30amp battery for 35amp controller

Chgoizzy

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Hi! I found a good deal on the battery for my E bike which is rated at 30 A constant and 60 amp max. My controller is 35 A. Will it be safe to use this battery?
 

Chgoizzy

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Sure the battery will only supply the max current the controller calls for. What voltage is the battery and whose cells are they using?
Thanks for the reply! I’m not sure what cells are in the battery pack. It has a 30A BMS, while my controller is 35A. From what I understand the motor will try to pull 35A, which is higher than the battery. Will the BMS limit the draw to 30A or will it shut down or allow the 35A and damage the battery? It’s 36V, btw.
 

Hoggdoc

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Thanks for the reply! I’m not sure what cells are in the battery pack. It has a 30A BMS, while my controller is 35A. From what I understand the motor will try to pull 35A, which is higher than the battery. Will the BMS limit the draw to 30A or will it shut down or allow the 35A and damage the battery? It’s 36V, btw.
Actually the BMS is only there to manage the charging and balancing of the cells within the battery pack. The controller is what determines the amount of power (currant/amps) can be drawn from the battery pack.

Do you have any information on the programmability of the controller through the display unit. On my bike the Key-Disp model KD51C-U display has the ability to set up many of the operating parameters of the controller/motor. One of those settings is the maximum current (amps) the battery pack can supply to the motor.

Based on what you have told me about your set up I think you will be ok.

Hope that helps you.
 

Frogslayer

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Actually the BMS is only there to manage the charging and balancing of the cells within the battery pack. The controller is what determines the amount of power (currant/amps) can be drawn from the battery pack.

Do you have any information on the programmability of the controller through the display unit. On my bike the Key-Disp model KD51C-U display has the ability to set up many of the operating parameters of the controller/motor. One of those settings is the maximum current (amps) the battery pack can supply to the motor.

Based on what you have told me about your set up I think you will be ok.

Hope that helps you.
This is not entirely true. Most ebike battery BMS do regulate output as well. If you try to pull more amps than the bms allows it will "trip"and cut power until it cools off. If you repeat this abuse, you'll get a bad smell and a puff of magic smoke and fry the bms. Ask me how i know this lol.
 

Chgoizzy

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I have a basic controller and old fashion 810 led display. I cannot connect the controller to a computer or app. It is what it is I guess. Yes, I thought that the battery’s BMS limit should be equal or more than the controller. I’ll play it safe and make sure that the battery is sized equal or greater than what my setup needs. Thanks again for your help!
 

Chgoizzy

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I have a basic controller and old fashion 810 led display. I cannot connect the controller to a computer or app. It is what it is I guess. Yes, I thought that the battery’s BMS limit should be equal or more than the controller. I’ll play it safe and make sure that the battery is sized equal or greater than what my setup needs. Thanks again for your help!
By sized I mean same 36V, BMS rated at least 35A.
 
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