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Overkill BMS defaults?

2Big2B

Free Wheeler
Joined
May 7, 2021
Messages
73
Location
Chesapeake, Virginia
Question: How reliable are the Overkill BMS pre programmed parameters?

I just finished building my 8s 24v 100ah battery pack using the Overkill BMS for it. It appears to be working great. A Bluetooth module was included, but I don't use a smart phone or anything that I can run its program. I purchased a UART USB box but I have not been able to make it work with the downloaded software. I get the "comm port already in use" error. Still trying to trouble shoot that. This is for my power wheelchair. Do I really need to concern myself, or can I rely on being able to install the battery and start using it? I have a yet untested 8S 24v 10a charger designed for this from Aliblablah. Can I just go with my gut and trust the BMS to protect the pack right out of the box?
 
You really need to set the parameters before use. Once set you can probably get away with not using the app. Can you borrow a phone or ask someone else to set up the bms for you?
 
Not really. That's why I bought the UART USB box that is being so antisocial. I am still trying to wrap my head around how USB communicates to a comm port. I am old school and how USB talks to the system has always been a mystery in this regard.

And my other mystery to solve is about calibrating either my Drok hall sensor monitor or my Aliblahblah shunt. I have both. I have yet to find a clear instruction about how to program them to measure available remaining power. I want to use one as a "fuel gauge" for my battery pack installation into my power chair.
 
purchased a UART USB box but I have not been able to make it work with the downloaded software. I get the "comm port already in use" error.
You need to have a look in "Device Manager" to find the USB UART and pick the right port.

Here's an example using one of my RS485 USB dongles:
1625313116030.png
COM3 is the bit you're interested in.
 
It would be worth getting a SH Android smartphone or tablet and using the Bluetooth communication. Apart from setting up the protection limits to more conservative values , if required, knowing the status of the battery and cells via a portable unit could be an advantage. The display clearly indicated the remaining power. Since one of the design requirements of the app was for electric scooters and similar I would think it would suit your needs.

Mike
 
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