I never knew, either. It was just 'there'...
I think the battery bank was an afterthought by the PO. AGM batteries are heat sensitive and I wouldn't have put them so near the engine. There is room in the locker where the other bank resides. I always planned on reworking the locker to hold both banks but, like so many other projects, it just didn't get done.
Sven, I have the circuit board that goes in the autopilot. If you want to install it, I can mail it up to your home address. There is about a 1% chance that the autopilot will rejuvenate itself - worth a try. It mounts just below the two circuit boards at the top of the unit. There is a small screw that ties the boards together. I left it in place so I wouldn't lose it. Anyway...
Sorry for the lousy weather down here. I did get out for a sail with my brother-in-law today - on his Catalina 30. We hit 7.2 knots


in that thing. We were screaming along and being tossed up and down and sideways - like being in a salad spinner. I kept thinking about Serendipity. She would have been trucking through that slop like the Polar Express.
On a sadder note, I think my b-in-l is nearing the end of his sailing days. He kept getting confused as to which strings to untie each time we tacked. I had to remind him gently and if we hadn't been thrashing around and laughing so much, I would have been near tears. When we made it into the sip, I had to untangle all the halyards. They were fairly crossed up - tangled, I should say - and he had no clue what I was doing. He's only 58. All you Ericson fans out there, grab the ones you love and hang on for the ride. Sometimes the ride doesn't last very long.
Take care...