Wednesday, October 1, 2014

Cooling Pump Follow Up

If I had one thing to add to the previous post, one thing I've learned, it's don't send a boy to do a man's job.  Let's recap the story of my attempts at cooling the Zilla controller in the car. 

The first cooling solution I installed in the car was essentially a kit sold by EVSource.  It came with a little 4x8 inch radiator, and a Laing D5 Strong pump.  The car hit the road in March of 2010, when the average daily high temperature is about 75°F.  All was right with the world.  However, by late April, when temperatures are beginning to approach 100°, I noticed the controller starting to over heat, and go into thermal cutback after I'd traveled a couple miles from the house.  It turns out that a radiator from a kit designed for a liquid cooling system for a computer wasn't up to the task of cooling a 1000 Watt controller.  Go figure!

What did I do about that?  I added a couple of 120mm fans to the radiator.  But as the car was off the road that summer while I re-did the battery layout up front, and removed the motor for repairs due to faulty balancing putty, I never got to test this solution in heat of the summer.  When next summer rolled along, I found out that it was only slightly more effective than the previous year when I had no fans. 

Attempt #3 at getting adequate cooling:  I swapped out the little 4"x8" radiator for a nice big 12"x14" that incorporated it's own 10" fan.  I hooked that fan up to a temperature switch on the Zilla so it would spin up if the Zilla got above 122°.  This system was far and away better, but the controller would still go into thermal cutback if I ran it on the freeway for more than 5 miles.  Now, you may notice through all of this, that I never changed out the pump.  The little Laing D5 Strong pump was still in the car spinning away. 

When that pump failed early this summer, I was forced to replace it, and I was fortunate enough to have purchased one of the OEM quality Pierburg water pumps from EVTV.  It would have been far easier to simply swap the bad Laing pump for another, I wouldn't have had to modify anything in the car, but I'm so glad I didn't.

I've run the car in our typical 105° August/September weather, on the freeway for 12 miles at a time, and so far the controller has not complained once about getting too hot.  In fact, I haven't even heard the radiator fan kick on!  If I'm honest, may have come on when I was on the freeway, but I never heard it due to road noise.  The bottom line is that thanks to this Pierburg pump, the controller is finally getting the water supply it needs for proper cooling.  And the properly sized radiator is providing enough cooling area to suck the heat out of that water.  This is a big relief.  Heat is the enemy of electronic components.  The better I can keep them cool, the longer they'll last.