Look at the BattleBorn site; you will find an area which says ‘ask us’.  They should know the answer as they support Victron.

Battle  Born was not very explicit about it in the Zoom meeting last week but in the long run it is very much advisable to use the 24 volt units instead of the 12 volt units. 

Using 24 volt units makes sure you will balance cells across 24 volts instead of 2 x 12 volt leaving a potential unbalance between the two 12 volt banks.
For capacity the answer is simple, as much as you wallet can last. You will always find ways to spend the available capacity in the end, so more is better. 

For your chargers you will need to investigate if you can set them to the exact same charging parameters. That may be difficult.
Also think about your charging regime. Again Battle Born was not very explicit about this but if you boat is connected to shore power for extended periods, you should lower your float voltage to reduce the state of charge to 70-80%. This can be difficult to achieve if you have several charge sources as this means adjusting it very precisely, up to tenths of volts accurate.
I did not like the way Battle Born played down this issue but Lithium batteries do not like to be kept at 100% charge level for extended periods. Even Tesla has extended logic in their battery management to handle this issue. So when Battle Born claims it has superior cells that do not suffer from this problem, I’m skeptical.

Just my 2 cents....

Regards,
Arno Luijten
SV Luna,
A54-121

Yes, and you should cut the altinator so that batteries are not always loaded in full during a long drive
Elja
SM Balu 222

Von meinem iPhone gesendet

Quote:
"In the long run it is even more advisable to abandon the traditional car batterie style and take one 24 volt 400, 500 or 600Ah lithium batterie instead building it up from 12 or 24 volt sections. "

At first I had the same opinion about this. However I did think this over a bit and now I'm not so sure anymore. The point being that with a set of "autonomous" 24 volt batteries you do build in a level of redundancy. If one of the batteries/BMS-es fails you still have the others left. With one BMS. etc. you create a critical path.

I'm not saying that should be avoided at all costs but it does add food for thought into to the discussion. For me I think this technology is still not fully mature in the marine environment. One way to get around the 70-80% problem is sizing you battery system so you don't need the top 20-30% and can never charge them up to 100%. To do this you need a BMS that can (actively) balance cells at any state of charge. I only found one company that sells those at the moment. It also make LiPo even more expensive.

Cheers,

Arno Luijten
SV Luna,
A54-121

Then you have to go to Victron , they have a seperate BMS
one for all batteries ,
and then you have all in one hand
Charger/ inverter
Solar regulation
and altinator .

One other question
What happens with the Li Batteries and the BMS
when you take a flshlighit ?

Elja
SM Balu 222


Von meinem iPhone gesendet

i've been working on Li Batteries for a few weeks since we're going to upgrade in spring 21.
for our SM, I have a narrow selection
the batteries from
Victron ,

https://www.victronenergy.de/batteries/lithium-battery-12-8v

liontron

https://greenakku.de/batteries/lithium batteries::7_56.html? gclid=EAIaIQobChMIjf61rvaZ6wIVjqmyCh33DAtUEAAYASAEgJzovD_BwE

or from a company Ripower in Germany that can build batteries on your desired dimensions! Price not much difference from standard batteries .

https://ripower.en/

Greetings to Elja
SM Balu 222

Von meinem iPhone gesendet

My 2 cents. My old boat has dual Lithionics 12v x 560AH batteries with external BMS. I like the lithionics brand, latest batteries are UL listed and IP rated. 1120AH or 14kwh was enough to run a 9k BTU AC all night and I had 14kwh of Solar whch was enough to put 600aH back in the following day.
I liked having 2 batteries. One battery gets knocked off by its BMS then there is one more. My engine battery was an AGM charged from the lithiums with a mastervolt smart DC-DC charger. There was a house/engine parallel switch which would start the engine from my lithiums BUT would cook the AGM if left on for more than a couple of minutes so parallel then, start the engine, turn it off. I had dual 3kw Victron multiplus running everything on the boat from the inverters.

What did I learn from my setup

• Seperate chargers and inverters are a good idea. Lets you run the boat in different AC regimes easily. The Victron charger/inverters will flow through shore power at its voltage and frequency so, seperate charger/inverter means the boat AC system is independent of shore power.
• Seperate BMS. What good is independence for each battery. Whats bad is if the boat floods then the battery DC cables are outside the battery going to the BMS and the BMS cannot deal with that situation, the salt water will short the batteries. An internal BMS avoids this problem and protects the battery in this scenario. Pump out the water and the batteries should be fine once the "external" short is removed.
• The location of the batteries on my 55 is right at the bottom of the stairs which is a crazy place to put them. A wave comes in, floods the cockpit, overflows in to the boat and now you've a problem. The Amel 53s having the batteries under the captain berth seems much smarter to me.
• Charging the batteries from the alternator is where most of the complexity comes in. When I do my Amel, I'll charge the batteries from the shore power/gen and Solar and not use the engine alternator for the lithiums. I would charge the engine AGM from the alternator but nothing else. Now, it's much easier. The Sterling alternator protector was rated Maine Yacht Center as voodoo and I trust them. The alternator is complex. I had a 360aH alternator from API with a Balmar 614 regulator. It generates 5kw of power ish. That comes with a lot of heat and you'll need a well engineering cooling system. I had to derate to 230a to keeps temps to 80c at the alternator, plus there is the wear and tear on the engine belt to worry about. Just don't use the alternator, MUCH easier...

So, when I do the Amel, my plan is 600aH of 24v Lithiums with internal BMS. Maybe 6 strings of Battleborn 24v x 100aH. Reuse my mastervolt chargers (100A and 60A) from the generator and my solar. Keep an engine AGM battery connected to the alternator and a DC-DC smart charger from the lithiums. At least thats the plan but I would not integrate the alternator in to my setup like before and I still don't like the location of the batteries at the bottom of the stair well but at least with the battleborns, the BMS should help in a flood situation. It would be nice if the battleborns were IPX rated, I'm not sure if they are waterproof and I'd like for ones which were.

I have gone all Mastervolt with my Lithium conversion, which was just completed by the local MV dealer.   I have 3x200 Ah 24V batteries and I’m using the existing MV 60 A and 100 A chargers and existing 110A 24V alternator .  I have 800W and 2.5KW MV inverters, all original.  The batteries, chargers, alternator and inverters are all interconnected and controlled by the Masterbus system and monitored on an Easyview monitor.  The Masterbus also switches off my solar, wind and hydro generators when the batteries are full.  The batteries just fit in the space where 4 of the existing gel batteries were stacked under the cabin floor.  That space is designed to be watertight so I’m not concerned about flooding as long as the engine room is not breached and fills up....

 One benefit of an integrated, one manufacturer system is there is no one else to blame if things go wrong.  So, Mastervolt has certified that everything was installed as required by the specs, which gives me a lot of peace of mind.    I look forward to actually using the system when I get back to the boat!

Joerg Esdorn
A55 Kincsem
Vigo, Spain

Kent,

Tom on L'Orient (who we met recently here in Oahu) called me the Lithium Evangelist or something similar. I do love my lithium and the impact that it has had on our comfort aboard, but I will add that I'm also a perfectionist with it so I'll quickly point out what I perceive to be problems that I perceive with my (and others') setups. My experience is not as an engineer but as someone who probably overthinks his lithium setup (because it was damn expensive and I don't want to damage it!) and on my most recent check, have run 2470kwh through my batteries, which is around 350 cycles at my 60% DOD average over the past nearly 2 years and they're as good as new. 

Here are some responses to your questions:

- Check that your charger inverter has a lithium profile. That's the easiest way to do it.

- The Skylla has a lifepo4 profile -  I own one.

- The Victron mppt have lithium profiles, use them. I own the 150/35. No temp compensation except there is a low temp charge cutoff. 

- I have 450AH. That is a good sweet spot IMO because once you have more than the amount of capacity you need to run 24 hours, you should be thinking about your renewable output. I put out about 250AH a day via solar. With our usage pattern, while stationary, we only run the generator to make sure it still works. You will have to do your own energy budget.

Example: If you have 1,000ah and use more daily than you put in with your renewables, all you gain from all that extra money spent on batteries is a longer interval between running the generator. Better to spend that money on renewables, imo. And unlike lead, you can take lifopo4 down to 20% very safely and still get 2000 cycles out of them. In fact, if I had a 1,000AH bank and kept it between 75-100% SOC, I'd probably be worse off because lithiums do not like being kept at the upper end of their SOC range. More is not always better.

Adding batteries later is not recommended, at least per my long conversations with Victron engineers. You really should have them all installed upfront or at latest 6 months later because while the batteries age slowly, they do age. Adding newer batteries to an old bank will cause charging imbalances.

- Making the chargers work together involves making sure they have the exact same charging voltages and durations. My Quattro and Skylla oddly do not talk to each other, but they work together perfectly because of this.

-I met with Peter Kennedy when I was trying to figure out how to safely shutdown my Mastervolt 110 alternator when I have a high cell voltage condition, aka cell imbalance. He seemed reasonably knowledgeable and as a Victron dealer understood how the Victron BMS sends out a signal that could be used to safely turn off my alternator when the BMS detects a high cell voltage condition. He suggested the solid state relay that I ended up using as he had tried it on someone else's setup. I will say that he admitted that he wired it incorrectly and fried it but still thought it would work. What was a bit surprising is that he didn't know that solid state relays cause a voltage drop and that causes problems with my/his proposed method of using the the Victron BMS to control the "reg-on" wire of the Mastervolt regulator. The problem was that the reg-on is also the voltage sense wire for the regulator, so you can imagine that a voltage drop on a sensing wire is not good. I solved that with the help of a very capable automotive ECU tuning engineer and detailed it in a post on my long lithium thread.

The point of that long story is that PKYS knows more than any other group I've encountered but it's your boat and even those who appear to understand lithium do not understand the intricacies of your specific setup and mistakes occur as a result of that or worse, the result of applying lead acid thinking to lithium. 

A few other thoughts in general and on others' responses:

-I chose 12v series pairs rather than 24v batteries to provide a backup to my starting battery. With 12v pairs, you do need to ensure that the individual batteries in the pairs are fully charged with a slow charger before installing them. Once a year, you disconnect and individually charge the 12v batteries in the pairs to ensure that they are balanced between them. I use a few cheap 12v/1.5a Lifepo4 chargers that run on 110-220v that you can get on Amazon for $20. As noted, the BMS will balance between batteries in parallel but not batteries in series. As a side note, each 12v pair is then, of course, put in parallel to create the 450ah capacity and as long as each PAIR is not too imbalanced, each pair will balance out with the other pairs. Hope that makes sense.

24v batteries does solve the problem of imbalance between 12v pairs, so that would be nice. If you go that route, just get a "backup 12v starting battery" that you keep charged via a dc-dc converter or even just a trickle charger that runs whenever you have the genset on, assuming your setup requires you run the generator now and then. That would probably be ideal.

I would be wary of going for a single massive 24v, say 450ah battery bank. Individual cells do die now and then and with a massive bank, unless you're very capable and confident about assembling/disassembling batteries, you won't be able to take it apart and remove those cells and continue on. If I'm in the Tuamotus and one cell dies, I just take that 12v PAIR offline and still have 300Ah of capacity left. Even I can do that without killing myself.

- Stop thinking float. That's lead acid thinking and will quickly kill your lithiums if you set it anywhere near your absorption voltage. If your charger requires you enter a float voltage, set it to 27v float and forget it. Controlling when charging stops with respect to SOC involves setting absorption voltage and duration. That said, it's very very difficult to try to target an ending SOC based on voltage. Lithiums have voltage "knees" on the top and bottom. The voltage with respect to SOC is nearly flat from around 10%-90% state of charge and then hockey stick up at 90% and down at 10%. But voltage is an unreliable indicator of SOC. To give you a real life example, I set my alternator's absorption voltage at around 27.2 volts, I believe. That was done so the batteries aren't kept at 100% during long motoring sessions. If I was going for fully charged, I set it at 28.4volts. During the last nearly 2 years, the alternator will stop charging anywhere from 85-95% SOC, as indicated by my battery monitor. It's not easy to target SOC using charge voltage on lithiums. And it's even harder if you're not targeting high terminal SOC because of the flat voltage vs SOC relationship when you're not at SOC extremes.

This is also a reason why most balancers only work when the batteries are at 28+ volts. When my own batteries were imbalanced a year ago, the cell voltages looked perfectly equal until 90% SOC and then and only then did the imbalance show itself. As a side note - charge your bank to 100% once a month. It helps balance the batteries and also resets your battery monitor since that really only tells you SOC based on amps in vs. amps out and charging to 100% calibrates it.

- You need a way to shutoff your alternator that is related to both overall bank state of charge and high cell voltage. Your state of charge may be at 90% but one cell may be at 4.2v and since your absorption voltage setting look at overall bank SOC and tells the alternator to keep charging, that 4.2v cell will keep getting fed with current and will therefore die shortly. This cell imbalance does not show itself when you look at overall bank voltage, but is detected by the BMS, which monitors cell level voltage.

Solving this honestly took me over a year and the help of aforementioned car tuning engineer to solve. Note that I spoke to countless lithium "experts" including Victron and Mastervolt engineers prior to this without a solution. I took a quick look at your regulator's manual. It says:

"Many LiFePo4 batteries have a Battery Management System (BMS) that may disconnect the battery from the alternator as a protective action or when charging is complete. The regulator must be shut down before the battery is disconnected .Running an alternator without a battery will damage the alternator and may damage any attached system. This is doubly true if the battery can be disconnected during
(1) You need a signal from the BMS to tell the alternator to turn off. The BB batteries seem to have an internal BMS that cuts off charging if there's a high cell voltage condition - does it send a signal that you can use to tell the alternator to turn off? Perhaps it's not a problem because with each BB battery having an internal BMS, maybe only that one battery is taken offline?

(2) You need to use that signal and use it in a way that safely turns off the alternator without frying it, per your Balmar manual. 

As noted in my long thread on my install, on my Victron BMS, there's a signal wire called "charge disconnect" that I use to control my Mastervolt regulator's "reg-on" wire. Seems you may be able to something similar on the Balmar as long as your BMS can send a signal when there's a high cell voltage condition.

Also with the alternator you will need to install a temp sensor. Balmar says that in their manual. When you're charging lead /agm/gel, the alternator only outputs full current for short period and tapers off quickly. I understand that internal resistance goes up at higher SOC. Lithium does not have this problem so your alternator/chargers will output full current until the battery is nearly full. That may cause overheating and fry your alternator. The Mastervolt engineers said my 110a alternator can handle that heat, but just to be safe, I installed an alternator temp sensor anyways. I recommend you do the same.

This has been long enough, I hope it helps someone at least a bit.

I will end by saying that I agree with Joerg on using one brand to the extent possible. I only went mostly Victron because I started with a Victron solar MPPT before I even knew what lithium was. Victron does not make alternator charge controllers and that was the source of my main issue, which is now solved thankfully. If you mix brands, be ready to have every company point its fingers at others if your batteries die. My understanding is that MV also allows you to set SOC based charging limits, which would be very useful. I haven't fully researched them, so I don't know what their disadvantages are but I'm sure there are some.  

Biggest disadvantage I've seen - If you think Victron batteries are expensive, Mastervolt will change that opinion.






--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com

Thank you for your detailed report

From all of this I think it will be silent to find an expert who will instruct the batteries and chargers in this way

thanks Elja
SM Balu 222

Von meinem iPhone gesendet

One last thought:

If BB batteries have internal BMS that can disconnect charging and load on a battery level, some questions come up.  For example, if battery 1, consisting of 4 cells, has a high voltage condition, the BMS in that battery stops charging in Battery1 only. 

At first glance, that seems ideal. You may not need an external charge or load disconnect circuit because the battery experiencing a fault just stops accepting charge or stops driving load if there's a high cell voltage or low cell voltage condition, respectively.

My question is what happens then? I only ask this because I don't know but it could cause problems. Say you have 12 batteries = 6 pairs of 12v batteries. Each 12v battery pair is in serial to create 24v and each pair of batteries connected in parallel to the other 5 pairs to create your AH total. Say Battery1 has a high cell voltage condition and the internal BMS cuts off charging to this battery, but still allows load. That means that Battery 1 is still connected to its Battery2 serial pair and hence connected to the entire bank. The charger is still outputting 26+ volts. But for this battery1-battery2 pair, only one of them is accepting charge. Is that ok?


--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com

Well,
I learned something today. The battery compartment on a 55 is watertight? Good to know. All MV is attractive given the bus and so on.

I think all batteriecompartment from SM , 54/55 are watertight

Von meinem iPhone gesendet

--
Brent Cameron

Future Amel Owner & Amel Owner Registry Moderator

Oro-Medonte, Ontario, Canada

He all

On the SM and I assume on the 54/55 each pair of batteries 2x12 V / 24 V is supplied by a seperate plus and minus . ?
so every package has one
extra line to load .
therefore, for solution 24v 50 AH, each battery itself should decide when the load is terminated ? The battery is not used to be used in the battery.

Elja
SM Balu
222

Von meinem iPhone gesendet