I'm posting this after reading the ongoing thread about the poor mileage in an '07 FEH and its A/C system woes.

If early models had the rear evaporator to cool the battery, why was that deleted from 2010 on? I assume that since the rear air filter is gone, all the rest of it was ixnayed also. So what do they do to manage the battery temperatures aside from the cooling fans, a pair of Ray-Bans, and advice to "think cool"? Did Ford decide that all the extra plumbing was unnecessary because the cabin A/C+battery fans were enough to manage the thermals? What effect does this have on the battery life, if any?

Inquiring minds want to know! Or maybe they don't...but I'm asking anyway!

 

Same reason Ford deleted the HV jump starter. It was costly, and "it wasn't needed."

They have intake vents and draw cabin air in for cooling.

IMHO, it's the only reason the FEH battery was as reliable as it was. The Sanyo cells in the FEH battery are also used in the 2006-2011 Civic Hybrid, which has one of the WORST cooling schemes ever designed for a hybrid battery and thus one of the most unreliable HV batteries ever made.

It's a deal breaker for me. The 10-12 FEH is a "would never own" vehicle for me, even if it was given to me. The "D" cell form factor has proven to be a cooling challenge ever since the 2000 Honda Insight (and the Japan-only 97-00 Prius). Ford knocked it out of the park with a rear evap, but they turned it into a **** show in 2010.

 

Well, that's a bummer, but thanks for the unvarnished answer, I'd much rather have that than BS happytalk. I'll make sure to try to park it in the shade on hot days and do my best to keep the cabin cool. I'll get a sun shade for the windshield, too. They're cheap enough. The A/C's working very well, the battery fans are good, and I'll do my best to keep it that way.

As Bob Seger once sang, "Wish I didn't know now what I didn't know then." Such are the ups and downs of life.

 

Make sure nothing is ever blocking the vent the HVTB uses to draw in the cabin air.

 

Affirmative. Roger that.

 

"Same reason Ford deleted the HV jump starter. It was costly, and "it wasn't needed."

They have intake vents and draw cabin air in for cooling.

IMHO, it's the only reason the FEH battery was as reliable as it was. The Sanyo cells in the FEH battery are also used in the 2006-2011 Civic Hybrid, which has one of the WORST cooling schemes ever designed for a hybrid battery and thus one of the most unreliable HV batteries ever made.

It's a deal breaker for me. The 10-12 FEH is a "would never own" vehicle for me, even if it was given to me. The "D" cell form factor has proven to be a cooling challenge ever since the 2000 Honda Insight (and the Japan-only 97-00 Prius). Ford knocked it out of the park with a rear evap, but they turned it into a **** show in 2010."

reading what you said carefully but not following it all.
in the second sentence the statement that "it wasn't needed" is said in sarcasm. no problem - i follow that.
the statement that it was the only reason it was as reiiable as it was would not follow from the previous statement - that says that "they have intake vents and draw
cabin air in for cooling". That is on the 10 -12 FEH and as you go on to say that is a very poor design.
the best design draws in outside air and then exhausts to the outside (that is what i have in my 2009 (the last year for that - with an evaporator for the hybrid battery))
also. the cost of the non-ordinary ac compressor for the 2010 and on is Very Expensive (8 to 9 hundred)

 

(1) Nope. When the battery can be maintained in the mid-80s, it uses outside air as you describe without using the evaporator. When it can't maintain that, the blend door closes and completely seals the battery off recirculating the air in the system and looping it through the evaporator to chill it. The best design is one that maintains these cells below 90°F. No Honda has ever been able to do that reliably, and the only reason the 05-09 FEH could is because of the rear evap. I guarantee you that the 10-12 FEH can't do this.

 

Can the 2010-12 FEH's computers turn on the cabin air conditioning system automatically if the battery gets too warm? Is the HVTB temporarily disabled if the AC system stops working in hot weather?

 

I can't answer the first half, but I really doubt it. The car will progressively dial back the charge and discharge limits of the battery as the temperature increases. I've seen limits as low as 1,500W with a hot battery when normal is north of 30,000W

 

I tried a simple experiment yesterday: The car was parked for most of the day, with the heat where I live in the high 80's, low 90's. I shut the A/C off on the dashboard when I parked it the previous night, making sure the little orange LED in the "A/C" button was off. The climate control temperature was set to 72 degrees on both the driver and passenger side at the time. When I got in the car the outside temperature registered 90 degrees atop the center console.

So when I got in the car the cabin was warm/hot, which means the battery temperature was ambient with the interior of the car. It may have been a little cooler in the back because of all the window tinting back there, but not much. Regardless, it did not automatically turn the A/C on. I waited about 2 minutes while the car sat "Ready to Drive" in EV mode, and it didn't turn on, although air was blowing from the vents, it was in non-recirculating mode. I hit the button and it came on right away, and you could feel it blowing much colder air.

So it doesn't appear to turn the A/C on automatically, at least if it has been switched off through the climate control system. This isn't a complete characterization of its behavior, obviously, but for what it's worth, the answer appears to be "no."