Thanks, I was wondering why i was having so much trouble figuring out what was wrong, nothing is wrong. Before i replaced the battery fans, the ICE only turned off within the first 20 minutes, after that it always stayed on.

I have another question about the FEH in general. I was driving through the foothills yesterday and while going up the hill the RPMs were redlining (6k), i was also going 85mph. Is that normal? If i stay at about 65mph it only jumps up a little to 4k rpm. On another forum, someone posted that the 4x4 model had a very low high speed, but was also the person that said my model had an electric AC compressor too.

 

Yes it is. The transaxle is a true eCVT and the engine RPM does not correlate with vehicle speed *AT ALL*, it depends on the control strategy the computer is using to run the car and supply the power the driver is demanding for the road conditions and speed. On a steep hill at 85 MPH it's possible to see 6K RPM. It sounds maybe a little bit high but it's in the realm of possibility.

How is the MPG otherwise on the car? Lower than average mileage may signal that the HV battery is weak and thus the ICE is being called upon to "work harder" to move the car, instead of splitting the load with the traction motor. 6k RPM at 85 on a steep uphill sounds a little high to me but it's not necessarily a sign something is wrong.

Let us know what your average MPG looks like over a good range of varied terrain and speeds that are a little lower. You might have to balance your HV battery and buy FORScan so you can check it out.

 

Also, is your car a 4WD?

 

My average MPG is 25, which i'm pretty sure is low, but i also don't think it is accurate. I have a 2020 Nissan Sentra SR that i get an average of 26 mpg because of the way i drive. I have Forscan and everything looks good. The SOC stays between 40 and 60, though before i rebalanced it it only went from 40 to 56. Someone told me to replace my 12v battery because the hybrid battery will drain itself trying to charge the 12v if its going bad. I was going to check that next.

 

yep, 4WD

 

The 4WD system will take a few MPG and also probably require a few more RPM from the ICE on the highway. No matter what you do, you're spinning around more mass and pushing power through another set of gears and so forth.

My '10 2WD, running well turns around 2650 RPM on a flat highway at 85 with the A/C on, but it varies quite sensitively with road grade. I've seen 5k RPM before and even 6k a couple of times, but I don't think I've ever tried to climb a "serious" hill at 85 MPH, at least not while I was watching the tachometer. Lol.

Your car sounds like it's "in range" maybe a little bit low, but a lot of that can depend on the basic condition of your engine at whatever mileage you're running, basic state of tune, tires, and so forth. All the usual suspects like air filter, oil+filter, plugs, etc. plus the level of wear on the ICE, best established through a compression test. You're not way out, maybe a little but not much in my estimation.

 

Actually my understanding is that it's the other way around. You never want the 12V battery to go bad because the system uses it to keep the HV battery alive when the car has been sitting for a long time. And your car has the "emergency start" jump feature, so you should always have a good 12V battery in it. They're not very big batteries, only 550 CCA. Mine died this past winter and you should have heard the relay-click racket it caused. Anyway, if yours is getting old/weak, replace it. It's not worth the heartache. I bought a NAPA and got a $20 rebate.

 

Yeah, ive never had a CVT transmission except in my Nissan Sentra, but that one imitates a regular transmission. I just changed the oil/filter,plugs, air filter, "Cabin air filter"(they call it that even though its for the battery), and the battery fans. I had a shop refill the AC, which was a ripoff since i paid $100 to add one pound of freon, and they had no idea about my FEH.

Yeah, i was wondering if it might have something to do with the 4WD, because to me it seems like i have a super heavy vehicle that has trouble going fast. I guess i should learn the proper way to drive it, but at lower speeds it has a lot of power and i can usually get up to 65 fast. Thanks for the help, i'm probably going to replace the 12v battery today and see if that changes anything.

 

I mean since the hybrid system charges the 12v battery since there isn't an alternator. They said that if its not fully accepting the charge then the hybrid system keeps trying to charge it which is draining the hybrid battery or at least not letting it get fully charged.

 

By the way, if you've never changed the fluid in your transaxle, do it. Also see ShadyEscape's "As the Wrench Turns/Just What Have I Gotten Myself Into" thread regarding the fluid in the PTU. Your car will use MERCON V for the transaxle, somewhere between 5 and 6 quarts. The transaxles can live more than 300,000 miles with 60k fluid changes but the PTUs will destroy themselves much faster than that without them.