Just to be clear here as I have a 350h, does the 450h+ show you the state of charge of the 12 volt battery in the trunk or is everyone referring to the large traction battery and calling it the 12 volt in error? Or are we to assume some have added an aftermarket meter to display 12 volt battery state of charge.

The 350h only shows the graphic image of the traction battery with little blue bars to indicate as an image, how much it is charged.

 

You need to a battery monitor to get a real good picture of what happens

 

I have observed the same. I have a voltmeter that plugs into the cigarette lighter, sometimes shows 14.5 for a while while driving 45 min. +, sometimes 13.8; it varies, not sure why.

 

I used the OBD data to log the 12V battery voltage and current during my commute.
The "high voltage" charging is only occurring at the beginning and at the end.
I need to track other parameters to understand what is happening.
I have traffic / traffic lights in the middle of my commute so there were certainly times when I stopped, but somehow the battery wasn't brought to more than 13V at these stops.

 

At the beginning and end we're you in Park and not in drive?

 

If you put it in Park Reverse or Neutral the cage will jump up to 14.4. Most of the other times it just seems to sit at 12.8

 

What year is your car? I wonder if they changed something for the 26; when I go into town (10 miles, 17 + minutes), it reads 14+ volts. I want to see what happens when I try to start the car tomorrow to go into town, if the ice is gone; been in garage for 14 days.

 

I have a voltage meter plugged into my 12 volt socket under the charging tray as well in my 350H. I also typically see 14.1 to 14.6 volts on display and only after longer trips a half hour or longer does it go down to 13.8 13.5 V roughly. With that being said and others showing the same, it's odd that you're recording only roughly 12.8 volts at battery in your chart. The difference would be going to the 12 V load as the car is running I would assume.

You could do a test and follow up on this observation report that a Rav4 owner has done. He's unplugged the 12 volt battery monitor on his car, forcing it to utilize a 'dumb' charging procedure, which coincidentally has helped to improve the 12 volt battery health and longevity.

https://docs.google.com/document/d/1...h.t75rusbfgz8u

 

I have unplugged the temp sensor at the battey and it will constantly charge at about 14.1.
It send to be an odd set up. I have never had a battery go dead and dont want to but when
i see the voltage sitting around 12.2 when just sitting in the drive way it makes a person nervous

 

I logged the gear selector position and the engine rpm.

At the end the dip is voltage is me turning the low beams ON and OFF to see the effect.

 

As you can see voltage for most of the trip is 12.8 there abouts. Same as mine a 2025 450h+. Your battery will never be fully charged The people that built this are smarter than us but this really makes no sense

 

How long have you had the negative battery sensor unplugged?

 

I tried it for a few days to see if what i heard was true. It deffienaty does what people have but not leaving it that way. I have warranty to take care of this but dont want to be left in the middle of no where with a dead battery. I put in one of the emergency batteries to help the eaze of mind. We do a lot of hiking and mountain biking where were all alone

 

The battery is supposed to be charged, so it just "disconnects" it: almost no current flowing.
This makes more sense than constantly forcing the battery at 14.5V.

Just from my graphs I don't think I can tell that anything is wrong.

I suspect the spikes over 14.3 V followed by a decreasing voltage is the car measuring the battery state of charge.
At the beginning it measures and decides that it needs to charge even though I am already driving.
Same at the end: you can see the car measuring and charging because I intentionally kept it ON for a long time.

So basically the car starts: measures SOC --> charges
When driving: keep battery floating
When stopping: measures SOC --> charges, if given time --> so waiting a little can help maintain your battery.

 

I turned on my car and left it in park for 1 hour and 40 minutes before driving.
I stays in "charge mode" and the current stabilized to 1.7A.

Then after driving upon reaching my parking space, it does it's battery SOC check.
I wonder how it decides that it's time to do it. Does it use the camera to detect that I am parked, or the proximity sensors feeling the obstacles around my spot?
But it only measures and then goes back to the "driving mode".

And then when I park, it again does the SOC measurement + charge mode.