What all devices in prius will affect gas mileage?

Mileage is a matter of power consumption; only devices that consume large amounts of energy have a significant impact. On your list, the A/C and heater are the main culprits, although in the case of the heater it's not the electrical load so much as the fuel being burned to make heat.

Tom

 

I think the top MPG killers are the heater, a/c, and headlights.

When you demand heat, the engine needs to run and consume fuel.

While the a/c is electric, it still consumes fair amount of power (I've seen current drain up to 10Amps in the summer).

The headlights use around 2 Amps. While not a lot, when you are sitting in traffic, they can drain the HV battery down faster.

Others on your list are negligible, IMHO.

 

<_< All devices will have some effect on fuel consumption. I agree that the heater has more than most others since it causes the ICE to run more. Whatever runs on electricity will cause the battery to be recharged and there's efficiency loss through the systems generating electricity. The halogen headlights actually consume about 60 watts and the HID headlights 35 watts [Page 419 in my 2007 Owner's Manual]. I agree that heating and air conditioning probably have the most effect. Some Prius drivers "warm up" the Prius before driving away - that would be a MAJOR reduction of fuel efficiency. With the ICE coolant thermos, the Prius warms up in a reasonable time. Another waster or fuel would be underinflated tires increasing rolling resistance. Some Prius drivers run Goodyear Integritoes at 44psi front/42psi rear to help a bit on MPGs - you can gain MPGs at the expense of a 'harder' ride. On my 2004, I ran at 40/38 psi, but on the new 2007 Touring, I run at 37/35 psi - too soon to evaluate fuel economy on the 2007, only ~1,600 miles on the clock.

The only source of energy in the Prius is gasoline, the Prius just uses it much more efficiently than conventional cars.

ENJOY YOUR PRIUS... it is, indeed, a remarkable example of superior engineering.

 

<div class='quotetop'>QUOTE(Tideland Prius @ Jan 9 2007, 06:12 PM) [snapback]373327[/snapback]</div>

ohhh yes... I forgot about that. Thanks for pointing that out.

 

<div class='quotetop'>QUOTE(poodlemaster @ Jan 9 2007, 07:27 PM) [snapback]373352[/snapback]</div>

I think it takes higher *voltage*...which is not really a measure of 'quantity,' but more of 'pressure' (if you think of an electrical wire like a water pipe).

 

HIDs need a very high voltage with a bit of current behind it to *start* the arc, but that's only for a fraction of a second. Once the gas in the bulb is ionized, it forms a very low resistance path, and will stay ionized with very little power. Conventional fluorescent tubes work on a somewhat similar principle (ionized gas), and this is part of the reason why they are so energy efficient..

 

I can't speak for really cold places (like San Francisco... tee hee), but here in Los Angeles, if you are on the freeway, your IC engine is always producing excess heat as part of the combustion process. It is hard to believe, but only 25 to 30 % of the energy in the fuel is used to move the car. The rest of the energy is just converted to waste heat that must be gotten rid of.

Part of the waste heat goes out with the hot exhaust to the tailpipe. The majority is transported via the coolant to the radiator in the front of the car.

When you raise the temperature in the climate control system, some of the hot coolant is diverted to a small radiator underneath the dash. The air passes over this small radiator and heats the passenger compartment. This is how every normal car operates, and I am assuming that this is the same in a Prius.

So, using heat for the passenger compartment will not use up any energy (at least while the engine is running - such as on the freeway). In fact, you could think of it as increasing the efficiency of the engine, since some of the waste heat is being put to good use.

 

John,

Those of us who live in the northern states will think otherwise. (you lucky bastard! )

This morning's outside temp was in the 30's. During first couple of miles, if I set my cabin temp to 70 and wait at a red light. The ICE will need to kick in to provide heat. Fuel is being consumed but car is not moving, MPG = 0!