24 v battery with different amps hrs.

[AST]

Hi
I always get good answers here. Thanks in advance.
I m getting a 450 watt solar panel from a freind and already have renogy rover 20amp mppt controller. And already have one 100amp hr battery and one 50 amp hrs battery. Both batteries are LI (different brand).
I m thinking of connecting the 2 batteries in series to make 24 v system and use my 20 amp controller to charge them simultaneously.
Any issues with that?

If one of the batteries was at 25% charge and the other is 90 % charged what happens when I charge the simultaneously (in series).
Thanks

[smac999]

You can’t put different batteries in series.

When same batteries are put in series you must charge them equally first before you install them.