HV battery going bad?

Weird stuff happening? MPGs dropping? Test The Battery | PriusChat Let's see if its the 12 volt battery first. Given your mileage, it is possible that its the HV battery. Does the battery meter on the MFD fluctuate from Pink/Purple to Green?

 

Yeah, defiitely test your 12V battery first.

Another thing. Does the charge stay low (like 1 or 2 bars) for a long time, or does it only happen near the beginning (first few minutes) of each journey? If it's only happening at the beginning of each journey then warming the engine for 1 minute can actually help.

 

What warning lights are on? Any messages or warning icons in the MFD? If there are no lights or warnings present, then it is not likely there will be any DTC to retrieve.

 

definitely check your 12v just in case. that's the easiest place to start. it could be your hv, but you usually get some warning or the charge meter keeps going rom full to empty over and over.

 

could your battery cooling fan be clogged?

 

Brian,

Keep a eye on the MFD. If you start seeing mad swings from purple/red to green and back down real fast that is a sign of impending doom on the traction battery.

First thing in the morning when car is warming up traction battery is used heavily since the ICE is working hard to heat the cat's up IIRC. It is normal to see the battery drop in the morning if it is getting weak and tired. Bisco suggests letting Prius run for a minute before driving off when cold. Helps to get the battery charged up a little before you start off.

Check the vent in the rear seat. Put the Prius in "Ready Mode". Then place a dollar bill over the vent. If the dollar bill does not stay on the vent and falls off, the fan is NOT working properly. If that is the case, the fan either needs to be cleaned or replaced.

Best of luck to you,
Ron (dorunron)

 

have you checked your oil level recently?

 

These cars are known to burn some oil at high mileage. When the reminder light turns on, that means you've already gone 5000 miles. The cars can develop a burn rate about 1qt - 2qt every 5000 miles. Some even more severe than that. Make sure you keep an eye on the oil level and add BEFORE it gets low.

 

Watch out for an engine oil consumption rate that may now be greater than the rate that you've documented, now that the oil level dropped below the minimum acceptable level. The engine oil capacity is 3.9 quarts and the difference between the upper and lower dimples on the dipstick represents 1.6 quarts. Hence the minimum acceptable oil amount is 2.3 quarts.

If you were able to add 2 quarts to bring the oil level to the upper dimple, then the prior oil level was at only 1.9 quarts. If the oil level is now somewhat below the upper dimple then the prior oil level would be correspondingly lower. This means that permanent damage may have occurred to the engine while it was operating with the prior minimal amount of engine oil. This is especially likely since you noticed driveability symptoms such as poor engine power.

 

Was this a lucky guess or is there a connection between low oil and battery charging?

 

No, it's not a lucky guess, it's a PC educated guess. Low oil is associated with bad performance as the engine is starving for lubricant. He thought it was his battery but he said the 12v battery was new and it didn't make sense for it to be the battery again. After reading his comment about the maintenance light on and having 180k miles on the clock, I thought he should check his oil level first.

 

I'm a little bit doubt that lack of this much oil (0.4 qt) will cause lot more friction internally, that show such dramatic engine performance drop, especially when this happens suddenly. Just my guts feeling.