Hello guys,
Just wondering what turns the air cond's compressor in these type of cars when the engine is not running(hybrid) or the car is not moving? For example if i'm stopped at the traffic lights, the engine in a hybrid car would shut off. In an electric car the motor doesn't turn. What turns the air cond compressor then? If it relies on the car's movement then how about in a traffic jam?
Thanks.
Uses an electric motor like an 'in house/office' air con unit would?
Doubted so because that kind of motor would be a high torque motor, high torque motors drain very high ampere and it would deplete the battery quite fast, of coz not as fast as the car's main motor but it still would.
Even if you say it's powered by a c>
Well its either gonna be a seperate electric motor, or via a pulley connected to whatever is moving. If you work under the assumption that its only used when hot and sunny, then it could be solar-powered. Although i suppose that wouldnt really produce enough power. Maybe they just dont have air con? Maybe it just uses the cars battery when not moving, and eventually shuts off in the battery power becomes too low?
There are many methods. Some DO use electric motors. Think about it on an EV car the motor on the compressor will be nothing compared to the motor that actually MOVE the car!!! Others use peltier heat pumps, but these are not as good at cooling as they are heating. EV cars also have heaters. These are electric heaters :)
Ed
Well, don't just worry about air-con, but what about the heating? We're used to having about 5,000 watts of heating available in a 'normal' vehicle. That translates to almost 7 bhp - which would be enough to trundle a low energy vehicle at about 30 mph.
K11 Nissan Micra.
Features (current setup):
AC Electric Vehicles AC-drive system Battery type: Optima Yellow-Top, capacity: 300V, 14kWh (2h rate) Heater: heat pump, maximum heating power 4.2kW Air Conditioner: heat pump, maximum cooling power 1.6kW
Performance (current setup):
Motor output power: 120 hp @ 4700-8000 rpm, 90 hp @ 11400 rpm Motor torque: 180 Nm @ 0-4700 rpm Top speed: 200km/h Acceleration 0-100km/h: 10s Range: 180km@40km/h, 120km@80km/h, 100km city, 20km full power (190km/h avg.) Recharge time, normal charge:
Ed
Interesting. 230v at 16A for 7 hours equates to 25.7 kWh to re-charge a 14 kWh battery. So the inefficiently generated electricity from the mains is losing another 50% or so in the charging process. I'd say you're better burning the gas used for electricity production direct in an I/C engine...
It is interesting.. It shows just how inefficient the some of the best best lead acid batteries still are!! Not to mention all the power lost from generating the energy in the first place and getting it to the house to do the charging.
Ed
Yup.
A modern coal-fired power station can manage about 35% calorific efficiency , then you have about 5-7% losses in the national grid, and approx 50% efficiency in the charging process, gives an overall efficiency of about
16%. The efficiency of a modern petrol engine is about 26%, and that of a diesel is about 40%, so Dave is quite right - you burn 60% more fuel to run the electric micra than you would an equivalent petrol-driven version, and 145% more than a diesel equivalent!Battery technology sucks :(
Pretty well all common batteries are. Ni-Cads etc need charging about 50% more than they actually 'hold'.
Woooo an electric car using lead acid batteries sucks... it's better off using NiCads like in a hybrid car because NiCad has much higher capacity compared to lead acid of the same weight.
So it seems these 'electric' cars use a peltier element to cool the air or heat it up... hmm >Dave Plowman wrote:
So does hydrogen. The only way to use fuel sensibly is to burn it in the engine as efficiently as possible. Anything else is just wondow dressing.
Sadly politicians are too thick to understand the difference.
It's not that simple though. It takes a lot of energy to refine the fuel so it can be used in an engine. You also need to transport it to where it's needed.
But they cost an arm and a leg, and Ni-Cads are likely to be banned on environmental grounds.
Well, many power stations use natural gas, and there's already an infrastructure for moving that around the country.
They also have a memory effect, so unless you drain the batteries totally, they're useless after a couple of years.
NiMH or Li-Ion are better, but lead acid is utterly reliable in comparison, and lower cost.
Richard
It's a bit of an urban myth, unless you really do discharge them to
*exactly* the same point before re-charging - unlikely with a car. It is a convenient excuse for cheap and nasty chargers as supplied by many for power tools etc.Yes. There's still a lot to be said for lead acid. Despite the billions spent on alternatives.
Interesting thanks for that. I was having a discussion on battery tech the other day - and yes indeed. Its very poor!!
Agree they are pretty durable by some standards, and as mentioned cheap. Li-ion are not suited at all for applications like that and cost a fortune!
Ed
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