2020 NC 795 Electrical

[fritz]

Picked up new 795 a couple of weeks ago, either an evil genius or really bad timing. The upshot is I have had a lot of time to explore and label things that should have come pre-labeled from the factory.



Attached is a diagram of the wiring as it came from the factory, Sundance swears they have not touched the wiring. It's worth noting that Sundance however did provide the batteries.



So what I need help with…



1. All three batteries are “crank batteries”. All my research indicates that the house and thruster batteries should be deep cycle or dual purpose. Here’s where I am getting my information from:

www.discoverboating.com/resources/marine-battery-basics#. Thoughts?



2. The Windlass and main fuse block are on the engine battery, shouldn’t they be on the house battery?



3. Charger is connected to 2 of the 3 batteries. While the ACR should pass through from the house to the thruster battery it does seem old it’s missing. The charger does support three directly connected batteries. It’s also right next door to the thruster battery.



4. Based on BlueSea (ACR) and Cristec (Battery Charger’s) web site those connections should all be fused, they are not. Is that ok?



5. I have two wires directly attached to the engine battery switch that are not labeled, my best guess is Bow Thruster control power and something else. Thoughts?



6. Cover for the main fuse block is missing, standard practice from the factory or is it missing? It’s there on the small block that has the trim tabs.
The small block cover is even labeled!


7. Trim tabs on engine or house? (currently on house)



8. Battery switches do not match the documentation. They are vertical instead of horizontal, not a big deal.


Thanks,



Fritz

Wiring diagram: ibb.co/VC606YN

[ihsan]

Fritz high, is this electrical diagram from the manual supplied with the boat?  I can't check it because mine is with the boat. Somehow I think this is not the same diagram and ıf it is missing some of the connections it may mislead. Regards. 

[fritz]

The diagram supplied with the boat is not complete. It shows the battery switches horizontal when in fact they are vertical. It also does not explain what is connected. I made the diagram to build my understanding and confirm it's wired to US standards. I need to go double check but I am pretty sure it's missing fuses per BlueSea and Cristec, I do not want my new boat to catch on fire. Spending another $1,000 to make the boat safe after spending $130K seems pretty ridiculous. 

The jury is still out on if the house and thruster batteries should be crank, deep cycle, or combo. Quick the bow thruster manufacturer recommends "deep cycle". Bad things can happen if the wrong battery type is used over time, i.e. fire and battery explosion. 

"A deep cycle battery is constructed differently than a cranking battery, with thicker, heavier plates. The longer, higher amperage requirements of trolling motors and windlasses, for example, would heat and distort the thinner plates of a normal cranking battery."
-Source

It would sure be nice if Jeanneau provided some guidance to the dealers when it comes to batteries. 

[ihsan]

            Fritz, I think I am in a position to answer electirical questions no. 4 and 7. My electirician in İstanbul works with 795 and 895

             According to him,  trim tabs should be connected to service batteries, Engine batteries should only be connected to the engine battery as a rule.

             895's have one engine connected to the service and the other engine to the engine battery. This may later cause a risk for the owner. 

             ACR and battery charger (redressor) have their fuses. In order to find the fuses you have to open their covers. 

             As for the deep cycle battaries advised by Quick, ours I think are normal crank battaries.

              The electrical material used in the boat is of good quality but betterment of the system is possible, However the cost would definitely rise for the builder. 

               Labeling of the electrical system must be done by the customer. It is not supplied. This is in my to do list. Trying to read the book to find out iwhere is what may only lead to loss of valuable time. 

  
             

[Capt’n Ron]

It’s good to see this topic come back up.  Electrical really is more than turning the house and engine switches on, and it’s good to get familiar with your boat and how the electrical operates. For this post I’ll only cover the battery topic. 

Which type of batteries should you have:  This topic was brought up last year when some found both house and engine batteries were crank batteries installed by the dealer.  We even had a local dealer jump in on the discussion and mentioned the factory indicated this is OK. I’ll go out on the limb and say that information is WRONG. Will it work, yes for a while, but will more than likely have bad consequences.  I like to rely on facts and expert recommendations and all the experts say the same thing,  your house battery should be a deep cycle and your engine should be a crank.  Fritz provided the link above which provides a good explanation of what type of battery to use and when.  Here is a link to a video from Pacific Yacht Systems on DC electrical and batteries and you will hear Jeff talk about what can happen when a crank battery is used as a service (House) battery with deep cycle loads.  After two years he had one boater where the battery exploded blowing the hatch off the boat.   

Based on my research I have 1 crank battery for my engine, and two AGM 120AH batteries for my house, and the thruster still has a crank battery with it’s own charger.

Once you understand your house battery should be a deep cycle, you then need to know how to manage the battery and how battery types are managed differently. To get the most life out of your batteries here are some guidelines for how much of that battery you should use.  Exceeding these guidelines will reduce the life of your batteries. I learned the hard way and it was an expensive lesson because all the batteries in the bank needed to be replaced at the same time. 

Flooded - Do not discharge below 50% capacity: Actual usable capacity is 35% (50% to 85%)
AGM/Gel - Do not discharge below 30%: usable capacity is 55% (30% to 85%)
Firefly AGM - Do not discharge below 20%: usable capacity is 65% (20% to 85%)
Lithium - Don not discharge below 20%: usable capacity is 80% (20% to 100%)

It’s good to take into account the usable capacity as it could help you determine what type of battery you should purchase.  For example, I had four 100AH flooded batteries, so my usable capacity was 140AH.  I replaced the four flooded with two 120AH AGM and my usable capacity is 132AH. So I ended up with about the same usable AH and gained some space and dropped some weight. 

Here is a table to understand the difference is between the percentages in volts. You will notice that even though you have a 12 volt battery, it does not go from 12v to 0v.

Percentage	12V Battery
100	12.7v
95	12.64
90	12.58
85	12.52
80	12.46
75	12.4
70	12.36
65	12.32
60	12.28
55	12.24
50	12.2
45	12.16
40	12.12
35	12.08
30	12.04
25	12
20	11.98
15	11.96
10	11.94
5	11.92
0 - Fully Discharged	11.9

In order to really understand how much capacity you have in your batteries and how long your can run house loads you really need to install a battery monitor.  I installed the Victron 712, but there are others out there as well.

I hope this information helps to keep your boat charged up!

Cheers,
Ron 




 

[ihsan]

Thanks for this valuable information on battaries..

[fritz]

Thanks Ron!

[westboating]

Fritz,

     Here's the thread Capt'n Ron was referring to: jeanneau.proboards.com/thread/7118/check-batteries

In a related note, our bow thruster battery seems to be near dead and not really charging.  I haven't dug into it, but If it's dealer installed it should be a fairly new battery as we've only had the boat for 16 months or so.

[fritz]

My bow thruster battery will only charge if the bow thruster controls are energized. The common wire from the ACR goes to a relay instead of directly to the battery. The relays are not in Quick's manuals or wiring diagrams.


To test, energize the bow thruster then look for the green LED on the ACR near the bow thruster. This assumes your house is charged and the bow thruster battery is connected to it via the ACR. 

[Capt’n Ron]

I’ve been scouring the different forums on the internet and the opinions on thruster battery type are sometimes religious one way or another. I’ve not found anything from PYS on which type of battery to use for thrusters, but this is my take-away from the reading I’ve found.

Deep Cycle seems to the the predominate recommendation for bow thruster batteries, mainly due to the fact that a bow thruster, even though it uses burst, it does drawl the battery down quite a bit and fits closer to a deep cycle profile.  It also seems most people and some experts recommend the bow thruster battery should have it’s own charger in the same compartment.  Although my thruster battery is a crank, I do have a dedicated charge in the thruster compartment and I’ve never experienced an issue with performance of my thruster.  I should add I’m not going to go out and replace my crank battery for a deep cycle, I just realize I might have to replace it sooner. 

In the situation Fritz has, and I suspect many others as well (695, 795, and 895), the thruster battery only charging when the thruster system is turned on is not correct and could lead to an unfortunate docking situation. 😬

Ron

[Capt’n Ron]

Mar 31, 2020 23:11:11 GMT Capt’n Ron said:

I’ve been scouring the different forums on the internet and the opinions on thruster battery type are sometimes religious one way or another. I’ve not found anything from PYS on which type of battery to use for thrusters, but this is my take-away from the reading I’ve found.

Deep Cycle seems to the the predominate recommendation for bow thruster batteries, mainly due to the fact that a bow thruster, even though it uses burst, it does drawl the battery down quite a bit and fits closer to a deep cycle profile.  It also seems most people and some experts recommend the bow thruster battery should have it’s own charger in the same compartment.  Although my thruster battery is a crank, I do have a dedicated charge in the thruster compartment and I’ve never experienced an issue with performance of my thruster.  I should add I’m not going to go out and replace my crank battery for a deep cycle, I just realize I might have to replace it sooner. 

In the situation Fritz has, and I suspect many others as well (695, 795, and 895), the thruster battery only charging when the thruster system is turned on is not correct and could lead to an unfortunate docking situation. 😬

Ron

Correction on my comment on thruster battery type.  I heard back from Jeff Cote at Pacific Yacht Systems (PYS) and he said thruster batteries should be Crank, not deep cycle because thrusters should be used in short burst, much like the engine starter.  

[odetta]

I had the same problem of diminishing voltage for the thruster battery in my 2019 795, and almost no power in the thruster after several months of use. On checking the electrical connections, I found a never-connected large gauge wire "doubled-up" in the opening of the plastic wiring tube (apparently done for keeping it from banging around when shipping). Once hooked to the proper terminal of the battery, and after I had charged up the battery with a portable charger, the charging of the thruster battery is working fine. I hooked up a small digital gauge to the battery to keep track that everything stays OK.

Could that also be your missing connection that I see on your diagram?

[lynnardm]

895's out of the USA have (or had) a known issue with the thruster battery not charging all the time.  The battery should be charged with the engine running regardless if the thruster is turned on or off and also via shore power..  My boat (hull no 33) had the problem.  It was addressed under warranty.  I don't recall the details but it needed a power cable from the charger.  

My boat has a starting battery.  I think this is the proper approach for providing short bursts of a lot of power.  The thruster should not be used for long periods.  Although I'll admit that for fun when I had my 695 I sometimes spun the boat in a circle with it :.)

Captn Lynn