ST44 house bank upgrade
I meant to post this a few months ago!
Pics of completed install below.
Wasn't too difficult:
- Moved engine battery bank 6" back and extended sub-floor 6" on either side
- Installed new battery boxes for house bank (was hoping to use the existing but it was sized weird for european batteries)
- Had to use one style battery box and cut down height along with cut holes for wires to fit tight space next to engine bank
- Had to use other style battery box and cut off handles to squeeze into where existing house bank was
- Sizing the battery interconnect wires for custom order was tough as I attempted to do before hand and batteries ended up sitting spaced different than I initially thought. I could've stuck with what I ordered but then I would have to unscrew wires every time I wanted to check the water level. I eventually was able to size so I could add water without hassle.
- Realized existing house batteries had a MRBF fuse on each positive post. Converted to a Blue Seas Class T Block 300A fuse
- Then had to raise the engine room floor which I was very nervous to do because of already limited space but it worked and I was able to raise a smidge above the battery posts
- Ended up removing the ladder to the engine room as the increased height of subfloor wouldn't allow it to work. I was going to make a modification to re-install but realized I do not really need it.
- Installed the Balmar battery monitor in my salon and also added a galvanic isolator
I was not excited to have the batteries so low in the boat (in case of a water intrusion emergency) but I had no choice. That was where the builder decided the banks go but in terms of weight distribution it worked well. It would take a couple feet of water at which point I have larger issues... I was originally going to have 10-12 6v batteries but decided to try 8 and it is sufficient enough to give me 3-4 days of power at anchor.
Now the next thing I need to figure out is whether I need to install a new charger... I have three existing on-board Cristec 25amp three bank chargers. One is dedicated to the genset. The other two are divided: A) house, port engine, stern thruster, and B) house, starboard engine, bow thruster. So it appears the house theoretically can get 50amps since it has one lead from each of two chargers (that is assuming the other banks are fully charged)? I am wondering if it makes sense just to take one of the two empty ports on the genset charger and run it to house that way I have a theoretical maximum of 75amps? Or just disconnect house from existing and get a new 50-60-75 amp charger? The thing I don't like right now is my two thruster banks and two engine banks are AGM and my house and genset is lead acid. Cristec says that it is not ideal to match different types of batteries on a charger because they require different volts to re-charge but I have it set to a compromise setting just dont know what harm if any I am causing...