HV cooling fan question

It starts at 35c or 95F of battery temperature. As the temperature rises fan speed increases.

 

As "Valde3" says the speed increases with temperature, but this is not a gradual increase rather it does the speed increase in 6 steps. The speeds of the fan can be monitored, and controlled "tested" in Techstream, and also I believe with the Scanguage.

John (Britprius)

 

Unfortunately we do not get or have only just begun getting Fords offerings in the hybrid vehicles in the UK so we have no experience of them. I think the HV battery cooling in cooler climates such as the UK must help considerably with battery longevity.
Perhaps this is why in the UK Toyota extend the battery guarantee to up to 10 years irrespective of millage when the car is serviced at the dealers. The 10,000 mile service for the Prius is £150 ($240) including materials, and includes a 10,000 mile or one year extension to the battery guarantee. This cost is very cheap compared with almost any other manufacturers services. As an example my last car "Hyundai" 5 years ago the service was £450 ($720) for the 10,000 mile service.
It's a pity there is no facility on the Toyota modules for hydrating the cells. Water loss over time is possibly a big factor in there life.

John (Britprius)

 

Yeah, the filter is definitely a good idea. I really wish that they had included this (and a maintenance schedule on it) with the Prius.

As for the fan responding to acceleration I'm not so sure it's actually needed. The battery temperature is a fairly slow moving variable compared to the instantaneous energy demand. It's only really the battery temperature that the fan needs to respond to, and that it definitely does do.

BTW. From what I recall, the fan starts out at very low speed at 35C (as Valde3 said), and that it speeds up in a number of steps and becomes loud enough to hear (from the drivers seat) somewhere at around 42C to 44C. The first summer that I owned my (second hand) Prius the fan started running at high enough speed to hear much of the time, and I found that the fan was very badly blocked with dog hair (from previous owner). Since then I check and clean the fan about every 18 to 24 months, but it's generally fairly clean compared to that first time.

 

Just to confirm: with Scangauge there's a couple of XGauges you can add in: one for fan speed (I believe 1 thru 6 as mentioned above) and the other for temperature. There are 3 temp sensors (at least on 3rd gen). You can monitor any one of them; typically the #2 is monitored, since it's central on the pack and tends to be hottest.

All of these are to monitor only. I've seen max temps in low to mid 40's and corresponding fan speed 40 on ours. This was in summer, stop and go conditions.

 

This is great information THANKS!!!! I actually just sent my ScanGauge in to be upgraded this week so I can add these XGauges to monitor Ema. I will look for them in the XGauge list once I get it back. Ema has had trouble with a POA84 that was traced back to some corrosion on a connector but since getting that fixed has generated the POA82 error. That is "Cooling Fan Stuck Off" even though its running. Best guess is the temperature isn't dropping fast enough when the fan comes on? Anyone know how long above what temp before the POA82 error is generated?

This is the link I was diagnosing and discussing with Patrick about my fan issues. The pictures of the corrosion are on Post #46 I think?

DASH Error Lights Exclamation w/Triangle, VSC, and small Exclamation - Car runs great? | Page 3 | PriusChat

Anyone know what the resistance of a new cooling fan motor should be? I'm thinking maybe there is some corrosion on the fan motor and even though it is running it isn't running at full speed generating enough CFM to properly cool? Yes, I cleaned it.

Happy driving,
Chris

 

Just to mention that, to aid in prolonging the life of my traction battery, I always use the Airconditioning when the weather here in the UK starts getting warmer.

Surprisingly, I've observed that with the A/C aiding in cooling the battery, I tend to get a much better performance out of it, and by the time I get home, the traction battery's cooling fan isn't running at high revs.

John (Britprius) is right in saying that the generally cooler weather in the UK helps prolonging the life of traction battery's over here in general.


iPad ? HD

 

Good data...we don't get too many folks telling us how bad it looked....I am still procrastinating on checking it at 145k miles. I agree FORD seems to have very good reliability, but we do not have any real data to compare. Gen3 I believe have a filter. I only hear the fan rarely in summer on hot days.

 

One time we parked after extended drive on a hot day, left the car in hot sun. Maybe 1/2 hour later restarted, and off another extended drive. This seems to be perfect storm for elevated battery temps.

Anyway, went about 15 minutes with windows half down and no AC. Battery temp sensor 2 was showing around 42C, and fan speed 4 I think.

Then I rolled windows up and started AC. Another 15 minutes, sensor 2 temp had dropped, but only about 2C. My impression, AC has some benefit, but it's marginal.

Even this time of year, with ambient temps under 10C, I'll see sensor 2 temps in high 30's (C).

 

Mendel,

Do you know what the XGauge is for the fan speed? I can't seem to find it on ScanGauge XGauge list that I downloaded and printed out. I did find the "Battery Temp (upper read)" on the list and assume this is the one to read the battery temp.

Any help would be appreciated.

Chris

 

Yeah, this is apples oranges, 3rd vs 2nd gen. I downloaded second gen spreadsheet at this link:

Toyota/Lexus/Scion Specific : Linear Logic : Home of the ScanGauge

And see the values you mention, but not battery fan speed. The excel document is authored by Dan Bryant, same author for my gen 3 document. Keep hunting I guess.

 

What temperature did you set your AC to, and what speed setting?

I usually have my AC on recirculate, and between 16c to 18c. Speed setting is normally the lowest. I'll put it on one step up on a really hot day.

Over the last 2 years approximately, that I've had my Prius, I've always used the AC during hot days in summer. Usually in the afternoon, during the voyage home. With temperatures hovering around 7c - 9c in the mornings, I can manage without it.

It's worth noting that when I achieved my best ever 66.3mpg figure last year, I WAS using the AC everyday in the afternoon.


iPhone ?

 

I don't use AC that much. When I do, I'll settle around 24C, with fan speed just determined by Auto. Initially, I'll again leave it on Auto, and set temp around 28~29C, whatever it takes to prevent the fan from racing. Then as the cabin cools, and trust me it does, even with that high setting, I start ticking down the temp, aiming for eventual 24C, approximately.

But again, unless it's punishing hot, I'll just run the windows down.

 

Early in the morning ambient temp usually around 73F and battery temperature hovers around 83F at "READY"...10ish degrees above morning dew temp, even after resting all night. I notice shortly after driving along at 65 MPH, windas down, keeps BATT happy at around 93F with no cooling fan blowing. Shortly thereafter during the drive the Battery cooling fan kicks in around 95F (BATTERY TEMP SENSOR2) on 1st speed. pretty much 20 degrees above ambient air temp. I've seen the sensor around 103F causing ECM to kicks on fan to 2nd speed. I've seen as many as the 3rd speed kick on around 105F still early, still mild air temp.
Although a not so hot day today but still, those darn "lovebugs" force the windows to be shut tight in a 91-ish sunshining beating down, no shade to park under kinda weather. Interior Temps roar extremely hot...BAT-TEMP 3 runs 109F-ish at READY...Driving down 5-10 minutes with windas down only seem to irritate the daylights out of it, much less move the needle in a southerly direction! So I cranks up the windas and the same for the A/C-on outside circulate button as opposed to re-circulate. I see the temperature needle on BATTEMP2 start moving down within a few miles/minutes. 20 minutes into drive I pull out infared laser thermometer and the vent temp=65F..ambient temp in car 72F on doors,seats, etc.getting pretty darn comfee i must admit. I notice the Batt temp 2 is at 98F. And dropping. I watch it literally drop degree by degree to 93..i point infared laser temp towards battery cooling fan vent and it is a chilly 73... Cold air sucking into vent directed towards BATTERY STACK! As Battery cooling fan runs silently on 1st speed... Pushing Temp down to 93F... And fan shuts off. the temperature hovers there for 30 minutes untill I shut off the A/c, open the windas and immediately begins the Battery's RISE back into the 100's along with the 90degree weather circulating/rushing thru the cabin towards the Battery. Shut the windas, crank up A/c and chilly willy goes the Battery! Im not covering that vent up any! Its too easy to check and or clean! Gotta keep it flowing freely.