I noticed today when my car when into Auto Stop mode something I don't think I ever noticed before...dead silence. My radio and climate control was off and I noticed something missing. The IPU fan was not running at all.

So my question is: Does the IPU cooling fan only come on when needed? Or is it supposed to be on all the time? It is not very warm today so maybe it was not on because it was not too warm (the battery)?

Anyone know if it is normal for the battery fan to be off at times?

 

Pretty sure it's an "as needed" sort of thing. To be honest, I don't think I'd recognize the sound if it were.

 

I'm sure the pack has to reach a operating temp ASP , so you would not want the fan on? It probably has a temp. sensor. Hal

 

Thanks for the replies. It's only that I never noticed it not on until last night after driving an hour (and this morning). I usually have HVAC and radio on so it would go unnoticed. However, I had everything off last night and noticed there was no sound coming from the IPU. I was under the impression that it was always on but after thinking about it, I was not 100% sure. That is why I thought I would ask. The manual says nothing about temperature thresholds and such so I was just looking for some second opinions.

 

Well, the engine has to get up to temp, but as long as the batteries aren't frozen, it's actually better not to run a fan to try heating them up, since more than anything else, heat kills batteries. You won't get quite as much juice out of them while cold, but thats' better than cooking them intentionally.

 

So does anyone else hear their IPU fan on their HCHII when idle or auto stop? It seems mine makes no noise. Would the IMA light come on in the event of a fan failure?

 

on my 2010 Insight the IMA control unit has a malfunction and the bat cooling fan always runs at max speed , also IMA error appears

 

Actually I only became aware of hearing the battery compartment fan as my IMA battery was starting to constantly recal. There are 3 temperature senders inside the IMA battery pack. I assume the fan runs when one or more of them reaches a certain temperature, but I haven't looked at an electrical diagram to confirm that.