Switching a Battery Isolator?

Question:

Jeff came to my boat several years ago to conduct an audit. I found having him look at my boat helpful and re-assuring.  At the time, I had just completed a complete upgrade of my batteries, wiring, monitors etc. At the time I installed a ACR relay by blue sea systems. On reading his article, I noted that maybe the ACR is not quite suitable.  Instead I should consider an isolator, particularly if I have uneven battery banks - in my case 4 golf carts and one starter battery.  I could inadvertently trip the fuse. Additionally upon his recommendation I moved my alternator wiring from the starter motor to the house bank bus bar - it seems that everyone does this.  

My concern is, should I switch to the isolator? I have noticed that my starter battery according to my balmar monitor is dropping to as low as 9.9v after starting the engine - at 5 years maybe my battery is dead (I will load test it soon) or maybe the configuration I have is wrong for my battery and it is not getting enough charge. I went back and looked at the instructions that came with the ACR, but no mention of uneven battery configuration existed.  - Neville

Answer:

Hi Neville, thanks for the feedback. A battery isolator should not be switched, see this conceptual diagram of an installation:  https://www.pysystems.ca/site/assets/files/2532/pys_battery_isolator.pdf   - Jeff