BMS with built-in relay?

justgary · Jun 11, 2022

Idle current measurements in 16S LFP setup: The BMS draws ~45 mA (~2.4W) awake, but with no current on the battery. After about a day with no current on the battery, the BMS will drop the relay (you hear it click) and switch to a draw of about 9 mA (~0.5W). The battery still measures full voltage, so the BMS must also use a FET to provide voltage and sense a load. After a few more days with no load on the battery, the BMS will go to sleep. All the LEDs are dark, the BMS is drawing about 0.9 mA (~50mW), yet the battery still measures full voltage.

Applying a load to the battery (I used a 100W light bulb) causes the BMS to instantly wake up and set the relay. The LEDs are then flashing again. The process will repeat if you leave it without a load again.

Note here that "battery" means the series cells plus the BMS in functional configuration.

Swing · Jun 11, 2022

Well described. Yes there as an extra wire that bypasses the relay, that measures of there is charging applied or power being drawn.
I think it is this behavior that caused me problems when starting again, with them paralleled.

Edit: In the JBD functions menu, there is a "load check" function that you can disable. To influence this behavior.

But you have a much more controlled situations, and more time than I had.

However, economically, wanting to charge my hours to the customer, I think it was a mistakr to go for this BMS. A more expensive centralized BMS costs way less time.

Saxonetter · Sep 9, 2022

Hallo, habe so ein Jbd bms als 16s verdrahtet. An dem Relais liegen nur etwas über 26 Volt an? Es müssten doch über 52 volt Anliegen? Weiß nicht wie ich das Ding starte. Geht das nur wenn Ladestrom fließt? Die bluetoothverbindung klappt auch nicht. Die unterste Aluplatte vom bms Board wird etwas warm

Saxonetter · Sep 9, 2022

Saxonetter said:
Hallo, habe so ein Jbd bms als 16s verdrahtet. An dem Relais liegen nur etwas über 26 Volt an? Es müssten doch über 52 Volt anliegen? Weiß nicht wie ich das Ding starte. Geht das nur wenn Ladestrom fließt? Die Bluetoothverbindung klappt auch nicht. Die unterste Aluplatte vom bms Board wird etwas warm

woran erkennt man überhaupt, dass das Teil gestartet ist, die Spannung an den eigentlichen Batteriepolen liegt z.bzt. bei 52,8 volt

Swing · Sep 9, 2022

@Saxonetter: Better to reply in English.

I think the voltage around 26v is to sense if there is a load or not.
You will need to get Bluetooth app to work, to get further.

justgary · Sep 9, 2022

Saxonetter said:
Hallo, habe so ein Jbd bms als 16s verdrahtet. An dem Relais liegen nur etwas über 26 Volt an? Es müssten doch über 52 volt Anliegen? Weiß nicht wie ich das Ding starte. Geht das nur wenn Ladestrom fließt? Die bluetoothverbindung klappt auch nicht. Die unterste Aluplatte vom bms Board wird etwas warm

Überprüfen Sie Ihre Verkabelung, um sicherzustellen, dass alle Sensordrähte richtig angeschlossen sind.

And I agree that it is much better to reply in English. Google Translate is your pal.

Faiz Rajpoot · 2024-07-15T23:19:24-0700

justgary said:
Idle current measurements in 16S LFP setup: The BMS draws ~45 mA (~2.4W) awake, but with no current on the battery. After about a day with no current on the battery, the BMS will drop the relay (you hear it click) and switch to a draw of about 9 mA (~0.5W). The battery still measures full voltage, so the BMS must also use a FET to provide voltage and sense a load. After a few more days with no load on the battery, the BMS will go to sleep. All the LEDs are dark, the BMS is drawing about 0.9 mA (~50mW), yet the battery still measures full voltage.

Applying a load to the battery (I used a 100W light bulb) causes the BMS to instantly wake up and set the relay. The LEDs are then flashing again. The process will repeat if you leave it without a load again

Note here that "battery" means the series cells plus the BMS in functional Sure, here's the text translated into English:

justgary said:
Any one help me The BMS with 2 MOSFETs on each side can be used on a 3S battery, but the BMS with MOSFETs in a single line does not work on a 3S battery and only works on a 10S battery. Please tell me how I can use this BMS on a 3S battery ."

Faiz Rajpoot · 2024-07-15T23:20:59-0700

Hi friends.

MullerEnergy-Australia said:
I just came across this BMS (I'm not affiliated) that seems to have a somewhat reasonable balancing current, as well as something that looks like a built-in relay. I don't have any experience with this type of BMS at all, but it looks like a pretty good solution to me. Has anyone used this one or one like it?

Unfortunately there's very little info in the listing.

View attachment 42545

Hi friends kindly help me. My question is that

"The BMS with 2 MOSFETs on each side can be used on a 3S battery, but the BMS with MOSFETs in a single line does not work on a 3S battery and only works on a 10S battery. Please tell me how I can use this BMS on a 3S battery."

BMS with built-in relay?

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