diy solar

diy solar

Heltec (JK) 200A Smart BMS with 2A Active Balance

Interesting. Your software is VERY dated. I have 9.0 on my old phone and this one is Android 11. I think we found your issue. Its your device.
But it says it's up to date ? How do i update it,,, I only had it maybe 3-4 yrs now..
 
Android v8.1.0

That's API level 27 (Oreo iirc) - last version of that was released at the end of 2017.
Normally this could explain the issue, but I'm running the app on an Android 8.0 device without issues. That said, I'm using a much older version of the app... Let me see if I can get that one for you to try.
 
You don't - there are no updates for that OS anymore. At most, the phone manufacturer will push security updates.
Ughhhh... That sux...
OK,, well, I'll try to do it on my friends phone later on this weekend...
I guess you just can't get 5 yrs out of a device anymore..lol
 
Ok, Good news finally...
I got bit n pieces and confusion in order now..
there is a step more to make it take the edit... I'll try to explain m and make another video if need be..
ok,, so, log in to the bms.. click the pen to edit the name.. type the name you want, in my case (BMS1) then, you should see, suggested names above the numbers on the KB..if its not there, just hit the space bar,, then tap the word you typed.. then it should be in the bar with suggested names it remembers, tap that,,, then hit OK..
NOW IT ACCEPTS... EUREKA.
By the way it works with both apps i have, the Heltec app and the JK app..
Thanks to everyone that has patience with me...
Screenshot_20211012-193124.jpg
 
ok,, so, log in to the bms.. click the pen to edit the name.. type the name you want, in my case (BMS1) then, you should see, suggested names above the numbers on the KB..if its not there, just hit the space bar,, then tap the word you typed.. then it should be in the bar with suggested names it remembers, tap that,,, then hit OK..

So it seems that the text you type in in the text field is not accepted due to a missing return or something.
In any case - happy it works!
 
It's normal that it jitters a bit, but shouldn't jump all over the place. You can try to calibrate it in the settings of the app - see if that makes a difference.

Not sure what you mean by calibrate.. calibrate which parameter? I have two of these units, JK-B1A20S15P, and they both behave exactly the same way, using the JK BMS app on iOS, and the Enjpower app in Android (makes sense, since the jitter is triggering stuff like overcurrent/undervoltage, so it isn't due to the apps).

Here's a short clip of the jitter in action:


Note how the amps and Battery Power wander all over the place, even though my external ammeter shows that the current is rock steady.
 
Not sure what you mean by calibrate.. calibrate which parameter? I have two of these units, JK-B1A20S15P, and they both behave exactly the same way, using the JK BMS app on iOS, and the Enjpower app in Android (makes sense, since the jitter is triggering stuff like overcurrent/undervoltage, so it isn't due to the apps).

Here's a short clip of the jitter in action:


Note how the amps and Battery Power wander all over the place, even though my external ammeter shows that the current is rock steady.
Thats a lot of bouncing, especially the cell values. My cell values are stable except the normal selection of highest and lowest while balancing. Turn off balance to see if that makes a difference. I tried to upload a vid of mine, but this site does not like Mpegs.
By the way, your clip says JBD. Mine are Heltec/JK.
 
Ah, during a discharge. Yes, that's normal since the load (an inverter I assume?) is not constant. Your meter probably averages over longer periods.

The vid clip is of charging. It also does it while discharging. So yours wanders similarly? I just want to make sure this is normal behavior. Thanks.
 
Thats a lot of bouncing, especially the cell values. My cell values are stable except the normal selection of highest and lowest while balancing. Turn off balance to see if that makes a difference. I tried to upload a vid of mine, but this site does not like Mpegs.
By the way, your clip says JBD. Mine are Heltec/JK.

Oops, I'll change the name of the clip, yes, it's JK-B1A20S15P
 
Looking at the video again after @Sanwizard comment - agreed, there is more jitter that I would expect on the cells.



But your current is negative. Are you sure it's all connected correctly? Charging definitely should give a positive current in the app.
Sorry, my bad. I took a few vids yesterday. you're right, the one I uploaded was discharge, but charging is similar. I'll check again later today see if it's actually a bit less on charging.
 
Sorry, my bad. I took a few vids yesterday. you're right, the one I uploaded was discharge, but charging is similar. I'll check again later today see if it's actually a bit less on charging.

Double check all connections. The only time I would see that much jitter on my cells is when I was doing tests and the connections (cell, balance leads, main leads, etc.) weren't good. If you can, and you're charging/discharging at these currents, see if you can find any hot spots.
 
Double check all connections. The only time I would see that much jitter on my cells is when I was doing tests and the connections (cell, balance leads, main leads, etc.) weren't good. If you can, and you're charging/discharging at these currents, see if you can find any hot spots.
I Agree with this. Also, what version are you using. Mine is 3.0
 
Pure sine wave inverters, and power factor corrected chargers all have a lot of ripple current on the DC side. The current ramps in a half sine wave from zero up to maximum and back to zero, every half a cycle of the AC side. Many meters have a low pass filter built in to average out line frequency ripple. The JK-BMS clearly does not filter it. I se it on my current reading. It can bounce a couple amps as it samples either near the peak or near the zero. It really should average a few cycles and smooth it out, but that would take more memory and programming.

But in this case, the voltage is also bouncing quite a lot. On mine, the voltage on each cell bounces at most 2 mv (0.002 volts) from the current ripple. Are all of your cells showing a lot of ripple, or is it just some of them? The total voltage on the JK BMS is actually all of the cell voltages added up, so any ripple per cell is added as well. But they are not sampled at the same time. So some cells may get a sample a the peak while another is sampled at the zero, and yet another samples right in the middle. So there is a small averaging effect on the total voltage. If you do notice it is moving more on some cells, I would certainly double check those connections. A poor buss bar connection between cells could cause those cells to have far more ripple.

Another odd issue I ran into on mine is when I use my 48 to 12 volt buck converter. I installed it in my battery bank so I have a 12 volt 30 amp output available to run any accessories. When I turn it on, I see the balancer jump into action on a few cells. It turns out, the switching noise from the cheapo buck converter is causing some of the balance leads to pick up the noise and show it as too high or too low of voltage, so it tries to balance them. I tried adding filter capacitors, but it made no difference. I think the balance leads are picking up the radiated electrical noise in the air. I want to try taking the buck converter out of the cabinet with the BMS, but it is not a simple job with how I built it. I have thought about adding small film capacitors at the BMS balance lead plug, but 14 little caps is a pain to fit there.
 
Thats a lot of bouncing, especially the cell values. My cell values are stable except the normal selection of highest and lowest while balancing. Turn off balance to see if that makes a difference. I tried to upload a vid of mine, but this site does not like Mpegs.
By the way, your clip says JBD. Mine are Heltec/JK.

Yes, it's still wanders when the balance is off.

Oh, another question, does yours run really hot? Mine is rated at 150A continuous, 300A surge. I was pulling ~40A last night, and the MOS temperature was around 71C, which is well below the 90C default cut off in the app, but the thing was so hot, I couldn't even touch it for more than a second.
 
Back
Top