Beneteau 343 Battery Wiring

[Northstar1014]

Hi all,

I recently bought a 2005 Beneteau 343 and am excited to have found this community. I am going through the house and starting battery system and need to replace all batteries (mine only came with 1x house battery) with new.

Option 1: buy 2 of these for house bank, gets me 210 amp hours
https://www.westmarine.com/buy/west...-105-amp-hours-group-31--15020332?recordNum=3

Option 2: buy 2 of these for house bank, gets me 230 amp hours
https://www.westmarine.com/buy/west...ine-battery-230-amp-hours-group-gc2--15020340

The advantage of Option 2 is I would get more amp hours out of the 2x 6v wired in series. And according to MaineSail, the 6v bank will yield much longer life due to superior construction of the batteries. Price comes out the same. The only question is if we have the height under the berth to fit, because the 6v are slightly taller. I'd be curious if anyone with a 343 has fit the extra height of the 6v without issue
https://marinehowto.com/what-is-a-deep-cycle-battery/

As I have reviewed the wiring diagrams, I am confused about how Beneteau has wired the house and starting batteries together. Specifically, I cannot understand the operation of the "parallel switch" connecting house and starting positive battery switches (indicated with a blue wire in the attached). My understanding is that this switch (label says Albright SW80-68) will parallel the starting and house batteries, but I cannot identify under what circumstances. Is it automatic whenever both positive switches are on? Or manually activated? "General 12v Schematic" below matches the configuration currently on my boat:

I don't believe my configuration matches MaineSail's diagram below, because the jumper parallel between my house and starting positive batt switches runs through the Albright Parallel switch, which is not shown in this diagram.

Thanks! Ted

 

[helmfam]

The next time one of my batteries goes out I will replace it with a Li Fe PO4 battery. More expensive yes but theoretically can undergo MANY MANY charge cycles and no maintenance and MUCH lighter weight (half or less) vs lead. Read about them here:
https://www.custommarineproducts.com/lifepo4-marine-batteries.html
My opinion re series option: Don't. If one of the batteries goes out you're dead.

 

[Ward H]

Yes, the GC2 batteries have a good reputation but the price looks high at that WM link. I bought Duracel GC2 230 Ahr at Batteries Plus for something like $125 ea last year.

 

[Stu Jackson]

Don't ever buy batteries at WM. You pay double for the label. There are plenty of battery source threads on this forum.
Good luck with your wiring.

 

[Gunni]

No idea why they put some “battery parallel” gizmo in the system. It introduces black box failure modes and removes the bone-simple function of the jumper wire between the house load side and the starter load side. You switch off your dead battery bank and use the other to start or run the house. I have the “common beneteau” wiring system and it works flawlessly. Lose the complexity is my suggestion, 86 the battery parallel box, run the wire as shown in your second diagram.

 

[jssailem]

Hi @Northstar1014 and congratulations on your new boat. Moving up. Bigger, more space, and more complexity... It happens.

Looks like you have a fairly good handle on the issues. Bigger boats demand more electricity. How to feed the beast is the issue. It is all a compromise.

First, depending on how you plan to use your new boat will influence your need for electrical storage. 230 amp hours (really only 115 since you want to only draw the battery down by 50% to extend it's life) seems like a lot until you start turning on all the available gadgets on the boat and do it from an anchorage that you want to spend the next 5 days exploring. Cruising folk tend to look at the problem as bigger is better and solar/wind/and generators (either a separate one or big alternator) are essential. Not so much needed for a daysailer.

The point of 2 6volt batteries in series to feed a 12 volt system is that if one fails they both are useless in the system. If you are only going with 2 batteries, consider getting 2 12 volt batteries. There are many more designs out there than the typical car battery. explore the type of battery that industry uses in a sweeper or air lifts.

Here is one that I found met my needs. http://www.dynobattery.com/products/sweeper-and-aerial-lifts/30tmx.php
There are several manufacturers in your local are. I think EastPenn is one.

Advantage is one battery goes bad you still have a 12 volt backup and a functioning system.

 

[GBGraham]

I can not get into your shown web sites as I am in a different country and it is blocking me. But looking at the amp hours I would gather the first option is the 2 x 6 volt 105 ah. You put these in series and you will still only have 105 ah.
For me go for the 2 x 12 volts in parallel and have your 230ah. Buy the best type and make that your pocket can take.

 

[GBGraham]

Again I'm not sure what part of the diagram you are exactly referring to, but if it is the blue one that goes through a relay just below and to the left of the mark X. If so you can assume this is an auto charge relay, either alternator or voltage controlled, the diagram is not to well defined but I would go for the latter.

 

[jssailem]

Welcome @GBGraham . Really great to hear from our Greek Neighbors.

The 6 volt batteries most often used here are the Trojan 105 batteries (or their copy cats). They are true deep cycle batteries and each has a 225 amp hour rating. 2 in series as you say will give you a 225 amp hour bank with 12 volt output. And as you say the useable amp hour performance is half of that (about 112 amp hours).

The often used 12 volt car (labeled deep cycle) batteries in the 24/27/31 size are not true deep cycle batteries. They come in 77 to 102 amp hour ratings and are suggested to only be discharged to 50% of their rating.

The battery I identified is a true deep cycle battery. It has thicker plates and more designed in space in the base so it has a higher "Cycle" rating than the typical 12 volt car battery. The battery has a 135 Amp Hour rating. 2 of these in parallel give you a house battery size of 270 amp hours 135 usable, based no the 50% discharge plan.

While not perfect for a long time cruising boat it serves the purpose for me as a coastal cruiser.

 

[GBGraham]

Thank you for the greeting @jssailem, although distant neighbours. Trojan's are generally regarded as a market leader in lead acid deep cycle batteries over here in Europe and you are correct with your information

As for the OP, @Northstar I have taken a look at the Albright contactor. This is to amperage heavy for a charging relay, although there is no provision on the circuit diagram for a charging circuit to the house batteries. It's more like the type you would find on a windlass or bow thruster. It is designed for heavy loads so may be it's there as an intermittent bridge for starting, i.e. to put both the battery banks into circuit for starting. It will be remotely controlled though.
Have you the key for the diagram, i.e. for what the lettering stands for.