I end up accidentally slowing too much and wasting energy having to speed up again.

I mostly stick with kers 2 but use 1 for the fast roads and 3 when going down hill or when I'm having to slow down regularly. The point is that kers is only ~60% efficient. It's far more economical to maintain as constant a speed as possible rather than slowing and accelerating.

 

[Gomev]

Kers 3 isn't more economical in any way. It just gives you stronger regen when you come off the power. In many situations that could waste more energy. It does the same job as applying a little pressure to the brake pedal, nothing more.

The kers setting is just about making the car respond how you want it to - feel rather than anything else.

I personally find level 3 too strong for any kind of normal driving where I hope to maintain a relatively constant speed so I end up accidentally slowing too much and wasting energy having to speed up again.

I mostly stick with kers 2 but use 1 for the fast roads and 3 when going down hill or when I'm having to slow down regularly. The point is that kers is only ~60% efficient. It's far more economical to maintain as constant a speed as possible rather than slowing and accelerating.

I agree. On motorways or fast roads in 3 lifting off slows the car too much and you have to use any power regenerated to speed up again. KERS 3 around town and locally, and 1 or 2 on fast roads, this means you can drive as per an ICE car but also regenning a surprising amount in 1 for longer periods.

 

[Alb]

Ooh interesting Alb. Could you expand on what that looks like in practical terms please? Thanks

The trick is to never allow KERS3 to precipitate a subsequent period of acceleration that would otherwise not have happened. If you can do this, none of the energy generated is wasted so it will inherently be the most efficient mode.
Doing it in practice as speeds get higher is quite difficult and requires constant attention so it will not exactly be a relaxed mode of driving.
In short, easy to theorise over but difficult enough to enact to make it not worth the effort for most people.

 

[smokie]

I don't get how using Kers3 is causing people problems, all it's doing is slowing the car and you can still use the brake and accelerator as necessary to smooth out the ride. Reading the road ahead obviously helps.

Anyway on motorways in general using the aids seems to me to be easiest and, of course, safest, generally speaking. I use Kers3 all the time (when I remember to turn it on!!)

 

[Alb]

I don't think it's causing anyone a problem.
My contribution is about whether it delivers (or can deliver) maximum efficiency.
To some that matters and to others (including me) it doesn't.

 

[smokie]

When I wrote that I was really thinking of Gomev, who found it slows the car too much, and Petriix who said he accidentally slows too much on KERS3, but no offence or slur was intended to anyone.

I'm with you on not really worrying too much about maximising efficiency, It is (relatively) so cheap to run anyway that in normal times I just drive how I want. I did do all the hypermiling etc in the old Ampera, and had quite some fun doing it! My driving style has, I guess, adapted to slightly heavier "engine" braking hence why I don't mind being in 3 all the time.

 

[Dekkerb]

Thanks for all the replies guys.