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[Justin Andrews]

I went toe-to-toe with a sports bike the other week, pretty much on the speed limiter for about 7-8 miles, I got the temp warning light up, but I did'nt manage to trip the actual temp overheat and associated power cut back.

[CScalpeL]

The only time it happened on a cooler day was when a guy pulled up next to me at a light, hollered at me about "is it electric??" and then bugged me into drag-racing him through the next few lights (for some reason traffic was really light). After about four one-block races the overtemp light started blinking and I started acting my age.

I understand that the overheating can be mitigated by slow and easy riding but I didn't pay the premium price for the SR only for the red color and the extra R in the lettering I want to be able to be able to exploit the performance of the bike to its fullest capabilities and if there is a malfunctioning component that is limiting me from doing so, I'd like to get it taken care of. As it stands now, I now have a trade-off between heating and range since the bike doesn't shed heat when using full Regen (even only when set on braking), I keep Regen to a minimum and pay for it with reduced range while still hitting the overtemp limiter frequently.

ctrlburn, so just to clarify, after having the thermistor replaced the bike no longer suffers from overheating (or significantly less so)?

[protomech]

The Zero size 6 racers would frequently employ large side-mounted ducts to force air over the cooling fins, or in some cases through the motor after opening the case (hopefully with an air filter at least!)

Obviously these ducts weigh a little bit, and they introduced a little bit of drag. And for a street application, they wouldn't do much for you unless you were moving at highway speeds.

Has anyone tried directing air over the fins using a 12V electric fan or blower? I don't think it'd be very efficient, but it might be better than nothing.

Ex:
http://www.noctua.at/main.php?show=productview&products_id=83&lng=en&set=1

107 CFM, 2.16W, 38 dbA. 12V IP67 would be fine for this application. One or two of these mounted to direct air over the motor fins .. not sure if it would be practical.

[NoiseBoy]

Those fans need a PPM header, they wouldn't work correctly with 12v from the bike.

I remember seeing pics of quite a few motocross Zeros in the early days with computer fans blowing over the motor. It was apparently quite effective.

[jheth]

This happens to me too (temp warning after fast riding). 2015 SR, in San Jose CA. Taking it to the dealer today. I'll keep y'all updated.


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[dkw12002]

My 2011 Zero S had a fan that would come on quite a lot and stay on long after the bike was turned off. When Zero improved the motor, the next year, they dropped the fan. I had some issues with my 2013 S not charging on a hot day after a ride, so I think the heating fix will have to address both the battery and the motor. Even though the bike might run and charge, all this heat can't be good for it. I think they are going to have to circulate some coolant to both the battery and the motor even though nobody wants to deal with that extra system and the weight it would add. Zero needs to test these bikes in a Texas summer. N. California is not a good test ground.

[evtricity]

I've fitted a 40mm EDF (Electric Ducted Fan) to my Zero SR and push air through the motor (have cut ventilation holes in the motor face plates as other racers have done) to reduce overheating on the race track. The EDF runs off the 12v accessory circuit via an ESC/speed controller. Details and pics @ http://www.diyelectriccar.com/forums/showthread.php/zero-sr-race-mods-124073p4.html

I've only run it at about 100W (7A x 12V) and I haven't seen a significant reduction in motor temperature on the track. I've recently upped the EDF speed controller so that it will run at a continuous 17A (removed the headlight 10A fuse and upped the accessory fuse from 10A to 25A). Hopefully that will provide greater heat dissipation.

While you could try and simply attach an EDF to blow onto the motor fins I doubt you'd get as good an effect as blowing air through the motor itself so until I can get a significant motor temperature reduction I wouldn't recommend using an EDF as an accessory fan for existing owners.

I think the 2016 SR and DSR motors will be better from an over heating perspective with their "interior permanent magnets".

[Richard230]

According to Zero their new 2016 Internal Permanent Magnet 75-7R motor design, which is used on their ZF13.0 SR and DSR models, is virtually impervious to overheating. So apparently Zero is well aware of overheating concerns in the previous motor designs.

[jheth]

Conclusion from dealership (with input from Zero) is that my bike is not defective. Dealership was able to reproduce occurrence by riding at 90+mph for a while. Motor hit ~100 deg C, and power output is limited by the SW. This is to prevent overheating obviously.
Bottom line: it is normal behavior, part of the design. Sounds like Zero has known about this, and improved 2016 motor design to address this.


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[Electric Terry]

Nice work evtricity!  I like it!

Yes, although it will be 3-4 months perhaps before anyone here can trade in, the 2016 models seem to have addressed this.  Luckily we are going into winter months which should help bridge that gap.  For many owners who ride more conservatively they never have issues, and for them it's fine as it is.  But for those who experience frustration or overheating anxiety as was stated, I would recommend upgrading before next summer if it's important enough to you.  The small incremental extra battery capacity and range won't hurt either.

I read some comments in the other thread about the 2016 and everyone seemed to think there weren't a lot of improvements, but the IPM motor is a huge improvement!  I promise, people on this forum will still be able to overheat it if they try, but it will take more to get there.  The sustained top speed for the SR went from 85 mph to 95 mph.  That takes A LOT more energy to maintain 95 mph vs 85!

So that's a huge improvement!  For those who don't care about overheating the 2016 might not be worth upgrading to.  But for those who wish their bike didn't, Zero was listening to you! They did something about it!  And in as soon as 3-4 months you can do something about it if you want to.  If you're reading this thread, chances are you are one of those who likes to go faster for longer, and you've probably already decided to test ride the 2016 the day the bike is available to see for yourself if it's worth upgrading.  My guess is most of you on this thread will do exactly that.

And a side note.  Shops like Hollywood Electrics were ahead of the curve, installing size 6 controllers into bikes in 2012 and 2013, before they were available.  If a higher power controller were to become available through them, you now would have a motor that could better handle it.  Meaning you could lower your 0-60 times, or 0-102 times.  It would not change your sustained top speed, that would remain at 95.  And all of this might not happen, but then again, it could.

I got a size 6 upgrade for my Zero from Hollywood Electrics back in 2012 and it was totally worth it.  Let's hope something like this will happen again.  But you need the correct platform first and that will be a 2016 bike.  Now we wait over the winter until the first of us can go demo ride a 2016 to see, and hopefully next year we will hear about a power boost option for these new bikes from the aftermarket.

[ctrlburn]

With everyone driving differently and attempting to compare results i fret that inconsistencies mar findings.


Rear of Bike well anchored on stand.
Bluetooth app readouts

With motor starting at 80F  (warmest IR reading was 69F in the fins)

25mph
after 1 minute is reads 82F
after 1 minute is reads 84F

increase to 55mph
after 2 minutes it reads 93F
after 1 minute is reads 100F
after 1 minute is reads 106F  (warmest IR reading was 84F in the fins)


To compensate for ambient and starting temperatures I suppose run at 25mph until 84F then increase to 55mph and see how you compare at the 4 minute mark.

[Killroy]

With everyone driving differently and attempting to compare results i fret that inconsistencies mar findings.


Rear of Bike well anchored on stand.
Bluetooth app readouts

With no load on the drivetrain, you many not get any significant differences, even though in the real world, the bikes perform differently. 

In the real world, the size, weight and riding style may be a large variable  and that goes for range too.

[CScalpeL]

ctrlbrn thanks for posting that! it will be a good point of reference.

I need to get my hands on a stand so I can do a run and compare.

Did you do anything similar to that prior to getting the thermistor taken care of?

[ctrlburn]

No I didn't test like that - and it was really disappointing.

My Thermistor fault was very evident from the experience - by faulting very quickly - and having IR temperature reading nearly half the anticipated cut out temp.

Someone cutting out at 80% would not have that same "ease" and someone cutting out at 120% should not be used to compare experiences.

There was a really lack of diagnostic empirical data... last year.
Among steps - I was asked to check the resistance of the thermistor. 
When I asked "What should it be?" I got the product sheet on the thermistor rather than a particular target.
 
Clearly support was asking a question on behalf of engineering, returning the results to engineering and waiting for them to digest the results and come up with another test. Not diagnosing from established troubleshooting process put a lag in every diagnostic step.  I asked for the whole process so I check several things in each exchange and only got one thing at a time.

Having some benchmark data (like this) for context would have shortened or better directed the process.
A thermistor giving bad readings, has to be detected by measuring something else.  (And comparisons just to ambient temperatures is only one data point)


(Think about comparing otherwise unobservable driving styles by which one boils the brake fluid. One may think they drive aggressively because their brakes regularly fade out... when actually they just may have bad brake fluid - while someone who really drives harder rarely has the same experience because their fluid does not boil at the same temperature. You could get temperature from the brakes after a drive... or check for glow... or smell... or do 0-60 60-0 over and over and count how many times it takes to fade out with odometer as a checksum).

[RNM]

What about oil cooling? read ˜4 posts after this one:
http://electricmotorcycleforum.com/boards/index.php?topic=4424.msg29049#msg29049

"simply filling the motor slightly less than halfway with ATF almost doubled the continuous power output. "