Question about: ANT BMS

I just noticed that my ANT BMS is still giving (leaking?) some voltage (and low milliamps) out when turned off!
Anyone here with an ANT BMS who can check if it’s doing the same?

But all bms do the same, no? As I understood you should have some cut-off switch on bms

The BMS has an on / off switch (pulse)

When I give it a short push (pulse) it turns on, and the BMS is turned on, LED’s and Bluetooth turn on, and I have +50 volts on the output.

When I give a long push (about 6 seconds) the BMS turns off, LED’s and Bluetooth turn off on the BMS.

When I measure the voltage on the output I still get some volts.
I thought that it was some capacitors holding voltage, however I can power a external LED on it, and it stays on. Even after one day of not turning the BMS on.

The FETs in the BMS are likely to be leaking, every FET does it to some level. Some manufacturers / designers put a resistive load on the output that overrules the leakage current and make the output as close to 0V as possible. But if the designer of the BMS didn’t make this a priority it is probably omitted, then you can do it yourself. Depending on the leakage you could experiment with like 10kOhms over the output.

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I see. I’m going to give this a try.
Thank you.

It’s the same for me with the ICGOGOGO antBMS, switched off I have 13 volts output.

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Thank you for the update.

The problem is normal on a battery not connected to a load ( ESC / UBEC …) as soon as you connect a load to the output of your battery the voltage drops to 0 volts.
This is a residual voltage.

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Thank you for the update.
Problem was (for me) that I had a LED as indicator that the battery (BMS) was on/off.
The “leaking” voltage was causing the LED to be still burning (more like glowing) when the BMS was in off position.


Hi! I’m thinking of purchasing an ANT BMS for charging and discharging. What is the controller? Is it necessary?

Controller = ESC
20 characters.

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