Smart BMS Firmware

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So I have one of those Smart BMS from LTT, and decided to change a few settings via PC since you’re very limited on what you can change through BT UART connection.

Installed the drivers and PC software from this site. Settings are visible when connected but unable to write settings. And yes, I hit read first, change parameters then write. Gave me unable to write error null. Tried a few things here and there. So stupid me, I decided there could be new firmware that would fix this. Google led me to this site. I downloaded the hex and proceeded to update my unit NOT knowing it was meant for 10s. Yup, you guessed it. I have a 12s. FML :man_facepalming:t5:

Does anyone have the hex for 12s or able to extract the hex file from their Smart 12s BMS? None at github unfortunately. Just arduino ones.

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now you done it… :flushed:

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Eh. Everything was working fine but wanted to change the end voltage per cell via PC. But it wouldnt let me write.

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I emailed LTT power if they are willing to send me the file. We’ll see.

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if you can get your hands on an ios device there are alot more settings to fiddle with there


i have the same bms, it has can, wonder if its possible to connect it to the vesc and use it like the diebiems with metr

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I thought of doing that since mom has an old iPhone but it’s too late now. I have already flashed the 10s version. I need the 12s fw first then I can mess w the iPhone.

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Update:

Make sure that you have your bms unlocked to be able to change settings using PC. Locking and unlocking is done via phone app.

I’m gonna leave this here for reference.

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Has anyone had any luck connecting the LLT Smart BMS to Windows 10 via Bluetooth? I think it is more a windows problem because I cant get the computer to lash-up with the BT adapter. I have a 12S BMS that I want to use on a 10S battery so I need to change the PACK COUNT variable in the firmware. Any hints are greatly appreciated.

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Here is the 10s hex link:

https://cdn.hackaday.io/files/1628066965491904/LH_SP10S006%2020180612-1.hex

All you have to do is flash it using the PC adapter. I accidentally loaded this to my 12s smart bms. Now, I can’t revert it back since I can’t find the 12s hex for it. Use it at your own risk.

Or we can trade. Mine currently is residing in my “I don’t know what to do with this” bin.

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Awesome. I’ll take a look. Didn’t think to get the PC adapter. Anyone tried any good alternatives?

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Good reference here:

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Good idea but I’ve already installed the BMS and i’m afraid the wire lengths may be be very accommodating. I’m guessing I can talk to the BMS using an FT232 TTL adapter instead of the PC comm box? Any issues with that? Traps?

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Never tried it. Proceed w caution? I’d read more though if I were you.

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My bad for not reading fully but that firmware you sent trashes the Bluetooth and makes it only uart readable. You dont by chance have a copy of the original firmware do you?

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I have asked LTT about it. James, who answers email from that company, sent me a 12s config file - not the hex. Needless to say, it didn’t work. However, I vaguely remember Bluetooth working w that 10s fw. So, are you sure BT isn’t working?

Unfortunately, we are in the same boat. I don’t have the 12s hex file, still looking for it. When I have time, I’ll start reading on how to extract the hex from a device. We’ll see.

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TTL to usb works on my LLT smart bms’s.

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Indeed it does. The BLE was working aces before I flashed the 10S Hex file. Not to worry though, I got a brand-new 10S in the mail this afternoon. Swapped it out and all is well. My wife’s new board is ready to rock.

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