# 1000W 48V BLDC Motor Stalls - Help Request



## Vinz (Oct 19, 2020)

You definitely need more torque, could be few reasons for controller to cut off, the draw of current or over heating, etc


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## L-L (Oct 20, 2020)

True, but the controller is not overheating, the 6AWG battery cables are not getting hot, and also the motor is not getting hot.
I am thinking to install a 48v-72V 1500W controller and hook it up to my 48V 1000W BLDC motor. Also reduce the motor sprocket to 14T instead 20T.
Initially I will try it with 48V battery pack and evaluate the performance.
If it stalls or if the max speed is too low, I will overvolt the motor to 60V and see if it gets any better.

Any comments/ideas?


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## electro wrks (Mar 5, 2012)

Going from 14 teeth to 20 teeth on your motor sprocket(plus the larger diameter tires) is a huge final drive ratio jump. Try increasing the number of teeth on the motor sprocket one or two at a time You're trying to use a relatively small, low power motor in an application that typically uses a much larger and heavier minimum ~ 2-3kW motor. You may be slamming the current limit on the controller so quickly that the motor, controller, and cables don't have time to heat-up.

Also, I just noticed you are using tiny, 8Ah LA batteries! That's only ~20 lbs of batteries. A typical golf cart uses ~100-300lbs or more of LA batteries. You have things way out of proportion here! As well as over-current controller shutdown, you probably have a steep voltage drop that triggers a controller low voltage shutdown. You can verify this with a voltage meter and an ammeter(a clip-on type will do for temporary use).


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## L-L (Oct 20, 2020)

Thank you electro wrks,
Indeed I am currently using small 8ah batteries. I take the extra weight of larger batteries under consideration though.
I just want to make sure that the concept will work before investing into 35ah+ batteries since good 35ah batteries are quite expensive. The small 8ah batteries I am using are brand new though and I checked the initial voltage drop of the entire pack as well as individually without noticing any significant drop. 
Unfortunately, my YALU motor uses dual D-bore sprocket and I can't find different sizes in the US. I had to order the 20T from abroad (40-days to arrive). My only other option is 16T, again from abroad...meaning another month or so to arrive.
I will purchase and install a Digital* Current/Voltage/ Power/Energy *Meter though in order to have a better view of the actual measurements. 
I agree that golf carts use 2-3kW motors, but this is a lightweight cart, similar to *Cricket RX-5* which apparently uses 800W or 1000W BLDC motors @ 36V or 48V, thus the reason i am thinking to try my 1000w/48V motor with a 1500W/48V-72V controller, overvolting it to 60V and also go back to 14T motor sprocket instead of the 20T sprocket. I understand that overvolting will only increase the rpm and also help the motor to run at its max power. I don't think that going from 48v to 60v will damage the motor. Also the motor has a fan, so hopefully it will not overheat.

Any comments/ideas will be much appreciated.

L-L


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## L-L (Oct 20, 2020)

....Update: I reinstalled the 14T sprocket. It still stalls on initial acceleration but not as bad as with the 20T motor sprocket. If I press the pedal slowly, it does not stall and it drives to its max speed.
The weird part is that it runs just fine on reverse. Zero stalling on reverse.


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## electro wrks (Mar 5, 2012)

Check your voltage drop and current in both directions. Reverse function with some controllers limits power to reduce speed in reverse, as a safety feature. The motor ratings for the Cricket might be a continuous one. Your motor may have more of a peak rating.


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## L-L (Oct 20, 2020)

Update: I bought a 48/60/72V 1500W Controller and replaced my old 48V 1000W controller. Still the same 48V 1000W BLDC Motor with gear reduction 1:5 and motor sprocket 14T. NO MORE stalling !!! It seems that the controller did the trick. 
Yet I only get 9 mph which is not what my goal is...but that was expected. The cart drives smoothly on the road and on the lawn. Both Controller and motor do not get hot.
I will try the 20T sprocket just to check if the motor will start to stall again. Since this controller is 48/60/72V, I am thinking to overvolt it to 60V to see the effect on the performance. I am not sure which test is better to try first...60V will result to more rpm, meaning higher speed but might result to stalling and pushing the motor to its max. On the other hand, 20T sprocket will result to higher speed but possibly causing the motor to stall. Any suggestions?

Thank you.


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## clintster7 (Jun 29, 2010)

L-L said:


> Update: I bought a 48/60/72V 1500W Controller and replaced my old 48V 1000W controller. Still the same 48V 1000W BLDC Motor with gear reduction 1:5 and motor sprocket 14T. NO MORE stalling !!! It seems that the controller did the trick.
> Yet I only get 9 mph which is not what my goal is...but that was expected. The cart drives smoothly on the road and on the lawn. Both Controller and motor do not get hot.
> I will try the 20T sprocket just to check if the motor will start to stall again. Since this controller is 48/60/72V, I am thinking to overvolt it to 60V to see the effect on the performance. I am not sure which test is better to try first...60V will result to more rpm, meaning higher speed but might result to stalling and pushing the motor to its max. On the other hand, 20T sprocket will result to higher speed but possibly causing the motor to stall. Any suggestions?
> 
> Thank you.


Did you overvolt? / sprocket change again?


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