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JK BMS 4S 200A Crashes - Why?

Tasker

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Joined
Sep 1, 2021
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I have a JK-B2A8S20P-H on a 2P4S battery assembled from CATL 200Ah LiFePo4 cells. Settings as per Andy’s Off Grid Garage video on this BMS. Running for about a month now as the 12V house battery in my motorhome, completely separate from the 24V truck system.

All good - except the BMS randomly crashes when the app is opened.

What do I mean by crash? When opening the app, the BMS does the initial two beeps then tries to reboot. It shuts down the battery and gets into a loop, beeping and rebooting every few seconds - now over 1300 reboots! While in the loop the BMS won’t respond to the app or the on/off button.

Crashes are usually early in the morning with little or no charge from the solar controller and very light loads, battery 70-80% charged, 13.2-13.3V. Cells stay within 0.004mV even with balancing off.

What could possibly be causing this?
Is anyone else experiencing this problem?
 
Hi Steve, thanks for the link.
All the defaults are adjusted to suit my battery type.

Sometimes the app will open while it is looping and I have seen:
“Warning Equil Res too large”, followed by
“Cell count is not equal to settings”

During the crash all the Cell wire resistances show as zero, however when running normally they are all around .08 ohms and when it finally reboots properly, they are back to showing .08 ohms without any physical adjustments.

This seems like a sensing issue rather than a wiring issue - any suggestions for further investigation?
 
Hi Steve, thanks for the link.
All the defaults are adjusted to suit my battery type.

Sometimes the app will open while it is looping and I have seen:
“Warning Equil Res too large”, followed by
“Cell count is not equal to settings”

During the crash all the Cell wire resistances show as zero, however when running normally they are all around .08 ohms and when it finally reboots properly, they are back to showing .08 ohms without any physical adjustments.

This seems like a sensing issue rather than a wiring issue - any suggestions for further investigation?
Just to confirm, I have already updated to the latest Android and IOS apps and the BMS has crashed with both of them.
 
The wiring and being finicky is NOT an understatement. Recheck all wires, right order or "poofdah".

Their QC is very good,. Doa's are extremely rare.

Defaults per new manual !!!!

Check this out too. In case I forgot to post it before.
 
Wow, great job on the manual Steve!

Somehow I managed to download V1.0 yesterday, noticed your link said V2.2 so tried again and got the updated version.

I’ll go through the settings and notes and ensure that mine are correct.

Pleased that you’re having success with the BMS and really appreciate your efforts to help
 
Wow, great job on the manual Steve!

Somehow I managed to download V1.0 yesterday, noticed your link said V2.2 so tried again and got the updated version.

I’ll go through the settings and notes and ensure that mine are correct.

Pleased that you’re having success with the BMS and really appreciate your efforts to help
I've been trying to make things easier & better for those getting into this adventure for some time. A legacy that I hope lasts for some time.

Hope it all helps, good luck.
Steve
 
Slightly odd differences in the app Control screens.

Android V4.8.0

I have seen both of the screens below and managed a factory reset and data delete but I no longer have these options.

Did a full uninstall and cache clean yesterday, then fresh down load and install but the options did not return.

What are others seeing with V4.8.0?
 

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The UI code is being redone and cleaned up ATM. More is being done. It's taking some time to get done.

Fyi. I DO NOT HAVE ANY association with Hankzor, NEEY nor JiKong whatsoever. I'm just a member who documents to help. A Geezer here lol.

Also I'm just out of critical care in hospital and using a new unfamiliar phone which is foreign to me. I'm a hardcore PC guy.
.
 
Ha - I’m rapidly approaching geezerness myself.

It’s great to have access to people who have practical experience without product affiliation.

Hope you are doing well and manage to get back to your PC soon.
 
I had the beeping problem the BMS being on boot loop. It appeared immediately when I started the app on 30th september to have a look on the BMS status. I disconnected the BMS to restart but nothing changed and the app wasn't able to connect. I pushed the power long time (20s ?) and when I let it come back, I discovered that was getting off the BMS. Trying to connect the app multiple times, It same some times randomly but wasn't able to act on the BMS.
Finally, a had a look about the app on PlayStore and I saw that it was a new version published the 14th september. So I got an older APK version ( the 4.8.5) from here : https://www.pgyer.com/Cfq3. And it worked. I had other boot loop when I tried to change settings. I uninstalled the app and reinstalled it, maybe 3 times, and finally It's now working normally.

When I tried to reinstall the last app version (the 4.9.1) and launched it I got immediately the crazy beeping of the boot loop. So as I never had problems before, no special use of the battery, and it possible I didn't launch the app since it was updated the 14th september, I suspected that the problem was coming from the 4.9.1 version of the app. But it looks like others have the problem with older version ...
 
I'm just looking into BMS's for new battery pack and to replace the Chargery in the previous. So far I have been leaning towards JK but seems like there will be something with any of them you go with! I've been away from here for too long lol. So much changes in a short period of time.
 
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