Triangle of Death 2012 Prius 175,000 Miles

could be a million reasons. you will need a prius aware scanner to get the proper codes

 

I drive a 2012 Prius as well. If you did not get a message like "Hybrid system issue, Park the car in a safe place bla bla bla," it is probably NOT hybrid battery issue. What are the lights you have on? I I've seen traction, brake, ABS and another light lit up simultaneously. It has been on and off for me and still trying to figure it out.

 

Looks like code reader is low priority, let’s chuck parts at it first.

 

Make sure you charge that battery for at least 6 hours to give it a full charge.
They never charge those batteries, they just sit their and discharge over time.
5 amps or less.

 

Yes, you need to replace the 12v battery, but this will not keep the warning lights from coming back on until you determine what the problem is and fix it. You need to purchase a scan tool that can read all the trouble codes in a Prius. Read this thread: https://priuschat.com/index.php?posts/3290690
The Autel AP200 is a very good choice and is presently on sale for $55.20 on Amazon. Buy it while you can get it.

When warning lights are illuminated on the dash, that means there are trouble codes that need to be read. Determining the trouble code is the first step in the process of fixing the car.

 

With 11.5 volts, and the age, it’s replacement time. Do that first, and if all lights shut off, I’d dub it done.

a brand new battery will charge up fine without intervention, just regular use of the car. That said, I would look into acquiring a smart charger.

 

UPDATE??? Did you get he 12v battery and install it? After you charged it up?

 

11.5V is typical 1 cell dying. Normal battery voltage after 20 minutes driving is easily 12.6-12.7 V without disconnecting or 12.8-13V when it is disconnected from the car. Under the load, the reading voltage can be a low as 11V but it will be fine. once it drops below 10V during Start, it may trigger all kind of errors.

 

Maybe for a non hybrid car, but not for the Prius. If the 12v battery gets below
12volts, it won't trigger the hybrid system to start. 11 volts is NOTE fine.

 

11V under the load/during 60 Amps start dip. Without any load, I agree, minimum 12.2V.
I tested mine, 12.7V no load, 12.2 ACC mode. 11.9 Headlights on, 11.3 headlights, AC blower, heated seats On

 

When my 2011 Prius 12v battery is reading 11.8v, my car goes to "READY." I believe I have read that it can go to ready as low as 11.5v.

 

It depends on the actual capacity and internal resistance. It shows during heavy loads. A bad battery may read 12V but whenever we apply a load 100 Amps or more it drops below 10V and failed to Ready mode. 11.5V under no load is almost empty battery but no bad cells. That battery is very not happy and probably only have less than 50% initial capacity.
My Lithium pack jump starter is only 11.7V but it can stary my neighbor VW golf non hybrid. But, Li ion battery has completly different character. It does not like fully charged.
Essentially, as long as the close circuit voltage above 10V during start up, it is ok, no check engine lights.

 

Under load, 11 volts is NOT good. For the Prius. It MAY be for othe cars....
Only concerned about the Prius 12v battery.... Not others... That's a different forum.

 

I was just testing it with stupid test. Headlights On and battery reading 11.7V in ACC, and go to Ready without issue. Just to proove my theory. I agree, it is not good. The jump starter can start my car even without 12V battery. It only takes 60 Amps and the jump starter can give up to 300 Amps for start up.

It is known in Prius 2 also, if the battery ever droped below 10V, it will trigger all kind of issue including transmission code, ABS and brake code, etc.

If it is below 12V off, possibly will be below 10V when pressing the start button on dying battery.

 

Just because you get lucky sometimes, does't mean it will work all the time.
And you're stressing the computers, likely causing damage.
It's your car

 

That is the worst way to test your 12v battery. Without the engine on, loads like that will cause voltage to drop and accelerate the deterioration process

 

I think for a less than 1 minute, the load test I did 2 years ago was not too bad. The battery is 9 years old now and it still works. The battery tester from Dealership or Autozone takes much more amperage, it is probably 200 Amps or more with Graphite based tester.

If we remember our midschool/highschool Physics, Open voltage can be as high ~12.8 V, but in close circuit, it can drops depending on the load (external resistance). In high loads, with high Amperage (low external resistance (R)), the internal resistance (r) of the battery matters. The voltage on the ends of the battery is V_close=R/(R+r) V_open. In a bad battery, the internal resistance (r) is large. It cannot take a high loads such as Starting the car. That's how a battery tester works. If it detects the Close Voltage drops below 10V during the load test, the battery is considered bad. In between, they will say xx% capacity from whatever CCA it is rated.

 

You STILL don't understand how it works for a Prius, or other hybrid that uses the hybrid
battery to start the car....