Increase amp hour capacity on 2007 Beneteau 373

[Charleston Dave]

Currently have single battery located under aft stateroom aft of prop shaft next to water heater-standard location from manufacture. I would like to double amp hour capacity by adding second battery, primarily to handle frig load while at anchor.
Anyone with a 373 who has made change?
My ideal requirement is both batteries side by side or in reasonable proximity, outside of engine room and between mast and engine compartment. Actually, would be greatfull for any pictures and details on change in wiring both from generator and to panel.
Also, did you change out alternator? I appear to have 80 amp hitachi internally regulated.
My current plan is under port seat but physical size of battery-and thus amp hrs -would be limited. Could modify hitachi to externally regulated

 

[NYSail]

One battery? That just does not seem right. I am not familiar with the 373 but would think beneteau had a house and starter. Nothing in front of the engine??

 

[BigEasy]

I chartered a Beneteau 393 and 343 many times. They typically had a separate starter battery and a house bank consisting of two 4D batteries equivalent to approximately 400ah total. This can be accomplished with two 4D's, four Group 31's, or four 6 volt golf cart type batteries. Space availability may dictate how many batteries and type you can fit as well as how much weight you can personally handle. Just keep the chemistry of all batteries consistent.

 

[leo310]

Have looked at your owners manual?

 

[jssailem]

Dave. When feeling lost, start looking behind the battery on switch. Find the big red wire and follow it to the battery.
You might also follow the red wire from the alternator to the battery or to a big switch to the battery. The biggest thick red wires always lead to the battery or batteries.

 

[Ron20324]

Even my B323/ 3YM20 had 2 OEM batteries.

 

[Charleston Dave]

Indeed I have a starter battery in addition to single house battery "bank".
So my 373 has single house battery-
my request is who has a 373 with 2 house batteries and where are are they installed?
Beneteau shows two, lined up one behind other aft of prop shaft. The 373 is already stern heavy and am looking for clever solutions forward of engine compartment already achieved by someone else.
Additionally-anyone running a high output alternator off there 3JH4E Yanmar ?

 

[Ron20324]

323s have a battery in front of the engine, under the stairs. Some folks have put 2 x 6 in there.

 

[Charleston Dave]

indeed I have starter battery in front of engine. Not enough room for another house battery in that location
again-the focus is on a two battery house bank out of engine room on a Beneteau 373 specifically

 

[Gunni]

You sound confused about your battery system, suggest you retain the services of a qualified marine electrician to sort out your option. Below photo shows my solution - 4 grp 31 Lifeline AGMs under the port settee. Got the weight out of the stern of the boat and counterbalanced a genset install on the starboard side. Location is midships to port. This install was facilitated by an existing inverter in the settee, and related existing battery cables. 500 Ah house bank, separate Grp 27 starter battery aft the engine.

 

[Charleston Dave]

You sound confused about your battery system, suggest you retain the services of a qualified marine electrician to sort out your option. Below photo shows my solution - 4 grp 31 Lifeline AGMs under the port settee. Got the weight out of the stern of the boat and counterbalanced a genset install on the starboard side. Location is midships to port. This install was facilitated by an existing inverter in the settee, and related existing battery cables. 500 Ah house bank, separate Grp 27 starter battery aft the engine. View attachment 158185

 

[Charleston Dave]

Gunni-well I may have been confusing in my posts but not confused regarding DC electric. I have a solid understanding of DC.
My queries have been about the actual physical placement of the batteries. Your photo is much appreciated but
does not appear to be a Beneteau 373. Yes I can measure and calculate available space for my batteries under the port settee (the most likely place) but prior to jumping in, I am merely looking for someone who has already upgraded to two house batteries on a 373-why rediscover the wheel?
one of my concerns is off midline weight and you account for that with a genset on starboard. The Beneteau 373 has a water tank mounted aft and starboard which will somewhat counterbalance 300 lbs of battery weigh. I already have a 16,000 btu a/c unit under aft-most settee.

 

[CESLAW]

I did indeed add a second 4D battery to my 373. It is located in the starboard lazarette, in a battery box. That places it in close proximity to the battery located adjacent under the aft cabin boards. It is out of the way and the space it takes up has little affect on the storage space in that spacious lazerette.

An additional Beneteau red power switch was added so the two house batteries can be independently turned on and off. The engine battery remains in front of the engine in the same location.

This has worked well The possible temperature differentials due to the locations of the two 4D batteries has not been an issue. The balance of the boat has not been noticeably affected.

Regarding power consumption, I also modified the refrigeration system to convert the freezer to a refrigerator, using a Sea Frost BD Speed Control / Thermostat. That dramatically reduced power consumption. I don't miss the loss of the freezer at all.

 

[Issywa]

Not sure if you're still looking for comments. I have a 2006 373 and today just finished planning my cabling routing to allow for 4 - 6V batteries to be placed in the port locker immediately in front of the freezer. There is adequate room to run the cables under the aft locker in the state room, then under the fridge and stove. I had to cut a couple of holes in the storage locker under the stove to allow the cables to be threaded through, and to provide access to the area under the freezer. From there another hole allows access to the settee locker. Space is a bit limited for the 6 batteries but should work. I plan on running the cabling under the floorboards and over to the starboard locker and then up and into the power panels. Hope this helps you.

 

[ToddS]

I have a 373 (2004 three-cabin version) and recently upped my house bank from the standard... Originally the boat came with 1 starting battery under the companionway steps, and 1 house battery just to the starboard side of the water heater behind the engine. I took a less ambitious route (I know this isn't what you're describing), and replaced the single, house battery (which was a group 31) with two, side-by-side group 27 AGM batteries in parallel in the same location... Reducing from group 31 to 27 allowed me to turn the batteries 90 degrees and fit them (one forward, and one aft) just to starboard of the center line. I can see the appeal of moving them forward somewhere else, but I went the modest/easy route myself... upping my house bank amp hours from a little over 100ah up to what's now about 184ah... Only needed just a couple tiny lengths of battery cables, and the battery boxes and the batteries themselves. No major surgery or expenses (other than the batteries themselves). I also replaced my tired, old starting battery with a group 27 AGM (same size as before). All three batteries identical. With the 3 cabin boat, I have less storage than you do on a 2 cabin, and I didn't want to give up any locker/settee space. While my improved house bank isn't huge, it is big enough for my purposes... I'm pretty conservative with battery use aboard... In New England, I have no Air Conditioning, I have all LED lighting, My refrigeration use/needs are very modest the way I use the boat... It works for me. I'm wondering if there might be room for batteries under the navigation table/seat... probably deep enough that you could put batteries on the bottom, with a cover above, and still have a small space above the batteries for storage. but yours will be different from mine, as the 3 cabin nav seat is on the port side, whereas yours is presumably to starboard near the head.

 

[Newport Bob]

I added a second 4D battery and battery box to my 373 in the starboard lazarette. Also, upgraded to a Balmar 100 amp alternator with an external max charge voltage regulator. And added a Balmar smartgauge battery monitor. As I have the 3gm30 engine I was concerned with the horse power loss with the larger alternator load - added a cutout switch to the cockpit panel to remove the alternator load if I need the power fighting a strong current.
Couldn’t install battery under the port settee since I added a compressor there - separated the icebox and deep box to two completely separate systems.