LFP 48V Battery & Smart AC Inverter Charger

[SOLAR SUPPORT]

Hello everyone, We're in the process of investing in a smart inverter charger, which we plan to install on a friend's boat. It connects to a 48V LFP battery pack and integrates both a solar MPPT and AC-DC battery charger. Because this device has two MPPT inputs, we'll be using the energy from the solar panels via two separate lines at 150V. This smart inverter also includes a powerful pure sine wave inverter, a powerful AC-DC battery charger, a control panel for monitoring the operation of each device, and Wi-Fi connectivity for remote monitoring of production and consumption data. I'm aware of the disadvantages of using this system on boats, but I'm also aware of its advantages. Any feedback from those with similar equipment and installations regarding their own experiences would be greatly appreciated.

Using AC-DC converters powered by the smart inverter, the 12V LA service, engine, and bow thruster battery packs in three different areas of the boat will be powered, maintaining a constant 100% charge and floating level. The smart inverter will serve as the primary AC power source for all AC devices used in a home, enabling them to be used onboard the boat. The smart inverter and 48V battery system will be supported by the onboard generator on days when solar power is insufficient.

The technical specifications table is attached to this post. If you notice any technical features of the system mentioned above and the table that you believe may cause problems, please comment and explain the reasons. Thank you.

[Dockhead]

I don't know why you think there's anything unusual about such a setup.


Surely 90% of cruising boats in the last 20 years have inverter/chargers.


The overwhelming favorite device used in this community is the Victron Multiplus which is specifically designed for this use case. The prices for these have fallen to half of what they were years ago, and I don't see any good reason to use anything else, and certainly not some no-name, off-brand Chinese device. You won't be saving enough money for that to be worthwhile.


The usual setup on cruising boats is all your AC power, whether shore power or generator, goes through the Multiplus, which is the heart of the electrical system, connecting the AC and DC parts of your systems. You can use the "Power Assist" function to boost weak AC power using power from your batteries.


Solar controllers are normally connected to the DC side and not integrated with the charger/inverter.


You're looking at this, right? https://www.scribd.com/document/8098...%80%E6%96%B0-1


It's hard to tell, but it doesn't look like you have any control over the charge profiles.


If it were me, I would not take a risk with such a device.

[SOLAR SUPPORT]

The Multiplus boasts high quality standards, but it lacks two high-capacity solar MPPT chargers and solar power integration. In my country, the Multiplus device costs three times more per kW compared to a smart solar inverter and charger. The combination of many modular devices in one box, their integration with each other, and the fact that they are all housed in the same box simplifies wiring and reduces overall costs.

Smart solar inverter chargers, developed for off-grid operation of LI batteries in homes, have a very low kWh cost because they are produced in large quantities across a wide range of power levels. It is possible to economically utilize such hybrid devices with sufficient capacity to provide the AC power required onboard, as well as the energy required by the existing 12-24V system. There is no need for any modifications to the service, engine, bow thruster battery banks, or alternator systems, which operate smoothly onboard.

The increasing use of AC energy on boats, coupled with the reduced wiring and inverter costs associated with the adoption of 48V, provides significant advantages. Boaters' need for a wide range of useful AC appliances, such as infrared stoves, hot and cold air conditioners, water makers, and more, creates a high AC power requirement. Such needs naturally arose after the transition to LA-LFP batteries. This AC power requirement is no longer met with the existing 12V or 24V batteries on board.

As explained in my first post, the existing low-voltage battery banks and alternator systems onboard will be maintained, and three separate battery banks will be continuously charged with AC energy from the smart inverter. The cost of AC power cables to the battery groups is quite low. The smart solar inverter charger system, connected to the 48V LFP battery pack charged by solar energy/shore power/generator, will operate isolated from the existing low-voltage system and will meet all AC power requirements onboard.

[Dockhead]

Originally Posted by SOLAR SUPPORT

The Multiplus boasts high quality standards, but it lacks two high-capacity solar MPPT chargers and solar power integration. In my country, the Multiplus device costs three times more per kW compared to a smart solar inverter and charger. The combination of many modular devices in one box, their integration with each other, and the fact that they are all housed in the same box simplifies wiring and reduces overall costs.

Smart solar inverter chargers, developed for off-grid operation of LI batteries in homes, have a very low kWh cost because they are produced in large quantities across a wide range of power levels. It is possible to economically utilize such hybrid devices with sufficient capacity to provide the AC power required onboard, as well as the energy required by the existing 12-24V system. There is no need for any modifications to the service, engine, bow thruster battery banks, or alternator systems, which operate smoothly onboard.

The increasing use of AC energy on boats, coupled with the reduced wiring and inverter costs associated with the adoption of 48V, provides significant advantages. Boaters' need for a wide range of useful AC appliances, such as infrared stoves, hot and cold air conditioners, water makers, and more, creates a high AC power requirement. Such needs naturally arose after the transition to LA-LFP batteries. This AC power requirement is no longer met with the existing 12V or 24V batteries on board.

As explained in my first post, the existing low-voltage battery banks and alternator systems onboard will be maintained, and three separate battery banks will be continuously charged with AC energy from the smart inverter. The cost of AC power cables to the battery groups is quite low. The smart solar inverter charger system, connected to the 48V LFP battery pack charged by solar energy/shore power/generator, will operate isolated from the existing low-voltage system and will meet all AC power requirements onboard.

I'm not aware that LFP power systems has widely affected how people use AC power on board. We live on board more or less like at home so we have washer/dryer, induction cooking, etc. etc. etc., but we've had that for decades.


48V is great, and especially what concerns alternators (they run cooler for a given amount of power).


But 24v works fine too. I don't know why you would need 10.2kW of inverter power. 3000VA is plenty for most people. 5000VA in the worst case (I'll be converting to that soon). Never heard of anyone on less than a superyacht with crew of 10, who needed more than that.


I also don't know why you would want to integrate solar control with the inverter. Just use a separate controller.


And if you can't program the charge profile, then run, don't walk away from that device. You won't be able to use it with LiFePo4 batteries.

[cdoublejj]

Originally Posted by SOLAR SUPPORT

The Multiplus boasts high quality standards, but it lacks two high-capacity solar MPPT chargers and solar power integration.

expense and other reasons aside. while it's not an all in one it's not too hard to figure or watch videos on how it's all wired up.

[noelex 77]

Originally Posted by SOLAR SUPPORT

If you notice any technical features of the system mentioned above and the table that you believe may cause problems, please comment and explain the reasons. Thank you.

Have you measured the idle power consumption?

[SOLAR SUPPORT]

Originally Posted by Dockhead

I'm not aware that LFP power systems has widely affected how people use AC power on board. We live on board more or less like at home so we have washer/dryer, induction cooking, etc. etc. etc., but we've had that for decades.

Were you able to use these devices with LA batteries in the past?


48V is great, and especially what concerns alternators (they run cooler for a given amount of power).

I think we'll soon see 48V alternators in the engines of newly built large boats, and many winches, windlasses, and starters onboard powered by 48V. This environment is much more convenient to use smart solar inverter chargers.


But 24v works fine too. I don't know why you would need 10.2kW of inverter power. 3000VA is plenty for most people. 5000VA in the worst case (I'll be converting to that soon). Never heard of anyone on less than a superyacht with crew of 10, who needed more than that.

Imagine living as a small family on a modest boat. When you generously calculate people's daily needs for water, heating, cooking, cleaning, and entertainment, you'll come up with something close to this power output.

I also don't know why you would want to integrate solar control with the inverter. Just use a separate controller.

I can't say I'd like this very much, but it's the case with all smart solar inverter chargers.


And if you can't program the charge profile, then run, don't walk away from that device. You won't be able to use it with LiFePo4 batteries.

The user manual for the similar device you sent me contains information on this, and you can find it yourself. Of course, LFP batteries are used; the era of LA in these types of devices is over.

......

[Loredo]

So that would also be called a "hybrid" inverter, right? Well, I've installed one this spring but in a 24V variant. The limitation I can see with these inverters, the MPPT's are meant for "residential" installations with larger PV arrays. I don't know how practical (on a boat) an MPPT is that's 150-500V. Also, the cheaper ones have limited support for BMS communication. Most are limited to the Pace BMS. Their ventilation fans are rather loud.


I've installed one in my boat this spring but @ 24V. I know, it's not a 48V but give me a moment to get to the point. Personally, I was searching for a 100A @ 24V battery charger. Good luck finding one at a somewhat reasonable price... Well, I got a fully blown hybrid inverter for about 250 boat bucks but I only use the charger part of it since I already had everything else in place.


To come to my point, the "some no-name, off-brand Chinese device" thing needs to be re-considered. The electron freak I've been for all my working career had to know what's inside that hybrid inverter box I got. Expecting cheapo; after very close inspection I was very surprised by the quality of the actual product I got for close to nothing (Compared to named brands.). BTW, the charge algorithm can be tailored for LFP. After several months of use I've got nothing negative to report. To come to an end, would I've known of the existence of these hybrid inverters before, I'd have gone for it.


One last consideration, I've got a 7KW "off-brand Chinese" inverter on board, twas meant as a backup but has been used as the main unit for the past three years. One, it (still) works perfectly. Two, with electric everything on the boat I've found myself having to turn off something because 7 KW wasn't still enough. A 10KW inverter for sure isn't out of mind nowadays.

[SOLAR SUPPORT]

Originally Posted by Loredo

So that would also be called a "hybrid" inverter, right? Well, I've installed one this spring but in a 24V variant. The limitation I can see with these inverters, the MPPT's are meant for "residential" installations with larger PV arrays. I don't know how practical (on a boat) an MPPT is that's 150-500V. Also, the cheaper ones have limited support for BMS communication. Most are limited to the Pace BMS. Their ventilation fans are rather loud.


I've installed one in my boat this spring but @ 24V. I know, it's not a 48V but give me a moment to get to the point. Personally, I was searching for a 100A @ 24V battery charger. Good luck finding one at a somewhat reasonable price... Well, I got a fully blown hybrid inverter for about 250 boat bucks but I only use the charger part of it since I already had everything else in place.


To come to my point, the "some no-name, off-brand Chinese device" thing needs to be re-considered. The electron freak I've been for all my working career had to know what's inside that hybrid inverter box I got. Expecting cheapo; after very close inspection I was very surprised by the quality of the actual product I got for close to nothing (Compared to named brands.). BTW, the charge algorithm can be tailored for LFP. After several months of use I've got nothing negative to report. To come to an end, would I've known of the existence of these hybrid inverters before, I'd have gone for it.


One last consideration, I've got a 7KW "off-brand Chinese" inverter on board, twas meant as a backup but has been used as the main unit for the past three years. One, it (still) works perfectly. Two, with electric everything on the boat I've found myself having to turn off something because 7 KW wasn't still enough. A 10KW inverter for sure isn't out of mind nowadays.

Thank you for sharing your experience. You mentioned that you only use your 24V Hybrid Inverter to charge your batteries at high current. I realize that not all devices have the same features and quality, but I would appreciate it if you could answer a few questions about your device's performance and operation.

A Are you using solar DC or AC energy when charging your batteries with this device? The AC energy source can be shore power or a generator; which one do you use?

B How is the communication between the BMS and the Hybrid Inverter? Can you accurately monitor the battery's charge level on the Inverter's control panel? Could you please specify the LFP battery capacity, whether DIY or drop-in, and the BMS specifications? Was there a cable for the inverter BMS connection? Were you able to make a connection with the BMS?

C: Does your device get very hot when operating at the maximum charging currents specified on its label? Does the inverter's cooling fan run constantly or run when necessary

[Loredo]

Mind you, I'm an outside of the box thinker. My DIY battery is 6p8s 1680 AH nominal. NO BMS, nope not kidding, after the third BMS that failed upon me I decided to do without. I've build triple external protections around the battery to prevent over-charging. (This works also for the hybrid.)


A) Yes, I needed more charging power when using the generator to charge the battery. I already had 2x60A chargers but running the 11KVA generator that wasn't enough load on the engine. That's when I found out about the hybrid inverter(s). I got a 5KW-24V hybrid inverter with 100A (AC) charging power. From memory on solar that would be 120A. I have no solar, nor do I plan to ever install any. I have used shore power once with the hybrid to charge the battery. Now, with 220A total going into the battery even the generator is happy.


B) Since I got no BMS, I had to use the charge algorithm of the inverter.
Easy to set up and works like a charm! I've set it to 27.6V which it does just fine. I've not tested float voltage for obvious reasons. There was an RJ45 patch cable for the communication to the BMS included. Would it talk to any BMS? I doubt it since most of the cheap ones they say works only with the Pace BMS. If you have a Pace, nice. If not? I don't know.
Yet, there are not only to ultra cheap hybrid inverters out there! Spending a bit more, Deye, Growat, EG and the like come to mind. With those BMS communication integration is far better.


C) The fan modulates based upon the internal temperature. From zero to WAY loud / annoying. Though, mine is installed behind a cabinet and almost silent. Heat is not a concern even in summer.


Yes, the cheap hybrid has it's limitations. Yet, let me say this one more time, "cheap Chinese junk" is not one of them. Eventually, the opposite is true.
At 245 boat bucks, where can one find a 100A LFP battery charger that in an emergency provides a 5KW AC output and could eventually charge the batteries from solar? Yes, of course, I wanted to use it seldom only with the genny. Should it fail, I've got backup(s). But now that I've seen it in action over a few months = Thumbs Up.


On Amazon in the EU actually a 48V 11KW hybrid inverter goes for 500-600 Euro. I'd get one and start playing with it. If it's not what you think, you've not lost too much. I've wasted much more money on way stupider things in the past...

[Dockhead]

Originally Posted by SOLAR SUPPORT

.. Originally Posted by Dockhead

I'm not aware that LFP power systems has widely affected how people use AC power on board. We live on board more or less like at home so we have washer/dryer, induction cooking, etc. etc. etc., but we've had that for decades.

Were you able to use these devices with LA batteries in the past?

48V is great, and especially what concerns alternators (they run cooler for a given amount of power).

I think we'll soon see 48V alternators in the engines of newly built large boats, and many winches, windlasses, and starters onboard powered by 48V. This environment is much more convenient to use smart solar inverter chargers.

But 24v works fine too. I don't know why you would need 10.2kW of inverter power. 3000VA is plenty for most people. 5000VA in the worst case (I'll be converting to that soon). Never heard of anyone on less than a superyacht with crew of 10, who needed more than that.

Imagine living as a small family on a modest boat. When you generously calculate people's daily needs for water, heating, cooking, cleaning, and entertainment, you'll come up with something close to this power output.

I also don't know why you would want to integrate solar control with the inverter. Just use a separate controller.

I can't say I'd like this very much, but it's the case with all smart solar inverter chargers.

And if you can't program the charge profile, then run, don't walk away from that device. You won't be able to use it with LiFePo4 batteries.

The user manual for the similar device you sent me contains information on this, and you can find it yourself. Of course, LFP batteries are used; the era of LA in these types of devices is over
....

I've been cruising for several decades; half my life. Much of that time living on board for extended periods. Most recently this whole last summer. Last 16 years with a washer/dryer on board, used frequently.


A standard shore power connection in Europe is 16A @ 220V, so about 3.6kW. That's enough power for a full-valued domestic life on board, requiring just a bit of power management. A 5kVA inverter would already be in luxury territory.


Now that doesn't including air conditioning, not necessary at my latitudes. If you need to run aircon off grid, that's kind of a different problem, and inverter capacity is not the main thing (you can always buy DC ones with their own inverters which are anyway more efficient). The main problem is producing enough power to sustain them.


You're advocating use of a system designed for on-shore solar systems. You will be a pioneer if you go with this. Maybe it will work out fine.


But if I were you I would think hard about why the whole world of cruisers lives on 3000kVA and 5000kVA and doesn't complain about lack of power. And why they use proven, marine devices for their power systems.


Now I may be insensitive to your concerns because I have a 6.5kW heavy duty, low speed generator on board. So if for some reason I need a whole ton of power, i just crank that up. But I can't remember the last time I started the generator just because 3.6kW of shore power or 3000kVA of inverter power wasn't enough. Normally I start it when I'm running the washer/dryer and doing electric cooking all at the same time, to run the heavy loads and charge the batteries all at the same time -- very efficient like that.


And yes, life on board was more or less ok with 460AH x 24v of lead golf cart batteries. Just we use so much power, that off grid I have to charge more than once a day. My goal in converting to lithium was to eliminate that, not really to increase the amount of available power, although that's a nice bonus.

[Loredo]

Do you have a full electric galley? NO propane? When one hates to run a generator...that answers your concern about 10KW or more inverter power. Besides the fact that I'm a firm believer in using (most of the time) about 50% of the rated power of everything. Stuff lasts longer this way. BTW, I've never run the AC on battery power. Never needed to. Yet, it's nice to know that I could.


The real challenge with the LFP is charging in a reasonable time. Means, whatever AC charger one might already have with lead, switching to LFP that charger becomes a joke. A hybrid inverter with it's ample charge power comes in handy.

[SOLAR SUPPORT]

Originally Posted by Dockhead

I've been cruising for several decades; half my life. Much of that time living on board for extended periods. Most recently this whole last summer. Last 16 years with a washer/dryer on board, used frequently.


A standard shore power connection in Europe is 16A @ 220V, so about 3.6kW. That's enough power for a full-valued domestic life on board, requiring just a bit of power management. A 5kVA inverter would already be in luxury territory.


Now that doesn't including air conditioning, not necessary at my latitudes. If you need to run aircon off grid, that's kind of a different problem, and inverter capacity is not the main thing (you can always buy DC ones with their own inverters which are anyway more efficient). The main problem is producing enough power to sustain them.


You're advocating use of a system designed for on-shore solar systems. You will be a pioneer if you go with this. Maybe it will work out fine.


But if I were you I would think hard about why the whole world of cruisers lives on 3000kVA and 5000kVA and doesn't complain about lack of power. And why they use proven, marine devices for their power systems.


Now I may be insensitive to your concerns because I have a 6.5kW heavy duty, low speed generator on board. So if for some reason I need a whole ton of power, i just crank that up. But I can't remember the last time I started the generator just because 3.6kW of shore power or 3000kVA of inverter power wasn't enough. Normally I start it when I'm running the washer/dryer and doing electric cooking all at the same time, to run the heavy loads and charge the batteries all at the same time -- very efficient like that.


And yes, life on board was more or less ok with 460AH x 24v of lead golf cart batteries. Just we use so much power, that off grid I have to charge more than once a day. My goal in converting to lithium was to eliminate that, not really to increase the amount of available power, although that's a nice bonus.

As I understand it, you meet most of your energy needs on a boat with shore power and a generator. When calculating a boat's energy needs, I generally try to consider that shore connection is infrequent, and if a generator is available, it will rarely be needed. It's important to consider that the boat will be sailing at sea or anchored in a bay for extended periods, at least for a few weeks. While it's possible to cover the energy deficit on board with a generator or alternator on cloudy days, it's more advantageous to meet this need in the most economical way with a sufficient LI battery bank and solar panels.

High-quality, high-capacity LI batteries and solar panels with improved efficiency are constantly improving, and Wh costs continue to decrease. I don't know how customs policies change between countries, but these products are becoming more readily available every day.

I generally prefer to live modestly on my boat, but over time, many opportunities arise, and I think it's only natural to want to take advantage of them. Ultimately, the energy demand on boats increases significantly, especially when you consider the need for freshwater production, heating and cooling, and the safer use of electric stoves and ovens instead of propane, which you prefer not to use some of them.

I believe it's important to find the most economical way to fill the energy gap that some boats experience. If you're aiming for a sustainable life as independent of shore as possible, it's worth exploring the highly economical 48V LFP battery-connected off-grid hybrid smart solar and AC charging-inverter package solutions. I want to find devices that best meet the criteria of quality, safety, and cost.

[Dockhead]

Originally Posted by SOLAR SUPPORT

As I understand it, you meet most of your energy needs on a boat with shore power and a generator. When calculating a boat's energy needs, I generally try to consider that shore connection is infrequent, and if a generator is available, it will rarely be needed. It's important to consider that the boat will be sailing at sea or anchored in a bay for extended periods, at least for a few weeks. While it's possible to cover the energy deficit on board with a generator or alternator on cloudy days, it's more advantageous to meet this need in the most economical way with a sufficient LI battery bank and solar panels.

High-quality, high-capacity LI batteries and solar panels with improved efficiency are constantly improving, and Wh costs continue to decrease. I don't know how customs policies change between countries, but these products are becoming more readily available every day.

I generally prefer to live modestly on my boat, but over time, many opportunities arise, and I think it's only natural to want to take advantage of them. Ultimately, the energy demand on boats increases significantly, especially when you consider the need for freshwater production, heating and cooling, and the safer use of electric stoves and ovens instead of propane, which you prefer not to use some of them.

I believe it's important to find the most economical way to fill the energy gap that some boats experience. If you're aiming for a sustainable life as independent of shore as possible, it's worth exploring the highly economical 48V LFP battery-connected off-grid hybrid smart solar and AC charging-inverter package solutions. I want to find devices that best meet the criteria of quality, safety, and cost.

I'm all in favor of 48v, which is definitely the best way to design a yacht power system if you're starting from scratch. There is almost no downside and lots of advantages.


But i would study well-worked out marine solutions very hard, before experimenting with systems designed for other purposes. A lot of experience and lessons learned went into developing the systems which 90% of us use, like Victron.


You will not have the kind of solar arrays those Chinese off-grid devices are designed for. You will not have the kind of solar production which would allow you to spend 10kW for extended periods. And you will really want systems which have been developed and refined to be used in the way we use them on boats, which is different in several respects from large off-grid solar systems.


What concerns my own usage -- we have zero solar, since we do some racing. Off-grid -- and we go up to months at a time without a shore power connection -- power is produced by generator or as a by-product of propulsion using a large-case heavy duty alternator on the main engine.


A huge advantage of the much larger lithium power system we have now, compared to the old lead one, is that we can harvest free power when we are using the main engine, and store up to 13.5kWH of it. I'm expecting that this will actually fulfill most of our power needs, when we're anchored for less than a few days.


Another thing to consider is charging capacity. It's pleasant, of course, to be able to fill the batteries in a couple of hours when you have AC power, but it's wrong to consider everything in proportion to the size of the bank. We don't need to top off lithium batteries like we used to have to do with lead. the main thing is how much power altogether are we getting into the batteries.


I have 560AH x 24v and presently a 70A AC charger. It takes 8 hours from 0% to 100% or 4 hours to add 50% from some other partial SOC. That's using 2kW of AC power. The charger is only 0.125C but it's storing 1.8kWH per hour, leaving a bit of extra from a 3.6kW shore power connection, so this is really not bad.


I'm planning to upgrade to 120A x 24v charger, which is 0.21C. That will be pumping 2.9kW into the batteries but will need 3.2kW of AC power, which is almost the whole capacity of a 16A shore power connection and half the capacity of my generator.


So it's not really all that big a deal. On shore power, you don't care about 5 vs 7 hours, and on generator power, I will gain something with shorter generator runs, but that's also not a big deal. Because -- I'm going to run the generator for a few hours every couple of days anyway. The question is not what percentage of capacity of my bank I get out of those runs, but what total amount of power, and is that enough to last till the next one.

[SOLAR SUPPORT]

Originally Posted by Loredo

Mind you, I'm an outside of the box thinker. My DIY battery is 6p8s 1680 AH nominal. NO BMS, nope not kidding, after the third BMS that failed upon me I decided to do without. I've build triple external protections around the battery to prevent over-charging. (This works also for the hybrid.)

Your battery bank capacity is really large. Since you're not using a BMS or active balancer, don't you have balance issues with 8s cell strings?