Temperature Sensor on BBSHD

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sather   100 W

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Temperature Sensor on BBSHD

Post by sather » May 14 2016 1:08pm

Has anyone put a temperature sensor on the BBSHD? If so, what temps are you reading when doing steep climbing? Karl at Electric-Fat bike states that 140 degrees is the limit for the BBS02. I installed one on my BBS02 and it shoots to 145 even on moderate climbs. I'm curious about what my BBSHD is doing because both motors use the same plastic gear that is prone to melting.

Uilleam Gilvoni   10 mW

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Re: Temperature Sensor on BBSHD

Post by Uilleam Gilvoni » May 16 2016 6:19pm

Hello
I have installed the temp sensor on my BBSHD 5 days ago and untill now I have only got 95 degrees (35 °C) as maximum when I passed a 25° degree climb which was 1.5km long. The total trip in that day lasted about 1hour 30minutes including the climb, downhill, and some 10km on flat. I'm normally using PAS 7 (sometimes 9 when flat) and running at a 40km max speed programmed.
During my normal days I get 77-85 °F degrees (25-28 °C) on trips of 15-20km long.

Now I am wondering, what's the heat limit for the BBSHD before something goes wrong?
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spinningmagnets   100 GW

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Re: Temperature Sensor on BBSHD

Post by spinningmagnets » May 16 2016 8:04pm

When climbing steep hills, a mid drive allows you to downshift until the motor RPMs get back up into the efficient range. So, the question becomes...what's the highest/fastest gear I can use without overheating my motor and controller?

By this I mean, if you are a heavy rider, and your hills are very steep...you might have to swap-in a smaller chainring, but once you've done that...even a BBS02 should be able to pull very significant loads, if the lowest gear is slow enough.

To put it another way, the more powerful your mid drive, the faster you can climb. But, if you also want a higher top speed, you'll need the bigger motor.

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waynebergman   10 kW

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Re: Temperature Sensor on BBSHD

Post by waynebergman » May 17 2016 11:03pm

AS I am too lazy to install a temp sensor & readout I just feel my outer motor shell from time to time and it's never more than warm to the touch. Not sure if I am just wasting my time feeling the motor as the inside may get hotter than I think without knowing the actual reading inside the motor where it counts.

I would be good to hear from someone that has a temp sensor and readout and does the hand touch test when they are getting close to being overheating based on their sensors readout. Would the outer motor shell feel super hot to the touch or just kind of warm, I don't know?

GreyVlad   100 mW

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Re: Temperature Sensor on BBSHD

Post by GreyVlad » May 18 2016 5:27am

Uilleam Gilvoni wrote:Hello
I have installed the temp sensor on my BBSHD 5 days ago and untill now I have only got 95 degrees (35 °C) as maximum when I passed a 25° degree climb which was 1.5km long.
Uilleam Gilvoni What sprockets (front and rear T] did you use when climbing? And about what speed or motor' RPM?

sather   100 W

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Re: Temperature Sensor on BBSHD

Post by sather » May 18 2016 9:44am

Now I am wondering, what's the heat limit for the BBSHD before something goes wrong?
I have been pushing my BBS02 to 155 F so see if it will fail. So far no problem with the plastic gear wheel.
One of my rides is an 8 mile 4000 vertical ft climb. On this climb, I melted a BBS02 plastic gear without harming the old low power mosfets. ( using a 32 tooth chainring). This was before I installed the temp sensor, so I have no idea how hot it got. Now I am concerned that the BBSHD uses the same plastic gear.

Uilleam Gilvoni   10 mW

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Re: Temperature Sensor on BBSHD

Post by Uilleam Gilvoni » May 18 2016 4:34pm

GreyVlad wrote:
Uilleam Gilvoni wrote:Hello
I have installed the temp sensor on my BBSHD 5 days ago and untill now I have only got 95 degrees (35 °C) as maximum when I passed a 25° degree climb which was 1.5km long.
Uilleam Gilvoni What sprockets (front and rear T] did you use when climbing? And about what speed or motor' RPM?
I used 46T Front and 26t behind. 15-20km when climbing.
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Uilleam Gilvoni   10 mW

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Re: Temperature Sensor on BBSHD

Post by Uilleam Gilvoni » May 18 2016 4:36pm

sather wrote:
Now I am wondering, what's the heat limit for the BBSHD before something goes wrong?
I have been pushing my BBS02 to 155 F so see if it will fail. So far no problem with the plastic gear wheel.
One of my rides is an 8 mile 4000 vertical ft climb. On this climb, I melted a BBS02 plastic gear without harming the old low power mosfets. ( using a 32 tooth chainring). This was before I installed the temp sensor, so I have no idea how hot it got. Now I am concerned that the BBSHD uses the same plastic gear.
I don't know how much heat can the BBSHD, It never gets too hot with PAS, I think I'll try a full throttle day to see what happens.
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sather   100 W

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Re: Temperature Sensor on BBSHD

Post by sather » May 19 2016 9:10am

Karl was right. I installed a temp gauge on my BBS02 and have been pushing it past 145 to 155 degrees. This morning the plastic gear melted. Karl at Electric-Fatbikes guidelines:
140F + Stop riding and let it cool
130F + Don’t use full throttle, only half throttle
120F + Take it easy
110F or less go whole hog
https://electricbike-blog.com/2015/06/0 ... bs02-unit/

WoodlandHills   10 kW

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Re: Temperature Sensor on BBSHD

Post by WoodlandHills » May 19 2016 1:04pm

Interesting, nylon 6 melts at 428f/220c and nylon 66 at 509f/265c. I have no idea what sort of nylon is used on Bafang gears, but these temps imply that the gears got a whole lot hotter than what the thermocouple indicated!

Uilleam Gilvoni   10 mW

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Re: Temperature Sensor on BBSHD

Post by Uilleam Gilvoni » May 19 2016 6:12pm

sather wrote:Karl was right. I installed a temp gauge on my BBS02 and have been pushing it past 145 to 155 degrees. This morning the plastic gear melted. Karl at Electric-Fatbikes guidelines:
140F + Stop riding and let it cool
130F + Don’t use full throttle, only half throttle
120F + Take it easy
110F or less go whole hog
https://electricbike-blog.com/2015/06/0 ... bs02-unit/
Shit sorry for you dude, do you think that this would happen to the BBSHD too? people say that its the same component so should be the same.
Learning everything about E-bikes!

sather   100 W

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Re: Temperature Sensor on BBSHD

Post by sather » May 19 2016 7:16pm

I'm definitely going to put temp gauges on my BBSHD. The failure is caused by torque and heat. Since the BBSHD runs a lot cooler there hasn't been a problem so far. But the BBSHD has a lot more torque.

LyonNightroad   100 W

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Re: Temperature Sensor on BBSHD

Post by LyonNightroad » May 20 2016 1:09pm

In many ways I feel a watt meter is your best friend to protect your motor. If you train yourself to downshift to the lowest gear that is still at max amps for a given speed, you eventually train yourself to always be in the optimum gear. Then wait until the amps start to drop before you shift into the next gear (this should also produce the fastest acceleration too. You should always be producing near the maximum wheel torque for a given speed because you will have the highest possible torque multiplication before the chainring/motor torque starts to drop as the amps fall) For a while you will downshift one too many gears and see the amps drop too much but eventually you get it. If you ensure that you are always operating in that range I suspect you will never have a problem with heat in the first place.
Last edited by LyonNightroad on May 20 2016 1:44pm, edited 2 times in total.

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Alan B   100 GW

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Re: Temperature Sensor on BBSHD

Post by Alan B » May 20 2016 1:16pm

Battery Current is all you really need. The wattage is just a calculated value based on battery voltage and battery current, and the voltage doesn't change that much, the current is the primary indicator.

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