Modern lithium setup for boats

[s/v Jedi]

Originally Posted by BAD ORCA

Thanks for your unending patience. Its slowly starting to sink in.

Ha! yes i have watched Sail Life from when he was on Obelix. To be honest, I cant stand boats like Athena. Im slanted towards a purist in a lot of what i do and the idea of air conditioning and washing machines on boats is an abomination, but i do respect very few people are like me so to each their own. I guess i get more satisfaction in 'roughing it'.

Im still in the refit stage and hope to sail in high latitudes mostly where solar will be of little use. Im expecting my alternator/engine will do most of the work with the help of a Watt & Sea type tow generator, so im upsizing my diesel tanks to help with the load.

I appreciate that you take the time to write all these posts though...the electrical and the electronics that integrate it into a cohesive system are the most exciting part of the rebuild to me. I'm learning a lot from these type of posts considering i knew pretty much zero only a few years ago...

I am puzzled by your comments. You have a sailboat that you on purpose make dependent on fossil fuels?! And you find a washing machine and A/C an abomination aboard a cruising sailboat that you actually live on? How will you wash your clothes? It’s mind boggling, I don’t think it’s possible. You also severely limit your time out cruising because when you run out of fuel you run out of power and the next fuel station may be a thousand miles away!

For solar, you simply need to install more for higher latitudes.

[rslifkin]

Originally Posted by s/v Jedi

Yes, I find the negatives of the 2x120V a complete disaster. I see no use of 2x120 when the voltage between L1 and L2 is 0V on inverter and 240V when on shore power or generator. Completely useless imho.


I see zero disadvantages of using 230V Multiplus units in combination with an auto transformer. The Multiplus units are not in a split phase configuration… they are in parallel service just like the 2x120V units would be and thus you also get the full 6kVA output regardless of balance issues.

Then the generator. I have a Northern Lights 6kW unit 120V 50A that I could very simply change to 240V 25A. All I had to do is change two jumpers to put the output windings in series instead of parallel and on the voltage regulator change the jumper from 120 to 240 and done. I don’t even have the neutral wired from either generator nor shore power, just L1 and L2.

I could easily convert the generator to 120/240 split phase on my boat if needed, so that's not an issue. But if I were to go with either inverters just on L1 or with the 2x120 then the generator can stay wired for 120 single phase.

Requiring 240V input from shore power is a deal breaker for me. If I can't power the boat from a single phase 120V shore power feed in at least some capacity, then anywhere I go that only has a single 120V / 30A connection available means I cannot plug the boat in at all. And that also means that when the boat is on land for winter, I have no way to power it up while doing work on it, as there's rarely more than a single 120V connection available.

So if I went with the 240V Multiplus + autotransformer solution, I'd need to include a separate 120V shore power input and an additional transformer for 120 -> 240 step up (allowing power to either come in as 120/240 split phase or as 120 single phase and step up to 240 depending on which inlet I select). And in that situation there's still a restriction to 32A for imbalance between L1 and L2 on the boat panel due to the Victron autotransformer (even the 100A version has that restriction). And I'd need to find space for 2 autotransformers.

The operating method of the Multiplus 2x120 doesn't work if you have any 240V equipment on board. But if everything is 120 and wired either L1 - Neutral or L2 - Neutral, then it's fine, as nothing cares if L1 and L2 are in phase or out of phase. The only flaw is that L2 doesn't get power assist when you have split phase shore power coming in (which may be a deal breaker in some installations).

Realistically though, I'm thinking that for me it might make sense to just stick with only inverting L1 and leaving L2 alone (and accepting that I have to manually account for whether I'm using HVAC when setting the input current limit on generator power). Switching the shore power configuration to use a 120/240 inlet, etc. looks to be about $1500 worth of new power inlets, power cord, adapters, etc. to replace the current equipment.

[Mal Reynolds]

Originally Posted by wholybee

Does a 50A/48V alternator generator less heat than a 200A/12V? Both 2400W, but I would expect the 48V to run cooler. Not sure though.

Much less heat is intrinsically generated at higher voltages for the same output power. Joule's Law of heating says that heat produced is proportional to the square of current or

Heat = I^2 x R x Time

In electrical systems, all efficiency loss is heat making 48v systems compelling and why the world will eventually move there.

[s/v Jedi]

Originally Posted by sleepy

jedi what do u think of the balmar alt protection module?

Well… they are not in my diagrams so that says enough

If you depend on these to prevent damage from a HVC or LVC then your setup is wrong, because these are a last effort device meant for when other safeties fail.

This means that when you use an alternator direct to LFP without an LA battery connected directly to the alternator then you need a BMS that can stop the alternator field before disconnecting. If your BMS can’t do that then you need a better one or use a dc-dc charger like in my diagrams.

[noelex 77]

There is no perfect electrical system for a cruising boat. Everything is a compromise.

Just because you can fit a complex electrical system with a generator, wind, hydrogeneration,
multiple inverters etc does not mean that this is the best option.

The danger with complex systems is that so much time in spent in repair/maintenance/troubleshooting etc that little time is left for the real joy of cruising (exploring ashore, snorkelling etc).

A relatively simple, but well designed, electrical system can provide all functions such as electric cooking (in areas of reasonable solar insolation), fridge, freezer, watermaker, washing machine, heating, hot showers etc. There is no need not to live in luxury. These are relatively simple requirements and with the right system design these goals can be achieved with a simple and reliable electrical system. KISS.

[s/v Jedi]

Originally Posted by rslifkin

I could easily convert the generator to 120/240 split phase on my boat if needed, so that's not an issue. But if I were to go with either inverters just on L1 or with the 2x120 then the generator can stay wired for 120 single phase.

Requiring 240V input from shore power is a deal breaker for me. If I can't power the boat from a single phase 120V shore power feed in at least some capacity, then anywhere I go that only has a single 120V / 30A connection available means I cannot plug the boat in at all. And that also means that when the boat is on land for winter, I have no way to power it up while doing work on it, as there's rarely more than a single 120V connection available.

So if I went with the 240V Multiplus + autotransformer solution, I'd need to include a separate 120V shore power input and an additional transformer for 120 -> 240 step up (allowing power to either come in as 120/240 split phase or as 120 single phase and step up to 240 depending on which inlet I select). And in that situation there's still a restriction to 32A for imbalance between L1 and L2 on the boat panel due to the Victron autotransformer (even the 100A version has that restriction). And I'd need to find space for 2 autotransformers.

The operating method of the Multiplus 2x120 doesn't work if you have any 240V equipment on board. But if everything is 120 and wired either L1 - Neutral or L2 - Neutral, then it's fine, as nothing cares if L1 and L2 are in phase or out of phase. The only flaw is that L2 doesn't get power assist when you have split phase shore power coming in (which may be a deal breaker in some installations).

Realistically though, I'm thinking that for me it might make sense to just stick with only inverting L1 and leaving L2 alone (and accepting that I have to manually account for whether I'm using HVAC when setting the input current limit on generator power). Switching the shore power configuration to use a 120/240 inlet, etc. looks to be about $1500 worth of new power inlets, power cord, adapters, etc. to replace the current equipment.

No, my diagrams do not require 240V shore power. They will accept 120V 30A -or- 240V 15A.

This is the second time I have to explain this… isn’t my diagram clear in that?

[rslifkin]

I took another look and now I see what I'm missing. The systems you drew assume the biggest shore power input you'd want is a single 120V / 30A (3600 watt) feed. That's where my problem comes in. I'm working with a system that can take far more shore power input than that. As configured currently, I can take in 12kw of shore power. A single 120V / 30A feed wouldn't be adequate in my situation even with power assist, as if I want to run all 3 HVAC units I'm already well above that. If the weather is hot enough and I want to run anything else on board my average load could easily be well above 3600 watts, meaning I'd be constantly drawing down the batteries even with the boat plugged in. At which point I'd better hope it stays sunny.

For my situation I want to be able to use a 120/240 volt split phase input at either 30 or 50 amps (depending on what it's adapted to on the shore side) or a single phase 120V feed at 15 or 30 amps. That's where things get complicated (both due to the larger amount of power involved and needing to take power from 2 different input voltages. Wanting the ability to use 50A feeds instead of 30A means the nifty auto voltage converting isolation transformer Victron makes won't work (it only comes in a 3600 watt rating).

Realistically, when traveling we only bother to plug in if we're staying somewhere for more than a couple of nights or the weather requires HVAC, so handling high sustained HVAC loads is the most important purpose for shore power.

[JustMurph]

Originally Posted by noelex 77

There is no perfect electrical system for a cruising boat. Everything is a compromise.

Just because you can fit a complex electrical system with a generator, wind, hydrogeneration,
multiple inverters etc does not mean that this is the best option.

The danger with complex systems is that so much time in spent in repair/maintenance/troubleshooting etc that little time is left for the real joy of cruising (exploring ashore, snorkelling etc).

A relatively simple, but well designed, electrical system can provide all functions such as electric cooking (in areas of reasonable solar insolation), fridge, freezer, watermaker, washing machine, heating, hot showers etc. There is no need not to live in luxury. These are relatively simple requirements and with the right system design these goals can be achieved with a simple and reliable electrical system. KISS.

Horses for courses. Do what makes you happy!

It needs to be reinforced that having a well designed modern system IS about simplicity. I designed and built my system so that I just didn't need to worry about power at all on a day to day basis and so I could run my dive compressor electrically.....and that exactly what it's done for me. I don't need to think about how much power I'm using, I don't need to worry about flat batteries, I don't need to think about managing power sources, I don't need to think about charging batteries before making hot water....it just does its thing. Everything is properly designed, sized and protected. 3 years in and it's been bullet proof.

What Jedi has proposed certainly can be simplified depending on the use case. I have a performance cat, so minimising the number of heavy items is important. For example, I have no shore power, isolation transformers or autotransformers. Solar covers 99% of my load, with a small petrol genny as the back up that gets used maybe once a year when it's rained for a week straight, or we're running the dive compressor for multiple days in a row.

Some of the redundant components can be removed, just as long as you understand the impact of that component failing and can tolerate that, or have a backup. E.g. I have a single 5kW multiplus, because I can live without all of the big AC loads. I do have a small sine wave inverter as a backup for critical charging applications. I have one 24->12V converter, but can easily parallel the house 12V bus into the start batteries. For longer voyaging I will carry a spare.

[Toccata]

Not mentioned to date is diesel powered cooking/heating.
Perhaps this is this an anathema in todays age?
I am currently refitting a Stuart 47 (wheelhouse style motor sailer) The electrical diagram by Jedi looks incredibly comprehensive and will inform my electrical design, with the addition of a diesel oven, cooktop and hydronic heater.
The Wallas Diesel equipment (beautifully made in Finland) should unload the electrical system making it balance easily with smaller solar input.
Fuel consumption will be interesting comparing electrical generation (via diesel engine) with direct burning of diesel in the cooking equipment. I wonder which will be more efficient?

[noelex 77]

Originally Posted by JustMurph

Some of the redundant components can be removed, just as long as you understand the impact of that component failing and can tolerate that, or have a backup.

Reliability and redundancy are vital for a long distance cruising boats that are visiting remote places. The first step is is to simplify systems. Complex systems are inherently less reliable.

Simple systems are more reliable and failure of individual component’s are less likely to bring the system down.

Ideally redundant systems are independent. For example we can cook using electric systems (our preferred option), propane or diesel.

In contrast multiple means of achieving electric cooking (such as multiple inverters, generator etc ) have less, not more, versatility and redundancy.

[s/v Jedi]

Originally Posted by rslifkin

I took another look and now I see what I'm missing. The systems you drew assume the biggest shore power input you'd want is a single 120V / 30A (3600 watt) feed. That's where my problem comes in. I'm working with a system that can take far more shore power input than that. As configured currently, I can take in 12kw of shore power. A single 120V / 30A feed wouldn't be adequate in my situation even with power assist, as if I want to run all 3 HVAC units I'm already well above that. If the weather is hot enough and I want to run anything else on board my average load could easily be well above 3600 watts, meaning I'd be constantly drawing down the batteries even with the boat plugged in. At which point I'd better hope it stays sunny.

For my situation I want to be able to use a 120/240 volt split phase input at either 30 or 50 amps (depending on what it's adapted to on the shore side) or a single phase 120V feed at 15 or 30 amps. That's where things get complicated (both due to the larger amount of power involved and needing to take power from 2 different input voltages. Wanting the ability to use 50A feeds instead of 30A means the nifty auto voltage converting isolation transformer Victron makes won't work (it only comes in a 3600 watt rating).

Realistically, when traveling we only bother to plug in if we're staying somewhere for more than a couple of nights or the weather requires HVAC, so handling high sustained HVAC loads is the most important purpose for shore power.

I also have a 12kW shore power feed…. in addition to a 3.6kW shore power feed. That said, the 12kW feed requires a 120/240 50A pedestal outlet.

But my system design has the rule that you must have enough power to switch on any normal loads without needing shore power or a generator or even solar. So your inverter/chargers and batteries must be able to carry that load.

Next you look at average consumption. You don’t have to use less than the 3.6kW shore power from my diagram because you have solar…. right? How many kW of solar?

An 16,000btu A/C uses about 900W on average so three of those is 2,700W.

But with such high A/C use, you get into a very fringe part of this, not average at all. Also I understand you have a motorboat and my system is for sailboats. Motorboats often go from marina to marina because they need shore power while my system is designed to set you free from shore side facilities.

[s/v Jedi]

Originally Posted by noelex 77

Reliability and redundancy are vital for a long distance cruising boats that are visiting remote places. The first step is is to simplify systems. Complex systems are inherently less reliable.

Simple systems are more reliable and failure of individual component’s are less likely to bring the system down.

Ideally redundant systems are independent. For example we can cook using electric systems (our preferred option), propane or diesel.

Multiple means of achieving electric cooking (such as multiple inverters, generator etc ) have less versatility and redundancy.

I can cook on diesel… I simply start the diesel genset

[noelex 77]

Originally Posted by s/v Jedi

I can cook on diesel… I simply start the diesel genset

But a diesel gen set is inherently less reliable and requires far more maintenance and specialised parts than a drip fed diesel heater.

In addition it requires a working electric cooking cooking appliance (induction stove or similar) as well as well as robust electrical system to distribute the power.

There is no perfect answer, but this option inherently less reliable than having multiple independent cooking systems such as electric, propane and diesel. The suggestion that installing a complex electrical system relying on generators etc is more reliable is false.

[s/v Jedi]

Originally Posted by noelex 77

But a diesel gen set is inherently less reliable and requires far more maintenance and specialised parts than a drip fed diesel heater.

In addition it requires a working electric cooking cooking appliance (induction stove or similar) as well as well as robust electrical system to distribute the power.

There is no perfect answer, but this option inherently less reliable than having multiple independent cooking systems such as electric, propane and diesel. The suggestion that installing a complex electrical system relying on generators etc is more reliable is false.

Yet you can wait all day watching your diesel tank but it won’t fill by itself while my batteries do. Independence from fossil fuels means independence from shoreside fuel stations, which is very handy when there’s no such stations anywhere near you

[noelex 77]

Originally Posted by s/v Jedi

Yet you can wait all day watching your diesel tank but it won’t fill by itself while my batteries do. Independence from fossil fuels means independence from shoreside fuel stations, which is very handy when there’s no such stations anywhere near you

.

I am advocating doing without a diesel generator.

With a well designed solar power system can cover the electrical demand in areas of reasonable solar insolation without the need for any diesel consumption.