Markybear999
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Was wondering if anyone could advise on how to make the air on switch on the fiat 500 dash any brighter?
Styling Aircon light
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Styling Aircon light
I would guess the light is integral to the switch, you may be able to install a brighter bulb or Led equivalent, however it may become distracting at night?
Generally you should never turn the AC off(meaning you don't need to know when its on) as it, always is?
Although there are some advantages to this, it costs too much in fuel for me to leave it on when it's not needed.
I've done some experiments and calculations from time to time. For my driving style, the difference in fuel cost between A/C on and A/C off is about 1p/mile; a bit more in summer, a bit less in winter. I use it when I need to, and exercise it at least weekly, but it stays off when it's not doing anything useful. The saving is almost enough to pay for my insurance.
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I don't know how much you're paying in insurance but at 1p a mile an average 12,000 mile a year driver is only looking at £120 saving over the course of a year. Even very very cheap insurance policies are not going to be that cheap.
foambullets
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I turn of the radio, lights and air con before switching off the car and don't switch them on until I start it next time (the air con after she's warmed up for a few minutes). So I encounter this problem as well and I agree that air con light is certainly a tad hard to see during the summer days especially with direct sunlight on it. I just put my hand over the top of the light to see if it's on or not. As other's have said I would think that a brighter light would be distracting during night time driving. If possible perhaps another colour light would be more easily seen during the day without being distracting at night?
£133 Last time around
.But I'd agree that the savings are modest and some folks won't mind paying that to have their A/C running continuously.
Still, every little helps.
I also don't like starting the car with the A/C on (or anything else for that matter) as the additional load on a stone cold engine is significant (about 2-3kW).
The shift towards hybrids and EV's will see more cars using electric A/C compressors, which AIUI are generally more efficient.
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Air con clutch won't be engaged when you start the car and won't be for a few moments after start up either, the engine ECU controls this.
In driving, anything below 30mph it is deemed more efficient to open the windows, anything over 30mph the added drag means it's more efficient to close the windows and turn on the air con. That however is from quite an old study and modern systems are much more efficient.
Your reported 1p per mile saving is equivalent to traveling about 500 feet which is about the length of a long motorway slip road, when you're getting down to those sort of small numbers, a low pressure tyre, a slight hill or a head wind are all likely going to make more of a difference than putting the air con on
Recent tests have debunked this; current thinking is that running with the A/C on costs you money at any legal speed.
My own tests in a 1.2 Panda 169 have shown that at 50mph on a motorway on a hot day, A/C increases fuel consumption by about 15%. That's absolutely in line with what theoretical calculations would suggest.
A/C systems of all types use more power than some people think.
Systems which can vary the compressor speed are the most efficient.
All of these will significantly affect economy; even a modest hill can double your instant fuel consumption. Low pressure tyres are to be avoided, not just for economy but also for safety reasons; the other two are unavoidable, but tend to cancel each other out over time.
It's precisely because many other factors affect fuel economy that it's hard to measure small (as in 15% or less) changes over a short time or distance, but if you repeat a known longer (100 miles+) journey on several occasions, changing one thing at a time, you can get reasonably close to making some meaningful comparisons.
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Main reason to turn the A/C off when not needed is if you've got a non-turbo 4 cylinder car, it will feel like crap at low revs. If the A/C kicks in during a hill start it can be enough to cause a stall or if you're rev matching gearshifts, it can mean less than smooth shifts. I've absolutely hated having the A/C on in every NA 4 I've ever owned. Fortunately the TA doesn't have this issue at all.
Mitsubishi's I-Miev AC is rated for 3kw, or almost the same power it takes for a Fiat 500 to cruise at 30mph. It's potentially a massive hit to economy.
Mitsubishi's I-Miev AC is rated for 3kw, or almost the same power it takes for a Fiat 500 to cruise at 30mph. It's potentially a massive hit to economy.
It certainly challenges the 1.2 FIRE below about 1800rpm. When ecodriving below 35mph, you need to be one gear lower with the A/C on. If you change into 5th at 1400rpm (Fiat's recommended change point on ecoDrive), it practically kills the engine. With A/C off, it'll pull away cleanly at these revs.
HVAC places some challenging demands on an electric vehicle. IIRC some burn fossil fuels for winter warmth, which to my mind defeats the point of having an EV.
In town on a very hot day, a 3kW drain from the A/C would seriously impact the range - IIRC it's got a 16kWh battery that's supposedly good for 99 miles.
But it illustrates the point well; A/C systems by their very nature are power hungry and to cool a hot car reasonably quickly, are going to draw around 3kW of power. Granted, they won't need as much to maintain temperature once the car has cooled down, but the impact will still be significant.
There's no such thing as a free lunch.
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This is where is helps to check your sources, firstly... well it's the daily mail, secondly it's a story taken from another site who are specialists in creating news, then on top of which it's their interpretation of one study where they don't even give a definitive answer and disregard other evidence.
Cars and the electronics in cars are very good these days at squeezing the most out of every drop of fuel so as not to fall foul of the emission testers, aircon is no different, on a Car with an internal combustion engine the ECU will match the cycles of the compressor as best it can with coasting in gear and rolling down hills etc, running the air con system with out burning fuel in these instances, evenwhere a little fuel is used this is just to keep things ticking and the inertia of the car also adds some power to the system.
You can't compare an electric car air con compressor, it requires a dedicated motor just to spin the compressor and keep it going without any other outside forces acting upon it. So all the time the aircon is on, the motor needs to be running and burning fuel, it's not practical to keep switching a motor on and off so the system will be balanced to operate constantly with the motor giving a set speed.
Window down causes a lot of drag, stick your arm out the window, yet more drag.
My point with the above is your estimated 1p per mile saving turning off the aircon, it's such a small amount, less than 10% and even repeatedly doing the same journeys the air temp, group temp, wind direction, condition of the car and amount of fuel in the tank are all variables which could equally make a similar level of difference to the efficiency.
I would be more understanding if it was a bigger number 3 - 4 p a mile but my actual point is the claimed saving is so negligible it's in the realms of being more perception than hard fact.
No different to people who only buy tesco petrol rather than Asda because they get an extra MPG here or there, their car runs better, or the car goes faster, it's all from the same sources and any difference is not going to be measurable in normal daily use.
1p a mile difference falls in the that category, it would not be possibly to scientifically prove a 1p a mile difference from using the aircon in normal every day use, too many other variables including confirmation bias.
Actually my confirmation bias started the other way - for a long time, I've been trying to refute all those who claim that A/C doesn't significantly impact economy. I'd love to be able to leave it on with a clear conscience.
But I can't.
Cooling a small car using A/C on a summer's day requires at least 10% of the energy that's needed to propel it along at 50-60mph. That's just basic physics; there's no way round it.
I wish that you were right, and I were wrong.
But I'm not.
Then feel free to publish all your scientific data, all the measurements you've taken and the paper you wrote to confirm all your findings.
Seriously, confirmation bias is confirmation bias no matter which way you look at it and whether or not your view has changed. Scientists no matter what have to factor out their own belief when doing experiments regardless of their point of view, they then get peer reviewed and others then may replicate the experiments to see if they get the same results, to come to the conclusion on a hypothesis may take many different people doing many experiments following the same or different methods over many years. Whatever the case I don't really care, in this instance your claimed 1p per mile saving is too insignificant to draw any conclusion and could just as easily be explained with you having had a big meal or it being a particularly damp day. What ever the situation 1 bloke with 1 car and to many variables to measure, without their being specific and scientific analysis, I still declare BS
I would also declare the same on the insurance costs, many insurance companies have an absolute minimum amount they charge now, somewhere in the region of £250-300 no matter what you drive, your age or mileage covered, maybe if you had a classic car that was only coming out for events and traveling less than 1000 miles a year but then classic cars tend to cost a lot to repair pushing the price up again.
We have two cars.
One is a Clio we've had since brand new in 2001, and the other is a 500TA.
Clio has aircon, and 500TA auto climate control (air con of course).
I've experimented.
Not done actual figures or produced a paper, but I have found no problem whatsoever in leaving the systems running.
Years ago, I was driving up the M5 in the Clio with the tip computer displaying average fuel consumption. The M5 is flat for mile after mile, and I went along for a while after resetting the computer in aircon, then turned it off, reset the computer, and went along again. I saw no difference whatsoever.
However, if we get into either car when it's boiling hot, there is a distinct lack of power as the engine has to work harder. Generally though, there isn't a downside or a suffering in economy. No doubt it costs something as there is no such thing as a free lunch, but the "lunch" is a very cheap one and a penny a mile is way over the top in my opinion.
Also, do not forget, that air con is air conditioning. It doesn't have to be freezing cold.
Aircon conditions the air. It cleans it and it dries it.
I'm a big fan of aircon. Both our cars have it on permanently. The Clio has done close on 100,000miles now, and the system has never been serviced, but works perfectly.
By the way, last insurance renewal with the 500TA was £154.
Regards to all,
Mick.
One is a Clio we've had since brand new in 2001, and the other is a 500TA.
Clio has aircon, and 500TA auto climate control (air con of course).
I've experimented.
Not done actual figures or produced a paper, but I have found no problem whatsoever in leaving the systems running.
Years ago, I was driving up the M5 in the Clio with the tip computer displaying average fuel consumption. The M5 is flat for mile after mile, and I went along for a while after resetting the computer in aircon, then turned it off, reset the computer, and went along again. I saw no difference whatsoever.
However, if we get into either car when it's boiling hot, there is a distinct lack of power as the engine has to work harder. Generally though, there isn't a downside or a suffering in economy. No doubt it costs something as there is no such thing as a free lunch, but the "lunch" is a very cheap one and a penny a mile is way over the top in my opinion.
Also, do not forget, that air con is air conditioning. It doesn't have to be freezing cold.
Aircon conditions the air. It cleans it and it dries it.
I'm a big fan of aircon. Both our cars have it on permanently. The Clio has done close on 100,000miles now, and the system has never been serviced, but works perfectly.
By the way, last insurance renewal with the 500TA was £154.
Regards to all,
Mick.
............ and I agree with you on the rest too.
Our Fiat does not have ac but the Mazda has, I'm more that happy to spend that little extra for a cool car, given its not that great on economy especially the way it's driven I don't notice any increased fuel consumption 30-32, about 42 MPG on the motorway
The basic calculation is quite simple.
Petrol has an energy density of about 9.6kWh per litre; a modern engine like the 500 will likely be about 25% efficient, so a 2.4kW A/C compressor running at full power will burn about a litre of fuel each hour.
Now most of the time the compressor will be cycling on & off; if it's working 50% of the time (and 1.2kWh is a reasonable figure for the energy needed to keep a small car cool on a summer's day) then you're buning an extra half litre of fuel an hour. Cruising at 55mph, I'm using a little under 4.5l/hr for propulsion, so that extra half litre an hour broadly agrees with the 10% mpg reduction I've measured over a number of different trips.
Petrol has an energy density of about 9.6kWh per litre; a modern engine like the 500 will likely be about 25% efficient, so a 2.4kW A/C compressor running at full power will burn about a litre of fuel each hour.
Now most of the time the compressor will be cycling on & off; if it's working 50% of the time (and 1.2kWh is a reasonable figure for the energy needed to keep a small car cool on a summer's day) then you're buning an extra half litre of fuel an hour. Cruising at 55mph, I'm using a little under 4.5l/hr for propulsion, so that extra half litre an hour broadly agrees with the 10% mpg reduction I've measured over a number of different trips.
Energy for heating or cooling is measured in BTUs or British thermal unit. 1 BTU there are several explanations of this but it's basically 1 BTU is equal to about the energy released by a match.
To cool a 100 sq:ft room you need something like a 5000btu air conditioner. A fiat 500 is considerably smaller than this but cars are more complex as they are generally badly insulated and act like mini moving green houses car air con units are capable of very high levels of thermal cooling, but an aircon system like a car getting up to speed, will use more energy to get the temperature down but once the temp is down to what's require it can cruise, using very little energy. Further points you should note l, that mechanical power is not directly comparable to electrical power. The amount of power the system uses varies massively depending on the conditions inside and outside the car and within the refrigerant within the system.
You can't simply pluck some figures out of the air, make some assumptions and come up with some numbers that suite you. As simple as it seems, squeeze expand and cool, aircon is amazingly complex and the maths involved in working out these complexities goes well beyond some simple number crunching on a forum.
One degree in ambient temperature change either inside or outside the car will totally change the equations and the amount of energy needed to keep the car cool.
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