House battery disconnect doesn't seem to disconnect
My new-to-us 2004 MADP 6V batteries weren't behaving very well so I checked them and discovered the prior owner had neglected them--looked dry. Sadly the cables are so tight that I can't get all the caps off to fill the cells, so I disconnected the house batteries with the switch in main electrical panel over the windshield. But...when I started unscrewing one of the positive terminals some arcing and sparking happened so stopped.
When I hit the "store" switch position on the battery switch it and the inverter/charger panel both went dark, so I assumed there was no power to the coach. Any idea why it would be sparking when I started to remove the positive cable?
2004 MADP 4018 "BamBam" FL chassis, Neway IFS
2020 Wrangler Sahara Toad, Roadmaster Nighthawk, AF One