bluetooth BMS?

[SilverLine]

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.

Thank you very much ....

Very good explanation. The BMS shows the charge output in the app, and i noticed that when close to 4,2v pr cell, the current drops.

 

[serious_sam]

Thank you very much ....

No problem.

The BMS shows the charge output in the app, and i noticed that when close to 4,2v pr cell, the current drops.

I see the same thing also. The measured voltage at that point will be 4.2V per cell. That's what we'll see on the app.

The actual cell voltage will be just *slightly* below that. For example, I have a 20S5P pack of Sony VTC6. Total pack resistance is approx 0.1 ohms (varies with state of charge and temp, but 0.1 ohms is a good approximate). My charger is similar to yours, but 4A.

4A x 0.1ohms = 0.4V (so at 4A charge current, the difference between the charger voltage and pack voltage is always approx 0.4V)

So the current will start to drop when the charger voltage hits 84V, and at that point the pack voltage is 84-0.4=83.6V.

So if you disconnect the charger at that point, and give the pack a minute to rest, then remeasure the pack, it will be at approx 83.6V.

That's why it's often not worth continuing to charge once the current starts to drop. The pack is basically charged at that point.

 

[Fionn]

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.

Thanks for the help.
I tried it with GPS enabled & disabled, it makes no difference.
A single tap is sufficient but it can take up to 4/5 seconds to change back to the lock symbol on my phone.

 

[st35326]

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 ?

You're overthinking it. When I scroll through my peak measurement in the CA from my ride Im seeing 160 amps and peaks between 10-12kW. Those are peak measurements being drawn from the pack I built.

 

[serious_sam]

A single tap is sufficient but it can take up to 4/5 seconds to change back to the lock symbol on my phone.

Yeah, it can be a bit annoying. My expectations are set low for that app, so I'm usually not disappointed by it too much.

 

[thundercamel]

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.

This is interesting to me, because since updating to the newer version which allows access to more of the parameters, I HAVE to enable GPS for the app to even list any devices on the bluetooth screen. I even have Privacy Guard as a second layer of permissions, and the new version of Xiaoxiang somehow toggles the "allow fine location" setting in Privacy Guard! Sure seems like blatant data collection for China.

I'm thinking about forgoing access to the extra parameters (without the laptop) for the privacy I should be entitled to for a friggin smart BMS...

 

[eee291]

Just go to App settings and disable the "GPS open" toggle switch :wink:

 

[Miwer]

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 ....

Hi Marco - take a look at this thread for more information about lithiumbatterypcb.com (LLT). Might be useful to you also.
https://endless-sphere.com/forums/viewtopic.php?f=46&t=105566

Br,
Miwer

 

[Fionn]

I'm pretty convinced that the release settings for overvoltage protection have no effect.
The time limit defines how long the threshold has to be exceeded before the corresponding FET bank is opened.
For example if using OVP to protect from overcharging, the charge continues until the voltage exceeds the threshold voltage for the set number of seconds.
The charge FETs open but then immediately close again & the timer restarts.
This means the pack voltage continues to climb and over voltage protection is not really functional.

 

[john61ct]

That BMS is faulty then.

Link to source?

Do you think a QA error, or bad design all of that model the same?

 

[thundercamel]

Just go to App settings and disable the "GPS open" toggle switch :wink:

Just checked, and "GPS open" was already disabled. Tried enabling it, and don't see any change in behavior. My phone still needs GPS on to have any devices show up on the refresh list. Xiaoxiang V3.1.1013

 

[serious_sam]

My phone still needs GPS on to have any devices show up on the refresh list. Xiaoxiang V3.1.1013

So, I just tried that version of the app with gps enabled on the phone, and it worked. So all this time it was just not working because I had gps disabled.

 

[Hertzelz]

Hi,
Has anyone tried the IC GOGOGO bms's?

https://a.aliexpress.com/_dTt09Be

I tried to get ahold of the LLT 200A bluetooth BMS but their Aliexpress store doesnt have them and the seller isnt responsive at all, So I ran into those new IC GOGOGO Bluetooth bms's that have 2A balancing current which will be good for my 20s1p battery (72v60ah).

Has anyone tried them? How's their app?

 

[eee291]

This one is not from LTT, it's from a company called Chengdu Jikong technology...
link to the App and Documentation: https://active.clewm.net/BApbC0?qrurl=http://qr17.cn/BApbC0&gtype=1&key=02e1c15f1854bb29a8730158783b63a5c04b43d237

 

[Hertzelz]

This one is not from LTT, it's from a company called Chengdu Jikong technology...
link to the App and Documentation: https://active.clewm.net/BApbC0?qrurl=http://qr17.cn/BApbC0&gtype=1&key=02e1c15f1854bb29a8730158783b63a5c04b43d237

I know it's not from LLT,
I said i tried to get a 200A bluetooth bms from LLT but they're not selling it on aliexpress and the contacts on their website isn't responding, so I asked about that BMS as alternative..

 

[eee291]

My bad I don't think LTT even has a 200A BMS in the first place.
I have a modded one that can probably do 200A, I didn't end up using it, the cells behaved so well I'm just relying on the Controller shutoff.

BTW I have the 2A version of that other BMS, you can't really call it a BMS since it only balances the cells.
I tried balancing some 50Ah lifepo4 cells with a set accuracy of 0.07V and it did get close to it but it would never finish, it would just keep draining the highest cell until it became the lowest one and the cycle would just repeat.

I guess you could set the value higher especially for lifepo4, but I decided to just turn it off after a night of balancing.

 

[Hertzelz]

My bad I don't think LTT even has a 200A BMS in the first place.
I have a modded one that can probably do 200A, I didn't end up using it, the cells behaved so well I'm just relying on the Controller shutoff.

BTW I have the 2A version of that other BMS, you can't really call it a BMS since it only balances the cells.
I tried balancing some 50Ah lifepo4 cells with a set accuracy of 0.07V and it did get close to it but it would never finish, it would just keep draining the highest cell until it became the lowest one and the cycle would just repeat.

I guess you could set the value higher especially for lifepo4, but I decided to just turn it off after a night of balancing.

Here's LTT's 200A without bluetooth:
https://a.aliexpress.com/_dYP3rcg

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?

 

[john61ct]

I thought there are lots of sellers of the "Xiaoxiang / yellow elephant" type, either the exact same units

JBD Battery PCB Board Store
Jiabaida Technology
Dongguan Jiabaida Electronic Technology Co., Ltd.
LLT Power
SHEN ZHEN LI LU TONG ELECTONIC TECHNOLOGY
SZLLT
BotoXbz?

or very similar

RJXZS?

Does EM3EV sell his separate from battery packs?

Then you have the Ant type, highly recommended by many here.

Personally I would use the lower-amp version in voltage mode only, FETs controlling robust external contactors rated for those high currents.

 

[penny]

With the “Ant BMS”, is there a way to reset the SoC back to 100% after a full battery charge?

Sometimes it resets by itself, sometimes not.
Have been scratching my head over this..

 

[j bjork]

Does anyone know what temp sensors the ant bms uses, and is it possible to change to other sensors?
I already have temp sensors in my pack, and would like to seal it. The bms seems to take its time to get here..

 

[larsb]

My app is on a burnt out phone unfortunately, cannot check. I think you can install the app and check for temp calibration. I think there is, then you’d likely get a variety of sensors to work.

Otherwise pm me your adress and i’ll send some ant sensors so you can get moving

 

[tmho]

I have the ANT BMS. I have no problem in using the Android App.

But when I try to use the app for iphone (downloaded from App Store), it just keeps on scanning (as shown in the attached photo) and cannot connect to the BMS. Could somebody kindly help me on this?

 

[thundercamel]

My phone still needs GPS on to have any devices show up on the refresh list. Xiaoxiang V3.1.1013

So, I just tried that version of the app with gps enabled on the phone, and it worked. So all this time it was just not working because I had gps disabled.

I guess it's good to know this behavior exists for other people too... BS, isn't it?

 

[tmho]

I guess the above post from thundercamel is for me. If I am wrong, then sorry, English is just my second language.

I just checked my gps setting. Under Settings, Privacy, Location Services, I could not find the "ANT BMS" so as to enable to use gps. Will it because of my iphone is too old (iphone 6)?

 

[thundercamel]

Sorry tmho, I was just responding to serious sam. We're using JBD brand units, and I haven't tried an ANT one yet. It wouldn't surprise me if there was some similar "accessibility" requirements with the ANT software though, as in accessible data to mine for China. You're sure the ANT BMS is all connected and powered up with the bluetooth module?