When I was looking at switches Eaton tech recommended DH221NGK rated to switch 250 volts DC and 30 amps. I have about 100 volts 8 amps.
try Google shopping "DH221NGK" for best price. It is a bit bulky and only rated NEMA 1 for indoors.
I am actually using
DP221NGB but it is not rated for DC current. It does arc a bit during disconnect but seems to extinguish the spark OK and it is in a metal box. I think it helps to cut both sides together which actually doubles the gap the power must jump.
OP is only about 30 vdc so not such a big deal.
You Tube video on switching 220 vac vs 220 vdc