Some comments:
* Send the alternator to the house bank. That is the one that will need the charge, so send it there first (instead of having it go through the ACR). It will also minimize ACR cycling.
* FUSES! There should only be one wire on a battery positive (OK, 2 if you are parallelling them as you show). Come off the battery, into a fuse, and then on to the ACR, 1/2/B, etc. This reduces risk of fire from overload, and also reduces confusion when removing and replacing a battery.
* Your bilge pump right off the battery is good, but it's only the start of that kind of thing. Over time, you'll find that everyone wants to go right to your battery -- battery charger, solar charger, bilge pump, battery monitor, smart regulator, stereo backup, fridge (long wire runs are VERY bad for fridge startup), etc. I have something like 5 on my main battery and 3 on my reserve (my second bilge pump goes to the reserve). To manage all this, I've put two small 6-fuse blocks right off the battery fuses. None of these things are "on the battery" but they are VERY close.
* You can reduce lug pile-up by moving your ACR to the 1/2 terminals on the 1/2/B switch. Depending on your layout, that can make for a very neat installation with very short wires.
* I'm confused by your 1/2/B switch. Is it a standard switch (it looks like one). In that case, you don't have a "start" and "house" battery. You simply have 2 batteries, with a 1/2/B switch, and the engine and the house both come off the output. That's a great setup, and what I use (and many here recommend). However, I'd change the label. It's "main" (for me, that's #1 and a 225Ah Trojan bank), and "reserve" (for me, that's #2 and a Grp 28). I run 24/7 on "main" and "reserve" is there if I wake up to a dead battery -- switch to #2, start the engine, swtich back to #1.
Harry
I am getting ready to add a 3rd battery for starting, a new 30A battery charger, and an
ACR between house bank (2 batteries) and the new starting battery. Also have a 125 watt solar cell. I have uploaded a schematic of how I am planning to do this, but would like any comments the experts would have. Will the solar cell, alternator, and battery charger co-exist without blowing up? This is on a 1986 Pearson 36 on Lake Erie. We do anchor overnight.