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Have you done a close examination of the cells to see if you can locate where it is leaking from? I don't trust that BB would be transparent about the issue. I know a lot of people have purchases these types of cells, and am wondering if there is a weakness with them that could be identified...

The seller doesn't seem to be in the US, look at the delivery dates. Also, it doesn't look like it's part of Amazon's EZ return, so you might have some trouble getting your money back if these turn out to be junk.

Yes, you can charge that cell directly. I have a few BYD packs too, and cell 8 is the runner, but evens out by 3.35V and another cell takes over as the runner, so you should keep an eye on all of the cells as you reach your voltage target.

Yes, you definitely can. Just come back when you figure out how to generate the checksum. :)

Yeah, the app just changes the values of the functions, not change the functions themselves. Chinese software (the app) is typically pretty poor, they sort of work, but they won't go back to update or fix bugs. That's why people would spend a few more bucks for slightly better software, VBMS...

Wow, never been to the coast in Oregon, will have to check it out. Thanks! I am in CA, and around 8-10kWh/day. Since Covid, have been using a little more power but have been working on power efficiency and that has given me pretty good results. Don't think I can get much lower than 8-10kWh...

It is. Try this: #AH Remaining data = (Antw33.encode('hex') [(79*2):(82*2+2)]) data = float.fromhex(data)*0.000001 print "AH Remaining: ", data

http://rjxzstech.com/electric-bike-bms-.html I think they are the ones behind the BMS... The app for Android is called Mayi-BMS and there is a link to download it from their site, then you can side load it.

I haven't but I'd imagine if someone had the skills and effort, it might be possible, but maybe not worth the effort since almost any PI could work, and without Python, it might take some work to debug?

All my close friends have switched to aluminum foil hats. Tin foil hats are soooo 1920s.

In case you haven't seen this, this is what the manufacturer says the values are intended to do...

Holy shit! That's a great find! I've been trying to figure out how the checksum is calculated, and made very little progress, so this definitely helps a lot.

okay, never mind, I figured it out. Looking at the chips on the Bluetooth Module, I noticed there is a HT7533 LDO, so that is how the made it safe to power the module. Leaving this post in case someone else runs into this question.

Not really, they should have an E&O policy or a specific rider for product defects that should cover the cost. Of course, if it's 11 defects out of 100K, I don't think that would qualify for recall action? Now the sticky part is this: BB has been made aware of the issue, there is a video...

I guess we should never let a good crisis go to waste.

Have you tried adjusting your reference voltage? Also, set the number of actual cells and cell type? from the manual:

Which ANT BMS did you get? 7S-16S or the larger one?

@burtonmadness I'd be very interested in building something like this, too. I have recently moved from big servers to smaller compute nodes that can off about 19V DC. This has significantly cut my power usage and I am sharing a single PC power supply for multiple servers. Anything, not t...

You don't have to have a Pi for each BMS, I am not sure what the limit is, but I have a Pi talking to 2 right now and I am sure rfcomm can do more than that.

Make sure the MAC is not for the BLE interface. Does it see it when you do "scan on" and "devices". I was not able to connect to the BMS when I tablet was already talking to it, so if you have another device already talking to the BMS, pairing might fail.

I don't think some of the stuff you listed is correct, at least it does not match my experience. Low cell protect, for example, DOES shut the mosfet when that voltage is reached (any single cell), and recover is the voltage when it enables the mosfet again after going into protect. Did you...

Unfortunately, the checksum method doesn't seem to work, or something else is required (maybe a secondary command with the "apply" address has to be sent, not sure), but thanks for the link. I did take a look at the addresses for the temps, and looks like you can get battery sensor 1 and 2...

Buy once, cry once. If this is your first set of batteries, you may want to stick with something that is in common use, so if you have some questions, there is someone here that can help. If you are just relying on the vendors, you may be left disappointed--they have your money already.

The Mac address in the file isn't actually used; If you look a few lines down, you will see that sock.connect is actually commented out. This is due to Python needing indents in the code. If you cut and pasted it into your Pi, it probably did not properly keep the indents (tabs) and that is...

I'd be interested in this too. Maybe also include discharge rate, DOD, and charge cell or pack voltage? Which cells # are you low or runners?

Okay, I get that, but why is disconnecting the B- lead from BMS to battery *LAST* a cause of death for BMS?

Sounds like it, if it's not under warranty, maybe it's time to take it apart and see if you can reset the BMS (or just call their support people to see if there is an easier way) :)

Thanks, all good points. I'll stop by the box store and see what's available and if nothing fits, I'll just make my own.

I need to use a power distribution block to connect various components together, for the positive side, I found an old car audio block that has a few terminals that will accept 2AWG wiring, it's some sort of ferrous metal, is from the 90s I think. I don't have a matching one for the negative...

BTW, I can control the BMS now. The checksum is just the sum of the 3 bytes (address + data + data). So.... sending it: 'A5A5FA0000FA' # Turn Off Charge MOSFET 'A5A5FA0001FB' # Turn On Charge MOSFET 'A5A5FE0000FE' # Reboot BMS 'A5A5F90000F9' # Turn Off DisCharge MOSFET 'A5A5F90001FA' #...