Legend 37.5 - Inverter and battery placement

Mar 13, 2018
18
Hunter Legend 37.5 California
Hey folks! I'm looking at seriously beefing up the battery bank on our boat to LiFePo4, and adding a powerful (3~4kW) pure sine inverter. These things take up space, and I was wondering where other people might have located their components?

To get the thread started: I thought about putting the battery bank next to where the current one is (the starboard lazarrette), and the inverter where the current charger is (under the starboard settee). However a 3~4kW inverter running at 12V would pull up to 333A, which requires at least 2/0 AWG! I think wiring that distance doesn't make any sense, and it's probably better to keep the bank next to the inverter. But where?
 

Ctskip

.
Sep 21, 2005
732
other 12 wet water
From what I have been able to gather in looking for information on the Hunter 375, I understand the factory designated a space under the forward berth for the genset option on the 375 . I can’t tell all that much as we are in the process of buying a 92 legend model and haven’t done a whole lot of investigation on the vessel. Come the end of next week I will be able to talk more about it only because by then , with any luck , my butt will be in it.
 
Mar 13, 2018
18
Hunter Legend 37.5 California
That's great! I started modelling things in CAD so I think in the end, I'll have a good idea of everything. I'm preferring under the settees right now because it's drier and away from the salt, plus it brings the weight closer to the keel, instead of at the ends of the boat (which are already loaded with the tanks and the dinghy).
 

MDBack

.
May 9, 2013
13
Hunter Legend 35.5 Cornucopia, WI
We have a 1993 Legend 35.5. We removed the head and holding tank and replaced with a Nature's Head composting toilet. This freed up a giant space where the old holding tank was behind the panel in the stern berth. I made a new battery box to hold 4 new batteries. They are low, almost on centerline, easy to access from the stern berth, and close to everything they need to be close to. Added a 2kw inverter, solar panels and charge controller, circuit breakers, etc. This worked for us and got rid of that smelly tank as well. Good luck with your project!
 
Mar 13, 2018
18
Hunter Legend 37.5 California
So far it seems all 8kwh of battery along with the inverter and MPPT charge controller will fit under the saloon settees, the section that runs beam-wise, which is low and almost in line with the center of the boat. Should keep it all dry and avoid misbalancing the boat!

For solar I managed to fit 915W on a custom arch on the stern. I won't share pictures because y'all probably will scream looking at what my L37.5 looks like now!
 
Feb 26, 2004
22,759
Catalina 34 224 Maple Bay, BC, Canada
all 8kwh of battery
Do you mean 666 AH at 12.0 volts?

My Freedom 15 has a 1500 W inverter which required 2/0 cables, too. That unit came with cables already connected, of limited length. This was in 1998! Later on they "allowed you" to make up your own cables, but didn't reduce the price of the I/C - but I digress.

Of course, distance will determine the cable size, which you undoubtedly know. But I recall manufacturers back then suggesting that was probably because of the limited lengths they then provided. I used Power Posts to make the final short connection to the fuses and the bank.

I faced the same challenge as a fellow C34 owner and we decided together via internet, he in CT me in CA, go put it under the nav station. That was the closest we could get to the batteries.

Don't hide it, it needs ventilation.

Good luck, worst case you run one bigger size wire. Yeah, PITA, I know, but needs must...
 
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Mar 13, 2018
18
Hunter Legend 37.5 California
Do you mean 666 AH at 12.0 volts?
It's a 3p8s bank of 100Ah LiFePO4 cells, which actually test at 116Ah per cell. So about 8.9kWh if using it at full capacity, or 8kWh if I keep 10% off for cell longevity. So if this was a 12V bank, it'd be about 666Ah indeed.