A/C hose attachment to battery fan vent

Where are you seeing this major degradation? Source?

 

If you keep pointing out my lack of documentation I'm telling Mom! No. I'll pull up a video. But did I dream that when you pull a traction battery and test the cells that they always show a U shaped curve of degradation expressed in the lower voltage and poorer performance under a load of the middle cells as compared to the outer ones. What.... I may have been transported to an alternate dimension where Prius batteries don't get hot. OMG. I wonder if my wife looks better in this dimension . I gotta get my butt home!!

 

This is the source? Youtube?

 

It is a very good idea and I kind of finished it yesterday.
It cools the battery so effectively.
It's a gen 3 though.
Anyone interested let me know and I'll upload photos.
I've added an extra blower fan, connected it in line with the original hv battery blower.
It turns on with a temperature controller and a relay.
Then passed a 4cm hose from the ac to the secondary blower.
Also I added a junction where two air valves will open in case the original hv battery blower decides to join in.

It's all an amateur's job I know but it's mine.
I'll make a more professional one when I get the time.

 

I would love to see photos. I'm planning to do this for my hot part of Australia.

 

My son drives the car and very rarely lets me touch it.
I'll take pictures of it and upload them for you to see. As i said it is not nice looking.
Basically i closed three outputs / vents that blow air to the feet of driver and front and back passenger. The fourth vent that blows air to the rear passenger i made an adaptor and connected a vacuum cleaner hose to drive the cold air directly to the battery fan.

 

AC cooling in the battery box is not a bad idea.

I always wanted to add an extra radiator to cool the inverter and isolate it from the engine coolant. I kicked around some ideas but space is just really tight under the hood. They made a mistake putting the inverter coolant in the same box as the engine coolant and there's a huge heat soak issue especially when you shut the car off. The Invert is the heart and soul of a prius the cooler it runs the better the mileage.

Toyota realized that in later Gens and they all use 2 separate radiators. They probably were not able to get away with a combined rad with the much more powerful mg's and inverter.

 

Here's what I did to cool the batteries in hot weather...

 

Hard for me to see just what's happening at the battery end of all that, but with a ribbed hose of that diameter and that length, I might be worried as much about restricting the battery airflow as about anything else.

 

I "think" these are all of @Panicos pictures, from post #30, with the duplicates stripped out:

 

The black square box i made 3 inlet valves just in case the oem fan decides to suck in some air so, no, it wont have a problem. The battery temperature is kept under 38 Celsius in a 45 Celsius car...

 

My bad, sorry i uploaded so many photos. I tried deleting some but... no result..

 

Just a recap of the photos i posted above.
All vents blowing air to the feet are blocked to almost 100% except the vent under the driver's seat. On that vent i molded a plastic in order to feed the air to a vacuum cleaner's tube that goes to a box in the back. Lets call that box "manifold" . That manifold has 3 inlet valves that allow air to be sucked in but no air to get out. So the cold air is being sucked in by an additional blower that is connected to the oem blower. So, cold air is being pushed in the HV battery either the oem fan is on or off. Of course the additional blower is controlled by a temperature sensor and a relay.

 

An expression that crops up a lot for me lately is “just because something can be done, doesn’t mean it should be done”. Not meant to be a blanket statement either, that it shouldn’t be done, but weigh the need, benefit and drawbacks.

thoughts/questions:

1. did Toyota’s engineers miscalculate cooling requirements, and if so by how much?

2. were you monitoring battery temps, and had they recently gone up? Perhaps battery is degrading?

3. what are optimum operating temps?

 

For sure the battery is degrading.
I've added temperature sensors to 3 modules so i can read the temperatures while charging and while driving.
I've noticed that when driving on highway the temperature is reasonable, but when i reach the city, the temperatures start rising to 45plus if i remember correctly. This means the blower fan works less in low speed driving or in traffic. So i added the extra blower to keep it cool.

So, yes i believe they miscalculated the blower fan operating parameters.

 

It is normal for battery temp to rise with use, or when charging too I think. The Toyota fan is multi speed, 5 or 6 speeds (can’t recall exactly), and I’d think you can glean from the observed battery fan speeds at various temps , just how concerned they were. If for example you see the fan climb to top speed in reaction to a temp (say 55C) and then you see temps climb significantly further, then maybe extra cooling may be needed. But it begs the question: is it better to just replace the battery, on the assumption the overheating is symptom of battery failure.

 

I've read that at 45 Celsius the efficiency is lower so i'd prefer to keep it as cool as i can to prolong the battery life. I know for sure they need replacement because it keeps giving the code (A080 cant remember now) but i cant afford it now.

 

Here's a post from another thread regarding the fan speed:

On the other hand, the fan turns on at 39° C, implying that that is above the optimum temperature range. If I recall correctly, the optimum operating temperature range for maximum battery life of NiMh batteries is generally considered to be between 10° C and 30° C (50° F to 86° F). And maximum efficiency typically tends to be around or slightly above that range.