Chargery BMS16T users? Possible Issue and a few questions...

fstop

Just received mine, which I'm planning to use as part of a leaf 14 module pack.

Connected the BMS to 20v PSU, (but nothing else) and am getting cell voltage readings other than 0.0 volts.

Now maybe it's an odd situation the electrical design never anticipated (no voltage on any of the 14 inputs), but it seems like they all should read 0.

As you can see from the photo, some read 0, but some read as high as .034v, blipping to maybe .036 or so.

Since the accuracy of the voltage readings is pretty key, this is concerning. I guess I should check with some voltage (or better yet, the leaf modules...).

Any thoughts on this behavior?

Also I notice that when I remove the 20v PSU power, all the setup parameters in the BMS are reset - #cells, all of it.

In use I'd be powering it probably from the 57v of the leaf pack, but it would be nice to be able to power down the whole thing w/out having all the memory lost.

Is this normal? If powering by the pack voltage does it retain this info through a power cycle? (there is a physical switch to select pack power or external power - obviously I'm on external).

Thanks for any from those familiar with the Chargery units.

Attached Images

bms showing wrong voltages.jpg (225.6 KB, 0 views)

BGW

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fstop

For some reason I can't edit the above post...

But, I see now that the unit retains the setup upon removal of power - it just keeps coming up with "0 cells" asking for a basic config only because nothing is connected. Connecting a battery I see allows the unit to default to whatever the highest probe wire is, so it looks like it will power on and return to expected operation.

Still a little unsure about voltage accuracy, and if the apparent .01-.035v error on a few cells is enough to worry about. There doesn't seem to be any way to calibrate / correct voltage readings that I can see.

I don't plan on charging to 100% or running down to 20% or below - one reason I'm going with 14 instead of 7 is to be very conservative on cell stress / voltages - so maybe the .035 max error wouldn't be critical.

I just have no idea - and maybe the voltage accuracy for some reason is "off" with this design when there is no voltage anywhere (except what is powering it). I guess if it is somehow more accurate between 3 and 4.2 volts that's really all that would matter...