TSDZ2– No overheating for me

Electrically assisted bikes, trikes, etc.
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bikes4two
Posts: 1156
Joined: 12 Jan 2010, 10:14pm
Location: SE Hampshire, UK

TSDZ2– No overheating for me

Post by bikes4two »

TSDZ2– No overheating for me
Firstly, apologies to Pedelec.uk readers who may have seen this article already.

Here’s my observation about motor overheating (or not). I hope those who may have been put off looking into using the TSDZ2 because of this issue, find the following useful, and of course your own observations and comments are welcome (but no repeating unsubstantiated web chatter please).

• You won’t have to look far on the internet, especially the Endless Sphere forum, to find tales of the TSDZ2 overheating, causing the motor magnets to demagnetise and rendering the motor useless. And there’s a whole group of folks who have come up with different methods of keeping the motor cooler.
• What you won’t find much about is exactly how the motor was being used. By this I mean was it being driven at full assist with a 52v battery at maximum current on a red hot day somewhere in the wilds, or maybe driven by someone like me using the lowest power setting on a 36v 250w version of the motor in UK temperatures.
• Whilst I have no doubts that under certain circumstances the motor can overheat, what I can tell you is that I’ve ridden my TSDZ2 for nearly 3,000Km now and the last 300km was in France last week (June 2022) during their heat wave in temperatures toping out at 35degC at times and I have not had an overheating issues or even anything approaching it.

My Riding Profile
• Firstly, how do I use my TSDZ2? I’m retired, fairly fit for my age and ride on road around 150Km a week this time of year (if it’s not raining or too cold – yeh, a fair weather cyclist!).
• The TSDZ2 is on a converted Dawes Galaxy which with all the paraphernalia on it comes in at around 20Kg plus me at around 97Kg.
• I also run the motor with the Open Source Firmware (v20.1c) using only the Power Assist Mode with ECO set to 50% assist.
• I first used the bike to recover from a long downtime and I now ride it almost exclusively on the lowest power setting (ECO) and in my home area of South Hampshire, where the terrain is a mix of flat and the South Downs hills. (I get 50+ miles out of my 10Ah battery).

Temperature Monitoring
• To monitor motor temperature I used RS Components ‘RS Pro RS PRO Non-Reversible Temperature Sensitive Labels’ which come in various temperature ranges and cost less than £20 for 10.
• These are on shot temperature sensitive strips and I fitted one label to the outer motor casing for any early warning of over heating, and one to the motor itself (It takes around 10 minutes to remove the left crank, motor assembly lock nut and motor casing and re-assemble).
• As you can see from the pictures, neither label has registered any temperature above the label’s lower reading of 77degC. (The red gunk in the pictures is ‘red rubber grease’ which I use on the motor casing seal).
• Further, I did on a regular basis during riding, put my hand on the motor casing to see how warm it was and it never got anything above luke warm.

Conclusion
For my style of riding I have no concerns about overheating. However, if say you use the motor more aggressively than I do, e.g. consistently higher assist levels, high voltages and higher rated/powered motors, then maybe you should read more about the issues around overheating and cooling on Endless Sphere. You could of course buy some RS Pro labels as a first measure and maybe save yourself some time and trouble fitting goodness knows what to your motor when you don’t need to.
Footnote on De-magnetisation of Neodymium Magnets
• I read a number of articles on this subject and found this one here quite useful.
• In essence it seems that whilst the magnets seem to like cool operating conditions, its also the case that the composition of the magnets can manufacture to perform at different temperatures.
• Further, to quote from the article “… some grades of neodymium magnets can also be exposed to very high temperatures before their properties begin to change and they lose their magnetism, either temporarily or permanently.”
• So far I’ve not found anything about the design characteristics of the magnets used in the TSDZ2, so from that point of view I’ve no idea what a ‘safe’ operating temperature range might be.
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Bonzo Banana
Posts: 310
Joined: 5 Feb 2017, 11:58am

Re: TSDZ2– No overheating for me

Post by Bonzo Banana »

I have no experience of the TSDZ2 but being a mid-drive motor but they are mostly used for mountain bikes where steep climbs would cause a huge amount of current to be used and if its based on a torque sensor for governing output power then perhaps stronger cyclists get more power output. Most mid-drive motors are based around quite a small motor that is run at very high rpm speeds and then a series of nylon cogs and sometimes a belt delivers the torque needed which is typically higher than direct drive and geared hub motors. Mid-drive motors are typically the least reliable type of motor as they have the most complex design and also have to deal with the cyclists own power being delivered partially through the motor, i.e. bearings. It sounds like your application is kinder on that motor and therefore less likely to face problems. I thought all mid-drive motors constantly monitor temperatures and will reduce power when temperatures get too high to enable safe operation at all times so it sounds like the TSDZ2 is for some reason a bit crude in that regard. This contrasts dramatically with direct drive hub motors which due to their larger size have excellent heat dissipation and can even use ferrofluid/statorade to allow improved cooling on top with a 40% improvement in cooling so even though have less torque can deliver that torque more consistently without being thermally throttled even on long hill climbs. Admittedly though even a thermally throttled mid-drive motor is probably still delivering more hill climbing torque than a legal direct drive hub motor.
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