bluetooth BMS?
- Thread starter aethyr
- Start date
first time i run into weird problems.
an old battery with 10S LLT bms installed quit the discharge fets.
so the APP either the PC software report with ANY errors that discharge is OFF (charge enable)
if i try to enable or disable it via PC it doesnt work.(switching on/off charge port works)
also tried to disable temp sensors but no success.
i know its pretty cheap 10s bms but it worked quite good and replacing it sucks just about the time factor.
any ideas?
an old battery with 10S LLT bms installed quit the discharge fets.
so the APP either the PC software report with ANY errors that discharge is OFF (charge enable)
if i try to enable or disable it via PC it doesnt work.(switching on/off charge port works)
also tried to disable temp sensors but no success.
i know its pretty cheap 10s bms but it worked quite good and replacing it sucks just about the time factor.
any ideas?
I posted this over on the DIY powerwalls FB group also, but thought I might ask here in case anyone's seem similar.
Has anyone seen this kind of thing before?
My BMS seems to be generating AC to it's casing. My BMS is touching onto my cell casings also. It dissipates very quickly and does nothing when shorted, but I can see about 500ma across it also. My battery is approx 57-58V fully charged so the ~100V AC seen is probably just that doubled, but it's strange to see it generating current.
Is it normal for a BMS shell to generate voltage of any kind like this?
Some of the suggestions from FB were that it could be the A/C ground (not shared neutral) on my battery box casing, or to do with the BMS mosfet switching frequency.
I'm thinking it's the BMS as my A/C is 240V anyway. I need to find the time to partially disassemble the pack and move the BMS out of the cell holder it's currently in, but the pack is still running fine at the moment.
Cheers
Has anyone seen this kind of thing before?
My BMS seems to be generating AC to it's casing. My BMS is touching onto my cell casings also. It dissipates very quickly and does nothing when shorted, but I can see about 500ma across it also. My battery is approx 57-58V fully charged so the ~100V AC seen is probably just that doubled, but it's strange to see it generating current.
Is it normal for a BMS shell to generate voltage of any kind like this?
Some of the suggestions from FB were that it could be the A/C ground (not shared neutral) on my battery box casing, or to do with the BMS mosfet switching frequency.
I'm thinking it's the BMS as my A/C is 240V anyway. I need to find the time to partially disassemble the pack and move the BMS out of the cell holder it's currently in, but the pack is still running fine at the moment.
Cheers
I'll answer my own question...it had nothing to do with the BMS (Thankfully).
Turns out it was the ground as some suggested.
I'm just glad it wasn't the BMS as it would have been a huge PITA to disassemble the battery to fix that.
I still don't understand exactly how a separated ground could be doing this, but maybe it points to another problem where another device (maybe my inverter) is generating voltage on the ground.
Cheers
Turns out it was the ground as some suggested.
I'm just glad it wasn't the BMS as it would have been a huge PITA to disassemble the battery to fix that.
I still don't understand exactly how a separated ground could be doing this, but maybe it points to another problem where another device (maybe my inverter) is generating voltage on the ground.
Cheers
nardcox
10 W
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- Apr 14, 2020
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Anyone? Finally the seller got back to me (holiday in China apparently). They asked me to restart (already tried that ofc), and then they said ship it back... That's like having no support. Is there anyone that might have an idea of what's wrong? Dont want to loose the BMS for over a month or so...nardcox said:
j bjork
1 MW
Does the output turn off when you turn off the bms?
Have you checked the mosfets if it doesn't?
When a mosfet got shorted for me I got error, not abnormal. But I think it sounds similar enough to check, dont you think so?
My posts are just 2 pages back, so you must have seen them when you looked for answers.
Have you checked the mosfets if it doesn't?
When a mosfet got shorted for me I got error, not abnormal. But I think it sounds similar enough to check, dont you think so?
My posts are just 2 pages back, so you must have seen them when you looked for answers.
nardcox
10 W
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I assume with output you mean voltage?
Voltage on the + battery and - battery is 80.1V (20S @ 4.0V)
Voltage on the + battery and C- BMS is 77.2V
Voltage on the + battery and C- BMS is 80.1V with BMS on
Voltage on the + battery and C- BMS is 77.9V with BMS in error mode
I didn't find your post since I searched on 'tube' and 'abnormal'. Looking back at your post I do remember reading it but that is way above my knowledge level, I have no clue what you did exactly. I will take out the battery and inspect the BMS if I can see something funny.
I have three options now:
1. Send it back and wait
2. Send it back and wait but in the meantime buy a new one
3. Send it back and wait but connect it without the BMS so that I can at least attempt to continue with setting up the rest of the bike (lights, switches, etc).
EDIT: I've opened the BMS, all looks good as far as my non electrical engineering eye can see.
https://photos.app.goo.gl/QM4QRDUeZ66HfUPC6
https://photos.app.goo.gl/Ay6nXWr7jvS1Fgwo7
Voltage on the + battery and - battery is 80.1V (20S @ 4.0V)
Voltage on the + battery and C- BMS is 77.2V
Voltage on the + battery and C- BMS is 80.1V with BMS on
Voltage on the + battery and C- BMS is 77.9V with BMS in error mode
I didn't find your post since I searched on 'tube' and 'abnormal'. Looking back at your post I do remember reading it but that is way above my knowledge level, I have no clue what you did exactly. I will take out the battery and inspect the BMS if I can see something funny.
I have three options now:
1. Send it back and wait
2. Send it back and wait but in the meantime buy a new one
3. Send it back and wait but connect it without the BMS so that I can at least attempt to continue with setting up the rest of the bike (lights, switches, etc).
EDIT: I've opened the BMS, all looks good as far as my non electrical engineering eye can see.
https://photos.app.goo.gl/QM4QRDUeZ66HfUPC6
https://photos.app.goo.gl/Ay6nXWr7jvS1Fgwo7
j bjork
1 MW
That you get a high voltage when you measure dosent necessary mean that a mosfet is shorted, it can be small creep voltage that disappear as soon as you put a load on it. An easy test is if the bike still works when the bms is off.
You will probably not be able to see the problem by just looking at it, but it depends on what has happened.
You will probably not be able to see the problem by just looking at it, but it depends on what has happened.
nardcox
10 W
- Joined
- Apr 14, 2020
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The bike doesn't work at all, regardless of the BMS.
What happened is that I switched the positive and negative on the controller. I can't do much more than look? I read that you measured each individual mosfet, but I'm totally clueless about how to go about such a thing.
What happened is that I switched the positive and negative on the controller. I can't do much more than look? I read that you measured each individual mosfet, but I'm totally clueless about how to go about such a thing.
j bjork
1 MW
wtf?!Is there a problem with the bms at all?
If you killed the controller it is not very strange that you get a fault from the bms, you have to start at the right end..
Do you still get the fault if you disconnect the controller and then turn on the bms?
You complain about bad support, but you dont say that you caused the problem yourself.
nardcox
10 W
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- Apr 14, 2020
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Hmm..I posted this question on another forum as well with all the extra info, though I did it here as well, apparently I didn't, my apologies.
Yes I still get the error even when nothing else is connected.
I can still connect the controller to the pc and read the rpm when I turn the wheel manually and write parameters to it, so my guess was the controller is fine,the BMS isn't.
Yes I still get the error even when nothing else is connected.
I can still connect the controller to the pc and read the rpm when I turn the wheel manually and write parameters to it, so my guess was the controller is fine,the BMS isn't.
j bjork
1 MW
You said your bike dosent work, regardless of the bms. So I guess you have bypassed the bms, and the bike still dosent work?
But anyway, if you still get the fault even when nothing is connected to the output of the bms there probably is something wrong with a mosfet or something. You can try with light bulbs on the output, and see if it is possible to turn off.
If its not, then there is a problem. If you cant fix it yourself, you might as well send it back.
But anyway, if you still get the fault even when nothing is connected to the output of the bms there probably is something wrong with a mosfet or something. You can try with light bulbs on the output, and see if it is possible to turn off.
If its not, then there is a problem. If you cant fix it yourself, you might as well send it back.
Can anyone explain this? The app and the BMS itself is claiming that the 11th series battery is 0.1V and that the 10th is 4.9v. This is patently false because I checked each series with my multimeter and every battery is roughly 4v. And we also can tell that the 10th and 11th series voltage is wrong because if you actually add every group up it should be about 77v (according to the reported voltages), but the total voltage is shown to be 80v, which means that each series is roughly at 4v.
Finally the app's own "CellLow" is shown to be 3.975V and not 0.110V, and the cell high is shown to be 4.069, not 4.99. The BMS won't charge and then out of the blue, maybe after a few minutes or more, it starts charging and when I look at the cell voltages, the 10th and 11th cells are now fine.
I've wired up as charge only, BTW. So NEG battery wire to B- on the BMS and CHG- to C- on the BMS.
Any ideas?
Finally the app's own "CellLow" is shown to be 3.975V and not 0.110V, and the cell high is shown to be 4.069, not 4.99. The BMS won't charge and then out of the blue, maybe after a few minutes or more, it starts charging and when I look at the cell voltages, the 10th and 11th cells are now fine.
I've wired up as charge only, BTW. So NEG battery wire to B- on the BMS and CHG- to C- on the BMS.
Any ideas?
thundercamel
10 kW
The balance wire between 10 and 11 has a problem?
nardcox
10 W
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- Apr 14, 2020
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Sorry for the late reply, had some crazy days at work.j bjork said:
I haven't bypassed the BMS yet. I meant it doesn't matter whether the BMS is on or off, the bike doesn't work.
I still get the error even when nothing is connected. I've made a video and some pictures if anyone care to take a look, I really don't see anything wrong / burned / melted. There are some pictures and a video or the BMS taken apart.
https://photos.app.goo.gl/rWyHYPyg7BZbEREW7
It should be fine to hookup the battery minus directly to the controller right? I'll connect everything and turn on the fuse last?
j bjork
1 MW
nardcox said:
Yes, you will get a spark somewhere when the battery and controller gets connected. In the fuse or in the contacts. I dont think it will be a problem if it is a dc fuse, if it is ac it might be more sensitive. But my guess is that it will not be a problem anyway.
If no mosfets are shorted, but the bms think there is a problem it wont turn on. So to bypass the bms will be the easiest way to test if the controller works.
eee291
100 kW
It's a Bluetooth BMS not a GPS BMS 
nardcox
10 W
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- Apr 14, 2020
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I've bypassed the BMS and the controller is perfectly fine, the problem really is within the BMS.j bjork said:
For now I've taken out the BMS and did some small runs without the BMS.
Will order a new one now. Still think it's only a software issue and the hardware of the BMS is fine but I can't get it to work (charding = ok, discharging if gives an error) and a factory reset doesn't make a difference.
eee291
100 kW
Andrewol said:eee291 said:It's a Bluetooth BMS not a GPS BMS
You are wrong. In JBD smart bms there is gps speed function available. Why not to use this gps option for tracking purpose?
LOL :lol:
Your smartphone has GPS not the BMS.
You should first buy this BMS and only than claim about its GPS. Today not only smartphones have GPSeee291 said:Andrewol said:eee291 said:It's a Bluetooth BMS not a GPS BMS
You are wrong. In JBD smart bms there is gps speed function available. Why not to use this gps option for tracking purpose?
LOL :lol:
Your smartphone has GPS not the BMS.
serious_sam
10 kW
I have read this entire 64 page thread multiple times, and I don't recall a single unit discussed that has inbuilt GPS.Andrewol said:You should first buy this BMS and only than claim about its GPS. Today not only smartphones have GPS
I own one of the units regularly discussed here. I have studied the circuits. I have made modifications. I can guarantee 100% that there is no inbuilt GPS.
If your unit has inbuilt GPS, please post a link and details of the exact model.
Otherwise, "you should first buy this BMS and only than claim about its GPS"...
eee291
100 kW
Andrewol said:You should first buy this BMS and only than claim about its GPS. Today not only smartphones have GPSeee291 said:Andrewol said:eee291 said:It's a Bluetooth BMS not a GPS BMS
You are wrong. In JBD smart bms there is gps speed function available. Why not to use this gps option for tracking purpose?
LOL :lol:
Your smartphone has GPS not the BMS.
I have bought at least 2 dozen of these Bluetooth BMS. Just think logically about this, if it had GPS how would it notify you without a sim card module? I'm pretty sure Bluetooth doesn't work over tens of kilometers. So GPS without any supporting modules would make it useless and add to the cost.
It's nice to see people exited for a product, but please keep your expectations within reality. :|
