Boat Wiring Simplify and Upgrade - Beneteau Antares

[TheCoach]

So having had the Antares 9.80 for 3 years now we are pretty convinced it does everything we need and can't find anything that suits our needs better. As a result I am planning on investing some hours and $'s this winter upgrading various components including the core wiring layout. Having read lots of contributions and great info from the likes of @PaulRainbow on here (and others) as well as Geoff Cote at Pacific Yacht Systems I thought I would use this post to not only ask lots of questions but also document the approach I am taking given there are probably quite a few "french" boats with similar setups that could do with upgrading

So just as a bit of background its a twin engine motorcruiser with 2 engine batteries (140aH) and a house bank made of 4 x 85aH - all FLA as far as I can tell.


The batteries run to the normal Beneteau/French boat isolation/switch panel that includes 2 x engine isolators, a house isolator, a common neutral isolator and a battery combiner for the 2 engine batteries



Part of the reason for simplifying and upgrading is when you look at the back of the switch panel you will see an absolute mess, no busbars in sight, multiple stacked terminals on one switch etc etc. Also in classic boat builder fashion nothing is labelled and all the wires are either red or black



The initial reason for investigating is the house bank is foobar'd - only manages to last about 5 hours running the fridge and lights when at anchor. A couple of times I forgot to switch on the shore power when in the marina and drained the batteries, but I've not been able to identify where the parasitic drain is, so wanted to fit a shunt. Then looked at this and thought

So the plan is first off to try and identify the various circuits and draw up a new wiring diagram to help plan everything out and get the system set up properly before replacing the house bank (not mentioning the "L" word at the moment!)

So first couple of questions:
1. None of the battery to switch links seem to be fused. I am assuming best practice would be for all the connections to be fused, so would you fit MRBF type fuses to each battery terminal (inlcuding all the house batteries that are linked or just the final house battery bank terminals)?
2. The battery cables are all in 95mm2 cable which seems massive overkill? They also are excessively long (see pic of under switches). Is there any need for this size of cable (probs not worth replacing but interested to know).

Next step, start building the circuit diagram........

Cheers,
TC

 

[TheCoach]

So, first bit of work started and 1 question answered.

Checked out the house batteries and one of the four had no "green dot" showing, so uncoupled them all and tested voltage. 3 were at ~13.1V and 1 was at 7.0V . I'm guessing thats why I'm struggling to get any life out of the house bank as the dead battery is dragging down the others?

The original wiring was weird, not a layout I recognised, wonder if this has contributed to killing the battery.


Anyway, have now wired in a more balanced parallel setup with the batteries daisy chained and the +/-ve feeds coming from opposite ends of the chain. Have also temporarily removed the 4th (dud) battery and just running off 3 for now.


Also found that the +ve feed has a 300A MRBF fitted, just couldn't see it under the wire so at least that is fused.

Strange mixture of wires sizes though, all the +ve are in 95mm2 apart from the feed from battery to isolator swicth which is in what I guess is 50mm2 (haven't had a chance to measure yet)

The negative battery links are mainly in 50mm2 with one in 95mm2 and the main feed to the neutral isolator in 95mm2

Is it correct to think all links and feeds to isolators should be in the same gauge cable?

Cheers,

TC

 

[PaulRainbow]

I would expect them all to be the same gauge, but as long as the smallest cable is rated to at least the maximum current they won't do any harm.

Are there any heavy loads on the domestic bank, bow thruster, windlass, inverter etc ?

 

[TheCoach]

Hi Paul,
don't think the house bank has much loading. The bow and stern thrusters are run off the stb and port engine batteries I believe. Haven't tracked down where windlass is running from but suspect it is an engine battery as well. Will check that out next.

House has fridge, nav, webasto, lights etc and also an inverter to run the hot water tank although we hardly ever use it for that.

Part of the challenge is trying to track down where all the circuits run to/from but the boat is pretty much "as built" apart from the stern thruster

Cheers,
TC

 

[PaulRainbow]

Hi Paul,
don't think the house bank has much loading. The bow and stern thrusters are run off the stb and port engine batteries I believe. Haven't tracked down where windlass is running from but suspect it is an engine battery as well. Will check that out next.

House has fridge, nav, webasto, lights etc and also an inverter to run the hot water tank although we hardly ever use it for that.

Part of the challenge is trying to track down where all the circuits run to/from but the boat is pretty much "as built" apart from the stern thruster

Cheers,
TC

Make and model of inverter ?

 

[Hacker]

I’ll be following this one with interest. Your wiring seems to be quite similar to mine (although mine is a Channel Island 32). I think I’ve got a dodgy starboard engine battery but haven’t stripped all the wiring down yet as I need to map it out as well.