12 volt battery failing to start the car

The 30 day operation was for Canada and Alaska, though it wouldn't be surprising if there was a way to turn that on for cars outside those markets. You can get a North American i3 REx working like the European one after all.

 

A/C charger does not charge the 12-V battery. 12-V battery will only charge when the car is in the READY mode.

I left the car undriven for over six weeks in warm weather and there were no issues with the 12-V battery.

Do not leave the A/C charger plugged in when the car is not driven for more than a day, as the vehicle systems could drain the 12-V battery.

 

.

 

Is this the twilight zone?

 

What page of the manual is that noted on?

 

What are you talking about?

 

This was reported by many owners here. When the charger is connected, the electronic systems operate, checking the status of the cable, which drains the 12-V battery.

On page 123, it instructs not to leave the cable connected for a long time—probably because it drains the 12-V battery as the owners here experienced.

 

It depends upon the health of the battery.
The older and weaker, the less time it can sit without being driven, or maintained.

this is true for all modern cars but more so for Prius because of the small battery.

prime was notorious for dead batteries in the early years, and the amount of drain when off was documented and charted by @Salamander_King and others in a thread here.
I can’t say about the newer or gen 5, but this is a thread about dying 12volts

 

If you poorly operate your car—using the ACC mode, sitting in the car with the lights on and car not in the READY mode, only doing short trips, leaving the AC-charger cable plugged, etc.—of course the battery is going to drain in no time.

As I said, I left the car undriven for more than six weeks, and there were no issues whatsoever. I am pretty sure that there would be no issues if I left it undriven for six months. That is because I know what I am doing and keep the 12-V battery at 100% SOC at all times when the car is driven.

 

well, it's certainly good that one person here knows what they're doing

 

It is certainly good that one person here who didn't even ever own a Prius Prime knows all about it.

You keep bringing up the few threads about some Gen 4 12-V battery failures here; yet, you ignore the fact that 99% of us Gen 4 Prius Prime owners have had no problem with their 12-V batteries whatsoever.

 

i never mentioned percentages, and have no idea what they are.

like all things priuschat, we can only see what is reported here, and what happens 'out there' is impossible to know.

 

No, we can also see our own cars in action. That's why you should let the actual Prius Prime owners share their experiences rather than endlessly speculating merely based on a couple of anecdotal threads.

I just looked at the Consumer Reports reliability surveys, and Gen 4 Prius Prime PHEV actually had fewer electrical problems (including the 12-V battery) than Gen 4 Prius HEV. Gen 3 Prius HEV is worse than Gen 4 Prius Prime PHEV as well. This confirms my thought that the few 12-V battery failures reported here were likely caused by owner neglect than anything else.

 

your car is one data point.

what does the cr report say about the 12v?

 

As I said, the electrical problems reported include the 12-V battery problems.

 

Are you hearing something or someone? Like familiar voices? I read something in the 2023 manual about what you wrote about, that the battery discharges more, but not how much more, and it’s due to checking. That was quite a bit of time to find it. I don’t know what its checking, but since the power is off it must use the 12 v to check? Maybe I just imagine I read it at this point.
I always assumed the 12 v was charging during charging, no wonder mine runs down so much. So if it isn’t charging during charging I guess it still is checking.
That’s for the 2023.
I know we often say talking when referring to writing. Just a joke.

 

I thought you were since you mentioned the twilight zone.

Gen 5's PHEV-charging and 12-V system should be more or less the same as Gen 4's.

• 12-V battery only charges when the car is in the READY mode.
• PHEV battery only charges when the car is not in the READY mode.
• AC charger does not charge the 12-V battery.
• 12-V battery operates the charging system when the car is plugged in; so, that will slowly drain the 12-V battery, even when the car is not actively charging. I don't know the details though—perhaps the new-car features manual explains it.

From page 80:

■If the vehicle is not used for a
long time

●The 12-volt battery may discharge.
In this event, charge the
12-volt battery. (P.589)

In order to prevent the hybrid battery
(traction battery) from becoming
extremely low in charge,
charge the hybrid battery (traction
battery) from external power
source or start the hybrid system
at least once every 2 or 3 months,
and turn the power switch off after
the gasoline engine has stopped
automatically. (If the gasoline
engine does not start up even
after approximately 10 seconds
have passed since the “READY”
indicator came on, the power
switch can be turned to off without
any further action.)

When the 12-volt battery is discharged,
refer to P.589, “If the 12-
volt battery is discharged” and
perform the correction procedure.

●When the vehicle is left with the
AC charging cable connected, the
electricity consumption amount of
the 12-volt battery increases due
to controls, such as the system
checking, operating. When the AC
charging cable is not needed,
remove it from the vehicle.

 

Is this clearly stated in the Owner's Manual?
If you 'don't know what your doing' , how does one not get 'the 12V to 100% SOC when driven'?

 

To me this is an unexceptable way to design a PHEV, or a BEV.

If the car is plugged into a power source, I see no reason to drain the 12V by asking it for power, while the HV Battery is getting power from the grid.

And then it asks you to walk out to the car and "unplug it when not needed"....
You're supposed to go the the car after 'Charge Complete'???

What about the Thermal Management System when it's 0° or 110° F? Does the car heat or cool the HV pack as required?
What does the Prime have for TMS?

Is there any other PHEV or BEV that lets the 12V battery drain all the way to failure, even if it's plugged in?

Good grief, will toyota's BEV's have this same problem?