Chinese BMS arrived not fully populated?

[spaceship]

I ordered a Reenetion Polly battery case and BMS for a diy battery build. I just received everything and on inspeciting the 13s BMS they provided with it I notice that a number of components are not populated on the board I received, but the picture of what I was supposed to receive shows the board fully populated with components in this seciton. It appears to be a couple small ic, diode, electrolytic capacitor, some transisitors, and a large 220 ohm resistor. Is this something I should be concerned about?

Would anyone have any ideas as to what function those components would perfrom? Would it say not have under/over Voltage protection?

I have contacted the seller and have yet to hear back but am worried that they might feed me some lines on this. should I not worry about it and just build the battery?




Heres some pics of another version from a different seller that is 20A 10s

 

[amberwolf]

It could be for a number of things, including a power supply that runs the BMS off the whole battery instead of just one or two cell groups, or it could be a thermal detection/cutoff, or a 5v output for a usb port, or programming I/O port, etc. If I spent a while I could probably think of other things it could be...but not knowing what the parts are supposed to be, specifically, it's tough to say what it actually is supposed to do.

If you can get a pic of the parts in that area that shows the numbers on the chips, we might be able to give a better guess what it is for.

 

[E-HP]

Hard to see what's under the yellow component, but it looks like the USB out port is also missing. A common type of 8 pin chip is used for DC-DC stepdown to output 5V via USB. A common use of electrolytic capacitors is signal filtering on the input or output circuit. 63V seems like it could be input voltage filtering to the DC-DC step down, if in fact, the USB port is missing.


Just guessing; chip or component numbers would be helpful.

 

[spaceship]

Hard to see what's under the yellow component, but it looks like the USB out port is also missing. A common type of 8 pin chip is used for DC-DC stepdown to output 5V via USB. A common use of electrolytic capacitors is signal filtering on the input or output circuit. 63V seems like it could be input voltage filtering to the DC-DC step down, if in fact, the USB port is missing.

That is a pretty good guess. Since this case doesnt have any usb port a version of the board with stepdown circuit/usb port omitted makes sense. Thanks,

 

[4πr^2]

Fairly common for manufacturers to do that.... they will make one board, then depending on what options you get... bluetooth, USB, UART, CANBUS, battery voltage / series cells, etc - depends on what components get populated on the board, and to some extent, what firmware gets installed on any microprocessors.

I would say as long as it works as expected and all the features you expected are preset, then you got the right board.