bluetooth BMS?

[xfrankie]

...

I have activated the BMS by momentarily applying 4V to the two wires on the left

...

Thanks for the info but unfortunately mine is a different board than that. The one you linked has a mini-momentary switch with it.


I received an official reply from the seller on Ali-express (IC GOGOGO Store):
Q: "Hello, I have a 7S to 16S ANT BMS. Is it possible to add a switch to shutdown or turn off the BMS? Thank You"

A: "hi friend
in app you can turn off the BMS

can't add a switch to shutdown or turn off the BMS"

Yes, not good translation on my end. Sorry.

I thought that if both are from the same seller (IC GOGOGO Store), maybe have simillar brainbox inside, maybe same way to turn on is also the way to turn off (only for longer press).

But if seller officially says it will not work, then i would trust him...
He is chinese, it there was a way to do it, He would market it like hell, make it a selling point, increase price because of it... "look at our glorious bms, it can turn off, look look! nobody else can do that etc."
You know what I mean... Ať least thats my experience, lol.

Right now the only way i can think of, is to open up the board and identify the trace which powers the brainbox. Cut the trace and solder extension wires with a manual switch between them...
But honestly said, I personally would rather skip the turn off function completely, than to mess with traces inside like that...

If turn off is just for long time storage, maybe put a large ring terminal (screw connector?) between bms and battery, and disassemble before storage.

 

[john61ct]

for long time storage, maybe put a large ring terminal (screw connector?) between bms and battery

Could you link to ones you think would be suitable?

I was thinking just waterproof multi-pin connectors like TE Deutsch

 

[adamcooks]

and thats the 200A with bluetooth that they dont sell on Ali:
https://www.lithiumbatterypcb.com/product/13s-16s-48v-or-60v-72v-20s-lithium-battery-bluetooth-smart-bms-54-6v-58-4v-67-2v-84v-electric-tricycle-pcb-with-200a-constant-discharge-current/

What would you do? since no1 is responding in their web,
should I go for the bluetooth-less unit?

I would not buy from that site, i am still waiting 12/3/2020 fid a payment and still no response on any contact !


Verzonden vanaf mijn iPhone met Tapatalk

https://www.lithiumbatterypcb.com no response whatever


Verzonden vanaf mijn iPhone met Tapatalk

I was in the same boat with the folks over there at https://www.lithiumbatterypcb.com , until this morning. I placed an order on their website on the 4/26 and heard nothing from them. I sent them an email and attempted skype a couple of times and left a skype message. Two days ago i received a text from dhl about a shipment with a different shippers name and different address, the website still showed my order as processing. I wasn't even sure that it was from LLT as I also bought a chargery 10325 at the same time, but from aliexpress. This morning i received an email with a tracking number that matched the text. I was about to call my CC company and dispute the charge. Horrible customer service, and im not trying to be a shill, but there is a possibility that the current quarantine climate played a role here.

 

[xfrankie]

for long time storage, maybe put a large ring terminal (screw connector?) between bms and battery

Could you link to ones you think would be suitable?

I was thinking just waterproof multi-pin connectors like TE Deutsch

After i wrote that Wall of text below, I realize this is very off-topic from the focus of the thread. I apologize deeply...

I do not change Multipin conectors of the bms, I hard-wire (soldering+tight heatshrink) the balance leads from battery to whatever connector the vendor sends with my bms purchase, as that is the only thing guaranteed to fit.
I guess you could add some switch to the "last positive lead", if thats what powers the bms, and extend that wire to accessible spot.
Whether that is enough to completely isolate the bms, would have to be tested.

To connect power wires between Battery / bms / controller, I use crimping ring terminals like this :
https://www.amazon.co.uk/gp/aw/d/B07CZHG2NV/ref=mp_s_a_1_12?ie=UTF8&qid=1589307742&sr=1-12&pi=AC_SX236_SY340_FMwebp_QL65

Sizes vary with the thickness of wires used.
The hole for the screw i try to keep as two standard sizes, 6mm screw for traction power lines, and 4mm for everything else (12v regulator, lights, indicators etc... Low power stuff)

The crimped section is then insulated with a few layers of heatshrink tube.
Then the whole connection including the screw, nut, etc is wrapped in like twenty turns of insulating tape (paper tape, kapton, regular plastic... Anything i have on hand at the moment.)
Then the abomination is again wrapped inside a "chainstay protector", which is a neoprene strip with a velcro strap on two ends, like this one:

https://www.amazon.com/Lizard-Skins-Neoprene-Chainstay-Protector/dp/B0186OQS8O/ref=mp_s_a_1_3?dchild=1&keywords=chainstay+protector&qid=1589308826&sr=8-3

This I deem sufficient for my use, but then again, I only ride on road and never in a rain.
I really love this setup, as the screw allows me to add more things anytime later, and nothing is "destroyed" during disassembly(apart from the sticky tape). Not having to cut and re-solder wires, or change conectors, everytime i change headlights or add horn or whatever, is convenient and very valuable for me.

Like, OH you switched the polarity on the LED Light? Just swap the two wires around, no need to cut heatshrink, re-solder the whole connector, then add the heatshrink back on...

 

[john61ct]

No, I meant the ability to just plug the BMS in and out as desired, could use the same plug(s) for balance chargers, non-protective balancer gear, per-cell / group capacity testing etc.

So when time to put the pack away for storage, put it at say 60% SoC, disconnect the whole BMS and leave it maybe for years if cool conditiins without worries.

 

[xfrankie]

No, I meant the ability to just plug the BMS in and out as desired, could use the same plug(s) for balance chargers, non-protective balancer gear, per-cell / group capacity testing etc.

So when time to put the pack away for storage, put it at say 60% SoC, disconnect the whole BMS and leave it maybe for years if cool conditiins without worries.

Oh, now i understand. I dont really do that with my batteries...
The TE looks rugged, some are sealable and meant for offroad uses, those could definitely work.
I would také a look at things which are meant to run in rain /water, and take inspiration there. Off road cars, quad bikes, even "normal" modern motorcycle must operate in rain reliably, so i would look there for which connector type is used.

Alternatively, if you dont need waterproof, then the GX series (e.g. GX16-10 Pin) could be useful, even has a screw cover to really protect against coming loose from vibrations.
( https://www.amazon.com/Hxchen-Female-Connector-GX20-10P-Aviation/dp/B07V54B44Y/ref=mp_s_a_1_6?dchild=1&keywords=gx16%2Bconnector%2B10%2Bpin&qid=1589343688&sr=8-6&th=1&psc=1)

 

[john61ct]

The Deutsch DT type were used by Harley, and I believe Caterpillar

 

[Wald]

Hello,

as you can read here -> https://endless-sphere.com/forums/viewtopic.php?f=28&t=105158 i had to replace my Bafang Ultra controller with the X1 controller from Exess/ Wattwagons -> https://wattwagons.com/blogs/news/archon-x1-controller
My batterie pack is a 52V 14s5p unit with Sony Konion US18650VTC6 cells and a smart bms with 60A from LLT -> https://www.lithiumbatterypcb.com/p...cle-and-e-scooter-protection-2-2-3-2-2-2-2-2/.

So i tried out the app for the bms to see how much amps the new controller would suck out of the batterie while riding the bike. The X1 controller according to wattwagons description: "The nominal will be 52V with 45A pack- that’s ~2300watts nominal power. The motor can burst up to 3000W with no issues (with a 60A burst current)."
My problem is that the app newer shows me amp readings above 30A, no matter what. So i started to play around with the app and reduced the discharge current to 25A and then even to 15A max current discharge, but it didn't do anything (the oem setting was 70A).

Is the bms faulty or do i miss some settings in software? I also have the pc dongle to connect it directly to a pc if the app is not enough. But i didn't dare to change settings in the pc software, yet.

 

[eee291]

Those Archon X1 controller claims smell kinda fishy to me :|

 

[Wald]

Those Archon X1 controller claims smell kinda fishy to me :|

I paid over 400€ for it! so it better should provide those claims.

-----

Which parameters should i check in the pc Software? At my first glance over it i couldn't find the max discharge setting. Is the acronym named differently?

 

[john61ct]

So i tried out the app for the bms to see how much amps the new controller would suck out of the batterie while riding the bike. The X1 controller according to wattwagons description: "The nominal will be 52V with 45A pack- that’s ~2300watts nominal power. The motor can burst up to 3000W with no issues (with a 60A burst current)."
My problem is that the app newer shows me amp readings above 30A, no matter what. So i started to play around with the app and reduced the discharge current to 25A and then even to 15A max current discharge, but it didn't do anything (the oem setting was 70A).

Is the bms faulty or do i miss some settings in software? I also have the pc dongle to connect it directly to a pc if the app is not enough. But i didn't dare to change settings in the pc software, yet.

I never heard of a BMS doing **any** actual current limiting, much less at a user-adjustable amps rate. What makes you think this is possible? (besides the software UI)

At best overcurrent protection, usually latching style, shutting operation down until the user fixes the problem maybe have to reset / power cycle the BMS, just like a circuit breaker.

OTOH many BMS just burn if you allow over current, you're supposed to buy one that can handle greater ampacity than your controller will ever allow to be drawn.

Or put a fuse in the circuit, sized to blow befor the BMS lets out the smoke.

 

[john61ct]

Those Archon X1 controller claims smell kinda fishy to me :|

OT but why? The Bafang Ultra folk are all over it, apparently very hard to source without buying the whole kit with the upgrade already installed.

 

[john61ct]

Alternatively, if you dont need waterproof, then the GX series (e.g. GX16-10 Pin) could be useful, even has a screw cover to really protect against coming loose from vibrations.
( https://www.amazon.com/Hxchen-Female-Connector-GX20-10P-Aviation/dp/B07V54B44Y/ref=mp_s_a_1_6?dchild=1&keywords=gx16%2Bconnector%2B10%2Bpin&qid=1589343688&sr=8-6&th=1&psc=1)

Looks like cheap-chinese crap from here.

Stick to vendors like Digi, Mouser, Newark etc

 

[Wald]

What makes you think this is possible? (besides the software UI)

The UI software. :lol:
Probably the amp peaks are not long enough to make the bms cut off and thats why it doesn't do anything?

Or put a fuse in the circuit, sized to blow befor the BMS lets out the smoke.

I had installed a 50A fuse.

... maybe have to reset / power cycle the BMS, just like a circuit breaker.

Sorry i don't understand what you mean. Besides that it doesn't provide more than 30A it seems to work fine.

 

[eee291]

Sorry i don't understand what you mean. Besides that it doesn't provide more than 30A it seems to work fine.

It seems you don't since the BMS doesn't ''provide'' current but rather the Controller draws current.
The BMS monitors current and shuts off if the current being drawn is above the limit set in the App.
If the BMS was triggering you'd notice by losing power for a few seconds.

The only two things that could cause your controller to not draw the full 60A is the Battery voltage sagging too much (thin wires, weak battery etc) or the Controller itself.

 

[Wald]

The BMS monitors current and shuts off if the current being drawn is above the limit set in the App.
If the BMS was triggering you'd notice by losing power for a few seconds.

Thats what i was trying to do when setting the max current to 15A. But the controller was still drawing 30A without any noticeable differents in power.
So why is the bms not shutting off?

The only two things that could cause your controller to not draw the full 60A is the Battery voltage sagging too much (thin wires, weak battery etc) or the Controller itself.

As far as i remember does the voltage drop maybe around 2 Volts at full power.

 

[serious_sam]

So why is the bms not shutting off?

Some possibilities:
1. Faulty/broken BMS.
2. Incorrectly wired.
3. Incorrectly calibrated current measurement. There are shunts that it uses to measure the current, and that resistance value can be set up in the PC software (easy way, but not so accurate). Alternatively you can flow a set current through the BMS, and tell it what that current is (more difficult, but can get better accuracy).
4. Over-current cut-off also has a time parameter. For example "5 seconds", so you can go over-current for up to 5 seconds without it cutting out.

As far as i remember does the voltage drop maybe around 2 Volts at full power.

If the cells are genuine VTC6 (and good SOH), then you'll sag around 2V@30A for a 14S5P pack.

 

[john61ct]

Yes, just to restate, in case it hasn't sunk in

BMS do not limit your current, that is not their job.

There might be high-end exceptions costing many hundred$ but I have not come across any.

Sure would be nice, especially if the user could select the maximum level wanted, but afaik that's a fantasy.

The current limit rating on a BMS is like a fuse. If you even want that OCP feature, if not you could bypass it by driving external contactors instead.

But otherwise, you must buy a BMS rated to handle lots more current than you plan to ever allow to pass through it.

A CAv3 or a programmable controller is what you would use to actually limit current. Yes an anaemically underpowered battery would have that effect, but obviously not something to do on purpose

Or a fuse, sized much lower than what the BMS can handle.

And note, that with cheap-chinese electronics like these BT BMSs, what the BMS is stated to handle might well be fraudulently "optimistic".

 

[Wald]

3. Incorrectly calibrated current measurement. There are shunts that it uses to measure the current, and that resistance value can be set up in the PC software (easy way, but not so accurate). Alternatively you can flow a set current through the BMS, and tell it what that current is (more difficult, but can get better accuracy).

I monitored the charging process today and the bms app tells me the same charge amp as the charger is showing. So i guess it should be accurate.

4. Over-current cut-off also has a time parameter. For example "5 seconds", so you can go over-current for up to 5 seconds without it cutting out.

Like i thought before. In the app it's set to 5 sec as well.

BMS do not limit your current, that is not their job.

Got it.

And note, that with cheap-chinese electronics like these BT BMSs, what the BMS is stated to handle might well be fraudulently "optimistic".

So you say the continuous 60A rated bms i bought from LLT, actually does only 30A for real??


What kind of bms would be appropriate for my application?
----
Update:
No wait. If the bms only acts as a curcuit breacker then the motor controller should be a able to draw as much current as it wants, until the bms cuts off or burns away.
So the conclusion is that the X1 controller isn't doing what it is claimed to do?!

 

[eee291]

In my case all the BMSs that I bought from LTT could easily handle their rated current.

So you say the continuous 60A rated bms i bought from LLT, actually does only 30A for real??


What kind of bms would be appropriate for my application?

It looks like you still don't understand, it's not the fault of the BMS that the Controller is only drawing 30A.
Since the battery can supply enough current it looks like the controller is the only culprit remaining.

If you really think that the BMS is at fault you could temporarily bypass it and measure the current with a current clamp or shunt.
Spoiler alert: It'll still only show 30A

 

[john61ct]

Sorry, what evidence do we have that the battery can actually supply 60A for more than say ten minutes?

Without dropping too much voltage?

That should be easier to test first rather than the controller.

I agree best go take the BMS out of the current path, so long as you can still monitor cell-group voltages to help protect the battery while testing.

 

[eee291]

Why would it ever need to supply 60A for ten minutes, have you ever been on an ebike?
I'd like to see the Controller pull 60A even for just a second, a 5S VTC6 pack can handle 60A without catching fire for sure.

 

[john61ct]

Just responding to

So you say the continuous 60A rated bms i bought from LLT, actually does only 30A for real??

A 60Ah pack should not have much trouble, even made from cheap Chinese knockoff cells.

And this is a general BMS thread in the EV sub, so no we're not just talking "bikes" here.

 

[serious_sam]

a 5S VTC6 pack can handle 60A without catching fire for sure.

*5P

I regularly pull 150A from my 5P VTC6 pack. No problems (except a bit of sag). It's easily good for 75A continuous.

 

[agniusm]

Is there a physical difference between lipo and lifepo4 bms versions? Possible to program lifepo4 to work on lipo cells?