Electrical System Design for Lagoon 380?

[BrettB]

Hi All,

Apologies in advance for my lack of knowledge. Still learning and reading more and more every day... Unfortunately, I did flunk out of the Electrical Engineering department, in college.

The admiral is getting pretty frustrated as our new-to-us 2007 Lagoon 380 S2 (220V/50Hz) has batteries that are near death.

I'm looking for feedback in my design and suggestions, so that I can get moving and make the admiral happy again.

We plan to go cruising for about 2 years and want to the system to be versatile and hopefully live mostly off the sun.

Current System:
Batteries - 3 x Superior American 4D-HD
Shore Charger - True Charge 40
Alternator Charger - ProIsoCharge 2.4
Inverter - None
Solar - None
Generator - None

My Design:

Batteries - 3 x LiFePO4 300 Ah

Battery Monitor - Victron BMV-200

Charger/Inverter - Still not sure which one... Suggestions?
Victron Energy Quattro 12/3000/120-50/50 230V Inverter/Charger
Magnum MS2712E 2700W 12VDC Pure Sine Inverter Charger
Dolphin All-in-one 399123 - 12V 40A (seems versatile on the shore power front, 85V-265V,50 - 60Hz +/- 10%)

Solar - 4x270 Watt Kyocera & 2xOutback FM60 MPPT, to be installed when we get over to Florida

Alternator Charger - Do my charger/inverter handle this now? or do I need a new one? or will the ProIsoCharge 2.4 be just fine?
*** Engines will be our primary form of charging until we get our solar installed, after that, I hope it will serve as backup.

Generator - None? Perhaps get my Honda EU20i that came with the boat up and running to also serve as a backup.


What should I change and what am I missing? Thanks so much in advanced for all the help and suggestions!

[Suijin]

First of all, I think given your level of knowledge and familiarity with charging systems that going with LiFePO4 is a bad idea. They require a very carefully designed system and specific care. I know several seasoned electrical veterans who won't touch them for a variety of reasons. Just because they are the "latest and greatest" does not mean they are for you.

Second, have you created an energy budget? Do you know how much juice you need? Offhand, your solar looks like it will be more than adequate, but it all comes down to your projected use.

The Victron is OK. I have that unit. I use it pretty exclusively to monitor volts and amps in; it's "SOC" function is a bit tenuous. If you want something better, consider a Balmar Smart Gauge.

I think you need a beefier solar controller than that Outback. If my napkin math is right you're looking at a theoretical throughput that is 50% higher than what that one is rated for. Yes, you'll never see that, but it's wise to size your controller for it.

What alternators do you have now? I think the Promariner product you listed is just an isolator, not a regulator. Are your alts internally or externally regulated, and if the latter, with what? If you don't know the answer to that, you should definitely not be considering LiFePO4 batteries...

[DeepFrz]

Bret, there are numerous battery threads on CF. Another good resource is:
Welcome To MarineHowTo.com Photo Gallery by Compass Marine How To at pbase.com

Under the search button, at the bottom of the drop down box, is an item labeled "Google Custom Search". I suggest you learn to use that in order to search the CF forums. The regular search function is really horrible, IMHO.

[noelex 77]

Originally Posted by Suijin

I think you need a beefier solar controller than that Outback. If my napkin math is right you're looking at a theoretical throughput that is 50% higher than what that one is rated for. Yes, you'll never see that, but it's wise to size your controller for it.

The Outback regulators were 2x, but the rest of your post is great advice.

Other points for the OP:

The key of any successful system is to have the potential to on average produce more power than you use. As we don't know what you want to run, it is hard to predict if you wilł be happy with your new system although solar power is always wonderful. One of the big advantages of cats is the space to fit so much solar.

See if you can put off the new batteries until you get the charging side sorted out. It is a shame to subject new batteries to a low SOC, even lithium, although as Suijin points out this chemistry may not be the best fit in your case.

Consider some of new high efficiency solar panels. If they fit in the space, you will squeeze in a few more watts and it sounds like solar is going to be your main charging source.

You need 4 lithium cells in series to create a "12v" battery.

[BrettB]

Originally Posted by Suijin

I know several seasoned electrical veterans who won't touch them for a variety of reasons.

What are their main reasons for avoiding LiFePO4, other than cost?

Originally Posted by Suijin

Second, have you created an energy budget? Do you know how much juice you need? Offhand, your solar looks like it will be more than adequate, but it all comes down to your projected use.

Did some rough calculations that landed me at around 500Ah/day. Need to still tune the details and I am also working on trimming the usage, such as switching to LEDs. Will look more into my fridge as well.

It will be my wife and I most of the time with the occasional visitors. We like our share of technology and the occasional 1500W appliance, electric tea kettle and sous vide, but we also have no problem with some conservation. Most of our usage is before dark, but considering wind too, if we still need after dark generation.

Originally Posted by Suijin

The Victron is OK. I have that unit. I use it pretty exclusively to monitor volts and amps in; it's "SOC" function is a bit tenuous. If you want something better, consider a Balmar Smart Gauge.

Thanks for the recommendation. I went back and forth on the Balmar vs Victron, will look into it some more.

Originally Posted by Suijin

What alternators do you have now? I think the Promariner product you listed is just an isolator, not a regulator. Are your alts internally or externally regulated, and if the latter, with what?

Will look into this more. We have alternators on each engine. And looks like you are correct, the Promariner is just an isolator. What would you recommend for regulation?

Originally Posted by DeepFrz

Brett, there are numerous battery threads on CF. Another good resource is:
Welcome To MarineHowTo.com Photo Gallery by Compass Marine How To at pbase.com

Under the search button, at the bottom of the drop down box, is an item labeled "Google Custom Search". I suggest you learn to use that in order to search the CF forums. The regular search function is really horrible, IMHO.

Thanks for these tips.

Originally Posted by noelex 77

See if you can put off the new batteries until you get the charging side sorted out.

You need 4 lithium cells in series to create a "12v" battery.

Unfortunately, I've load tested our current batteries and they are gone. Fridge can't even stay cold when we are connected to shore power.

Where is the edit button, when I need it! Would love to add my additional details above... I also meant:
Batteries - 3 x LiFePO4 300 Ah 12V batteries, in parallel.

[PaulinOz]

My advice is go bigger with the solar, 2 x Outback 80's and 2,000 watts of solar is what I have and I still wish for more power.

Usage seems to always be 10% more than generation capabilities.

I just came back to marina after being out on anchor for a month, Australian Summer still needed to run generator 3 times to make up for lack of solar on cloudy days.

You will never here some one say I wish I had less solar panels on the boat, Mounting hardware and Installation cost more than the panels do.

[kcj]

I have a lagoon 470 and recently did the conversion to lifepo from gels-- while on a mooring ball. Best $4k I have spent. Thought I'd be happy running the genset an hour a day--now I run it a hour every three days, but I am in sofla/Bahamas with 750 w of solar. I'm going to rewire the hot water heater to run off the inverter so I don't have to run the genset just for hot water.

Some thoughts:
First, as mentioned above, read and research and repeat. The threads here and on Maine sails site are the best. But there are others. Absorb and try to understand it all-- then figure out what works for you. Take notes and reread. And reread. And understand.

I had 720ah of gels-- replaced with 600ah of calbs. 6p4s. Too much maybe, I think just right. Used 100ah cells because they fit right in the battery box.

You must monitor low and high side voltages, at pack and cell level. I use a celllog 8 and a house bms high side cutoff. Note that House bms is no longer available.

Once I was comfortable with the system requirements (see above), the toughest part was 1) getting the old batteries off of the boat and 2) installing the load contactor wiring. The contactor install was particularly awkward. It is a boat after all.

If you live on the boat and are good at monitoring things, the celllog monitor may be sufficient. The bms is inexpensive insurance. I keep a daily log of voltages and charging etc. in order to gain a deeper understanding of my system.

For two months since install the pack voltage has mostly ranged from 13.5 to 13.0v and the cell differential is around 10-15 mv.

I find that it helps to be involved with understanding how your entire system works--in fact intrigued by it. Lifepo is an ongoing process. This is not set it and forget it. If there are terms above that you do not understand there is a lot more of learning to do. I did not understand them all at first....

For your system -- I use externally regulated alts on each engine, the Maine sail 80ah with a balmar 614 reg. I chose the 80s because they were the largest I could put on my yam 38hp with out a serpentine belt kit. I mostly want to be able to shut the Alts off during long motor/ motorsails to prevent overcharge.

Get as much solar as you can fit. I have an outback controller and it is fine.

I am using a 100a victron charger, if money were no object I'd add a pro ultra charger to it, just to make genset times more efficient. The Honda may be sufficient. I'd get the biggest pro ultra charger the Honda can run. Covers shore anD genset charging

Making separate load and charge circuits was not too difficult from my existing setup. Use fuses liberally.

Ymmv. Good luck with the process!

[Suijin]

Originally Posted by noelex 77

The Outback regulators were 2x, but the rest of your post is great advice.

Oops used 12v instead of the native voltage output (38?) of the panels. At least I assume that was my mistake...I'm designing my own install presently so please correct me (further lol) if I'm wrong!

[jbinbi]

I have a 1 yr old 380. Came with 3 x 140 exide wet cells. 40A cristec charger. stock alt on 2 x 29 yanmars.

I made sure all lighting is LED. I have 2 chartplotters/AIS/AP/Radar, and 1 refrig. I use the boat mostly for sailing during the day, where the big loads are nav and refrig, and nightime is LED lighting and refrig. I also rarely use radar. If I was sailing during the nights as well, I would most certainly have radar on, and that would change my power budget. I use about 60 to 100 Ah depending upon how much sailing I do

So my config gives me 200Ah a day I can use till batteries go to 50%.

If you run both the engines for an hour a day, you probably are topping off the batteries from what you would use. If you are going port to port each day, this would almost always occur. If you are going a week without an anchorage, not so much.

I am on a mooring ball, I added 2 x 285 solar, with 2 x 20A controllers. The panels sit off the davits. There is not a heck of a lot of room up on the bimini without sacrificing space for you to move up there, plus it will be heavily shaded, but you can get another 500 watts up there. The 450/470 guys maybe don't realize just how much bigger their boats are;-)

I am looking to add a 4th battery for a total of 560Ah. I think that is all that will reasonably fit and still allow me some room to work under the port rear berth.

It had seemed that somewhere between at 0.8 to 1.2 ratio of watts to AH capacity is what most people were doing. YMMV.

[DeepFrz]

If you can't keep your fridge cold while on shore power you have another problem and I would suggest that problem is why your batteries have failed.

[noelex 77]

Originally Posted by Suijin

Oops used 12v instead of the native voltage output (38?) of the panels. At least I assume that was my mistake...I'm designing my own install presently so please correct me (further lol) if I'm wrong!

No. This is one of the common mistakes people make when they buy a controller.

The rating of a controller is normally the maximum current the circuitry can handle. The output current is always greater than the input current for a MPPT controller so this is the limiting factor.

So a 60A controller has a maximum output of 60A. So with a panel like the Sunpower models which put out about 57v the input might only be 20A, but this would still greatly exceed the capacity of the controller in a 12v system because the output would be over 90A at 12v.

To complicate things further, many controllers exaggerate their current handling capacity. If you read the fine print it will often specify the current rating only applies at say 20° C, which means the 60A controller is not really a 60A controller.

To ease this confusion most manufacturers specify the maximum array size. This is the simplest number to look at.

For the Outback 60 this is 800w @ 12v and 1600w @ 24v.

So your contention that a 1080w array will overload an outback 60 in a 12v system is completely correct, but the OP states he will be using 2x Outback 60 which I take to mean he will have two Outback 60 regulators. Each will only have to handle 540W, which is fine.

[smac999]

Originally Posted by BrettB

Did some rough calculations that landed me at around 500Ah/day

Unfortunately, I've load tested our current batteries and they are gone. Fridge can't even stay cold when we are connected to shore power.

500/day is huge! Most sail boats are probably under 200.

The fridge comment makes no sense. You have other issues then.

[BrettB]

I got 500Ah with electronics usage on passage, rather than being on the hook. Just trying to be conservative, so I don't wish for more later.

I know they are more expensive than putting cells together, but looks like some of the 12V batteries, such as the 12V 300AH RELiON LiFePO4 Batteries have an auto Low Voltage Cutoff of 8V and auto Over Voltage Cutoff of 16V, which will hopefully provide some protection.

Right now I am looking more into alternators/regulation. And will definitely look more into my fridge first thing when I get back to the boat tomorrow.