bluetooth BMS?

eee291 said:
What is the voltage delta between the two groups?
You could also try power cycling the BMS.

It's around 75mV. I will try power cycling it. Do you have any other suggestions if that fails?
 
I'm not 100% sure about the balance wires on that BMS version, but looking at the pics you will have to make it yourself.
This is the same seller as on aliexpress and the pins are already presoldered to the wires. Just pop them into the socket, as many as needed for your setup, and they'll stay there.
 
patrickza said:
A couple of questions before I hit the order button. I have a 24s 10AH lifepo4 pack, and while I generally only use 20A to 30A, I sometimes burst to 80A for a short while. Will the 100A version of this BMS be able to handle that for me or should I go for a higher amp version?
https://www.ebay.com/itm/8S-24S-Lifepo4-li-ion-Lipo-Battery-Protection-Board-Smart-BMS-Balance-Bluetooth/192713045620?hash=item2cde97b674:m:mmYGtW2LCsV0HOzua9mBVkw:rk:1:pf:0&shqty=1#shId

Then did you guys get a wiring harness with it or did it all have to be built up individually?

Thanks

They show the balance cables in the images and I have 2 of these BMS. They include the balance cables.
 
I have a 14s battery that needs a new BMS and was wondering if going Bluetooth route is worth it? The regular 14S 45A BMS sells for £12, while Bluetooth 60A is £37 or £30 for 30A version. The battery is used on BBS02. So it won't see much usage past 25A and 1.5KW. Is it worth paying 3 times more for the Bluetooth version?
 
hello right now i have 13s battery , but in future i will make 15s pack, can i buy now 15s bms and use it on 13s battery? i see option on pc app to change series number but dont know if this need any hardware modification ?
 
florkk said:
hello right now i have 13s battery , but in future i will make 15s pack, can i buy now 15s bms and use it on 13s battery? i see option on pc app to change series number but dont know if this need any hardware modification ?
For the one I have, it can work for 7s to 16s. The difference is just in the connection, no hardware modification is needed.
I guess most bluetooth bms should be in this way. But of course, you should check clearly on the specifications of the bms before you place your order.
 
I had a catastrophic BMS failure. Pics follow


IMG_20190120_013017.jpg
IMG_20190120_013043.jpg

This BMS was wrapped in duct tape and thick paint, but I don't think that was the problem.
file.php


I think the problem was that before sealing the battery I applied a spray called "Nano Protect" that is supposed to protect the electronics. I think this product degraded the rubbery thermal contacts and created an air gap to the aluminium outer sheets. The heat was so high that I found blobs of solder. The smell is nasty.

I think the board has no repair. I will reconfigure another 16S bms to replace this 18s board. I like that just joining some spots we can change the expected cell count on these "smart" BMS.

Anybody has another theory to explain this failure?
 
https://imgur.com/a/gevHkWj
Had a little accident today :roll:

I wanted to charge a Cell with my EBC-A10 Charger...while the UART programmer was still plugged into my PC :shock:
It blew the GND trace on the BMS and my UART programmer and probably did some more damage.

I tried soldering the blown traces but I wasn't expecting it to work anyways.

If anyone wants it you can have it for the price of shipping.
 
trazor said:
I think the board has no repair.
Anybody has another theory to explain this failure?

This looks very repairable to me. Only some of the mosfets are cooked. I'd pull all the burnt ones off and then install just one good one in their place. This will be proof that it works or not. IF it does, replace all the rest of them. Any 100V mosfet will work.

The thermal gap filler looks OK to me. Are you sure you didn't just over load the BMS? Something dead shorted or nearly dead shorted those mosfets to make them get that hot!

My BMS's are completely enclosed too and they don't over heat. This has to be some kind of overload condition.
 
ElectricGod said:
trazor said:
I think the board has no repair.
Anybody has another theory to explain this failure?

This looks very repairable to me. Only some of the mosfets are cooked. I'd pull all the burnt ones off and then install just one good one in their place. This will be proof that it works or not. IF it does, replace all the rest of them. Any 100V mosfet will work.

The thermal gap filler looks OK to me. Are you sure you didn't just over load the BMS? Something dead shorted or nearly dead shorted those mosfets to make them get that hot!

My BMS's are completely enclosed too and they don't over heat. This has to be some kind of overload condition.

I maybe try to repair it as you suggest. I don't get voltage on the serial port. Can that be an indication of a major problem, not only with the mosfets?

About the overload... I didn't pull so much energy. I was using my bike with a Kelly KBS72121X with a Denzel4500 motor. Probably not more than 60 phase amps and not full duty cycle. And... about overload... aren't BMS designed to cut energy if they detect an overload?

After changing the BMS (reconfigured one 16S to 18S) my bike works flawless now, so I don't think there was a short in any place.

Thanks for your input and keep ideas coming.
 
trazor said:
I maybe try to repair it as you suggest. I don't get voltage on the serial port. Can that be an indication of a major problem, not only with the mosfets?

About the overload... I didn't pull so much energy. I was using my bike with a Kelly KBS72121X with a Denzel4500 motor. Probably not more than 60 phase amps and not full duty cycle. And... about overload... aren't BMS designed to cut energy if they detect an overload?

After changing the BMS (reconfigured one 16S to 18S) my bike works flawless now, so I don't think there was a short in any place.

Thanks for your input and keep ideas coming.

Pull the mosfets, make sure there are no stray solder blobs anywhere. Then connect the BMS via batt- and the balance cables to your pack. Let's see if after a little clean-up if the logic and cell control electronics still work. If they are good, get more mosfets and consider doing a full upgrade like I've posted here.

https://endless-sphere.com/forums/viewtopic.php?f=14&t=95853&p=1403576#p1403576

Overload...yes, I was wondering about that too. The point of the P- mosfets is to shut off current flow in an over load. That didn't happen and there are reasons for that. A single mosfet with an internal short would be sufficient to keep the BMS flowing current even if the rest of them in fact shut off. That one mosfet would get quite HOT. Once you have the mosfets pulled, you can test the control logic to see if the mosfets are getting the right signal to shut off. It is possible that a mosfet gate was shorted somehow to something that held it active and caused this condition. I'd be looking closely at the board for solder blobs and other blown parts.

We can talk about testing later. Get the mosfets pulled first so you can start looking at survivability for the "brains" of the BMS. What I can tell you from personal experience with electronics is that it is common for the high current parts to die and the rest of the device is OK. I've blown all 18 mosfets in a controller and the rest of it survived. 18 new mosfets and a year later that controller is still running strong. I've seen many power components blow over the years in PSU's, controllers, DC-DC converters and other things. Replace those power components and the rest of the device is still OK. It's not guaranteed, but I'd give it 80%. I've been doing electronics repair since the mid 1980's. I've seen loads of electronic devices that let the magic smoke out and are repairable.

To me this BMS is an exploratory learning opportunity. Maybe that's not your thing? But then I am a modder and hacker of just about everything.

Getting your bike going again. That proves the problem is localized to the BMS...which is good!
 
ElectricGod said:
trazor said:
I maybe try to repair it as you suggest. I don't get voltage on the serial port. Can that be an indication of a major problem, not only with the mosfets?

About the overload... I didn't pull so much energy. I was using my bike with a Kelly KBS72121X with a Denzel4500 motor. Probably not more than 60 phase amps and not full duty cycle. And... about overload... aren't BMS designed to cut energy if they detect an overload?

After changing the BMS (reconfigured one 16S to 18S) my bike works flawless now, so I don't think there was a short in any place.

Thanks for your input and keep ideas coming.

Pull the mosfets, make sure there are no stray solder blobs anywhere. Then connect the BMS via batt- and the balance cables to your pack. Let's see if after a little clean-up if the logic and cell control electronics still work. If they are good, get more mosfets and consider doing a full upgrade like I've posted here.

https://endless-sphere.com/forums/viewtopic.php?f=14&t=95853&p=1403576#p1403576

Overload...yes, I was wondering about that too. The point of the P- mosfets is to shut off current flow in an over load. That didn't happen and there are reasons for that. A single mosfet with an internal short would be sufficient to keep the BMS flowing current even if the rest of them in fact shut off. That one mosfet would get quite HOT. Once you have the mosfets pulled, you can test the control logic to see if the mosfets are getting the right signal to shut off. It is possible that a mosfet gate was shorted somehow to something that held it active and caused this condition. I'd be looking closely at the board for solder blobs and other blown parts.

We can talk about testing later. Get the mosfets pulled first so you can start looking at survivability for the "brains" of the BMS. What I can tell you from personal experience with electronics is that it is common for the high current parts to die and the rest of the device is OK. I've blown all 18 mosfets in a controller and the rest of it survived. 18 new mosfets and a year later that controller is still running strong. I've seen many power components blow over the years in PSU's, controllers, DC-DC converters and other things. Replace those power components and the rest of the device is still OK. It's not guaranteed, but I'd give it 80%. I've been doing electronics repair since the mid 1980's. I've seen loads of electronic devices that let the magic smoke out and are repairable.

To me this BMS is an exploratory learning opportunity. Maybe that's not your thing? But then I am a modder and hacker of just about everything.

Getting your bike going again. That proves the problem is localized to the BMS...which is good!

Oh wait. I didn't connect my load to P-. I connected battery to B- and load to C-. As these BMS say "charge and discharge port: same" I thought it was the same. And is the vendors pictured connection method http://ae01.alicdn.com/kf/HTB1NfmBSXXXXXXOXXXXq6xXFXXXi.jpg?size=122085&height=525&width=750&hash=a1a66c652e6fae546ef51254cdf7c984

Is that OK?

About the power components being blown and survability... I had not so much luck as you. I've a couple controllers with mosfets rosted and 10mm around of traces and smd components vaporized (one kelly KBS with phase wires shorted and other no brand without known cause of failure). Other things like DC-DC converters, yes, i've repaired some just changing mosfet.

I will make some time to try to desolder these mosfets and post the results. Many thanks for sharing your knowledge!
 
trazor said:
Oh wait. I didn't connect my load to P-. I connected battery to B- and load to C-. As these BMS say "charge and discharge port: same" I thought it was the same. And is the vendors pictured connection method
It's ok to connect load to C. Even though it's C=Charger. And P=Power. So i connected my controller to P. Both ways should work. I just don't see any reason why i should route all current through the charging FETs AND the discharging FETs doubling losses.
 
trazor said:
I will make some time to try to desolder these mosfets and post the results. Many thanks for sharing your knowledge!
If you plan to work with FETs i'd suggest buying a hot air station. It makes working MUCH more easier. You can heat bigger parts of the PCB an ensure proper solder flow, as well as desoldering w/o damaging any traces.
 
izeman said:
trazor said:
I will make some time to try to desolder these mosfets and post the results. Many thanks for sharing your knowledge!
If you plan to work with FETs i'd suggest buying a hot air station. It makes working MUCH more easier. You can heat bigger parts of the PCB an ensure proper solder flow, as well as desoldering w/o damaging any traces.

That is a good tip!. I almost forgot that I have a cheap hot air gun with two speed settings. It is not the same but probably work. I've even reflowed a laptop BGA chip and make it boot again with it. Thanks!
 
izeman said:
trazor said:
Oh wait. I didn't connect my load to P-. I connected battery to B- and load to C-. As these BMS say "charge and discharge port: same" I thought it was the same. And is the vendors pictured connection method
It's ok to connect load to C. Even though it's C=Charger. And P=Power. So i connected my controller to P. Both ways should work. I just don't see any reason why i should route all current through the charging FETs AND the discharging FETs doubling losses.

I think that maybe the only reason to connect to C- is if you have a controller with extreme regen that can put high voltage and amps. If you connect to P- the BMS can't save your battery from that. I've not idea really, it is just a thought.
 
izeman said:
trazor said:
I will make some time to try to desolder these mosfets and post the results. Many thanks for sharing your knowledge!
If you plan to work with FETs i'd suggest buying a hot air station. It makes working MUCH more easier. You can heat bigger parts of the PCB an ensure proper solder flow, as well as desoldering w/o damaging any traces.

Umm, I checked with mouser.com tho get 32 IRPF4110PBF and the price is 105usd. That is the price of a new board! I don't think I will try to repair it if that is the case.

AND, the other issue is that I see these tiny SMD components (resistors?) fried too.

IMG_20190125_144238.jpg

Should I buy those too? I can't even read the designation on the cover.
 
This looks bad. I would not expect this BMS to ever work again, and i personally doubt that it's worth the time to invest. Those BMS sell for <$50, so i'd just buy a new one. I hate to throw things away and always try to repair them, but there might be some damage done to the CPU or other parts which are very hard to find if you are no electronics expert.
 
trazor said:
Umm, I checked with mouser.com tho get 32 IRPF4110PBF and the price is 105usd. That is the price of a new board!
Good (non-counterfeit) FETs are expensive.
AND, the other issue is that I see these tiny SMD components (resistors?) fried too.
Those are probably the gate drive resistors. Often when a FET blows the gate shorts to one of the other terminals. Which means your FET driver circuit is probably blown, too. So you will probably have to replace that.
 
trazor said:
Umm, I checked with mouser.com tho get 32 IRPF4110PBF and the price is 105usd. That is the price of a new board! I don't think I will try to repair it if that is the case.

AND, the other issue is that I see these tiny SMD components (resistors?) fried too.

Should I buy those too? I can't even read the designation on the cover.

I'd call it...probably not worth the trouble. Oh well.

Those are the gate resistors. 1K or 102 in SMD parlance.

I can get 4110's for a lot less that $10 each. $3.29 each if you buy 10 of them. 32 of them was even cheaper.

https://www.mouser.com/ProductDetail/Infineon-Technologies/IRFP4110PBF?qs=sGAEpiMZZMshyDBzk1%2fWi5%252bqVgN3%252bWS8WQjF01SFXSg%3d
 
Is it possible to connect/pair two bluetooth modules to the same Xiaoxiang app on the same phone, and read them independently?
 
Longlight said:
Is it possible to connect/pair two bluetooth modules to the same Xiaoxiang app on the same phone, and read them independently?

I was just going to ask this exact question.
I have a 14s bt bms on my bike and have just ordered a 4s bt bms for a mobile 12v power storage unit.
 
Longlight said:
Is it possible to connect/pair two bluetooth modules to the same Xiaoxiang app on the same phone, and read them independently?

Not at the same time. You disconenct from one to connect to the other.
I have 8 of these smart BMS, I do this pretty often as you can imagine.
 
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