I wonder how hard the learning curve was to get it all set up and dialed in? Any comments you care to share about that piece? Look like allot of good details to monitor and adjust that are making more sense to me as consider my investment in a 8 or 16 piece 24v 280 Ah or 560 Ah LifePO4 set . Looking to learn more about my BMS options here. Thanks for sharing ;+) Bill
Being a little bit OCD helps/hurts in this matter.
Sooooo... here goes.
New batteries from the same supplier and the same lot, 99.999% chance will
never have an issue that the BMS will have to step in and shut everything down.
There are
basically two ways to make a LiFePO4 battery fail.
Charging too hard when the cells are cold. (Yes you can charge below 0°C, but only do so very slowly.
And Overcharging the cells.
As soon as one or the other happens, the cells are irreversibly damaged. It is nothing at all like lead-acid batteries where you can
equalize them. The ion exchange changes what you have inside the battery, and that cannot be undone.
You can do two things to keep this damage from happening.
One, don't overcharge the cells. Simple enough, just never charge more than 3.65V per cell. It is really that simple.
Two, don't charge when the battery cells are less than 1°C. Yuuup, it's that simple also.
Use the battery as storage energy centers and not motor starters and it will be very hard to over amp them also.
I modern decent inverter has cutoff limits that can be set and will for the most part work plenty good enough, without a BMS.
A BMS can really only actually do just three things. Monitor/display the voltage and temperature of the cells and open the electrical circuit.
So if you have new cells all made at the same time with the same materials from the same production line, 99.999% of the time these cells are going to all behave the same way, all the time. They will have the same Internal Resistance, so they will be able to charge and discharge at the same rate.
So, if you have used old abused cells, the likely hood of having matching cells is pretty slim. So the BMS can step in and interrupt catastrophic damage much sooner than a simple Inverter/Charger is capable of. One cell in a series of 16 and have extremely low IR and discharge 10 times faster than the rest of the cells, and if that one cell dive bombs less than 2.0V that entire battery is done, this is where the BMS would step in and stop the discharge. The same can be said the opposite direction when charging. If you charge more than 4.2V you can have a volcano.
The Charger only sees the entire battery, which is the average of all the cells. The BMS monitors each cell and will save the battery, but severely limits the entire usable capacity. The limit from the BMS is a good thing though because 50% usable battery is still far more than 0%!