Only one positive and negative connection to the MPP Solar all in one inverter which means if the the BMS (or fuse, circuit breaker, etc.) disconnects the battery the built in MPPT controller is in an open circuit condition and the array goes to Voc. I am going to guess (perhaps someone with an all in one can verify) that disconnecting the battery does not damage the built in MPPT controller, as that is a likely condition at some point.
With an all in one seems unnecessary to have a BMS with seperate charge and discharge disconnects, one is all that is needed.
That all depends- the MPP solar units will cut charging if the detected voltage reaches the pre programmed cut off point. It will also pass the load off to line (or just disconnect load)if the voltage is below the set point. In general, while fuses are good, they technically should serve no purpose as the wire gauge should be able to carry more than the MPPsolar unit can draw or charge at.
The unit however cannot detect when a cell is falling being or getting ahead of any other cell, and it cant manage charge distribution.
You can I think in theory manage that with an active cell balancer.
However if you have more than 1 battery in parallel, the MPPsolar unit doesnt know. It just detects the voltage on the string.
The two batteries would try to balance out , since their parallel. But this balancing is outside the control of the MPPsolar unit.
If battery 1 is at a higher SOC, it will force it to battery 2. How battery 2 processes the power, would depends on if your using a BMS, an active balancer, or nothing at all.
If you use nothing at all, the battery would just take it where it can, just like regular charging. It may go out of balance, it may not, or it may be very little.
If you have a bad cell, or a dying cell, there's no way to know. It will try to push the voltage no matter what. On a 24V battery, it doesn't care if 1 of the 7 cells or 1 of the 8 cells is dying. It will shove it into the rest of the cells, damaging them.
If you had a BMS, it would disconnect due to over voltage to an individual cell.
In short, I'd say the BMS should be programmed to a higher boundary than the MPPsolar- BMSdisconnects should be lower than the MPPsolar setting, and over voltage should be higher than the MPPsolar settings. This would ensure that the only reason a disconnect would happen is if something got out of wack (i.e. dead short cell) .
Will it hurt the MPPTcontroller? That Im not certain. I will tell you that my LV2424 wont' even turn on without a battery at a minimum SOC. (15v?16?) So if the battery disconnects, the unit gets a hard shut off. If you have more than 1 battery in parallel, even if one battery disconnects, the MPPTcontroller will only charge until the voltage of the remaining batteries come up.
The only time this setup becomes problematic is if load demand or charge current exceeds what the remaining batteries's BMS can handle.
The other "gotcha" of this is when you have more than 1 MPPSolar unit in parallel. I haven't had time to setup my second one, so Im not sure what happens.