Weird stuff happening? MPGs dropping? Test The Battery

Thanks, Mendel, Richard, will do. And, a dealer drop-off is scheduled for Monday after what happened last night:

A short drive to a downtown parking garage for movies. When I parked and turned the car off the lights were on and window open. Closing the window was very, very slow as though there was no juice despite the lights appearing normal. Got a bad feeling. Founded, after exiting movies to a totally dead car. No tricks worked, had to find a good midnight samaritan for a jump.

-Phil

 

One thing to remember is you don't need monster jumper cables to jump a Prius. Make a nice long jumper cable yourself out of ordinary zip cord (lamp cord) and some small alligator clips, and it'll store nicely in the "secret" compartment in the back end. A couple amps, maybe, to start the computer and you're good to go. Caution -- of course, don't try to use this cable to jump a non-Prius.

 

Richard, to your questions: Assumed the battery was drained last Friday when I needed a jump. We always locks the car and have noted on rare occasions the long beep, usually due to one of us leaving a fob behind. Almost never use the ACC mode. (It hasn't worked properly for months anyway.) Third party options installed: seat heaters in front, activated by small switch, not used during summer when this all began; PriusChat-approved inline water pump for quick winter warmups, activated by plug and not integrated with vehicle electronics, also not used during summer.

The dealer replaced the battery and performed a "parasitic draw test". Nothing found. The conclusion was that "the battery checks out ok but is acting really weird." The good thing is that we were finally able to replicate the problem at the dealer whereas on all prior visits everything behaved as normal.

The vehicle is parked in an unheated garage (Denver just got its first snow of the season) where it will remain until we get a chance to drive it again on Friday. If you don't hear from me assume all is well.

 

Is it possible to have my headlights on all the time without harming something?

 

Thanks for posting this. I was just curious so I followed your steps. Everything checked out, except step number 2 where you press the power a second time, w/o brake pedal to check the current load, mine checked out a 11.8 V. Hopefully that is still okay.

I really never knew the Prius had so many hidden buttons, and I still wouldn't know if I had come across this forum site. I also was able to turn off the Reverse beeper thanks to another post.

This forum is very helpful.

 

I never turn mine off, I let the car look after it.

 

I'm going to add to this thread:

I have a 2007 with just over 120K miles (I travel 110 mile RT for work every day, which is partly why I have the Prius).

I've noticed my mileage dropping more than usual for the winter months, plus I had that one 'beep' when shutting the car off (started last week). The key fob red light blinks with no problem, but thought (thankfully, hopefully) that replacing the battery would be the answer.

Then I stumbled on this forum and did the battery test listed here (THANK YOU!!!). My results:

Unloaded: 12.2
Load: 11.9
Powered: 14.3

I'm guessing this means I need a new battery? And if that's the case, is it really going to cost me like $500 to do so? I haven't called the dealer yet... was hoping there would be another option; like charging it... but I'm guessing that does more harm than good?

I'm not very mechanically inclined - my husband MIGHT be able to do it, as could my father, but I'm worried if they don't do it correctly (if it's difficult to do) that I'd be worse off.

Should I just call the dealer? Am I on death's door with the battery or do I have a little bit of time to get through Christmas bills and hope a tax refund can help with this? :-/

 

With such a long and regular commute it's getting a good charge cycle. I wouldn't be optimistic that a charger or battery minder would help. Tho if I had access to one it'd be worth a try.
Calling the dealer and asking for a quote is harmless, then make your choice based on a real number instead of a feared one. And no, shouldn't be anywhere near $500. More like $200.

- D

 

Thanks for posting this thread. I've been having starting issues since the cold weather arrived. My prius is 6 y/o, and the onboard battery check showed 10.9 v, dropping to 9 something when I flicked the headlights on. tomorrow she goes in for a new battery.

come to think of it, i never owned a car that had a battery last 6 years, so it's easy to understand why I need a new one.

 

i have an 08 Prius. The screen is telling Im getting 42mpg, but a tank of gas is lasting around 185 to 200 miles. Battery is good, but it seems like my car only runs on electric power when it's sitting. Even at a light the gas motor kicks back on before it turns green. Do you think that these probs are connected? Any idea what's wrong?

 

The gas is getting worse.

 

If the weather in Ohio is anything like I think it is, you can expect poor mileage. I spent last Feb/Mar in Jacksonville during weather that was routinely in the 20s and 30s, and saw the same poor performance, with actual mileage in the high 30s and low 40s, instead of my usual 48 or 49. The Prius doesn't like severe cold weather, for several reasons. But you say "a tank of gas" -- how much gas is that, typically? If you're actually getting much below 40mpg, you've got a problem. Also, if you drive short trips, you'll compound the problem.

 

thanks for this! I have been getting less mpg. Its time for a new battery.

 

Uh oh, after spending £675 this week on two new tires a new exhaust back box section and an oil change...i've just done this test as my mileage isn't what it used to be (47mpg today in 28mi country/town roads usually 56-60mpg).

11.7v unload
11.7v load
13.7-8 power on

I had a new HV/traction battery put in earlier last year as well...

just spoke to dealer, service guy didn't even know the correct voltage off hand and had no idea what i was talking about with the display screen. to replace the battery it's £90 fitted.

I'm really getting frustrated with this car. After spending £22,000 on it getting new, most of the work and needed services at the dealership and only having 80,616mi on it...

I wish i was more technical so i could do some of this stuff you talk about myself. but i'm not in the USA anymore and the UK just doesn't have the resources for parts like the US does. It's so hard and such a mission to get parts here and the weather is dreadful to do any electrical work in with out a covered garage.

I'm not in London anymore and I'm out in the country, not even the QuikFit will touch it with the 288volts running through it! No one but the dealer will work on it.