Sorry for not responding sooner. The output from the TV seems to be good,. The problem seems to be in the trailer wiring. There is no change in battery voltage when plugged in or unplugged, motor running or not. I do get a slight increase when plugged into shore power. Don't have a digital meter so it's hard to tell exactly,but meter reads just under 13 v when not on SP, and around14 when on SP. Unplugging from SP yields no change when plugged into TV motor on or off; just under 13. Did have one cell that was a little low, but still covering the plates. Thx again for all the great ideas.