@ JamieC, you answered to Crissa that DC charging is not possible because the battery is only 100V, but that's exactly what he addressed in his post above:) he said a set of contactors would be needed to change the arrangement of the cells to achieve higher voltage. Zero batteries are 28S4P, (28 series 4 parallel, so in total 112 cells). With contactors it could be changed to 56S2P for example, or even 112S1P, giving 400V.
Not practical of course;) but possible