Inverter cabling question

[Helmsman]

Thanks! I supposed that the 2 gauge feed from the engine was insufficient for the case ground when I went to look at it today. I will take your diagram and compare it carefully so we are on the same page.

The shunt is in line between the inverter battery bank negative post and the negative post on the inverter. It is a shunt for a Victron battery monitor. I intend to bring the new negative off of that shunt to take to negative buss bar.

[bud37]

Two things....what is the amp capacity of the buss bar there with all the yellow wires.??...and I disagree about the case ground....it needs to go directly to the block, you don't want any short energy, should it happen travelling thru any of those small wires from that buss and it will even though ultimately they end in the same place.

Your instal from those pics doesn't look bad at all, I just don't like the look of that buss.

Without a schematic, I can't comment on the shunt position in the circuit....my old brain is really slow...

KM seems to be able to make nice diagrams....I wish I knew how to do that on here...

[Helmsman]

Source of the post Two things....what is the amp capacity of the buss bar there with all the yellow wires.??...and I disagree about the case ground....it needs to go directly to the block, you don't want any short energy, should it happen travelling thru any of those small wires from that buss and it will even though ultimately they end in the same place.

Your instal from those pics doesn't look bad at all, I just don't like the look of that buss.

Without a schematic, I can't comment on the shunt position in the circuit....my old brain is really slow...

KM seems to be able to make nice diagrams....I wish I knew how to do that on here...

Bud, I don’t know the amp capacity of the buss, but will try to determine it. It would seem to me to be ok, because it was previously handling the same capacity of charging ability from the isolator (140 amps) spread amongst three battery banks versus four now, right? Where would the place be that the short charge would end up?

[bud37]

There should be a spec on the buss somewhere....just make sure it is big enough to handle the amps going thru it and you will be fine. From the pic, there seemed to be quite a few wires attached to it , that is why I asked.

As for this case ground.....just follow the manufacturers instructions as to where they want it run to and what size cable to use.........good luck with it man, I think you will get it so you are happy with it.....

[Helmsman]

Source of the post If you can, I would move the 2/0 "safety ground" to the negative buss and I would also connect the new 2/0 "tie in" negative to the inverter battery at the same place.

There's no reason your "safety ground" need to be on the engine block. It is just a convenient place on most boats that establishes a "negative buss", as there needs to be a rather large connection from the negative battery terminal to the engine block. Now that you've admitted that the engine only has a 2 AWG negative feed, that lead is actually now "non compliant" since it also needs to be just as large as the "safety ground" to complete the circuit back to the battery negative. So, if you can just move the 2/0 safety ground to the negative buss bar then you also eliminate the need to upgrade that engine negative as well.

In a bit I'll run some more calcs on the 4 AWG run and give my updated opinion on that. Also, please clarify where your shunt is in the circuit and how other stuff around it are connected. With your description I will try and update that diagram I made with as much information as I can ascertain from your posts and you can critique it so I can correct it. That will make it easy for all to understand and make sure we're all on the same page.

KM and others.

Here is a jpg drawing of the setup I have currently with wire gauges and lengths. Note that the recommended negative to the buss bar is not pictured, nor is moving the case ground from the engine to the buss bar. I can supply in almost any format if you would like it formatted another way. That may require emailing. I am looking for advice to be able to actually safely utilize the alternators to charge the inverter bank as we have discussed. If after looking at this, you can advise further please do so.

Inverter Isolator Install.jpg

Thanks!
Nate

[Helmsman]

Ok. Been researching this since we last discussed. The thing I could not get my mind wrapped around was what amperage would flow from the alternators through the isolator to the batteries while underway. After reading Nigel Calder’s book focusing on the electrical section, I have finally figured it out.

I have two 70 amp alternators. The theoretical maximum that could flow to the inverter is 140 amps if both engine batteries and the house battery are fully charged and not receiving a charge from them. However, that will always be limited by the charge acceptance rate of the batteries which is then dependent on the state of charge level of the inverter batteries and the amount of current required by the systems using the inverter for power. The likely total amperage would probably be 120 amps total.

Knowing that has helped me understand what I need to do to get the inverter and batteries to ABYC standards from the current state it is in.

1) Currently, the batteries reside in a special built PVC case above the water tank aft of the engines and in front of the generators. The round trip to the inverter is 6 feet. The round trip to the alternator and negative buss bar is 28 feet.
2) The positive cable leaves the inverter, travels through the (right sized, engine compartment safe) fuse, and then to a battery switch (off on only) which also has a non-fused positive 4 gauge cable from the isolator connected to it.
3) there is no negative cable returning to a negative buss bar to complete the isolator connection.
4) The case ground is 00 cable and returns to the engine ground. That is ok based upon ABYC and manufacturer standards.

So, I am going to do this if possible to correct the above issues.

I have space on the bulk head in front of the port engine to place the charger inverter. I will not need to replace the AC wiring due to the two wires being sufficient length to make it to the new position. If I do that, and move the 4 6 volt batteries into the battery well with the original three batteries (which I think is doable) then that will mean a round trip to the batteries and return to the inverter of 18 feet. From the isolator to the inverter battery set will be 6 feet round trip. The case ground will have a 2 foot cable to the negative buss bar.

There are two caveats.

One is whether the battery well can handle 4 6 volt batteries. The measurements say so, but will need to make the move to ensure we can. If not, I may combine the house and inverter bank which means I give up the 105 amp house battery and dual use the 400 amp inverter bank.

The second caveat is to measure the heat at the new install point for the inverter in front of the port engine. It wasn’t a problem over the water tank aft of the engines. I will need to ensure the temperature In both places are close to each other. That will be the first test. I plan to take the boat 50 miles upriver in March for some work and will test the temperature in both locations while underway.

When I complete this I will post an updated wiring plan without the issues for the system in case anyone else could use it.

There is an app that helps determine cable size. It is great tool. It is called the ABYC Wire Sizer App and is available on the Apple App Store and google play.

[Helmsman]

Ok. After more study and significant discussions with several folks in the know, here is the latest and final plan.
I am going to keep the batteries and the inverter where they are. The isolator I am sending in under warranty to Pro Mariner. It has failed. They will get me a new one or repair the old one, though after much discussion with them I believe it will be a straight replacement.

I am replacing the smaller cabling on the inverter system with 4/0 cable (including the charge cable from the isolator and the return negative). A fuse will be added to the charge cable where it is missing, and we should be set. This set up will allow me to move the batteries forward to the battery well in the future when I replace the batteries. Update: Decided to re-install the original 2-3 isolator, and charge the house, and two engine batteries. I will use the generator to top off the inverter if necessary. More elegant and least invasive solution.

Here is the final diagram. Bear in mind that the system does not show the shore power Charles charger that currently maintains the house and two engine batteries. It also does not show the generator and its battery. Hopefully, someone will benefit from the countless hours I spent learning while pestering you guys! Thanks again for all the help.

Inverter Isolator Install Updated with proper wiring.jpg

[Helmsman]

I saw where Viper had posted that the pre-assessment for an inverter is critical and takes a lot of time to complete. The original install of this inverter is a classic example of that statement. I would have been able to save myself some money by learning the ins and outs of inverter installations prior to hiring the person to do it. On the plus side, nothing went terribly wrong though it might have, and the opportunity to learn about inverters was a lot of fun. So, all in all, things worked out ok and I learned a lot. Thanks again!

[Helmsman]

Unintended post

[Smoken]

We have a new to us, 2000 Carver Voyager 53. We have not been able to figure out how to use the invertor. We have turned on the breaker and the inverter button on the Link 1000. It is not coming on. What are we missing?