Added temperature guages to battery and motor (CMM1200) - see how hot it gets!
I was curious to see how hot the battery and motor in my CMM1200 got. Since I installed the lithium ion battery, the motor works quite hard as the new battery is able to supply a much higher amperage than the old battery. The highest measured amperage was 133 for only a few seconds, and it rarely goes over 50 amps.
After installing the temperature guages I mowed the lawn. The lawn was fairly thick and part of it was a little wet, so the mower did have to work hard today, although it has certainly worked a lot harder, it took about 20-25 minutes to mow. According to the coulomb counter, I used 6Ah mowing the lawn today which doesn't seem like a lot.
Results:
Starting temperature was 19○C (66○f) for both the battery and motor. About halfway through it had only risen to 21○C (70○f) for the motor and 19.5○C (67.1○f) for the battery. At the end of the mow, the battery's temperature was 22.6○C (72.7○f) and the motor's temperature was 34.7○C (94.5○f).
I am rather impressed that the motor keeps relatively cool despite working so hard. I don't know at what temperature the motor will fail, but given that the wires feeding the motor current are right there, those wires will certainly start to melt at I would guess around 100 degrees Celsius as they don't feel like a silicone wire.
I suspect that most of the measured rise in temperature of the battery is just heat convected from the motor. The battery's temperature did not rise until after the motor's temperature rose. The probe for measuring the battery temperature is attached to the middle of the battery, but only approximately 15 - 20 centimeters from the motor. The temperature probe for the motor is attached to the motor casing itself near the top of the motor, not far from the brushes.
I have attached a couple of pictures. The temperature guage on the far right is for the motor, the guage just to the left of it is for the battery.
Any questions or comments are welcome!
I was curious to see how hot the battery and motor in my CMM1200 got. Since I installed the lithium ion battery, the motor works quite hard as the new battery is able to supply a much higher amperage than the old battery. The highest measured amperage was 133 for only a few seconds, and it rarely goes over 50 amps.
After installing the temperature guages I mowed the lawn. The lawn was fairly thick and part of it was a little wet, so the mower did have to work hard today, although it has certainly worked a lot harder, it took about 20-25 minutes to mow. According to the coulomb counter, I used 6Ah mowing the lawn today which doesn't seem like a lot.
Results:
Starting temperature was 19○C (66○f) for both the battery and motor. About halfway through it had only risen to 21○C (70○f) for the motor and 19.5○C (67.1○f) for the battery. At the end of the mow, the battery's temperature was 22.6○C (72.7○f) and the motor's temperature was 34.7○C (94.5○f).
I am rather impressed that the motor keeps relatively cool despite working so hard. I don't know at what temperature the motor will fail, but given that the wires feeding the motor current are right there, those wires will certainly start to melt at I would guess around 100 degrees Celsius as they don't feel like a silicone wire.
I suspect that most of the measured rise in temperature of the battery is just heat convected from the motor. The battery's temperature did not rise until after the motor's temperature rose. The probe for measuring the battery temperature is attached to the middle of the battery, but only approximately 15 - 20 centimeters from the motor. The temperature probe for the motor is attached to the motor casing itself near the top of the motor, not far from the brushes.
I have attached a couple of pictures. The temperature guage on the far right is for the motor, the guage just to the left of it is for the battery.
Any questions or comments are welcome!
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