Marine system design

DIY
, ,
1

I posted earlier about my power cat and I am thankful for the replies. Just before I pulled the trigger on a Multiplus II I came across a true 12v air conditioning system for small boats. Without the need for 120v power while underway I completely changed direction.
Supply
2 x 120ah Renogy LiPo batteries charged by two 120w PV panels controlled by Renogy 20 amp MPPT (when the Renogy crap out I will get Victron to connect the BMS systems)

Distribution
Lynx Power In (two batterie and the MPPT output connected)
Lynx Smart Shunt (ordered a 60 amp fuse)
Lynx Power Distributor (AC, water heater, and inverter)

Load
Kingfisher 12v 5000BTU air conditioner (30amp start, 12.9amp run)
Water heater 3gal 12v (30 amp)
Phoenix 1000w inverter

Control
Cerbo GX MkII
GX Touch 50

When I didn’t need a 3000w inverter to run the A/C I realized I could get a fancy power management system instead.

2

You need to connect the MPPT battery negative cable to the Lynx distributor not the Lynx power in. If the MPPT -ve is connected to the power in the Lynx Shunt can not measure the charging current.

Your 60A fuse for the Lynx shunt is too small, the 1000W inverter will need a 150A fuse minimum at 12V (check the manual) plus the other loads, you probably need to be 250A-300A range.

3

Thanks. I will all the manuals for their max loads. I was going on descriptions from web pages.
Do I even need the Power In?

4

With just 2 batteries I would be happy connecting these to the left hand side lugs that stick out of the Lynx shunt. Msny people do this and it is what I am going to do when I swap my boats AGMs for 2 lithiums this winter. Just make sure you have protective boots over the terminals. This is mentioned in the manuals for the Lynx products.