Buying a used Prius- questions

The Energy Screen is certainly active, especially once the battery is topped up, I prefer the more sedate Consumption Screen as it seems way less distracting. (5 minute averages instead of second by second reporting)

The engine will turn on, as the battery discharges (headlights, foot on brake, A/C, Heater, radio, etc.) When the car first starts, the Engine will run to heat up the catalytic converter. If you have the heater on, it will run the engine to get hot water for the heater.

Once the car is warm, the engine runs less, as you are down to electrical load being the reason to start the engine.

Wild Speculation: It is possible the 12v battery is getting old on the 2005. If it has the original 12v battery, make a new one a condition of sale, or plan your offer lower by the price of a 12v battery. Four years is a typical life for a 12v battery in all cars.
http://www.elearnaid.com/12vo1topraub.html

As the 12v battery does not run a starter motor, our ability to recognize a weak battery is reduced in a Prius. In other cars, most of us realize our battery is bad while starting. In a Prius, a weak 12v Battery can spend a LOT of time and energy trying to charge.

Some folks report a 10 MPG increase from replacing a bad 12v battery.
http://priuschat.com/forums/gen-ii-prius-fuel-economy/71920-10-mpg-loss-solved.html

 

Short trips and cold weather hurt the fuel economy of every car; it's just more obvious in a Prius (not worse: more obvious because of the continuous display).

It's perfectly normal for the instantaneous fuel economy to jump around a lot.

The engine will start and run as needed for many reasons:
- to keep itself warm, which improves economy and emissions
- to keep the cabin warm (did you have the heater on?)
- to charge the big battery
- to produce power for the wheels

 

The Prius doesn't have a starter motor but instead uses the electric motor for this function, right? So what does the 12v secondary battery do? Can't the main battery supply juice to start the car as well?

 

The 12V battery boots the computers and also supplies power for the radio, lights, etc. when the car is not in Ready mode.

Once the car is booted into Ready, 12V power is supplied by a DC to DC converter from the HV battery. At this point you can remove the 12V battery and everything will still work just fine.

A failing 12V battery will not charge, so it continues to soak up electrical power. This power ultimately comes from the engine, so a failing 12V battery will cause the engine (ICE) to run more and more often.

Tom

 

It could in principle, but Toyota presumably found it safer to keep the two systems separate.

 

[Cynical] Toyota lawyers want to say with a straight face in a court of law that the High Voltage system is only engaged once the computers think it is safe. If you power those computers via the HV Battery, they can't say that. So we have a small 12v battery to power the computers through the start up checks. [/Cynical]

 

For the 2005 I'd insist it be replaced no matter how it tests - unless they can show that it already was replaced of course. For either car see if you can get them to check/correct the alignment as a condition of sale as well. They may not make it as perfect as it could be but at least you'll know it's not completely out of whack. Lastly, get the full service records. I was amused to see that on mine they'd done some minor parking lot ding repairs to prepare it for sale, but in another thread today I see that member spitinuri caught and then verified some major collision repair via service records.
Kudos for getting on the boards BEFORE buying - I certainly would have driven a harder bargain if I'd known more!

- D

 

Possibly ... but other factors can cause the ICE to restart. For example, when the main/traction battery pack needs charging, it's designed to come back on.

Have 'em show you the CARFAX too ... just to make certain it wasn't blackened with some kind of nasty history. As others stated ~ don't worry about the display showing mpg's in the 30's. Being for sale, that may simply represent numerous short test drives. Short drives & cold weather are the killer of mpg's for ANY car, including the Gen II.

and welcome to PC!
:welcome:
.

 

What about for a 2006 - 3 1/2 years old?

 

might not be a bad idea. the battery can EASILY be ruined in much less time than that.

my SPM (look in Sig) is 2006 and i have jumped that battery twice. my SO was washing car one day and my 2 yr old son was allowed to wander around inside. he sat there flipping dome lights on and off, etc. and that was enough to kill the battery.

now granted, it was one of those "nook and cranny" cleaning jobs that took an entire afternoon, so not like leaving the lights on for 15 minutes will do it.

but only have to do something like that a few times to cause damage. the battery is very small, nowhere near the size of a normal car battery.

 

Wow, this has been a very useful thread so far. I'm thinking about buying a 2004 Prius with 81K miles from a private owner. It drives well and apparently has been getting around 45mpg, but it has some cosmetic issues: much of the interior fabric is worn (like the sun visors), there's some residue from a previous set of vinyl lettering on the paint, and so on.

I've seen the KBB and Edmunds prices for cars in this year and mileage range. Having said that, what's the *real* market price? What would you pay for a vehicle of this vintage knowing what you know about the Prius?

 

The real market price depends on the market conditions in your area. How many used 2004 Prius models are available? You could also check NADA.

 

I'm probably buying a used 2006 Prius, 63K, certified, with Package #8 on Monday. 63K over 3.5 years means 18K/year, which is more than the recommended 15K / year. Is that of concern?