Dead 2010

With our low usage I just gave up, on relying on the car as the sole charger. Our's will sit 2~3 days. We're actually taking the bus somewhere today, lol. Just more practical. Anyway: unless the car's going to be used the next day, I plug it in to a smart charger, and leave it on. It runs through the charge regimen, that falls back to trickle charge mode. Have the luxury of secure garage though, appreciate this doesn't work for street parked, apartment dwellers and similar.

 

I have a lithium ion jump pack so a dead 12v would only slow me down by 5-10 mins and I could keep doing that until I got the new one


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I have the same setup for our 2010 Prius II bought in July 2009. Still on the original 12v. Trickle charge it once /month with a Battery MInder 1510. Check the voltage at the under hood jump point every Saturday morning (along with the oil dipstick ). I pop the hood as I exit the Prius Friday evening. Last Saturday's reading was 12.85 v after sitting overnight.

Not a bad way to spend 5 minutes on Saturday morning before weekend activities begin.

 

I prefer Found On Road Dead!

 

I've done this since I got my Prius. Every month or so when I power it down for the night I will pop the hood, exit & lock the Prius. Next morning (before unlocking) I check the batt voltage at the fuseblock under the hood. 12.86V at 0820 & 75° this morning. & still on original battery.

I do not use any aux charger.
I shut the headlights off manually 98% of the time - every once in a while I will forget & leave the headlights on but they timeout at 2 min or 5 min (I never checked).
I do not use the ACC position at all. Anytime I am drawing power from the 12V system the Prius is in Ready. This includes using a 12V air compressor (mostly for bicycle tires).
I have camped/slept in the Prius a few times - running the AC all night so Prius is always in Ready.

When in Ready the Prius will float the 12V battery around 14.4V most of the time.

If certain conditions are met, the Prius will drop the float voltage to ~13.4V. The ICE must be warmed up, the AC must be off, the headlights must be off & the gear select must be in Drive. If all of these conditions are met then the Prius will float the battery at ~13.4V.
I had documented this for the post below...
Auxilary battery voltage? Does the Prius do 2 stage charging? | PriusChat
If the 12V battery was being floated at 13.4V when I power it down, then the next morning the 12V batt will not be up to 12.8xV.
It will be in the 12.7x range.

 

My 12 volt failed on my 2010 at 103k with absolutely no warning symptoms, which really p***ed me off.

 

FYI to those measuring the voltage at the jump terminal, when my oem Yuasa failed, it still measured 12.7v. It simply couldn't supply the amps/current required to make the car Ready.

 

Now that you have had this experience, maybe in the future you should replace the battery before it fails - since substantial inconvenience is caused when the unanticipated failure happens.

I believe there are symptoms but they can be very subtle. For example, when the car is IG-OFF and you open the door as you are about to leave the vehicle, the overhead cabin light may be slightly dimmer than usual, which shows the 12V battery voltage is not holding up. However that is very easy to miss since most people are in a rush and thinking about other things.

 

I guess I'm the other extreme: a 12 volt hypochondriac. In ours that cabin light (and the hatch light) are shut right off. I appreciate that's just the tip of the iceberg, there's a dismaying array of electricity users that wake up whenever a door or hatch is ajar: on ours the illuminated door sills (didn't ask for them, they were installed from a sale that fell through??), diminutive courtesy lights in the front foot wells, maybe courtesy illumination around the start button, and on and on.

Plus I've amassed an arsenal of battery maintenance tools over the years. An armed-to-the-teeth cargo cultist, lol.

 

I have had this very thing happen. Bright light on an 04 with a new stock replacement battery. Dimmer light on an 05 with slightly dead Optima battery. Both came on to ready mode. Difference is, the Optima has more capacity so voltage doesn't drop off as fast and it may still "start" the vehicle computers when it should technically be "dead".


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Even better... check this out. We have a dead battery, because we live in NYC and had it parked in the parking garage all winter. We usually drive it at least once a month. This year, two people who each had two major surgeries prevented that. I had a feeling the 12V would be dead. But, we’ve just unlocked the driver door, crawled to the back and switched out the battery. No big deal, right? Wrong. This year, our keys (the ones in the fobs) WILL NOT unlock the driver’s door. I tried both, with WD40 in the keyhole, plus vice grips to turn the key to the left HARD, since I read multiple posts stating you have to turn it with a lot of force. I bent the key 10+ times, bent it back each time to try again. We never got in, and one of the keys broke (we got it out of the keyhole, thankfully).

It’s as if the locking mechanism is frozen solid inside. I drowned it in WD-40, so there’s no reason why it shouldn’t open. It’s our second Prius, and definitely our last! One key hole on the entire vehicle? Ridiculous and flat out STUPID on Toyota’s part. I’m now sitting here with a car we can’t get into, at all. Called AAA tonight, which we’ve paid for, for 20+ years and have only used once. Surprise! They refuse to send someone to unlock one of the doors because although the two-year NY registration is current, its annual inspection was due in February. Well, we’ve walked over to the parking garage to try (yet again, over and over) to unlock it, at least once a week since January. Why? To drive it one darn block to get it inspected! I’m so incredibly furious. I’m canceling AAA, and never, ever buying a Prius again. We’ll be selling this one immediately. Hell, we probably won’t even buy a Toyota ever again. I guess we call a $200 or $500 locksmith now? Or, whatever the hell its going to cost. Just lovely.

 

Let me guess...you've never lubricated the key lock before now. That's a must for the harsh winters and salt they use.

To keep the battery alive it would be a lot better to drive it once a week not once a month.

I have heard of some people having success reaching through the front grill with some kind of tool and pooping the hood. There are jump start terminals under the hood to provide power so the car can be unlocked. Also, a lockout kit can easily get into almost any car, not just the Prius. The locksmith won't charge too much for just getting the door open, then you can deal with the lock later


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Cyndee,
Are you the original owner of this Prius?
Any chance that the physical key is not actually the correct one for the car? I've seen that happen when buying a used Prius.

The dealer can make a new key for you using your VIN. They will likely need some proof that the car is yours as well. Call them and see.

 

They said it worked before up until this year... so the key is correct.


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I prefer Found On Road Dead=FORD