Higher temperature hall-effect sensors

[RogueOne]

Hello everyone

I burnt my hall effect sensors twice in 3 weeks during the hot weather. Just received the Hubsink and statorade delivery and will be installing them.

Since I am replacing the sensors for the 2nd time, is there any higher temperature resistant hall-effect sensors that can replace the 110°C sensors used in hub motors?

I've found this from google which claims to survive upto 150°C. APS11205
I can't be sure if they will do the same job as the datasheet says it's pins are unipolar.

Has anyone successfully replaced the sensors with a better sensor to withstand the heat?

I am also working on a water cooling system that will basically spray cold water over the hubsinks from outside when temperature hits 110°C on the stator. Just a thermal switch, DC pump and an aluminium bottle with heatsinks on it. Although I would rather have stronger sensors that won't die on my way to work everyday.
I have to climb steep hills with a 1000w rear motor and a 1200w controller. I will be filing the shunts of the controller too this weekend.

Thanks for any tips :thumb:

 

[markz]

replacing

Go to www.mouser.com or www.digikey.com and you can view all the hall effect sensors available that match what you already have, but may have a higher temperature rating. Hopefully the heatsink and statorade help you out, must be really hot weather where your from, combined with the heat generated from the motor, maybe you just gotta lay off the power a bit or keep a closer eye on the winding temp with a temp probe. You could get a more powerful, beefier motor that can shed the heat better. And also, speed up on the hills to stay out of the heat build up zone.

 

[goatman]

what are you running, 48v 25amp?
why file the shunt?
wouldnt it be better to butter the shunt to get more amps so you go faster up the hill than slower?
or get a 40 amp controller

 

[markz]

You want more amps, so you should add a little bit of solder to the shunts to get more power so you can go up the steep hills faster so theres not a lot of heat buildup, the faster the better.

As a matter of fact, Justin from Grintech just did a video
https://www.youtube.com/watch?v=dxJe_gygRGU&pbjreload=101
He talks about just that, going up hills faster and what is the optimal speed to go up the hills in an efficient manner.
Sorry I dunno what the time stamp would be for that part.
@34:30 talks about efficiency, and 2% grade, @38 minutes is good graph
@39 minutes talks about heat

 

[amberwolf]

Since I am replacing the sensors for the 2nd time, is there any higher temperature resistant hall-effect sensors that can replace the 110°C sensors used in hub motors?

Sounds like what you really need is a bigger motor / system that's capable of the continuous power you really need to climb the hills you've got.

Or put the motor you have into a significantly smaller diameter wheel. LIke if it's 26", go to 20", and it will go a lot slower but it will have a lot more torque and have a much easier time climbing the hill.

I've found this from google which claims to survive upto 150°C. APS11205
I can't be sure if they will do the same job as the datasheet says it's pins are unipolar.

Some motors have used unipolar sensors successfully, it depends on your controller's requirements, which there is no data for. You'd have to test them to find out if they work or not. These Allegro sensors are still open collector, so they'll still electrically work...but they have much tighter voltage supply requirements than the Honeywell SS411 series stuff usually used, so you want to make sure your 5v supply to them is stable without spikes.

I have to climb steep hills with a 1000w rear motor and a 1200w controller. I will be filing the shunts of the controller too this weekend.

If you file the shunts, you permanently change the values in a way you can't undo. Resoldering over them wont' put them bakc the way they were, either.

Instead, if your ocntroller is not programmable, and you want to reduce the power of the controller, I would recommend instead unsoldering (not cutting!) one of the shunts. If there are four, then you'll cut power by 25%. If there are three, by 33%. Etc. This is an easy-to-undo change.

Alternately, you can look up some of Fechter's posts where he's helped people find the voltage dividers / opamps that buffer the shunt voltage to the MCU, and then you can install a potentiometer to adjust it to whatever you want.

However...reducing current will reduce power, which you already don't have enough of. So what will probably happen is that the motor speed will be reduced, but hte load will remain the same, so that even more of the power into the motor is just waste heat vs what moves you forward, and the motor will actually run even hotter than it does now.

You can see how this can happen using the http://ebikes.ca/simulator . You don't ahve to use your specific system parts, just stuff that is comparable, then setup a comparable bike and slope, etc.


What is the worst percentage grade slope of the hills? Separately, what is the average grade? How long are the hills, in total? What is the worst case total weight of you, the bike, and everything else on it? What speed must you maintain up the hills?

Knowing those you can determine how much power is required to do the work, and thus how big a motor and controller you must have.

 

[serious_sam]

Has anyone successfully replaced the sensors with a better sensor to withstand the heat?

Honeywell SS41 and SS411A are rated to 150*C
https://sensing.honeywell.com/honey...ss41-l-t2-t3-s-sp-datasheet-32312814-b-en.pdf
https://sensing.honeywell.com/honey...ries-ss500-series-datasheet-32320997-b-en.pdf

 

[larsb]

Although it might seem like an easy fix at this point your hall sensors are telling you that you need to change your system. Just get a bigger motor or a smaller rear wheel or a geared setup and use it for years without hickups. Motors shouldn’t be hall sensor cooking hot in everyday use 8)