If your plan to use your 10 for IFR and it is all electric, then you should consider 2 batteries. Set up 2 electrical systems using a standby alternator as primary on the second circuit and install a cross-tie between them. This gives you great redundancy. It is in Nuckolls book.
The 10 uses a lot of current with everything being electric. The best value in having 2 batteries is the ability to keep going if you have a hard start and run down your battery. Close the cross-tie and you have more cranking amps. It has saved me a couple times.
I have the exact setup described above. It is known as a "Z-14" in Bob Nuckolls Aeroelectric forum. It is a well evolved design that you are invited to copy as I did. I use a B&C 40amp and the B&C standby with 2 regulators. SOP is to start with both batteries and busses linked, then to run with them unlinked for the rest of the flight. That way any sudden or slow motion failure like an alternator or battery can be detected, isolated and bypassed as needed.
I file and fly IFR almost exclusively and feel pretty much bullet proof with a 2 alternator, dual battery, dual bus installation though I do run 2 old school mags.
Actually, if you read Nuckolls' postings of the past year or 2, he seems to be leaning towards 2 alternators and 1 well-maintained battery.
That's true. He thinks his Z-14 is overkill in most applications.
I had a very specific desire to be able to run my (3) EFIS panel for extended periods on the ground before engine start without having to worry about having enough juice to start the engine when desired. The Z-14 lets me do that without concern.
I was surprised by just how much juice a fully electric, (3) EFIS panel needs and just how fast it will run a battery down below what is required for a say a cold engine, cold weather start. The light weight start shipped with my IO-540 doesn't help the situation either. What I thought was going to be a convenience that I would occasionally take advantage of turned out to be a necessity for my normal flying.
I also found that the EFISs and the G430 did not deal with the sag in power when the engine starts and that it often resulted in these units re-booting. An inconvenience at best requiring re-entry of flight plans, damaging at worse on early software versions of my EFIS that didn't respond well to being interrupted during its IPL. I added TCW's Intelligent Power Stabilizer to prevent re-boots during start.
What's the benefit of two batteries over one larger battery of the equivalent size?
Benefit 1: You can use and run down one battery while preserving the other for engine starts
Benefit 2: If you don't maintain your battery well or let it run until a cell starts to fail, you won't get stuck on some remote ramp. You have a backup.
I run (2) Odyssey 680s.