Catalina 30 electrical system feedback

[paulstraw]

Hi there, new to the forum and sailing. I didn't see a dedicated electrical/networking forum, but it seems like this type of thread is typically posted here.

I'm just finalizing purchase on a 1979 Catalina 30 TR. The electrical and instrument systems need to be revamped, so I've been starting to plan those builds out. I built a similar electrical system for an RV a handful of years ago, and have some electronics/PCB design experience. I've never wired a boat before though, and thought it would be a good idea to get input from folks here.

In particular, I'd like to know whether the separation of the starter battery from the alternator raises red flags for anyone. Of course, other feedback is also welcome. I've attached two diagrams:

1. Electrical: Note that this is high level, and doesn't include wire gauge, fuses, or bus bars.
2. Network: NMEA 2000 and computer networking.​

Thanks in advance for your insights!

 

[Davidasailor26]

Welcome to the forum and to sailing!

The starter battery should be connected to the alternator output, with the Orion in parallel to charge the house bank. Having the start battery connected to the alternator ensures the alternator’s field is excited properly. You could also consider the newer Orion XS instead of the ate-Smart. The XS has much higher efficiency so it’ll run cooler. It’s 50 amp maximum output but is programmable so you can limit it to whatever your alternator can safely provide.

One resource worth reading more from is Marine How To - DIY for Boaters - Marine How To. Rod Collins (Maine Sail on this forum) has lots of articles there about the nuances of boat wiring. I’d also recommend Nigel Calder’s Boatowner’s Mechanical and Electrical Manual if you’ll be undertaking a large electrical project. That has a ton of guidance on the right ways to wire things and the considerations to take into account.

 

[dlochner]

If you running windows, Marathon has a free N2K design program. It is geared towards Marathon products, but can be modified a bit include devices from other companies. They also have good manual on N2K.

There are a couple of routes to go with a computer system, same as on land, hardwired or wifi. Wifi is the easiest to install and many Chartplotters can serve as a hub. There is little need for a hardwired system unless you are using 2 chart plotters and have radar. If you only have radar, then it will be a closed network between the radar and the chart plotter.

I would offer comments on your schematics, however, my old eyes are a poor match for the tiny print on them. The only comment I have is the "InertiaNetwork" seems to have a lot of devices on it, maybe more than are necessary or useful.

Loading…

www.maretron.com

 

[Foswick]

If you haven't seen it, this could be of interest, as it gives you some information about the original wiring: https://sbo.sailboatowners.com/downloads/Catalina_30_78271039.pdf

There is not much special about wiring a boat, compared to, say, an RV. The main difference is that if a thing can corrode, it will.

 

[jssailem]

Welcome Paul. Always great to see another PacificNW sailor joining the crew.

There is nothing like taking on a big project at the start of boat ownership. I'll admit I am a little old school. I try to start an electrical project by assessing the power needs of the equipment on the boat first. Then, I build the storage and charging systems to try and fulfill that need, plus a little extra just in case. There are ideas for a spread sheet to calculate the power needs.
Here are a coupel of links that may be of help.
battery-runtime-calculator

Loading…

www.bluesea.com

David was spot on about connecting the alternator and the issue with LI batteries. If the LI BMS shuts down and you're running your engine with the alternator working to fill up the batteries, something has to give. Usually, it is the diodes on your alternator.

Your diagram does not show the capacity of the alternator. That is an important tool in your charging kit for your boat.

You chose a great boat. There is a lot of fun to be had on the Columbia.

 

[Stu Jackson]

Another handy resource for boat electrical systems in parallel with Maine Sail's website is this one:

Electrical Systems 101 Electrical Systems 101

 

[dlochner]

Had a chance to enlarge the drawings so I can actually read them.

When designing an electrical system the starting point is the expected daily demand or load. All the decisions that must be made need this information. Consider the loads, while at a dock, on anchor, sailing, and motoring, each condition will be different and they will differ whether you are considering daytime loads or nighttime loads. Once you have that information, the rest of the design will flow smoothly.

The BMS shut down problem is mitigated in one of two ways, by having a BMS that can communicate to the regulator and shut down the alternator safely. The other is to use a Balmar Alternator Protection Module. One of these solutions can be had for less than $100, the other not less than $2000. Your choice.

The alternator is a crucial piece of equipment. Again there are 2 choices, charge the start battery and then the LFP battery with a DC-DC charger. Or charge the LFP bank with the alternator and start bank with a DC-DC charger. The standard 35-55a stock alternators on most engines can not safely charge the LFP directly. These alternators are built to quickly recharge the start battery and LA batteries in particular. Because LFP batteries have a very flat charging profile they will take as much charging current as the alternator can provide, this can cause overheating which will destroy the electronics in the alternator. Some internally regulated alternators do have thermal controls which reduce the alternators output.

2800 KWh of LFP batteries is not really enough power for a 2KW inverter. The batteries will drain quite quickly.

There is no need for the Orion Tri Smart. If you are going to connect the alternator directly to the LFP batteries, you must use an externally regulated alternator with a regulator that can be programmed to charge the LFP batteries. Using a stock internally regulated alternator will result in a damaged alternator and/or a damaged LFP bank. Using the Orion Tri-smart in the circuit may well damage the alternator as it will pull as much current from the alternator as it can.

On average solar panels can be expected to provide 3 times the nominal rating of power per day; a little more on bright sunny days, a lot less on overcast and rainy days. Better quality panels and more efficient panels will produce a little more, lesser quality panels less. The 500w will on average produce about 1500kwh (125ah) per day. It is better to have separate controllers for the panels, for many reasons.

Not much to add to the N2K system, except Depth and Speed are usually in one transducer with one connection. Older instruments had separate transducers.

 

[paulstraw]

Thanks for all the thoughts and feedback! In no particular order:

1. Diagrams: Various updates based on feedback. I've attached scalable PDFs with larger text.
2. Alternator: After reading through the responses here, some posts on the Victron community archive (this thread in particular), and going through the Orion manuals again, I think I have a better grasp on how this should be set up. Davidasailor26, good callout on the programmable output current limit of the Orion XS, that seems like a good fit.
   
   The alternator will now be connected to the starter battery along with a Orion XS 12/12-50A to charge the house bank. Additionally, a Orion-Tr Smart 12/12-18 will be connected from the house bank back to the starter battery which can be turned on to charge the starter battery from shore/solar power.
3. House bank/solar capacity: Agreed the house bank was previously specced too small. I upsized it to ~4.8kWh, the same capacity as in our RV (Sprinter van) build. Four 160W panels (2S2P) was enough to keep us off the grid for weeks at a time, and we lived full time in the van for two years. Solar controller was also too small before, upsized.
4. Inverter size: The inverter will likely be off most of the time. Almost all of our typical loads will run directly off the 12V house bank. The inverter has two main use cases for us:
   1. Powering a high current AC device like a hair dryer for a short period.
   2. Charging various other medium/large battery packs (e.g. personal mobility devices). I understand that there will be double losses in this case from DC -> AC -> DC, but that's a hit I'm willing to take for simplicity for these various devices. I may add additional task-specific DC-DC chargers in the future.

EDIT: After thinking about it a bit more, I will probably replace the Smart IP43 12/50 and separate inverter with something like the MultiPlus inverter/charger. This would allow one set of AC outlets, and I think maybe replace the Orion-Tr Smart 12/12-18 house -> starter charger. Updated electrical diagram. Need to get back to the boat to measure for that and many other things!

 

[jssailem]

It looks improved.

You may want to consider a master power switch before the DC panel which provides for engine - house - or combined, this is what I did.


You may also want a power bar for those always-powered connections, like an always-on bilge pump.