HV cooling fan question

If it works in those apps, then it works in general. The fan isn't designed to work on a regular basis, only when stuff starts going wrong. If the fan is not on then nothing is wrong... To be sure keep an eye on the temperature readings in the apps.

 

I use a thermal imaging camera on battery packs to find overheated cells, so you could try that... And it is a bit concerning the fan doesn't start at 115, but if it starts at a slightly higher temp than that you should be ok. Majority of all my experiences with fan running are when car throws an error code and goes into limp mode. So until it throws an error code, it might not be anything to worry about.

Is your fan clean?

 

Can you hear it running?


I ask cus our 3rd gen is very quiet, I’ve never heard it. A few years back I had a scangauge connected, and it would report it running, various speeds. But yeah, couldn’t hear it.

 

Oh good... If you've the skills to rebuild the pack then we can troubleshoot with you...

--The relay system that gets the fan going is very slow and clunky, I've often let my impatience interfere with testing it via hybrid assistant, as well as by temp readings.

--Check the white plug that mounts near where the cooling fan is. It has 4 wires going in and out even though the plug could handle way more wires. These are known to corrode and throw an error code for battery fan voltage irregularity

--Hybrid assistant lets you control all the fan speeds. Have you confirmed that it works at all speeds?

--I've rebuilt packs before that tested great but had one cell that was running hot and before I got a thermal imagine camera I'd be unable to find those ones, so that might be the source of your problem. If you have a friend who does home inspections, they have a thermal camera. Or a Seek Thermal camera is the biggest sensor for lowest price.

--Are all temp readings similar / accurate when viewed in Dr. Prius App?

--You're located in an area with high temps, so you could easily test how hot it has to get for fan to operate, though that's not so good for the battery

--Forget about it till you get more data / lights / error code

 

If the fan spins at all speeds when you tell it to via an app, all the necessary electrical circuits through those connectors are already tested. The app doesn't spin it by telekinesis.

When you're not commanding it via the app, it's the ECU that decides when to run the fan and what speed. It seems like the gist of this thread is that you and the ECU are not agreeing about when it ought to run?

 

At this point it's clear that the only problem with your cooling fan is that you're trying to fix something that isn't broken... The only fix for these kinds of problems is for something else to go wrong so you lose interest in this on. I'm placing my bet on a bad cell in your rebuilt pack that's running hot that you can find with a thermal cam.

 

I installed the custom PID for Torque Pro found on this site to control/command fan operation. I picked speed 5 which I can hear from the front seat. By using a piece of paper I can see it is creating vacuum on the vent. The fan is clean and operates properly.
When driving today it seemed the temperature rise was same as always. Intake temp = 74 F batteries started at 76.9 F and after 30 minutes of urban driving they were at (sensor 2) 97.8F. This is a year old OEM battery pack that appears to be healthy. SOC was around 71% after a long, down hill, regen before getting home.
In the winter I see it start dropping even on speed 1 when I'm not in stop and go traffic but the fan turns off at 90 F so I just go in a loop between 90-99 F. In summer...temps rise fairly quickly and start at higher ambient than in winter. (Car is garaged) I never go over 100 F but I don't have to drive far. I would think twice, maybe three times about taking her on a trip.
The reports I have read here are totally different than what I have experienced. Someone suggested the battery air dams in my pack may be missing or improperly installed. All I can tell is that the fan is drawing air and blowing it somewhere.
For those watching battery temperatures...what affect does the fan have on battery temperature. Does the reading drop quickly? Does it still drop temperature when car is stationary? On a 90 degree day does the battery temperature quickly, or reasonably quickly, drop when the fan comes on?
Many who post here say their pack never goes over 100 F which I find incredibly hard to believe...

 

I've seen plenty of very low quality work performed on battery installations. If a new OEM pack was installed, then yes, it's incredibly important to transfer the correct parts as required from the old assembly to the new. If not? Cooling problems are heading your way. Much less the air ducts being mounted properly, or not being installed at all. Hard for a fan to cool a battery when no duct is mounted between them..........

personally, I wouldn't be worried a bit if my battery were over 100F in the summer heat.

The battery protects itself with charge control limits and discharge control limits based on battery temperature and SOC.

 

My 2007 hv battery fan onlly seems to work with the apps. My hv center cell temp occasional goes above 120f and the fan never comes ON. When apps are running… fan always works and cells never gets that high.

Any idea what Toyota fan temps are set to kick on?… or what’s wrong with Toyota fan management?
Thanks Frank

 

I can't say about your car. On my 2006, the battery fan does turn on, but I can't hear it if it's at speed 1 or 2. I only hear it at 3 or higher, and that kicks in at around 125°.

Personally, I'm not an engineer so I'm not going to second guess Toyota on battery cooling. They had to balance noise, battery life, and fan life-power use.

Some people like to fiddle with apps and fan controls. The factory settings kept the original battery alive in my 2006 for 15 years and 160k.

Posted via the PriusChat mobile app.

 

I’ve never heard the fan, on our Gen 3, including times I had Scangauge attached and was seeing fan speed 4~5 (forget which).

 

Well my 07 Prius battery is getting too hot…around 125f…which causes recharge rate to drop massively. This causes much more engine run time …thus resulting in lower mpg. I have not yet found what controls the fan speed. I believe battery temp sensors tell this controller to run fan at speeds 0-6. Fan works perfectly when controlled by my hybrid assistant app. I’m hoping it’s a controller module somewhere in the battery area…just can’t find such thing….

 

Any idea how to check or change fan operating parameters in the ecu? So that I don’t have to use the app to properply run the fan?
Thanks
Frank

 

You would have to reverse-engineer the ECU firmware, change it, and flash your changed version. I would not be surprised if the ECU uses cryptographic means to refuse flashing any firmware that isn't from Toyota.

It's possible what's more an issue here is that you and Toyota have different ideas on what 'properply' means.