Effect on LiFePO4 battery stability when wired in series

[Ocracoke]

Hi Everyone!

I've received a pair of 2SP1 30C LiFePO4 batteries for The Honey Badger. A single battery pack is 6.6v so the drive motor spins slower than that in the 12v 1.2ah SLA battery that was previously connected to the motor (the robot did have 1 battery per motor).

Would tying up the battery packs in series (to make 13.2v) be an issue for the stability of the cells in the packs at all (assuming they are charged at the same time)? My plan was to tie the two packs together to get to 13.2v so the motor spins at a similar rotational speed to the SLA batteries and then split the circuit after the removable link before a pair of fuses.