Battery backup (UPS) for computer while on house batteries?

OP, when I first started RV'ing, I had a bunch of UPS. So I used then for small inverter loads. Worked good wired into the house batteries. However going down some of the road was a little hard on them. Hit a few bumps in the road that would drop out the UPS system that was feeding my computer based GPS system. The other problem I ran into with the new UPS I started using did not like it when the batteries were on a high charge.