So close and yet so hot

<div class='quotetop'>QUOTE(TonyPSchaefer @ Aug 3 2007, 06:33 AM) [snapback]489898[/snapback]</div>

No disrespect Tony, but are you crazy? Is the few pennies you save in FE by not using A/C worth the sweaty discomfort of sitting in a 90ºF car?

OK, I admit, I play that "how high can I get the MPH" game too, but I like my creature comforts too.

 

<div class='quotetop'>QUOTE(paulccullen @ Aug 3 2007, 09:58 AM) [snapback]489916[/snapback]</div>

You're fuel efficiency must be pretty poor.

I used to play the "how high can I get the MPH" game all the time, then I bought a Prius, and fell under the spell of the Prius Affect. Now I am one of those drivers I used to complain about, tailgate, swerve around, etc.

Yes, I realize it was a typo and you meant to say MPG, but I just couldn't resist the joke.

 

<div class='quotetop'>QUOTE(TonyPSchaefer @ Aug 3 2007, 08:33 AM) [snapback]489898[/snapback]</div>

Ok, so:

Some people have moved some of their acceleration off of gasoline and on to "the grid" (Plug-In Prius)
Some people have moved some of their ICE warm up off of gasoline and on to "the grid" (EBH)

In both instances people are finding that "the grid" is a more efficient and cheaper source for the energy.

What I've been wondering in these past few days here in northeast IL, is if it would be cheaper and more efficient to move some of the passenger and battery cooling to "the grid", and what would be the best method to do so.

I haven't taken any of my thoughts too seriously, but excessive heat and sleep deprivation can lead the mind down odd paths sometimes.

For example, there are these "cooler packs" some sort of fluid with a low melting temperature encased in plastic. You pre-freeze them at home, then toss them in a cooler with food or beverages instead of ice. They make less mess as they melt since all the fluid is inside the plastic casing.

Ok, so my thought was, if I could find a way to tie, mount, or otherwise attach one of these next to, or just above the intake vent in the back seat area, then the air flowing into the battery compartment would be significantly cooler than the passenger compartment, thereby moving some of the battery cooling to "the grid"

 

<div class='quotetop'>QUOTE(paulccullen @ Aug 3 2007, 09:58 AM) [snapback]489916[/snapback]</div>

I also would choose to run the A/C on a hot day at the cost of a small reduction in MPGs, but no such tradeoff is needed in the Prius. The point here is that he *reduced* fuel economy by *not* using the A/C, because the traction battery and associated electronics got too hot. The cabin A/C cools the traction battery system along with the driver. People who drive around with the A/C off and the windows down on hot days thinking that they are improving the fuel economy of their Prius are in sweaty error.

 

I wonder if at some point the added effeciency of the battery at room temperature makes up for the small load by running the AC?

 

No offense, but this quote:

<div class='quotetop'>QUOTE(TonyPSchaefer @ Aug 3 2007, 11:43 AM) [snapback]489941[/snapback]</div>

makes it sound like you value money more than yourself.

Horde money to live well
Live horrible to horde money

Sometimes some things just done make sense.

Sorry, now that I review my post it almost looks like I'm bashing you. I promise I am not, I'm just curious.

 

The AC will cool the battery about 1 degree F every 5 minutes when starting from hot, documented by some other folks at the Yahoo PTS group. What helped more was doing something to drain the HV battery down a little from the 60% point. When you know the battery is warmer than normal, try driving with 4-5 bars of SOC, easier to put current in/out of a partial empty battery than one at 6 bars-so sayeth the BCM.

Wayne

 

Tony the heats getting to ya, turn on the AC
another tip : don't move to the Southwest in the summer

 

<div class='quotetop'>QUOTE(richard schumacher @ Aug 3 2007, 11:43 AM) [snapback]489943[/snapback]</div>

I have to respectfully disagree with this. I'm sitting at 70.2 mpg right now with 663 miles driven so far on my current tank. I'm down to one solid bar on the fuel gauge and probably have another 30-40 miles before it will start flashing. This week, the temp in my area has been in the mid 90's. Driving home after work (at around 5pm) with the AC on (manual at the lowest fan speed & lowest temp setting), my mpg average would always drop below 70 mpg by the time I got home. With the AC off and all windows down, my average mpg always climbs by the time I get home. Therefore, I have not yet experienced the drop in FE with a "hotter" running car/battery, as some others have observed. Therefore, I have a hard time believing that using AC will ever improve FE (regardless of the driving condition) versus not using AC.

 

<div class='quotetop'>QUOTE(efusco @ Aug 3 2007, 02:51 PM) [snapback]490062[/snapback]</div>

Thanks, Evan. Will ScanGauge II measure battery temp? I am think of getting one instead of CAN-View, due to cost & ease of installation.

 

<div class='quotetop'>QUOTE(paulccullen @ Aug 3 2007, 10:58 AM) [snapback]489916[/snapback]</div>

You have to ask?!?

Tom

 

This is what I have been seeing since last weekend. I had a horrible MPG day on Saturday, in fact all day Saturday. I live in Houston. Of course I normally drive with the windows down. Now I grew up on Long Island and when I first got here I was only miserable when the temps were above 80 deg. F. Now after many years of 90 days straight, each year, of three digit temperatures, I am use to driving with just the windows down up to 95 deg. F.

The high temperatures are the problem. I can’t get EV except only in the mornings for the first few miles into work. I have been trying to keep the AC on, but by the time the air gets to the intake vent in the back, it is already heated up, so it takes a very long time for my AC to cool the car down enough to then put cool air on the battery.

I have been working on a solution to this problem. I plan to somehow tap in with a small tube into the plenum and run it along my door jam, or even maybe under the car and then feed it into the battery vent intake plenum. I have a more intricate design that would snake back and forth across the roof, above the liner, to cool that first and to limit the affect solar radiation has on the passenger compartment. Then it would go down one side behind the plastic and into the battery plenum.

Now the PHEV conversion I have does modify the Prius battery fan to run faster, even full blast, but if it is only blowing hot air, what good does that do? I have noticed that the cut off for EV mode, on my pack temperature is about 114 - 116 deg. F. on the Can-View.

I of course will do a temporary tap from the AC vent, through the tube, over the passenger seat, over the back seat directly to the intake vent. However that will have to wait for a little while, and for a time that my wife is not in the car. I’ll post pictures.

 

Tony,
with the title of this thread I thought I was going to report it to the MODS. :lol:

 

<div class='quotetop'>QUOTE(efusco @ Aug 3 2007, 05:01 PM) [snapback]490144[/snapback]</div>

Thank you! I'll do just that before deciding to order. Wouldn't mind waiting a few months or so if it'll end up being a new 3rd gen unit.

And oh, my apologies to Tony for sort of hijacking his thread.

 

Mike Dabrowski did an A/C-vent-redirect in his Insight, when he
figured he would need extra cooling when making the pack work harder
with MIMA. Similar type of air inlet, behind the passenger seat.
.
I've been thinking how absolutely stupid it is that the interior of
the car picks up so much heat, while the engine block tends to stay
fairly cool even on a hot day. We want the exact *opposite*, and it
would be lovely if there was a way to pick up all that cabin heat
before it becomes cabin heat and send it all to the engine coolant.
Year-round EBH users wouldn't need to plug it in on hot days.
Unfortunately, it would involve a fairly complex pickup structure,
or maybe some sort of black rubber mat with water channels you'd
throw over the whole car and hook into the cooling system somehow..
.
_H*