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diy solar

Overkill / Jiabaida / JBD BMS faulty high temp cut off behavior

kiaora_

New Member
Joined
Nov 4, 2021
Messages
4
Hello,

Following the build of a 4S 160Ah battery with a JBD 200A BMS, I wanted to perform some tests on the safety triggers.

It seems to me that these BMS are reputed to be rather reliable and well designed but I noticed a strange behavior of the BMS for everything that is triggering the stops of charge or discharge following a high or low temperature:

This BMS is equipped with 3 temperature sensors, 1 internal, and 2 external that you can choose to activate or not in the BMS software.

- When all the sensors are activated in the software and one is physically disconnected, the BMS interprets this as a temperature of -30°C on the disconnected sensor, in theory this should turn off both the charge and discharge but it doesn't.

- In the same way, with all the probes connected, when I heat an external probe with a heat gun to above the BMS high temperature trigger values, it doesn't cut the discharge MOSFETs.
If on the other hand, only one probe is activated in the software, and I heat the probe up to the trigger value, then the load output is disabled.

I don't find this behavior very safe, I would prefer that when only one probe crosses the triggering threshold, then the charge or discharge is cut off.

Have you ever noticed similar behavior on your BMS? Especially on the 120A version which seems to be widely used here.

Thanks
 
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