Research on BMS

Hoggdoc

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Is there an easy way to determine the specs on the BMS that is part of a pre-made battery pack. I am particularly interested in knowing the maximum current draw (amps/watts) allowed to be drawn from the Himiway All Terrain Fat Tire bike 48v 17.5 ah battery. The setup in the display allows for maximum 25 amps through the controller. But I understand the BMS also has a limit built into it for protection.

The reason I am asking is I am considering changing the controller and display to allow more current (Amps/watts) to the motor to increase the torque the motor can provide. It wouldn't make sense to install a 35 Amp controller if the internal BMS in the battery was limited to 30 Amps.

I don't really want to open the battery and am not sure there would be information on the BMS that would give me the information I am looking for.
 

Frogslayer

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Is there an easy way to determine the specs on the BMS that is part of a pre-made battery pack. I am particularly interested in knowing the maximum current draw (amps/watts) allowed to be drawn from the Himiway All Terrain Fat Tire bike 48v 17.5 ah battery. The setup in the display allows for maximum 25 amps through the controller. But I understand the BMS also has a limit built into it for protection.

The reason I am asking is I am considering changing the controller and display to allow more current (Amps/watts) to the motor to increase the torque the motor can provide. It wouldn't make sense to install a 35 Amp controller if the internal BMS in the battery was limited to 30 Amps.

I don't really want to open the battery and am not sure there would be information on the BMS that would give me the information I am looking for.
Opening the pack is the only way i know of. You'll need to check the cells anyway to see what kind they are and if they can safely handle more discharge. Even assess the quality of the spot welding and straps. More than likely, you'd need an entirely new battery pack to pull more amps, not just a more robust bms.
 

Hoggdoc

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Mar 5, 2021
Messages
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Location
Longview, WA.
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activityphoto.com
Opening the pack is the only way i know of. You'll need to check the cells anyway to see what kind they are and if they can safely handle more discharge. Even assess the quality of the spot welding and straps. More than likely, you'd need an entirely new battery pack to pull more amps, not just a more robust bms.
The MFG of the bike claims their battery pack houses Samsung cells which I take to Samsung 16850 cells. I'm not sure if they make more than one cell, so yes it would be helpful to know exactly what cells are in the pack.

How would you determine what the BMS can handle, is it the number of MOSFETS or the capacity of the MOSFETS which would require finding them online via a number on their cases, right.

EDIT 4/28/21: I have more information from HIMIWAY. They tell me they use three mfgs of the battery packs on their bikes. I provided them with the serial number on the battery pack they respond with more specifics on the cells used in my pack.

My pack was mfg'd by TFI (Tian Fu Li) and contains Samsung 35E cells. These are quality cells that can store up to 3500 mah and discharge up to 8 amps continuously. I am still requesting and waiting for information on the BMS used in this pack as I want to know the current (amps/watts) the BMS will allow the pack to provide before shutting down.
 
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Frogslayer

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I believe they use a shunt to restrict current. When i bought my battery it stated the bms was only good for 1000 watts sustained draw. I found a new one by searching 13s bms.
 
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