Battery cooling via AC

I sat in mine while the AC was running at a charge point charger once. It ran for about 30 minutes, and during that time it didn't draw full power from the charger the whole time, but it didn't seem to lose range based on how much I had before and after charging. It was maybe a 50% duty cycle at 3.3KW for 30 minutes, so maybe 1.5kWh at most. I think it was probably less than that.

The AC cycle only runs when all of these conditions are true:

• After you plug it in
• When the battery is over a certain temperature
• When you say yes to the battery cooler prompt
• When it feels like it (sometimes it prompts me but then does not run)

I've only seen it run a handful of times. Usually I can avoid it by setting a timer so it charges overnight, when the air is cool and the battery has had time to cool off.

If you live in a very hot climate like Arizona, this might not be the car for you.

 

i think there is a thread with complete testing and data on all electrical use.

agree, buying ev's does not (necessarily) save money

 

If the car is plugged in but waiting for the timer, clicking on the A/C button on the fob will not only turn on the A/C for about 10 minutes, but will also begin the charging cycle. The charging cycle continues after the A/C turns off.

 

Here's an article about cooling batteries during charging.
The Electric Cooling Battery Test - MIT Technology Review

 

Wait a sec: doesn't the Prime have dedicated battery ventilation fans, aft? They will run, as warranted, at various speeds, regardless of what the cabin ventilation system is up to.

FWIW, our cabin vent system is pretty much always off, 6 months of the year, spring through fall. We just adjust temp by rolling down the windows, a bit or a lot.

 

this thread is about cost savings folks, not how the battery is cooled. or not.

 

Maintaining the battery is a cost savings.

 

stop trying to use logic on me!

 

It does have fans for the battery, but if it's parked in the sun charging, the cabin could be too hot to cool the battery.

During the traction cooler cycle, the AC runs full blast while the battery fans also run full blast. Higher than they normally run during charging.

Also, the battery fans are sneaky, and the fan speed depends on the vehicle speed while you are driving. If the battery is hot the fans only run when you are going above about 45mph most of the time so they blend in with the road noise.

It's unfortunate that the battery can't just use outside air for cooling when conditions are appropriate.

 

Ok this is fourth gen, and the Prime, so I really don't know what I'm taking about.

 

I've tried my darndest to hear the little cooling fan in the back...
3 years later with my Gen4, and still waiting.

 

Like nearly every Prius generation, the Prime's battery fans suck in air from the cabin. SO the car's S/C can indirectly cool the battery by cooling the cabin.

In the case the battery gets too hot while charging, the Prime can turn on the A/C for that additional cooling. It likely will only happen in hot climates, and even then, it should rarely be an everyday thing. If the cost of running the A/C for battery cooling is a concern, it can be turned off. In which case, the car will simply stop charging when the pack temp gets too high. Then it might not be fully charged well it is time to leave.

 

I haven't seen it start the AC mid-cycle. If it doesn't ask when you park, and if it doesn't come on within 5 minutes, it probably won't run even if the battery heats up while charging. I have seen it slow down to ~1.5kW on a Chargepoint station on a hot day when the battery was presumably just below the threshold to run the AC. I could be wrong, admittedly I don't watch my car as it charges, but usually AC use will show up on the Chargepoint graph as spikes or dips. It seems like the logic on when the AC runs is not the best.

I can only hear it if the battery is really hot, like after driving up and down a mountain doing a bunch of regen, and then cruising around 50-55mph. Even then the sound is pretty subtle. 90% of drives I don't hear it at all. Maybe have someone else drive and ride in the back seat?

For both of these (AC and fan), I wish we had options where we could prioritize keeping the battery cool, rather than quiet ride, fast charging, or lower electricity use.

 

I had my ScanguageII show me battery fan speed in my Prius v, and I was amazed how often it was running undetected at lower 3 speed levels. The Prius Prime keeps the cabin more quiet than the Prius v so you might hear it more often in the Prius Prime.

I thought the Prius vehicles always prioritize keeping the battery cool when needed and keeping the cabin quiet otherwise. If you want to use more electricity and keep the battery cooler, run the AC at lower temp settings and let the cooler cabin air blow over the battery cells. I noticed that the ScanguageII and other devices can set the battery fan speed (level 1 - 5) if you want to force air over battery cells.

 

I can't say I've tracked the additional energy consumed by the AC while charging, I don't think it was significant when it has ran in the past. I'm thinking something less than 500 Wh, of course right now I'm getting into the season where the battery heater might kick on and don't worry so much about those unless it is very cold the heater uses about 100 watts if I remember correctly, still can add some if it stays considerably well below freezing.

I will comment that I think a lot of people will default to that EV's cost less to drive and while it is pretty common to have affordable electricity it's not always the case. Last month I calculated, rough calculation, based on the number of kWh I used and the number of miles I had on the car I estimated that running on electric only was the same as gas costing my $1.35 per gallon. That's specifically for the Prime and at my electric rate which is 11.7 cents per kWh...12.xx after you count taxes and so on. Different cars are going to give different results, a Tesla for instance get worse...electric economy??? Anyway, they get somewhere around 3.5 mi/kWh as opposed to my Prime where I'm averaging 4.7-4.9 mi/kWh, yes others had posted in excess of 6 mi/kWh but that's a bit outside the bell curve. I do expect it to get a lot worse with winter around the corner but I think I can still maintain about 4 mi/kWh. So, in short there are a lot of hidden costs associated with an EV and savings...I mean a lot of people bring up changing the oil and whether it should be changed in the Prime if you're 80% of the time running EV...and of course if you've got a Leaf or a Tesla...or whatever, there's simply no oil to change. So you can be saving money on not having to do maintenance that other cars require.

 

Does anyone know at what cabin temp (or battery temp) the car warns to use AC for cooling traction battery? The manual just says "above a certain temperature". Living in northern climate where mid summer ambient temp never exceeding 90F, I have not yet to see that warning come up on my PRIME. I have had cabin temp as high as 110F, but that was usually after parking a car all day under the sun with windows closed at work and when I first get in the car after work. By the time I get home to do charging, the cabin temp is always comfortable range of ~70F.

 

Similar experience on our Gen 3 Prius: I never heard the fan, but saw speeds (with ScanGuage) up to 4.

 

I frequently get a request to use the AC while charging the battery. It's usually when the ambient temperature at my house is 85 to 90 or higher, which has been very often. I always tell it "yes" I want to use the AC while charging. I charge somewhere between 2 to 4 times every single day. Our gasoline costs, at the very least, between $3.50 and $4 per gallon right now, so running on electricity 99% of the time makes sense for me with my average 5.5 miles per kWh, (rare A/C use; no heater).

Posted via the PriusChat mobile app.
AChoiredTaste.com

 

Hummm, I certainly have had some 85-90F temp during summer, yet I have not seen the traction battery cooler pop-up notice when I shut down my car. Since I usually charge my car only once a day during night, it is not likely I will ever need the traction battery cooler to come on. Still, bit strange I have not seen the warning pop-up on my PRIME not even once.