The 200 Overnighter I recently purchased had a second battery installed by the previous owner. The 1/2/Both switch is wired to the engine so the battery selected starts the engine and receives charging from the alternator. The electrical bus and bilge pump, however, are hardwired to Battery 1. I plan on rewiring the electrical bus to the battery switch eventually, but until I do I'm debating how to manage my batteries. I'm considering running primarily on Battery 1 and using Battery 2 as an emergency backup only. I would run on Battery 2 now and then to keep it charged but primarily run on Battery 1. I'm concerned about running for long periods of time with the radios, etc. running off of Battery 1 while Battery 1 is not being charged by the alternator. It's a stupid way to hook up a battery switch but I've found that when buying a used boat it usually takes 2-3 years to find all of the "stupid" and fix it.