[dennismacleod]

My 2001 Insight which I purchased in December 2003 had been performing well until the heat of summer hit here in Phoenix. I then started getting recalibrations usually in the hottest part of the day when I was driving in a normal manner or waiting for a long time in auto stop. After being told by Honda that this is 'normal operation', (this sounded like Microsoft saying it’s normal to have to reboot your computer all the time) I decided to experiment. The symptoms led me to believe that this was a heat problem. I went to Fry’s Electronics and purchased to 70mm pancake computer fans. I then pealed back the carpeting and grill over the opening to the battery compartment behind the passenger seat. The fans fitted very well in the opening. I wired them in parallel to a cigarette lighter probe and plugged it into the dash. The fans run when ever the key is on and I have not had a recalibration since the beginning of August until my wife drove the car yesterday. When I got the car back it only had one bar on the SoC gauge. But I also found that the plug had been bumped and the fans were not running. I will continue to test this mod and look for a grill to go over the fans and a better place to wire them in. Did not see a thread on this idea so thought I would let the group know.

Dennis MacLeod
2001 Blue Insight

 

[Rusttree]

Sounds like an awesome idea. Whereabouts in Phoenix do you live?

 

[kapps]

Pics...

 

[ext1jdh]

Pics...

Hear Hear. I was thinking about doing the same thing but wiring it in so they'd be running all the time but never got around to it.

 

[Insightful Trekker]

I hate to pick at the technical terms used but there is a difference between a recalibration, forced charge and battery thermal management.

Since the recal term is widely and incorrectly used to fault the IMA system the myth is perpetuated. Recals do happen but they (in the majority of cases) are the minority as a cause of unusual IMA behavior.

My best guess given the circumstances of your IMA battery behavior is one of thermal management limits. Specifically under your conditions and driving pattern the IMA pack is discharged and thermal management is limiting its recharge.

Consider renaming the title? e.g. Battery cooling mod for better hot climate performance. Please?

Now for the warnings to others thinking of doing this mod.

The IMA pack uses multiple thermosensors to determine what thermal management should take place. Incorrectly cooling a/the sensor(s) _without_ assuring that the IMA batteries also get the full effect of additional cooling is a recipe for IMA battery damage. Additional fans that do not have carefully designed ducting to distribute the airflow can easily cool a thermsensor to a greater degree than the batteries. This will result in battery thermal management errors in that the sensor(s) indicate a "cool" enough battery when they are actually *not*. Rapid damage will occur under these conditions.

A better solution would be to wire in parallel a control switch that would enable manually turning on the existing fans. It would also be helpful at the same time to include some type of indicator to show when the fans are automatically on. Finally, it may be of some help to install higher flow fans in replacement of the existing fans to better cool the batteries.

And according to this study:

http://www.osti.gov/bridge/product.bibl ... =3&start=0

An area of the IMA pack runs hotter at least in part due to its proximity to other heat producing devices within the IMA case, fig 4, pg. 4 and written up in the paragraph below the figure. Additional fans that move air inside the IMA case _may_ be of some benefit. The fan(s) could be added with additional speaker "grille" holes cut from behind the seats for airflow.

If somebody wishes to try my suggested modifications I'd be willing to collaborate via email. I have some experience in advanced automotive electrical systems and the Insight ETM! <g>. There is some _real_ danger in poking around inside the IMA case (144v) so this is not a novice task! As busy as I am personally, and given the cooler climate here in east Tennessee (I've never experienced a thermal cut-off) I don't see the value of this mod for my car.

HTH!

 

[b1shmu63]

Hi Denis, welcome to the forum. It does sound like a heat problem to me too. Your fan mod seems to suport this. Here in Canada the problem of heat is reversed. Occasionally, in the extreme cold of winter the battery management appears to get confused by low voltage from the battery pack.

Do you use the air conditioning or do you crank the windows down to save fuel? I'm inclined to crank the windows myself. I'm assuming that the fans promote air circulation from the cabin into the battery area in a general sense. If the cabin is air conditioned this would certainly help. John's idea of increasing the air flow using the existing fan(s) sounds like it would be even more effective, but of course this would meen getting into the IMA pack, and I'm sure this would be a little stressful for some. Perhaps you could mount an external fan over the air inlet behind the passenger seat as a temporary measure to test out your theory. I suppose that there is a remote chance that the existing fan has stopped working. It will be interesting to hear what you discover.

 

[dennismacleod]

Hi thanks for the response and this great forum. I live in central Phoenix near 35th Ave and Glendale. We also have family in Canada, San Diego and Fort Worth. I get as high as 68 mpg running around Phoenix in the winter and around 52 mpg going to San Diego at 75 mph. In the summer a car out in the sun can get to 150 degrees Fahrenheit inside and of course the battery compartment is at least that. That can’t be good for the life of the batteries and I hope these fans will extend their life. Once I get the car cooled off some I put up the windows and run the A/C. Even at this point the air in the cabin has to be better than the battery compartment. I have quickly thrown up some pictures for you to see what I’ve done at: http://home.mindspring.com/~macleodd/ .

I did check out the article mentioned in the earlier email http://www.osti.gov/bridge/product.biblio.jsp?osti_id=783430&queryId=3&start=0 and it did mention cold weather cutting battery output. It showed the air flowing in from the intake and over the batteries with the first ones being insulated so the stack temperature stays more even. I also found one interesting paragraph I'd like to share from it:

"Overall, the battery thermal management is adequate on this mild hybrid, but does not aggressively manage extremes that can be encountered outside of mild climates. This strategy
may seem reasonable, but if harsh conditions are encountered repeatedly, this may lead to failures and/or reduced cycle life for the battery pack. Thorough life tests are beyond the cope of this case study, but a mild management strategy will surely reduce the robustness of the pack over time. "

I also feel that if the batteries were not getting charged, the output current would drop and the controller would reduce the SoC indicator accordingly. Hope this answers your questions. Talk to you later.



Dennis MacLeod
2001 Blue Insight
70K miles

 

[Insightful Trekker]

AHHA!

"Booster" fans in the existing ductwork. A nice proof of concept design choice.

Please keep the group posted with your research! <g>

 

[Rick]

Hi Dennis, I like it, a simple yet effective solution. I have had something to that effect looming in my head for a while now. I don't suppose you happened to be that Insight parked at Frys about a week ago that I put one of the InsightCentral web cards in it's window by the door was it?

Anyways, welcome to the forums.

 

[b1shmu63]

I like it! Those fans look like they were made to fit in there. Perhaps on the prototype, I wonder. :roll:

A couple of Insighters have mounted solar powered fans in the back to keep the cabin temperature reasonable in the sun. I think Figgy was the first to try the idea and he used 4 fans externally. Here is a link to one of the discussions I found using 2 fans internally.

http://www.insightcentral.net/forum/vie ... php?t=1796

 

[Guest]

Hi All:

___Although I have never had a Recal, I can understand those in warmer locales/environments pushing their packs temp specs to the limit when sitting in parking lots at work and such. I won’t be performing any of the mods listed here but one item I do perform that should help most of you during the peak temperatures of early afternoon is leave your windows cracked. Whenever it is going to be above 70 degrees, I crack both windows ~ 1”. When I get to the car in the late afternoon, the interior is ~ the same temperature as the outside. You will know exactly what I am speaking of the first time you try this for yourself. On days it is sunny when I arrive at work but it is supposed to rain, I will leave the downwind side window cracked and close it during a break or lunch before the rain arrives. We have a great system for tracking storms and such at work Even in a Phoenix, Sacramento, Miami, New Orleans, Atlanta, Knoxville, Dallas, or a DC summer, the interior should not reach much above 110 (100 – 110 degrees ambient external) with both windows cracked whereas I can imagine 150 – 170 degrees F if the Insight was bottled up tight in a high temperature environment. Even if you are not going to use your Insight on a particular day and it will sit outside, I crack the windows whenever I walk past her and close them up in the evening.

___Believe it when I say the internal temperatures will be much lower with the windows cracked vs. closed up. Even here in Illinois, we have 90 + degree days and you can easily get into the car and drive off without touching a thing vs. ever trying this in a 90 + degree and sunny day in anything when the windows are closed up tight.

___In the case of a non-work parking lot (mall, beach, restaurant …), there is the problem of our automobiles windows being cracked because of any number of jerks who might mess with our little beauties I just park in the back away from everybody else when at the mall or theater, and crack the windows. I haven’t had a problem with this technique in the many years I have used it which is well before I had an Insight.

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___[email:2s49v1rw][email protected][/email:2s49v1rw]