How much power do we actually use
Discussion
In terms of bhp, how much do we actually use on a daily basis.
I’ve recently got a Tesla, a RWD model Y. Or the slowest one they make by another name.
The car is full of data, and with the right apps connected you can pull pretty detailed info out of it. One I have found particularly interesting, being a bit of a nerd, is the instant power consumption for any given drive. Example below.
Something that surprised me a smidge was that in the above trip, I did use 290ish bhp, once. And that was overtaking a tractor.
A part of me wishes I had taken the hit on the cost, and got a perf model, but looking back at most of the trips since I turned the capture on, I regularly seem to genuinely use more than about 130-150bhp? I wonder if I’m getting old, or if most of us only use about half (or less) of modern cars performance 99% of the time.
NB: Tesla don’t give power figures on the new model y for some reason. The highest I have seen so far is 222kw, so 297bhp, but I’ll see what the highest figure I can get out of it with full charge is if anyone is interested.
I'm surprised you're surprised tbh. These look like reasonable numbers.
Engine/transmission sizing is based on balancing the edge cases (overtaking, max grade) vs maximising efficiency for the rest of the time.
When at steady speed on a flat road, you're fighting air drag (below 100mph not that big) and rolling friction. That's the order of magnitude these things have.
Engine/transmission sizing is based on balancing the edge cases (overtaking, max grade) vs maximising efficiency for the rest of the time.
When at steady speed on a flat road, you're fighting air drag (below 100mph not that big) and rolling friction. That's the order of magnitude these things have.
Having had a xe s and now polestar 2 with 400bhp I'd agree that chances to use power are often limited, and it would be quite tiring in reality to always be 'on it'.
To be fair to you, 90% of drivers would have stayed behind the tractor and so wouldn't have even used that spurt of power!
To be fair to you, 90% of drivers would have stayed behind the tractor and so wouldn't have even used that spurt of power!
The lowest power output cars on the road these days have something around 60bhp.
Even in one of those (such as the hateful base model Vauxhall Crossland which seems popular on hire fleets at the moment) can keep up with traffic without constantly needing to use the engine at the rev limit, and their top speed is at least 20mph above the speed limit. That must mean that in normal (legal) driving significantly less than 60bhp is used the vast majority of the time.
There will be brief periods where more power than that is used in a decent car, particularly during overtaking, though that is mostly because it is there and you might as well use it. It's still possible to overtake with 60bhp, it just takes more planning and using every bit of power available.
Even in one of those (such as the hateful base model Vauxhall Crossland which seems popular on hire fleets at the moment) can keep up with traffic without constantly needing to use the engine at the rev limit, and their top speed is at least 20mph above the speed limit. That must mean that in normal (legal) driving significantly less than 60bhp is used the vast majority of the time.
There will be brief periods where more power than that is used in a decent car, particularly during overtaking, though that is mostly because it is there and you might as well use it. It's still possible to overtake with 60bhp, it just takes more planning and using every bit of power available.
Very little. Peak power outputs are great for bragging, but people generally spend most of their driving time well below the peak. A bike magazine did an article a good few years back and the majority of riders were only using a handful of BHP, even on a fast (ish) ride. Unless you are foot to the floor and running every gear to the redline then your average power consumption (and as a consequence, generation) will be well below what you can theoretically achieve.
I'm guessing car power ratings are a bit like audio ones, with people boasting about their 300W amplifiers at home, not realising that, at normal listening levels, they're probably using about 10-20W.
That said, I probably use a higher percentage of the 400bhp in my car than I do the 16,400W available in my loudspeakers at home...
That said, I probably use a higher percentage of the 400bhp in my car than I do the 16,400W available in my loudspeakers at home...
LimaDelta said:
Very little. Peak power outputs are great for bragging, but people generally spend most of their driving time well below the peak. A bike magazine did an article a good few years back and the majority of riders were only using a handful of BHP, even on a fast (ish) ride. Unless you are foot to the floor and running every gear to the redline then your average power consumption (and as a consequence, generation) will be well below what you can theoretically achieve.
Ignoring (UK irrelevant) very high speed driving it's not actually possible to use peak power output unless you are rapidly accelerating the car.The cruise power demands are an order of magnitude lower than during rapid acceleration.
This chart explains it for a typical EV drivetrain in a large SUV:
70 mph cruise requires a measly 30 kW at the driven wheels plus a bit more for cabin/system cooling.
At 100 mph the cruise power is about 50 kW.
Yet 0.5G acceleration from 70 mph requires 400 kW.
Peak power is ONLY ever used for acceleration (unless you are trying to crack 200 mph).
Edited by GT9 on Friday 2nd June 16:49
Chubbyross said:
My last car (997.2 turbo) had approximately 500bhp and I probably managed to put my foot to the floor on no more than five occasions. It’s just not possible these days with our roads. Even when overtaking I’d go nowhere near the power limit.
But it’s not just putting foot to the floor. When I used to regularly put my Sport Displays on on my 335d, foot to the floor gets the turbo going and the torque reaches peak very quickly. It then stays at peak, as the power (bhp or ps) climbs with the revs. But as said, normal cruising uses very little power.
kambites said:
Not sure why this got moved to the EV section; the question was really nothing to do with EVs!
Anyway the answer on my drive home was a peak power figure of a mighty 52bhp.
No idea how accurate the ECU's calculations are, mind.
Agreed. Mods ! Back to general gassing.Anyway the answer on my drive home was a peak power figure of a mighty 52bhp.
No idea how accurate the ECU's calculations are, mind. Edited by kambites on Friday 2nd June 18:04
Walshenham said:
TheDeuce said:
I was looking for piston heads, I've found Mumsnet...
I'll let myself out
This man uses 800bhp on his driveway. I'll let myself out
Just found it interesting how little I actually use on a typical drive. I would have considered myself… someone who makes progress.
I would say in my EV I very frequently use full power, but only for very short periods of time in the overall journey. It takes seconds to get to 60/70, whatever the speed limit in force happens to be. Once there it obviously uses a lot less. But I like getting to those speeds quickly, it's fun. It's also fun to power hard out of corners on a decent (and well sighted..) b-road.
Obviously overtaking is the time at which it's extremely useful to have a lot of power - the more the better really. No one likes being hung out on the wrong side of the road for any longer than they have to be.
But mostly, it's definitely about fun, top trumps and enjoying driving a car that feels and is very powerful. It's not about need, 50-60bhp would be enough for the average size car.. But if you drove such a car you'd miss the power you "don't need".
Which was kind of my point.
I would have said I use a lot more of the power, a lot more of the time than I actually do!
That’s what threw me a bit, not the cruising power, I get that, but that I use less of it, and less often, than I thought I would.
Just found it interesting.
Nb. Managed 230kw peak a few mins ago. 309hp is my new record
I would have said I use a lot more of the power, a lot more of the time than I actually do!
That’s what threw me a bit, not the cruising power, I get that, but that I use less of it, and less often, than I thought I would.
Just found it interesting.
Nb. Managed 230kw peak a few mins ago. 309hp is my new record
IntriguedUser said:
I'd rather use 100bhp in a 200bhp, than use 100bhp in a 130bhp car.
Even though that's all your using, how that feels is going to depends on what your driving.
Personal thing obviously, but I'd rather use 100bhp in a 130bhp car; I'd even more rather use 100bhp in a 100bhp car. Even though that's all your using, how that feels is going to depends on what your driving.
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