RC-Monster Forums - View Single Post - Motor heat

VintageMA · 05.25.2008, 08:42 PM

Been a little while, but I tested both 15 and 13 gearing on this setup.

At 15 the motor temp was just a few degrees higher, nothing bad. Current draw did go up as well.

Interesting thing though was that at 13 gearing the motor temp shot up to almost 190* after a 10 minute run. This run was also with my new MMM.

I found it very interesting:
The buggy was very smooth on 5S compared with the MM, but my batteries were really hot - measured 140* on one spot on the battery.

I am a little concerned about that as I have never measured any of my batteries to be that hot unless I was running a way out of whack configuration to test things out.

I recall Patrick saying in one of the MMM threads that there was too much energy in the braking to dissapate the heat through the heat sink and thus the MMM was using a regnenerative power braking setup that would push the current back into the battery. This actually concerns me a lot. LiPos aren't designed to be charged at a high current - 1C is best for charging, 2 - 2.5C is possible with a balancer but will decrease battery life cycles by almost 50%. I believe NiMH can handle higher charge currents better. If this is the case, I will be very dissapointed if my battery life is decreased because of the braking method employed.

How much current do you think the braking could push back into the battery? 2C, 3C, 5C, 10C....... more?

	(#14)
VintageMA RC-Monster Aluminum Offline Posts: 660 Join Date: Sep 2006 Location: CT	05.25.2008, 08:42 PM Been a little while, but I tested both 15 and 13 gearing on this setup. At 15 the motor temp was just a few degrees higher, nothing bad. Current draw did go up as well. Interesting thing though was that at 13 gearing the motor temp shot up to almost 190* after a 10 minute run. This run was also with my new MMM. I found it very interesting: The buggy was very smooth on 5S compared with the MM, but my batteries were really hot - measured 140* on one spot on the battery. I am a little concerned about that as I have never measured any of my batteries to be that hot unless I was running a way out of whack configuration to test things out. I recall Patrick saying in one of the MMM threads that there was too much energy in the braking to dissapate the heat through the heat sink and thus the MMM was using a regnenerative power braking setup that would push the current back into the battery. This actually concerns me a lot. LiPos aren't designed to be charged at a high current - 1C is best for charging, 2 - 2.5C is possible with a balancer but will decrease battery life cycles by almost 50%. I believe NiMH can handle higher charge currents better. If this is the case, I will be very dissapointed if my battery life is decreased because of the braking method employed. How much current do you think the braking could push back into the battery? 2C, 3C, 5C, 10C....... more? “Everyone has a right to be stupid; some people just abuse the privilege.”