bluetooth BMS?

[john61ct]

The new normal will continue to impact.

but 2-3 months is often the old normal anyway

 

[Hertzelz]

Hey Guys,

I'm about to get a 20s1p LG CHEM M2.1 cells (total 72v60ah, 180A const current),
So I need a 200A BMS,

Should I go for the ANT bms?
or https://www.aliexpress.com/item/32804527877.html LLT one (but without bluetooth)?

There is an LLT 200A with bluetooth on their website https://www.lithiumbatterypcb.com/p...cle-pcb-with-200a-constant-discharge-current/ - but they're not responsive on emails or skype, so I prefer to avoid buying from the site directly.

I've heard mixed reviews on the ANT's as sometime it 'forgets' cell groups,
but the LLT is without Bluetooth, but looks far more 'robust' in terms of build quality to my eyes...

What would you choose?
The controller will be ASI BAC4000.

*I've searched this thread and didn't find any conclusive answer, is the LLT reliable enough to buy without bluetooth abilities?

 

[Miwer]

Anyone here recently bought something from the site www.lithiumbatterypcb.com, almost 1 month ago i bought a bms, no reply sofar, order is still processing

Marco

Hi Marco,
I am wondering the same. I also ordered a BMS from lithiumbatterypcb.com a month ago, and my order is also still "Processing". I've tried to e-mail them multiple times, no answer. I even created a skype account, and sent them messages there, no response. Even tried to call them, no pickup. If I don't hear from them soon, I will make a complaint with paypal to get my money back.

 

[st35326]

Hey Guys,

I'm about to get a 20s1p LG CHEM M2.1 cells (total 72v60ah, 180A const current),
So I need a 200A BMS,

Should I go for the ANT bms?
or https://www.aliexpress.com/item/32804527877.html LLT one (but without bluetooth)?

There is an LLT 200A with bluetooth on their website https://www.lithiumbatterypcb.com/p...cle-pcb-with-200a-constant-discharge-current/ - but they're not responsive on emails or skype, so I prefer to avoid buying from the site directly.

I've heard mixed reviews on the ANT's as sometime it 'forgets' cell groups,
but the LLT is without Bluetooth, but looks far more 'robust' in terms of build quality to my eyes...

What would you choose?
The controller will be ASI BAC4000.

*I've searched this thread and didn't find any conclusive answer, is the LLT reliable enough to buy without bluetooth abilities?

Here's the 300 amps Ant BMS Im using on the pack I just built ( 21s 7p Sony VTC6 cells).
https://www.aliexpress.com/item/4000136479622.html?spm=a2g0o.cart.0.0.45313c00Xa7t6T&mp=1
Its never forgot cell group (yet). According to my CA the most Ive drawn around 160 amps daily (10-12kW). I really like being able to completely power down the BMS when the bike is resting and monitor cell balance and temps on the fly.

 

[Fionn]

Has anyone had any experience with the pack over (or under) voltage release settings?
I've experimented with it extensively today and neither the release voltage nor the time seem to have any effect.
For example i tried the over voltage protection at 32.8V on an 8S lithium pack.
I set the release voltage to 31V & time to 10S.
This is a large pack (60Ah) so 1.8V is a lot of margin. The charge terminates correctly but the charger cuts back in and out with no hysterisis at all.
Any input would be appreciated!

 

[rexfordk83]

i just connected a 21s bms with lcd 300 amp , once I turn on controller - voltage jumps around then goes to zero and stays there? I have all wires correct, I don't understand. also I cant connect to the lcd screen. says connecting to bms then turns off. anyone had experience with this? thanks

 

[john61ct]

According to my CA the most Ive drawn around 160 amps daily (10-12kW)

Nitpicky I know

but neither amps nor kW make sense as a measure of energy used, both are instantaneous units only.

Perhaps you meant 160Ah per day and 10-12kWh ?

 

[Marsupilami]

Anyone here recently bought something from the site www.lithiumbatterypcb.com, almost 1 month ago i bought a bms, no reply sofar, order is still processing

Marco

Hi Marco,
I am wondering the same. I also ordered a BMS from lithiumbatterypcb.com a month ago, and my order is also still "Processing". I've tried to e-mail them multiple times, no answer. I even created a skype account, and sent them messages there, no response. Even tried to call them, no pickup. If I don't hear from them soon, I will make a complaint with paypal to get my money back.

I also tried the same e-mail and skype totaly silence on the other side, maybe it have to do with corona, but still they should answer the e-mail ....

 

[SGT_MAC]

Hi, Hope Everyone is Well!

I have several batteries from EM3EV with Bluetooth BMS (Powercore, I think?) Neither the recommended app, or any other I could find has worked since Android 10 was pushed out.

The BMS Doctor app just keeps searching for BT devices. VBMS and Xiaoxiang apps see the batteries but fail to connect.

Thanks in advance for any help/recommendation!

-JC

 

[Fionn]

What version Android are you running JC?
Xiaoxiang is usually a sure bet but you need the right version for your OS.
If you've the wrong one it usually behaves as you desbribe.

 

[Hertzelz]

What version Android are you running JC?
Xiaoxiang is usually a sure bet but you need the right version for your OS.
If you've the wrong one it usually behaves as you desbribe.

What Android version works best with those apps?
I run the latest 10 version

 

[john61ct]

varies, but older can work when newer doesn't

get a cheap phone to test

 

[Fionn]

Quite simply you just need the correct version of the app for your OS.
I'm running android 6.0.1and v2.1.1022 of Xiaoxiang & it works perfectly.
Newer versions of Xiaoxiang install, look good & everything on this OS but won't connect.
VBMS is the same, I can't get it to connect on this device.

 

[serious_sam]

Quite simply you just need the correct version of the app for your OS.
I'm running android 6.0 and v2.1.1022 of Xiaoxiang & it works perfectly.
Newer versions of Xiaoxiang install, look good & everything on this OS but won't connect.

Agree.

For the record, I'm running android 6.0.1 (Sony Z3) and Xiaoxiang v2.1.1024 with no problems.

However, Xiaoxiang v3.1.1013 did not connect to BMS on that OS version. Shame, because apparently it has more ability to adjust parameters like the PC software can. And possibly also has PIN capability? Not sure.

 

[Fionn]

I've edited my last post, I'm on 6.0.1 also.
Yes, the ability to change more configuration variables seems to be the primary advantage v3.
V2 is still great though, I find it very reliable.

One minor annoyance, does anyone know the trick to enable the lock/unlock feature where the speed display normally shows on thr dashboard screen?
It seems to require a random number of taps.

 

[SilverLine]

Question about charging

At the moment I have a 20s Li-ion battery, I am using the JBD Bluetooth BMS together with, it is working perfect. I am using this charger : https://www.aliexpress.com/item/32781966303.html?spm=a2g0o.productlist.0.0.484656ddXWUE1z&algo_pvid=5f559d45-073f-456b-a834-989103cf018e&algo_expid=5f559d45-073f-456b-a834-989103cf018e-31&btsid=0ab50f4915866186976531319e576e&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

What if I expand the battery, to 24s, and buy the 24s BMS from JBD, but still using the same "20s charger".... Will it work ? I know that they will not fully charge (around 3.5v pr cell), which is also my goal for now... But It would work right ??

 

[Fionn]

Yes, it will work but only charge the cells to 3.5V which is close to empty if you are using lithium ion..

 

[john61ct]

No you need to charge at 4.05V at a minimum to get any decent range.

4.10 or 4.15 are still conducive to longevity.

3.5V is below where you should be stopping in effect empty.

 

[SilverLine]

No you need to charge at 4.05V at a minimum to get any decent range.

4.10 or 4.15 are still conducive to longevity.

3.5V is below where you should be stopping in effect empty.

Yes.. but i´m only talking theoretical here.... Is it right that my CC/Cv charger, lower the charge amp when close to end voltage ?? (4.20v pr. cell) Or is it the BMS that does it...

 

[john61ct]

I do not understand your confusion, multiple things all mixed up there.

>> It would work right ??

That needs to be precisely defined, what are you trying to accomplish?

But in any case from a practical POV, going from 20S to 24S requires getting a new charger.

In your case a variable voltage industrial / lab-style PSU combined with an adjustable LVC might be worth it, let you experiment with a range of termination voltages.

eBay often has great units like Sorensen available for a small fraction of their value, much better than messing with random cheap chinese stuff, charging is critical and dangerous!

BMS like these are just to protect the pack against the failure of primary charge circuits, do not have anything to do with the actual charge regulation.

Finally, normal chargers do not regulate trailing current. It is the chemistry of the battery that does that, the regulation circuitry just hold the **voltage** setpoint maximum cap.

No need to keep charging after that anyway, unless you want every last mAh of range, it is stressful and reduces pack lifespan, better to just do CC and stop when the setpoint is reached.

 

[john61ct]

To continue this OT line of discussion, start a new thread and copy/paste or link to here

 

[serious_sam]

Yes.. but i´m only talking theoretical here.... Is it right that my CC/Cv charger, lower the charge amp when close to end voltage ?? (4.20v pr. cell) Or is it the BMS that does it...

Technically it is the charger that lowers the current.

However the charger doesn't actively taper off the current, that's just a side effect of the maximum voltage that it can produce.

The charger only limits the maximum current and maximum voltage available. It does this by reducing its output voltage, in order to satisfy this equation:

I = (Vc-Vb)/Rb

Basically, the charge current is set by the difference in voltage between the charger and the battery, divided by the internal resistance or the battery (and wiring).

During charging, as the battery voltage increases, the charger will also increase its output voltage, to maintain its maximum current.

Once the charger reaches its peak voltage, then it can no longer maintain the peak current, because the battery voltage is still increasing, so the delta V between the battery voltage and the charger voltage is reducing, so the current tapers off towards zero as the battery voltage approaches the charger voltage.

In any event, as previously mentioned by others, you need a new charger for the 24S pack.

 

[serious_sam]

One minor annoyance, does anyone know the trick to enable the lock/unlock feature where the speed display normally shows on thr dashboard screen?
It seems to require a random number of taps.

Just checked mine. Seems ok. Only needs one tap. It does take a second or so to activate though.

For the record, I don't use the speed function, and I don't allow the app access to the gps, and normally have gps turned off on the phone. Maybe that has some affect on the app response. Not sure.

 

[john61ct]

Technically it is the charger that lowers the current.

That is never true for mainstream chargers unless they allow the **user** to adjust current up and down. But only very very rare specialized charge sources of any kind do any "live" adjustment of current during a given charge cycle. Sometimes as a thermal protection measure. . .

Yes most chargers (and all designed for LI chemistries) are **current limited** but usually only to a single fixed cap.

As you explain very well, the declining current aka "trailing amps" is 99.99% of the time nothing to do with charge source control, actually "regulated" by the battery itself: chemistry, CAR, the relationship between, charge current, resistance climbing with SoC, voltage getting capped etc.

So I have no idea what your statement above is referring to.

 

[serious_sam]

Technically it is the charger that lowers the current.

So I have no idea what your statement above is referring to.

FFS, you're starting an argument over semantics.

In the context of the conversation, my comment was in response to a question whether it was the charger or the BMS which lowers the current towards end of charge.

Any change in output of the SMPS charger is caused by its algorithms reacting to feedback. So technically the charger is lowering the current. I never said it was user adjustable or anything else of the sort.

I then went on to clearly explain the mechanism how that current is lowered by V=IR. So there should be no misunderstanding what I am saying.