Weird stuff happening? MPGs dropping? Test The Battery

I'd say your 12V battery is OK, it could use a bit more charging but it isn't dead yet.

I'm not sure what to say about your HV battery. I'll leave that for someone else or another thread.

 

I have posted these results in a separate thread but wanted to add here just in case: I have an 07 with 76k miles here in FL. Have noticed a recent sudden drop in MPG from high 40s to mid 3os and can't work out why...

The voltage reading just now (it was driven an hour or so prior) was 12.3 in the unload mode and 11.9/12.0 (checked twice) with load applied (having pressed the power) and 14.3 with the engine started & idling

Does this sound like a battery about to die? Would it explain low MPG?

 

Join the club. Mine went from 50ish to 42ish for a couple of months recently, and now it's back to 47ish. Can't correlate it with much of anything. I'm wondering if there's some drag in the drivetrain -- subjectively, I feel that when I come off the accelerator the car slows down much more rapidly than "normal", and certainly more rapidly than my wife's '12 v. Time for some real measurements.

 

I have a Japanese made Prius 2007. Can't use the same procedure to enter maintenance mode since there is no info button on the MFD. There is info button on the steering, which is used to switch between the hybrid info and driving/mileage history modes. I tried using that while switching the lights on and off but didn't work. Any tips?

 

If you can't use the MFD or lights to do it just grab a cheap multimeter. I use this $20 meter amazon.com/gp/product/B0012VWR20 but you can use anything with 2 leads similar to that.

It doesn't let you sit in the drivers seat while testing but it's scientifically accurate and not that inconvenient. When I use the meter I open the hatch, pull up the rear cargo mat, turn the meter to 20v and touch the battery leads. Measuring directly will give you a couple of tenths higher reading vs what you'd see on the MFD but the difference between a dead battery and a good one is much higher than the .2 to .3 you'll see between the two methods.

 

With the weather turning much colder today I decided to check my battery after my 20 minute commute home. Looks like I will start looking for a new yellow top Optima battery as I'm pretty sure my 2008 still has the original 12v battery.

From the test procedure....
- Press “Vehicle Signal Check” - the battery voltage is shown and should be about 12.4 to 12.8 Volts (normal for an unloaded battery) ......mine read 11.2v
- Again without brake pedal, press Power button and release to put a current load on the battery - the voltage should stay above 12.0V.......mine read 11.1v
- Press brake pedal and press Power button once to enter "Ready" mode - the battery is now charging at about 14V (if less than 13.6V or more than 14.4 there may be a problem with the charging circuit)....mine read 13.9v

 

Optima DS46B24R Optima battery direct fit replacement for Prius 2004 + , Prius V & Plug-in Prius with Instructions


Exide AGM Car Battery (Group S46B24R)


are two direct fit batteries.

 

optima is on sale at pep boys right now for only $130 Optima Yellowtop® PRUIS Deep Cycle Car Battery Group Size DS46B24R | Product Details | Pep Boys

 

Omg. Thank so much for posting. I was dreading $190 for battery when i saw 160 last year.
My story, my 06 with 178k miles is still original battery. About 4th time died in about 10-11 months. Sometimes I get key left in fast beep, but it doesn't always kill battery beyond startable. Checked V this afternoon at work, was under 11V. Watched it as I started and dipped to 9.3. But I drive my car every day and it will probably start in morning. Am I pushing my luck? Battery is a month away 7 yrs and has 178k miles. I was hoping for 200k..ha! Car was originally sold in NJ, I bought in 8/11 and just came to NC with it. (We had a cold weekend)..

Is it true a weak 12V can cause Ecu to lose driving habit memory? I didn't think this car learned habits. My mpg's are still above 46 mostly and only dropped immediately from 50's after new tires last year. Still I wonder if mpg's will Improve with a new battery. Mine never really died dead, just a bit too weak to fire those contactors.


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I've been trying to order online for 15 minutes with no luck. I went ahead and printed off a copy of the website page and I'll take it to my local Pep Boys tomorrow to see if they will honor the online price.

 

Hey there. Did ya print to PDF by any chance? Page won't load now. It just did then almost full blank product page. Hope it wasn't pulled?? Ahh!! Earlier it said to call for my area.


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I can scan you a copy just message me your email

 

For anyone else that is interested here's a PDF of the screen shot I was able to print off last night. Not sure if Pep Boys will match the price as listed but it's worth a shot.

Good luck!

 

Seems optima yellow top battery for prius is discontinued. Called pep boys and that's what they said. No Prius on optima website. ...oh no!!e

 

I placed an online order for pick up and just received an email saying the battery is ready to pick up. Hopefully I can get away at lunch hour and get it. Total price with core charge and tax was right around $154.

 

I can't imagine it being discontinued. They still have it on amazon direct from optima and other sites still have it such as

Optima DS46B24R Yellow Top Dual Purpose Battery
Optima (8171-767) DS46B24R Yellow Top Prius Battery : Amazon.com : Automotive

if you have Amazon prime its about the same either way $170 after shipping

Prius Auxiliary Battery DS46B24R Yellow Top Optima has it about $10 cheaper with free shipping.

if you want to see it on the optima website it is at DS46B24R YELLOWTOP® Prius® Auxiliary Battery 8171-767 :: OPTIMA® Batteries

not sure why you couldn't find that when you searched.

 

I went to pick up my battery at Pep Boys but decided not to buy it. The battery looked used (dirty) and the parts guy told me something was spilled on it on the delivery truck. I'm not in dire need for a replacement so I'm going to try my local Advanced Auto Parts store tomorrow and see if they'll price match the Pep Boys price.

 

I got my old battery charged using a charger and worked fine. Thanks for all the help.

 

Excellent thread, just checked the 12v battery in my 2008 Prius, 116k miles, original owner and got 12.1v, 11.8v on load. No issues yet but mileage has slipped recently and ICE is on almost all the time so I'm springing for a new battery via Amazon.

 

Q: So, the general consensus is that the Optima Yellowtop 'Deep Cycle' battery is the BEST replacement battery choice?