I finished testing the Battery Hookup 16S 30A Common port LifePo4.
$26 Good Value / High Quality
https://batteryhookup.com/collectio...s-30a-bms-with-balance?variant=42283333648546
Its fine for use
It tolerates abuse
The balancing is excruciatingly slow but that is fine and normal. The LED's will show you that it is doing its work and it does not require >58V to keep balancing. With a grossly imbalanced pack it worked all night without the charger plugged in. I could detect the balance heat but just barely. Very low current, nothing that would overheat it if packed.
[youtube]zTjSoykEOco[/youtube]
It did not stop short circuit but was also not damaged, @ 22awg direct short. I usually do this with 12AWG on a different setup that has a lot of strikes on it. Maybe if I tried this there it too would stop the discharge within 500uS like my higher current BMS's do. For something like a 100A BMS, it really should be able to terminate a short like this and hold it off for a few seconds.
For this little one... it has the current detecting resistors but seems to ignore them. At least in very basic street testing.
[youtube]GP4ERFS6kfA[/youtube]
It did not stop short circuit across anodized aluminum, but it was not damaged. All normal tests passed after the short circuit test and that is what I really care about. You do not want to tap wires together and have your BMS mosfets go short on you. You can tell they have if it suddenly runs hotter than normal in charge or discharge AND/OR it fails to terminate a charge or discharge.
[youtube]OrUoq3mYWvU[/youtube]
It did not stop 1min of discharge at over 60A, but it was not damaged and did not get over 45C. I am somewhat disinterested in further testing as this is a BIG PASS for only $26.
.. pulling up the notes
LVC hit at 2.3V and released at 2.5V
VchargeBlock was at 1.3V, below that it will not charge
In use I did not see much more than 3.7 or 3.75V on any cell while doing other tests
All of the LVC tests tripped
I did not dig hard into HVC (I need to get out my supply) but Charge and Discharge terminate for over temp External and Over Temp Internal. I have every confidence that it would execute on an HVC event.
I am happy with it, moving forward
Application was some 1C 30Ah packs. They are rated to discharge 30-60A and charge at 15A. I have them massively ganged parallel in at least 5P.
My rig can do 200A Charge or Discharge now, so I will probably bump out to at least 10P. This can be problematic a 1, 3, 5 units fall off or lock up. In that event you are now depending on thermal in a lot of ways. Its pretty sketch. Seems like you should just upgauge but that does not work out practically.
* Fuses
Just fuse for your wires and it will be fine. Breakers tend to fail, so simple old fuses rated for at least 60V. I use 10AWG so 30A fuses. Yea they may pop, but that is better than having to characterize every failure mode that may result in 1 or 2 or 3 or 4 units seeing 2X or more continuous charge or discharge.
I... would really prefer a BMS that has programmable limiting... but that costs more than $26... and this is dragging out so long that I am about to go back to running NO bms.
-methods