PEM, motor gets too hot -- fans failed

[WarpedOne]

How big of a gesture would that be to replace all the PEMs on the Roadster for free with a liquid cooled one. Won't happen since its expensive.

A new LQ PEM for discontinued roaster probably won't happen. To expensive for ~2000 vehicle target.

What just *might* happen is a tweaked Model S motor/controller with 40kWh FW. It probably wont come from Tesla Motors but from some third party a year or two down the road when totaled Model S become "available".

 

[daniel]

The Ranger is coming today to do my one-year maintenance. I'll ask him what he thinks of the PEM issue. I.e. does he think PEMs are likely to fail in significant numbers between year 3 and year 6 (the extended warranty period)?

Well, he didn't have much to say on the matter, but he has not seen a lot of problems. A few, but not a lot.

 

[smoothoperator]

I suppose there's a chance doing this could cause condensation inside the enclosure.

Yea and if TM ever found this pic of putting ice on top of the PEM pretty sure the warranty would be voided, if the PEM failed and moisture was found inside the PEM enclosure.

 

[Eberhard]

How big of a gesture would that be to replace all the PEMs on the Roadster for free with a liquid cooled one. Won't happen since its expensive.

By moving the blower from the PEM down where it is now, the blower no longer sucks cleaner air from the side pipe but any kind of debris including salt via the wheel housing.

Thats what may called a technical disaster. this has to be corrected by tesla. its a fact of warranty. if tesla cannot fix the problem, they have to replace the current air cooled PEM by a correct working liquid cooled one.

 

[JRP3]

Unless it lasts past the warranty period.

 

[bonnie]

Yea and if TM ever found this pic of putting ice on top of the PEM pretty sure the warranty would be voided, if the PEM failed and moisture was found inside the PEM enclosure.

Of course they've seen it by now. That's a given. We are not the only ones who read posts on this forum.

 

[smoothoperator]

Of course they've seen it by now. That's a given. We are not the only ones who read posts on this forum.

Sign me up for that job at Tesla!

 

[TEG]

Yea and if TM ever found this pic of putting ice on top of the PEM...

Yeah, they don't want (an) ICE in any of their cars! :tongue:

 

[daniel]

By moving the blower from the PEM down where it is now, the blower no longer sucks cleaner air from the side pipe but any kind of debris including salt via the wheel housing.

At my annual service last week, the ranger installed a housing that is supposed to prevent snow, salt, and other road debris from being sucked into the blower.

 

[mgemmell]

Yea and if TM ever found this pic of putting ice on top of the PEM pretty sure the warranty would be voided, if the PEM failed and moisture was found inside the PEM enclosure.

I had the ranger round this week and he was "cool" about it (sorry .

He was upgrading the fans to the new single motor fan, firmware etc. and also blowing the dirt out of the PEM (which worked excellently BTW - No power limits now, even at 37C and driving hard in Performance mode).

We did have a conversation about liquid cooling. Clearly many are thinking the same, including some inside Tesla. The idea of a cooling blanket on top of the PEM looks promising... its a good option as it is non-intrusive to the PEM and a relatively easy add-on. Liquid cooling the motor could be done by feeding a cooling coil through the air duct around the motor. Both cooling circuits could be fed from the existing circuit, or could be fed by a compressor squeezed in the space where the fans are. Of course this is just for people driving hard in hot climates so its hardly top priority.

By the way, I am going to fit a cloth cover over the fans. I prefer to block a washable cloth than block the PEM (which is a major hassle to clean, and I have only done 16k kms). True, it may reduce air intake and therefore cause the fan to have to work harder, but I prefer this as the lesser of two evils. I will keep you guys posted on the "air sock" design and results.

 

[JRP3]

I'd try using real air filter material, ideally adapting an existing air cleaner element or air cleaner foam.

As for a cooling blanket on top of the PEM, what about condensation? Seems as if the underside of the cooled top would get condensation, which could then drip down onto the interior components.

 

[Doug_G]

I'd try using real air filter material, ideally adapting an existing air cleaner element or air cleaner foam.

As for a cooling blanket on top of the PEM, what about condensation? Seems as if the underside of the cooled top would get condensation, which could then drip down onto the interior components.

In case you haven't noticed, the PEM is exposed to the exterior environment when you are driving. Mine gets covered in dust after just minutes of driving. I'm sure it can get wet, too.

 

[wycolo]

At my annual service last week, the ranger installed a housing that is supposed to prevent snow, salt, and other road debris from being sucked into the blower.

Ditto here, but fortunately a new mod just arrived from the factory with an upper-level air loop featuring various choices of ventings. I chose the Cowboy Style, naturally, with better acceptance by the locals in mind. Just keep 'er movin' and it stays clean as a whistle.

 

[JRP3]

In case you haven't noticed, the PEM is exposed to the exterior environment when you are driving. Mine gets covered in dust after just minutes of driving. I'm sure it can get wet, too.

Well yeah, but since it's probably hot any moisture would evaporate. In any case my condensation concerns were misplaced, it would only happen if the PEM surfaces were cooled to lower than ambient, which is not likely. If the PEM is OK with getting wet, why not liquid cool it? :wink:

 

[Doug_G]

It's one thing for the exterior to get wet. It's another to run liquid cooling through the heat sinks. That would require a significantly different mechanical design

 

[JRP3]

Guess it wasn't obvious that I was joking. However, how about mineral oil bath?

 

[wycolo]

"the PEM is exposed to the exterior environment" [Doug_G said]

Tesla Shop just cleaned my well-dusted PEM. They remove PEM unit from car and expose the cooling fins. The PEM electronics side remains covered; they peer into it to ensure that it is still clean. Then they take it outside & air blast the fins. They also clean the openings to the charger. Don't know if they can peer into charger unit.

They installed the new 'single motor double blower' unit as well as the new 'snow dam' sheet metal housing.

They replaced 'PRND drive buttons+circuit board' assembly due to diagnostic errors on TS when CAR DIED WHILE PARKED, rather than any overheat faults. Cockpit of roadster was well dusted.

We still don't know why car died- was it simple over-heating or was it dust getting into PRND unit?? Or both?? The next morning the car seemed to work fine, what being tied down to trailer and all that. Taken to Tesla Shop it drove off trailer & around lot in normal fashion.
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[wycolo]

mgemmell said: "fit a cloth cover over the fans."

Once the 'snow box' is installed it will have to be made airtight somehow. It appears most of the cooling air is now sneaking in around the upper edge castellations, keeping out particles but not dust per se.

Proposal: Cut 3in round hole in bottom pan. Inject insulating type foam all around top edge of snow box. Verify that bottom edge of snow box is snug all around to bottom pan. Then cut 3in (4in if possible) hole in bottom of trunk which would enter snow box. Then mount your new filter box inside the trunk and feeding into this new hole.

An excellent filter element would be 12in x 24in x 5in (thick) made for 2010 Freightliner Cascadia 15L diesel. Cost is $67- at your local semi shop. This will fit nicely in the roadster trunk in a homemade box. This type of flat filter element is cleanable by slapping against a concrete wall to dislodge most of the trappings. Should have a long service life.

I have yet to seriously inspect my new snow box. Need to go downhill to find some smooth pavement. And use serious light beams. But seeing the snow box before it was installed led to to this approach. I hope the new sway bar was redesigned specifically to remove it completely from the snow box, which will simplify things.
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[WarpedOne]

Another proposal:
Make two holes one on each side and fill it with insulating foam.
Mount a vent inside both holes and wire them in a way that one sucks air in and the other blows it out.

On even calendar days first vent sucks air in and the second blows it out.
On odd calendar days reverse the polarity so the first vent blows air out and the second sucks it in.

Voila, automatic cleaning of filters.

 

[mgemmell]

Funky ideas people .

Let's see what we are dealing with here...

The photo is taken from the right side with the wheel off. You can see the new fan and the new rollbar going around it. The surface below is the floor pan and above is the floor of the boot (aka trunk).

Given the limited space and the new rollbar that curves around the fan (and rotates up and down a few cms as the suspension flexes) some creativity will be required to do much more than a cloth covering.

As the new fan draws air in from either side and also from the centre if the idea is to channel air to the fan from a single standard car air filter the fan covering will need to box the fan without fowling the rollbar, and then collect air from below or above in some kind of duct. There is enough space for a good sized airfilter behind the fan and rollbar.

A proper air filter does sound best. For now the cloth cover is a good first-pass as I can get it done quickly and test if it throttles the fan too much.