Lithium Battery Integration into our boats

[ttmott]

None of these were particularly great solutions.
The alternator output method relies on a temperature limitation.
The DC-DC converter has high losses.
The Sterling APD (have one sitting here on the shelf) had other issues, which don't come readily to mind.

The the last boat, the "least bad" choice was the DC-DC converter, for my application. Still wasn't particularly happy with it.

Had a couple of phone conversations with Clark (YouTube video posted above), about his bank manager. It appears to be the most elegant solution, but still requires a Lead Acid battery in the mix, to act as the 'shock absorber' when the LI BMS shuts off the charge.

Also spoke to the founders of BattleBorn (DragonFly Engineering) about the charging issue. At the time, they were working on the WakeSpeed controller. I have no experience with it, so can't opine. Maybe somebody else does.

ey were working on the WakeSpeed controller. I have no experience with it, so can't opine. Maybe somebody else does.[/QUOTE]
I'd like to discuss this some more but out of the Cat 3116 thread -
@SCFoster - I really don't understand technically what you are getting at -

The good/bad on lithium batteries is their capability of a high rate of charge. The good is they charge quickly, like 100 amps until they are 100%. The bad is using a standard engine alternator will cook as the batteries have nearly zero resistance and will allow pretty much unlimited current flow. So, if you want to have the capability to charge a Li battery bank using the boat's engine alternators the alternator needs to either be capable of the current or be tempered so is isn't damaged by heat. The highest efficiency is at that point of output where thermal conditions will not damage it. The second part is to allow a bulk charge until the battery bank is essentially 100% charged and to minimize the charge period. An engine alternator bo-haus enough to manage the battery current you are into custom alternator installations with multiple drive belts. The best solution is to have an external programmable field controller that can charge to the desired voltage, have the desired charge profile, and monitor the alternator temperature to extract the highest output. The Balmar Regulators do exactly this. What is your solution?
The second most important thing is to protect the alternator should the Li battery's BMS trip it off line. Without a buffer the alternator will certainty go high order and self-destruct. You could do an adjunct SLA battery as the buffer but then you are back to compromising the charge profile and voltage for the Li battery; a poor solution in my mind as some of the desired features of the Li battery are not used. The Sterling APD is a simple inert device that should a BMS trip occur the voltage surge will be absorbed. I think it is a perfect solution to the quandry. Can you explain why not?
I to was working with Battleborn Batteries and trying to technically use the Lithium battery as a starting bank as well as the house bank; a fellow at Battleborn named Denis Phares was working with the engineering company I had designing the system. They laid out the system as I outlined above. So I'm curious why they seem to have changed their technical position. Know why?

Thanks
Tom

 

[SCFoster]

Tom, thanks for starting the thread. It's been a few years, so I frankly don't recall the details of all of the discussions with each party.
Denis Phares advocated what is now the WakeSpeed controller. If memory serves, there were tie in requirements that my configuration wouldn't support.
Peter Kennedy at PKYS.com in Annapolis provided a lot of useful input. This was for my configuration. It became abundantly clear that each application would have enough wrinkles that 'my solution' may or may not work for or be optimal for others.
I had gone with the Balmar 170A alternator with the 600 series external regulator (I forget which specific model).
The 170A was the limitation choice due to a larger alternator not being able to have enough airflow.
But, was not a fan of just having the temperature as the limiting factor for output.
I'm going off of memory, so I could be completely off base. But, that's what I recall.

I have a Sterling APD on the shelf. I did a bunch of research and concluded it wasn't the route I wanted to go, otherwise I would have installed it. However, I don't recall the specifics. Clearly they are a suitable application for some as they are still being sold.

I do remember Victron with the external BMS as having the most elegant solution at the time. Spoke to one of their engineers at the Annapolis boat show. He drew out a pretty solid way to manage the BMS and the voltage regulator. However, the cost was too much for what I was looking to do. I think this linkage is also what the WakeSpeed controller does. Not sure how as there is no way that I know of to "talk" to a Battleborn BMS.

 

[ttmott]

ABYC has recent requirements for Li systems that are now adopted. One of the most impactful requirements is for the battery system BMS to provide advanced warning of an impending disconnect. Depending upon the scope and function of the lithium batteries a surprise disconnect can be quite catastrophic - loss of navigation aids, lighting, steerage, or even propulsion. Included in the requirement is avoiding unintended consequences like dropping off the alternators. A few of the dedicated marine lithium battery systems are in compliance with the new requirements but they are few and far between and quite expensive. The reality is that a standalone monitor system could do the same thing and not even be a part of the battery. But that is for someone yet to develop and qualify.
I have heard of the Wakespeed charge management system and it seems to be checking all of the boxes but still what does it provide that the Balmar regulators don't? Not much other than provide an alternator field disconnect before a BMS trips. The APD's will save the alternator just as effectively without the complex wiring and processing.
One thing about Battleborn is they are progressing on external data monitoring and I think actually have one of their battery lines on the market but again there is quite a premium for the feature. For us boaters we really need that integration in the NEMA 2000 protocol. Victron is already there (on NMEA 2000) but that is through their GX hardware like their CERBO. I understand their batteries are quite impressive in the data provided through the GX hardware but the downfall is limitations on electrical current and the lack of capability to series / parallel a large bank.

 

[SCFoster]

ABYC has recent requirements for Li systems that are now adopted. One of the most impactful requirements is for the battery system BMS to provide advanced warning of an impending disconnect. Depending upon the scope and function of the lithium batteries a surprise disconnect can be quite catastrophic - loss of navigation aids, lighting, steerage, or even propulsion. Included in the requirement is avoiding unintended consequences like dropping off the alternators. A few of the dedicated marine lithium battery systems are in compliance with the new requirements but they are few and far between and quite expensive. The reality is that a standalone monitor system could do the same thing and not even be a part of the battery. But that is for someone yet to develop and qualify.

At the time of the prior boat refit, the ABYC was still working on the guidance. The release of the guidance should help tremendously.

Per Clark, during our phone conversations and emails, this is what he's done with the Bank Manager. It combines the monitoring with a contactor, to disconnect the LI house bank from the charging circuit.
Since the Sea Ray 380 already has 3 sets of starter batteries, the requirement for the Lead Acid "shock absorber" isn't an issue. Might be for clean slate installs where the Lead Acid requirement is undesirable.


I did purchase one to monkey around with it, but other projects are more pressing.

I have heard of the Wakespeed charge management system and it seems to be checking all of the boxes but still what does it provide that the Balmar regulators don't? Not much other than provide an alternator field disconnect before a BMS trips. The APD's will save the alternator just as effectively without the complex wiring and processing.
One thing about Battleborn is they are progressing on external data monitoring and I think actually have one of their battery lines on the market but again there is quite a premium for the feature. For us boaters we really need that integration in the NEMA 2000 protocol. Victron is already there (on NMEA 2000) but that is through their GX hardware like their CERBO. I understand their batteries are quite impressive in the data provided through the GX hardware but the downfall is limitations on electrical current and the capability to series / parallel a large bank.

Agree 100%. Victron has the most complete solution, but then one is all in on the Victron brand. And, as you pointed out, it's expensive. Very expensive.

 

[GnrlPatton]

Thanks for starting this thread! I'm still working on building out my Lithium bank, setting it up on the bench at home before taking it to the boat. I'm building a 3x 304 aH bank (so ~900 aH total), 12 individual cells in a 3P4S configuration with all Victron equipment - Multiplus, smart shunt, Solar controller and a Cerbo. I went with a Rec Active BMS to manage the bank.

I'll have 2 legs coming off the batteries, one for the Victron leg (basically just going to the inverter/charger) and another for the non-Victron DC loads. I'm not currently planning to connect to the alternators just for simplicity, but I figure I can add it later if I really want it. I've been working on this for 18 months, just tinkering, but now have decided to simplify it so I can get it installed, and then add to it later. I had planned for active heating and cooling, integration with alternators, etc. That was too complex, so I'm simplifying it just to be done with it. I'll post up some pics later, it's been quite a learning curve getting things right.

One question I'm facing at the moment is where to put the breakers and contactors. I see conflicting info on the Rec aBMS pages, so wondering if you guys know the correct configuration (or if it even matters). I was planning on connecting battery > contactor > breaker, as in the first image, but then saw the schematic in the second where it goes battery > breaker > contactor, which is my preference for simplicity.

Contactor first:


Breaker first:

 

[ttmott]

A couple of items from my perspective -
Battery cable length - It is important for each battery (each "series") to be cabled with equal length cables to a common buss. For large Li systems like yours it's not a good idea to simply parallel the batteries together. They will not charge and discharge equally.
Victron makes this buss system called a Linx Distributor. One distributor is the fused buss from the batteries and a second is the fused distribution to the devices. You can add between the distributors a Linx Shunt also. Very cool system and not that expensive. The system for a BMS you are showing doesn't lend itself to the Linx distribution system. But in reality it would be best for a BMS for each of the paralleled batteries rather than the entire storage system. If one cell should have issues your design will trip everything off line. It would be better if it only took out that battery series.
I suppose you could have massive copper buss bars to parallel then land the negative on one end of the stack and positive on the other end to try and implement a no loss charge across all of the batteries.

 

[ttmott]

A couple of items from my perspective -
Battery cable length - It is important for each battery (each "s") to be cabled with equal length cables to a common buss. For large Li systems like yours it's not a good idea to simply parallel the batteries together. They will not charge and discharge equally.
Victron makes this buss system called a Linx Distributor. One distributor is the fused buss from the batteries and a second is the fused distribution to the devices. You can add between the distributors a Linx Shunt also. Very cool system and not that expensive. The system for a BMS you are showing doesn't lend itself to the Linx distribution system. But in reality it would be best for a BMS for each of the paralleled batteries rather than the entire storage system. If one cell should have issues your design will trip everything off line. It would be better if it only took out that battery stack.
I suppose you could have massive copper buss bars to parallel then land the negative on one end of the stack and positive on the other end to try and implement a no loss charge across all of the batteries.

A quick sketch to illustrate what I'm trying to describe -

 

[dtfeld]

There is a ABYC spec for the breaker/ fuse. I belive it is to be installed closest to the battery and there is a maximum distance from the battery that must also be met. I don't remember off top of my head but I'll see if i can find it.

12V systems are easier to integrate with existing 12V boats but the wiring/amperages/voltage drop/heat make for some challenges. I moved to a 24V (2x 304s in series) system this year. Of course this creates problems getting both batteries to the same SoC. I installed a Victron battery balancer to help keep the batteries balanced and so far so good. Not sure if there is a similar product that would work for the 3P config.

 

[ttmott]

There is a ABYC spec for the breaker/ fuse. I belive it is to be installed closest to the battery and there is a maximum distance from the battery that must also be met. I don't remember off top of my head but I'll see if i can find it.

12V systems are easier to integrate with existing 12V boats but the wiring/amperages/voltage drop/heat make for some challenges. I moved to a 24V (2x 304s in series) system this year. Of course this creates problems getting both batteries to the same SoC. I installed a Victron battery balancer to help keep the batteries balanced and so far so good. Not sure if there is a similar product that would work for the 3P config.

Dave - there are no limitations on length of battery cables without overcurrent protection. There is, however, a requirement for a secondary cable cover (chafe protection) if the positive cable is greater than XX length. Consider length of cables to the engine starter. Obviously, for the sake of cost and voltage drop, we want to keep cables as short as possible.

 

[GnrlPatton]

A quick sketch to illustrate what I'm trying to describe -
View attachment 147992

I'll upload pics and a diagram of my setup. I've actually made custom buss bars and connected the batteries with them all in a single battery box. The box has a single positive and negative connection that goes to the shunt (negative side) and then the breakers/contactors (positive side) I mentioned earlier.

I was concerned also about the BMS not monitoring each individual cell, but the research I did, I found that if the cells are properly top balanced and then you occasionally check on the individual cells, the REC BMS will do a good job of balancing and monitoring each 12v bank.

 

[dtfeld]

The spec I remember was specific to inverters and chargers for the distance from the battery to the current limiting device (fuse/breaker). For unsheathed + cable the over current had to be within X” (very short distance…I want to say 7”) of the power source, and if you sheath, it was like 7 ft. No limit on overall length, other than voltage drop becomes problematic.

 

[ttmott]

The spec I remember was specific to inverters and chargers for the distance from the battery to the current limiting device (fuse/breaker). For unsheathed + cable the over current had to be within X” (very short distance…I want to say 7”) of the power source, and if you sheath, it was like 7 ft. No limit on overall length, other than voltage drop becomes problematic.

Assuming we are talking about 100Ah 3.2 volt cells, both of these configurations will provide 12.8 volts at 300Ah.
The first is a common configuration that is economical but, like you said, unless the cells are maintained top balanced problems can ensue up to a BMS trip on overvoltage. The second issue, in the event of a BMS trip the entire system goes down. Also there are current limitations on standard BMS units unless a solenoid style is implemented like you have.
The second is less common (unless a standard packaged battery from a vendor) due to expense but also a 12.8 volt 300Ah battery system. Actually three separate batteries of 12.8 volts and 100Ah each. This configuration will maintain top balance across all batteries plus provides assurance the battery will stay active in the event of a BMS trip. That is unless something radical happens and trips all three.
If my boat was to utilize these batteries for any of the critical systems (bilge pumps, Nav, lighting, etc) I would definately implement the second.

 

[Bill Curtis]

Assuming we are talking about 100Ah 3.2 volt cells, both of these configurations will provide 12.8 volts at 300Ah.
The first is a common configuration that is economical but, like you said, unless the cells are maintained top balanced problems can ensue up to a BMS trip on overvoltage. The second issue, in the event of a BMS trip the entire system goes down. Also there are current limitations on standard BMS units unless a solenoid style is implemented like you have.
The second is less common (unless a standard packaged battery from a vendor) due to expense but also a 12.8 volt 300Ah battery system. Actually three separate batteries of 12.8 volts and 100Ah each. This configuration will maintain top balance across all batteries plus provides assurance the battery will stay active in the event of a BMS trip. That is unless something radical happens and trips all three.
If my boat was to utilize these batteries for any of the critical systems (bilge pumps, Nav, lighting, etc) I would definately implement the second.
View attachment 148004

Plus, the second is preferred so that a string may be removed from the array in the event of a problem with it or for maintenance.

 

[SCFoster]

Victron has a wealth of information and a lot of demo schematics, from which a system to fit one's needs can be designed.
Here is a link to the downloads page. The best place to start is to select Multiplus from the dropdown.

All of the pdfs can be downloaded.

 

[dtfeld]

Victron has a wealth of information and a lot of demo schematics, from which a system to fit one's needs can be designed.
Here is a link to the downloads page. The best place to start is to select Multiplus from the dropdown.

All of the pdfs can be downloaded.

Those are great. However, one of the biggest issues is how to fit all this equipment into our boats. It’s one thing to hang all this on a wall lined up side by side, as with a solar project, but quite another altogether to get it working on/in a boat.

I think their equipment is top notch, except for one thing. It’s not overly marinized/robust/waterproof. The Cerbo GX is a great example. Love the functionality, but the connections are not great for a mobile application. They are little plastic clip-in things. I’d prefer a threaded and sealed positive catch mechanism on all connections. As is, it’s pretty difficult to guarantee everything remains connected unless you add some fancy DIY zip ties.

They may be moving that direction as they recently came out with the IP65 rated Smart Shunt. It’s a little more expensive but a much better product for the bilge of a boat. Keep it coming Victron.

 

[SCFoster]

Those are great. However, one of the biggest issues is how to fit all this equipment into our boats. It’s one thing to hang all this on a wall lined up side by side, as with a solar project, but quite another altogether to get it working on/in a boat.

Agreed. I'm not a fan of putting anything in the engine bay, if at all possible. Have been noodling over how to make it happen in the 380.

I think their equipment is top notch, except for one thing. It’s not overly marinized/robust/waterproof. The Cerbo GX is a great example. Love the functionality, but the connections are not great for a mobile application. They are little plastic clip-in things. I’d prefer a threaded and sealed positive catch mechanism on all connections. As is, it’s pretty difficult to guarantee everything remains connected unless you add some fancy DIY zip ties.

They may be moving that direction as they recently came out with the IP65 rated Smart Shunt. It’s a little more expensive but a much better product for the bilge of a boat. Keep it coming Victron.

In prior installs, I've ditched a lot of their connectors, in favor of waterproof connectors. But, that's not something most folks would ever feel comfortable doing, along with the requisite testing of each and every connection.
The land based market (vans/campers & solar) is a lot bigger than marine, so it's difficult to get Victron to accept the added cost of marine grade connectors and enclosures.

My intent of the posting was actually not Victron specific. It was to provide a starting point for folks to delete unnecessary items and add one's own components.

Attached is an example of one of my rough designs, based off the Victron diagrams as the starting point.

 

[dtfeld]

I’ve been doing the same thing. One of the ideas is to convert to a 50A service. It makes a lot of things easier with the extra power it provides (if/when available) but also a lot more flexible if you have less power available as you travel.

 

[ttmott]

A word about the BMS (Battery Management System). Essential to understand is the BMS protects the battery; It does not, will not, nor is designed to protect anything on the load side of the battery; your boat.
Lithium cells that make up a battery are sensitive little things and can easily be completely destroyed in an instant by undervoltage, overvoltage, low temperature, high temperature, and overcurrent. It is the BMS' job to prevent these damaging conditions. It is also important in lithium cells that every cell charges and discharges equally to maintain what is called their Top Balance and their Bottom Balance. Top Balance is all cells in a battery are exactly the same voltage at their highest stored potential and Bottom Balance is all the cells are exactly the same fully discharged. If they go out of balance in a battery arrangement then there is the likely chance one or more will become overcharged and fail or only one will become fully charged and all of the others undercharged. The design of the cell integration and the BMS are critical to maintain these balances. Essentially, Lithium battery cells are drug addicts, crack heads; in that, they will consume and spit out electrons as fast as they can regardless the effect on their own health, they have no buffer.

A typical BMS is an electronic device that connects to and monitors each cell in a battery assembly to ensure it remains within specification and the BMS will sense a cell that is out of balance and trickle it back to the level of the other cells. If the BMS senses an anomalous condition wither internal or external to the battery is will take the battery offline by disconnecting the negative side of the bank's cabling. The thing we are mostly concerned with is the BMS taking the battery offline during battery charging as that typically sends very damaging high voltages through the boat's systems and can/will damage the charging device. Obviously, we also don't want a BMS trip when the batteries are powering critical equipment at critical moments. There are BMS' internal to a battery assembly like in the Battleborn batteries and BMS that are external like in the Victron batteries. Both have pluses and minuses but both will protect the cells. One of the most important thing about a BMS is it's electrical current capability; both from a charging and discharging capability. Are you building a battery that you need to deliver 100 amps continuously but installed a BMS that can only manage 25 amps? Things to think about. The last thing is there are a plethora of BMS devices out there at about every price and quality. Do you want to invest four or five hundred dollars in battery cells and protect them with a twenty-dollar Chinese BMS or throw another hundred dollars at a robust rated high amperage BMS?

 

[dtfeld]

I've really come to view a BMS as a "safety fuse of last resort". I realize there is a lot more going on with these things, but I think the best systems are designed such that the charge and discharge voltage and current never get near the limits of the individual cells, battery packs or the bank of battery packs. Easier said than done as the battery bank increases in size and complexity, but needs to be thought out.

Lesson from my very basic system is limit the current/voltages of your loads and chargers, and the BMS wont have to work very hard, basically monitor and balance the cells. You might trade 10%-20% of the stored energy, but the cells will live much longer and happier.

 

[SCFoster]

I've really come to view a BMS as a "safety fuse of last resort". I realize there is a lot more going on with these things, but I think the best systems are designed such that the charge and discharge voltage and current never get near the limits of the individual cells, battery packs or the bank of battery packs. Easier said than done as the battery bank increases in size and complexity, but needs to be thought out.

Lesson from my very basic system is limit the current/voltages of your loads and chargers, and the BMS wont have to work very hard, basically monitor and balance the cells. You might trade 10%-20% of the stored energy, but the cells will live much longer and happier.

That was the really hard part in the past refits. Having to lay out everything in a diagram, then going over it with someone who knew what they were doing. In my case it was Peter Kennedy at PKYS.com. Given he's a Balmar and Victron dealer (amongst other things), he was able to recommend or shoot down some of my "bright" ideas. For instance, he nixed the larger Balmar alternators I had planned, convincing me that there wasn't enough cooling for them.

Adding LI to the boat is not a drop in and forget, despite what some advertising might claim.