# Soliton Junior Cooling Strategy



## Tesseract (Sep 27, 2008)

I tried to write a response twice to this post and it kept coming up blank when I hit preview on it. Something is bugging in the forum, methinks.

Anyway, the derating schedule is illustrated graphically on p29 of the manual, so it hardly required any sleuthing to figure out.

That said, the Jr is not going to be capable of delivering more than around 500A continuously regardless of how well you cool it.


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## GerhardRP (Nov 17, 2009)

Thanks for the interesting experiment, but I suggest you make it slightly more "scientific". Re-do the runs, but in preparation for each, run the full time cooling to get the starting temperatures the same. I would think that some sort of anticipatory cooling could be turned on when the battery current exceeds some chosen value.
Gerhard 



Yukon_Shane said:


> Awhile back a made an observation that the Soliton Juniors derating schedule started to reduce power from the controller at 40C which was exactly when the controllers fans would kick in and the controller would turn on the liquid cooling loop (if you chose to use that function). This didn’t seem to be entirely ideal to me given that I assumed the controller would benefit from having a bit of a head start in keeping the controller cool before power began to cut back.
> I made a post to this effect on one of the Soliton threads at the time and then didn’t think about it again until recently when I incorporated a liquid cooled DC/DC converter into my controllers cooling loop. Because the controller temperature likely had very little correlation to the DC/DC converters internal temperature I decided it might be better to have the liquid cooling pump turn on as soon as I turned the ignition on rather than when the controller got to 40C. This approach seemed a bit wasteful but I thought I’d give it a try and see how it went. On my first test drive I noted that the car seemed to have a noticeable amount more power available particularly getting up to speed on the highway. Since that initial test drive I’ve continued to notice a significant improvement in the cars acceleration and hill climbing ability so I decided to do a small test and post the results here for folks to take a look at.
> This is far from a perfect scientific study but I think it might be informative. What I did was 3 (close to) full throttle runs on the highway from a near stop up to around 4,500 RPM: one run with full-time liquid cooling; one run with the liquid cooling turning on at 40C (controlled through the Soliton’s output pin); and one run with no liquid cooling at all.
> Here are my results:
> ...


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## Yukon_Shane (Jul 15, 2010)

GerhardRP said:


> Thanks for the interesting experiment, but I suggest you make it slightly more "scientific". Re-do the runs, but in preparation for each, run the full time cooling to get the starting temperatures the same. I would think that some sort of anticipatory cooling could be turned on when the battery current exceeds some chosen value.
> Gerhard


I see your point here but I'm not sure I agree. The take away I'm getting from this test is that, depending on your cooling strategy, your controller will start cooling at a different temperature. So for no liquid cooling you're controller is going to be sitting around 40-50C even after a short run down the street while if you use the soliton's liquid cooling control function your controller will likely always idle just below 40C until you put you foot into it at which point it will climb from there. For full time cooling your going to start at whatever your ambient temperature is.


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## Yukon_Shane (Jul 15, 2010)

Tesseract said:


> I tried to write a response twice to this post and it kept coming up blank when I hit preview on it. Something is bugging in the forum, methinks.
> 
> Anyway, the derating schedule is illustrated graphically on p29 of the manual, so it hardly required any sleuthing to figure out.
> 
> That said, the Jr is not going to be capable of delivering more than around 500A continuously regardless of how well you cool it.


I didn't intend this as a critique of evnetics, I think the supporting documentation for this controller is pretty great and the inclusion of the datalogging program is awesome. For me this is intended more as an opportunity to get a real world feel for how the derating schedule works and how different cooling strategies might effect real world performance.

The derated schedule in the manual is excellent but I had no real impression as to how long it would take my controller to get to 40C or if it would ever get to 60C so this type of testing is valuable for me.

I also think that this analysis proves to me definitively the pointlessness of focusing on controller peak current as a means of comparison. In all three of these runs the controller had pretty similar peak output (550ish for no liquid cooling and just above 580 for both liquid cooling runs); however, the difference in the driving experience between the three was significant. With no liquid cooling after a second of acceleration on a flat surface I felt like the car was dragging a trailer or something. In comparison, with liquid cooling I can charge up long, steep hills with no problem at all. I expect even without cooling the soliton junior performance better then one of the classic Curtis controllers rated at 500 amps. So how can you compare a Curtis 1231C to a soliton junior? Just because they're both rated around the same peak output does not mean they're going to perform the same.

The industry is obviously too small to worry about such things too much but I'd say at some point it would be worth looking into establishing a set of standard test conditions that would be applied when rating a controller. That way you can compare apples to apples.


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## Tesseract (Sep 27, 2008)

Yukon_Shane said:


> ...The derated schedule in the manual is excellent but I had no real impression as to how long it would take my controller to get to 40C or if it would ever get to 60C so this type of testing is valuable for me.


Ah, sorry. I thought you were trying to ascertain the derating schedule. Believe me, the number of emails I get everyday from people asking things that are spelled out in the manual (even Seb just asked me yesterday how the minimum pack voltage function works... sigh...) has all but convinced me no one reads the manual... especially any appendices to the manual...



Yukon_Shane said:


> I also think that this analysis proves to me definitively the pointlessness of focusing on controller peak current as a means of comparison.


Yes, that was precisely our perspective when we designed the Soliton1, but after two years of failing to break the stranglehold of the Z1K we decided to, A) make a controller that competed against a less formidable/respected competitor (ie - the Curtis 1231C) and, B) rate that controller on peak current, same as the competition. It almost makes you feel dirty, but, well, as the saying for the stock market goes, "the market can remain irrational longer than you can remain solvent".


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## Joey (Oct 12, 2007)

Tesseract: For what it's worth, I've read the manual at least a dozen times, and refer to it all the time. It is one of the best written manuals I've read for any electronic component I've encountered for personal or professional use. It is only bested by the actual HW.

Yukon Shane: I've been driving my Soliton 1 with air cooling for about a year now. I recently installed a radiator and circulation pump. Once I get a reservoir tank mounted and plumbed, I will be liquid cooled. I think I will try to collect the same temp graphs as you have. Not because of any issues, but because this data is fascinating to me. I only notice temp cutback with air cooling on warms days, after at least 5 miles, and going uphill (a rare combo for my daily driving), but as a rule of thumb electronics are happier when you keep the temperature lower and consistent. My plan was to circulate water with the ignition switch, and kick on the fan of the radiator when the temperature reach some, as yet unknown, set-point. Thanks for posting the data.


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## Yukon_Shane (Jul 15, 2010)

Joey said:


> Tesseract: For what it's worth, I've read the manual at least a dozen times, and refer to it all the time. It is one of the best written manuals I've read for any electronic component I've encountered for personal or professional use. It is only bested by the actual HW.
> 
> Yukon Shane: I've been driving my Soliton 1 with air cooling for about a year now. I recently installed a radiator and circulation pump. Once I get a reservoir tank mounted and plumbed, I will be liquid cooled. I think I will try to collect the same temp graphs as you have. Not because of any issues, but because this data is fascinating to me. I only notice temp cutback with air cooling on warms days, after at least 5 miles, and going uphill (a rare combo for my daily driving), but as a rule of thumb electronics are happier when you keep the temperature lower and consistent. My plan was to circulate water with the ignition switch, and kick on the fan of the radiator when the temperature reach some, as yet unknown, set-point. Thanks for posting the data.


 Let us know how this goes. I'm curious to see how your results with the Soliton 1 compare to my Soliton Junior experience.


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## rwaudio (May 22, 2008)

Yukon_Shane said:


> Let us know how this goes. I'm curious to see how your results with the Soliton 1 compare to my Soliton Junior experience.


I used my Soliton1 with only air cooling for quite awhile, it wasn't until I looked at some summer log files that I noticed the temps were pretty high. I only noticed the current limit when accelerating on the highway slightly uphill, however the around town temps were still higher than I would have expected. With water cooling I never had current limiting again even with aggressive driving (street not track) and the average temps dropped into the 30's with peaks in the 40's(C). 

I would recommend liquid cooling any Evnetics controller.


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## Joey (Oct 12, 2007)

Yukon_Shane said:


> Let us know how this goes. I'm curious to see how your results with the Soliton 1 compare to my Soliton Junior experience.


It is taking longer than I expected to get my water cooling set up finished. I might be able to finish it tomorrow. I collected the data for the air cooled configuration.







I made three runs, separated by 20 seconds between runs. I normally start in second gear for daily driving, but I would only be able to drive for about 6 seconds before needing to shift, so I decided to do the test entirely in 3rd gear. Each run is a 0 to 70 mph burst with the throttle all the way to the floor (as much as my nerves would allow). Ambient temperature was 70 deg. F.

The first run did not encounter much thermal cutback at all. Maybe a tiny bit between 7.5 and 8 seconds. I must not have had the pedal all the way down because I was "only" getting 900 amps for most of the run.

I'm making a bit of an assumption about the Soliton logging, but it looks like motor current and throttle will overlay except when the controller is in thermal cutback. 









For the second run, I did a better job of requesting full current. Thermal cutback kicked in at about 7 seconds and continued until I lifted my foot at 14 seconds.

By the third run, the controller was starting at 60 deg C, and the max current was limited at the start, but still >800 amps was being delivered for 10 seconds. I'm impressed. 

One difference I noticed is that the extra mass of the Soliton 1 leads to slower temperature rate of change than Jr.


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## Yukon_Shane (Jul 15, 2010)

Great data.

It's following a pretty similar pattern to my soliton Jr. but obviously much better performance and much more limited thermal cutback.

Like my earlier data, this data seems to show the value in starting at as low a temperature as possible and gives some further credence to continuous liquid cooling; however, the soliton 1 clearly has less need for cooling then the JR.

Your observation that the Soliton 1 is taking longer to heat up due to it's thermal mass makes sense but it might also be a function of how the two different temperatures are measured. If I understand correctly the soliton Jr. uses a temperature sensor that is located internally to the IGBT while the soliton 1 is a bit more remote. 

Thanks for Posting this. Just another reason for me to look to upgrade to the soliton 1 at some point.


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## Joey (Oct 12, 2007)

I got the liquid cooling set up tonight. I did three runs, just like before.













There is current cut back, but not due to temperature. My temperature now peaks out at 42 deg C. Water cooling is great. 







My battery is low on charge and I was hitting the minimum 150 volt cutoff set in the controller. Looks like I will need to retake the data with a fresh charged battery.


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## Yukon_Shane (Jul 15, 2010)

Nice. It looks like with the soliton 1 and water cooling you practically never have to worry about thermal cutback.

What are you using for water cooling? Are you using the soliton output to turn on the water cooling or is it on full time. I'm guessing full time cooling.


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## Joey (Oct 12, 2007)

This is my cooling loop. I need to take pictures now that it is installed.
I am turning on the circulation pump with the key switch. I will turn on the radiator fan with the Soliton output and a relay, but that is not hooked up yet. It would probably only be needed in the summer, going up a hill.

I do have an issue. My Soliton is seeping coolant from between the black anodized base plate and the main body of the controller, near the screw terminal strip. I have an inquiry submitted to the evnetics website and I'm waiting to hear back. I haven't powered up the controller since I first spotted the leak. When warm I was seeing about a drop every few seconds, and now that it is cold, I just see a slight wet band all the way around the black base plate, that comes back each time I wipe it dry, but no visible dripping.


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## Tesseract (Sep 27, 2008)

Joey said:


> View attachment 27409
> ...My Soliton is seeping coolant from between the black anodized base plate and the main body of the controller, near the screw terminal strip. I have an inquiry submitted to the evnetics website and I'm waiting to hear back....


The online form goes to info/sales, not technical support. In all cases the fastest, surest means of obtaining technical support is to send an email to support at evnetics dot com.

That said, coolant seepage is a serious problem and indicates there may be a crack and/or porosity in the casting, or that you are simply running too high a coolant pressure. The latter is unlikely as it looks like you are using the solar water heating version of the Laing D5 pump. In any event, you'll need to get an RMA from us to return your controller for repair.


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## Joey (Oct 12, 2007)

Tesseract said:


> The online form goes to info/sales, not technical support. In all cases the fastest, surest means of obtaining technical support is to send an email to support at evnetics dot com.


Tesseract, thanks for the support email address. I sent in a request. You are right about the D5 pump, it is specified at 4.5 PSI static pressure, and it goes down as the flow increases. Also the reservoir tank cap will vent above 7 psi. I should be well within the limits of the 20 psi listed in the Soliton manual.

Yukon_Shane, water cooling is so effective compared to air, and the pump is effectively silent. I only wished my motor could be water cooled, too. Someday.


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