Mark,

I looked at his first post and a few things he stated that is not consistent with the known characteristics of lithium:

1) Take a look at the voltage vs. SOC graph for a Lifepo4 battery. 
https://www.powerstream.com/lithium-phosphate-charge-voltage.htm

At 3.2v per cell or (3.2*8 = 25.8v) you are at around 3-8% state of charge.
At 3.3v per cell or (3.3*8 = 26.4v) you are at around 20-31% state of charge.
At 3.4v per cell or (3.4*8= 27.2v) you are at around 96-99% SOC. 

But it's not just the spread, it's the shape of the curve. The challenge is that the lithium curve, unlike lead, is NOT linear. The middle portion between say 10% and 90% has a very flat voltage curve.  See link above. I can attest that with my Mastervolt 110A charger set to 27.5v absorption, the alternator has stopped charging anywhere between 75-100%, averaging 85%.

If you set your charger to stop charging at 26.8v, you may be charging your batteries to only 40-50%.

And as you can see with lead, the voltage vs. SOC curve is quite linear, making it far more useful to determine SOC from voltage.
https://www.researchgate.net/profile/Jeff_Cherry2/publication/315847359/figure/fig2/AS:633864561106948@1528136496496/Typical-Open-Circuit-Voltage-OCV-of-12V-Lead-Acid-Battery.png

2) He stops charging at 3.45v per cell and has a high voltage alarm at 3.5v. His high voltage ALARM is below Victron's absorption voltage of 3.55v and below Mastervolt's absorption voltage of 3.6v. Keeping voltage low like that will help avoid high SOC induced imbalances but there are other sources of imbalance too, namely high load or imperfectly assembled batteries. And most cell balancing systems require you to charge to near full before they start balancing, as indicated by low charge current acceptance rate - namely because of the non-linear charge curve. I have had batteries that show perfect balance until you approach 3.5v+ and then one cell goes wildly out of balance.

By not charging your batteries fully every once in a while, you may end up prolonging a cell imbalance issue that, in the event that you need to draw the batteries quite deeply (big storm, can't run the genset because of sea state), could result in a cell LOW voltage problem that will destroy the battery or cause your BMS to disconnect your loads at the worst time. Further, most battery monitors determine state of charge based on calibrating to 100%. And 100% on my battery monitor is determined when charge current is below X for time period Y. That means the battery is full and no longer accepting charge. As such, Victron explicitly recommends charging fully once a month to recalibrate the SOC monitor.



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

Arno,

Voltage may not be as bad an indicator of SOC of LiFePO4 batteries as you might think.  Here's a quote from the owner of MV Tanglewood who has had his LiFePO4 bank in operation for about ~18 months now:

First, counter to what everyone says, I think battery bank voltage is a sufficiently close indicator of SOG.  People say it's a much worse indicator for LFP vs Lead, but I disagree.  My lead bank was 50.4 volts when fully charged, and 48.0V when is was 50% empty and the generator started.  That's a spread of 2.4 volts.  In contrast, my LPF bank is full at 53.6V, and ready for recharge at 50.4V.  That's a 3.2V spread and is 30% more voltage swing than lead.  The difference, though, is that in the mid area of charge, the LFP voltage doesn't vary much, so there isn't as much differentiation between 60% and 50%.

Granted, this 3.2v spread is for his nominal 48v system but even with our nominal 24v system it would be a 1.6v spread which is a significant enough spread to monitor and act on.  I am literally in the middle of installing my LiFePO4 system and I am not yet living full time on the boat so I don't have a ton of personal experience with it just yet.  However, the experience that I do have so far lines up with Tanglewood's experience.  I think that if you operated an LiFePO4 system simplistically such that it is assumed to be "full" at 26.8V (stop charging) and then "empty" at 25.2v (start charging), the battery bank would be quite happy and would give you many years of service.

Here is the full blog post:  http://www.mvtanglewood.com/search/label/Lithium%20Batteries  

Be sure to read his other LiFePO4 related posts.  They are full of great information.
 
--
Mark McGovern
SM #440 Cara
Deale, MD USA

He jose 

Arno,

I actually think if you're on shore power most of the time, lithium is a bad idea. At best, it's a waste of money that adds additional complication. 

I do agree with your lack of confidence in the warranty. Unless you are using batteries and chargers from one brand, I am almost certain the battery manufacturer will point fingers at the charger and you will left paying for a new battery bank yourself. 

For me, the big pluses are the charge/discharge curve as you mentioned, the lack of need to keep it full, the ability to run virtually all 220v appliances on battery and one thing that people don't often think about is that it could effectively double your solar output. The charge acceptance rate and near nonexistent charging efficiency issues means that, for the same solar array, you will get almost twice as many AH per day into your batteries compared to lead. I believe it is Porter who is in the tropics and has a similar solar array and the same MPPT as we do, but we are able to put nearly twice as much cumulative power into the batteries as he is. Our only difference is AGM vs. lithium.

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

Sounds about right with Mastervolt. I haven't studied their system in detail but from what I've seen, they're the most hands off, from the user perspective, that I've seen. But you pay for it!

I have the Mastervolt alternator and Alpha pro II (3 is even better) and it took me over a year and the help of an engineer who used to break into car ECUs to reprogram them. It turned out to be quite simple, but neither Victron nor dealers understood the problem or could provide the solution.

I describe how I do it here:
https://amelyachtowners.groups.io/g/main/message/50689

One final alternator tip: I did not use the standard lithium profile on the mastervolt charge controller. This is because I did not want to keep the lithium batteries fully charged when motoring for a long time as this is not good for the batteries. I set the absorption voltage for 27.5v and the "float" at 26.5v. As mentioned before, voltage is NOT a good indicator of SOC, but I've seen over the last two years that this seems to result in charging stopping at around 85% on my system.  You'll need a Mastervolt USB interface to program your charge controller.

https://www.mastervolt.com/products/masterbus-interfaces/masterbus-usb-interface/


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

I do something similar but it's just a Ryobi portable fan that I direct at the compressor when I'm filling tanks. Bauer techs told me that it will extend the life of the compressor and the filters. Your blower fan will certainly work better.

One other idea is to take a long hose and bring fresh air into the intake. This is something gasoline powered compressors have to do but we do it also because our cockpit locker also stores chemicals that I prefer not to breathe underwater (or above water, for that matter!).

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

I was searching over internet for marine Lithium Batteries and found the “Ionic” brand that sells a 12V 125 Ah with the same size of the BattleBorn 12 100 Ah battery.
Ionic only give 5 years warranty vs BB 10 years, but they will provide 25% more capacity for our boats and each battery can be monitored independently with a smart phone via blue tooth communication.
I am inclined to go BB but wonder if any one has heard good or bad things of the “ionic”

Jose Venegas
IPANEMA SM2K 278
Curaçao

Hi!  Bill Kinney & I have been doing some work with new owners of an Amel 54. The outhaul is really stuck. Is there anyone in the group near Annapolis with a pulled for the outhaul that we could borrow? It would be greatly appreciated! If you are in the area we will be at Bert Jabins Yacht Yard please stop by and say hi!

Karen Smith
s/v Harmonie
SM #160

Mark,

My SM is a 2004 with a Yanmar 4JH3-HTE engine.  It does have a Hurth ZF25 gearbox.  However, it may not be the same gearbox on your SM with a Perkins M80T. 

In any case the ratios on my gearbox are as follows:

Ratio 1:  A = 2.80 B = 2.80

I'm not sure what you are going to use the ratio information for, but the only way to be 100% certain what is on your boat is to look at the plate that is on the gearbox in your engine room.   Maybe you can get someone to go on your boat and take a picture for you.  Here is the plate on my gearbox:



I find that Google Photos is a great way to store information like this "for posterity" so that you can find and access the information even when you are not on your boat.  That's what I just used to grab the photo above.  I took that pic over a year ago for no real particular reason but to document what I had while I was replacing the Vetus coupler.

--
Mark McGovern
SM #440 Cara
Deale, MD USA

thanks for the details. Why did they put it on a track? 

thanks Scott! Great tip...I plan to install a blower fan as well on it to help keep it cool...

Thank you! all good to know. anything I should be aware of to check if I buy a used system?

Hi Sheriffdep,

Drop in replacement have build in BMS-es that is correct. The quality of those can be from excellent to abysmal and you have very little clues to determine this from the outside.
I do think that assembling your own battery pack is currently the best way forward if you have technical skills. It's cheaper and you determine for yourself which BMS system gives you the best facilities for your usage case.
It also enables you to make better use of available space. An example of company that facilitates this route is https://shop.gwl.eu/index.php?force_sid=nc4jtsqa8h85c6d1m7j3t8ncnj& (I have no relation with them and never bought anything there)

Your assumption about 15-30 year investment is highly optimistic at best. Personally I would assume a lifespan of 8 years simply as a result of lack of evidence that these things last longer. Your best bet is looking at the way Tesla's from 2013 are behaving and those use different chemistries (Li-Ion instead of LiFePO)
As said before, my main beef with this stuff is that to get the best life expectancy from these things you need to treat them carefully, meaning not fully empty or fully charged for extended periods and keeping them balanced. Most systems can only balance them at 100% SOC. This means you will need to think of the SOC of your batteries in relation to your cruising plans and modify the configuration accordingly. The latter is can be quite the hassle as you need to "tell" all your charging sources to keep a certain maximum float-voltage (more accurately maximum SOC). Alternatively you can also make them stop charging, but that means you will be short-cycling the batteries needlessly because of the never ending consumption by systems on the boat. The effects of this are unknown to me and I cannot find clear information about it. It also means your battery bank is not "set and forget" as many supplies claim is some form or shape.

My point is that it is not so hard to put a well working system together but designing one that minimizes stress on the battery system and maximizes longevity is quite the challenge. It is also depending on your use-case provided you can predict that for the coming 8-15 years (I can't). The Battle Born batteries give you very little to control the SOC and don't provide you with information on what's going on inside the black box. Their 10-year warranty doesn't mean much to me. Who knows if the company is still around in 10 years and what they will tell you then.

So in the end, I think there are some good reasons to switch to Lithium but life-span discussions in relation to total cost of ownership and comparing them to alternatives are risky at best. My thought is that the charge/discharge curve of lithium and the lack of need to charge them to 100% every time are the VERY big plus arguments. All other points are secondary and maybe even debatable.


Cheers,

Arno Luijten
SV Luna,
A54-121

He Scott , first many thanks for your detaild awnser . 

I have been asked for the gearbox ratio of the gearbox and I am away from the boat. 

The boat is a 1993 Super Maramu hull number 110. It is a Hurth gearbox.

The engine is a Perkins M80T

Can anyone help please?

Many thanks 
--
Mark & Nicky Barter
S/V Nunky
SM 110

Hi Arlo,

Bauer PE100 on Onan MDKAL 50Hz 220V

Best regards,

Stefan Jeukendrup
sv Malaka Queen
SM2k  #348 @Turkey

Some of my thoughts, original in regular font and my response in italics

Sheriffdep

As a thought - I also am considering if purchasing the SM2k doing a separate 12v bank purely for electronic usage and anything 12v. The Beneteau 57 has a 280amp hr bank for that and separated the 24v bank. Haven't done the calculations for that completely but would dedicate 1x solar panel for keeping that topped off (engine alternator when running also) and be able to charge cameras, flashlights, and run the depth and wind MFd's all day everyday without draining any of the main battery bank. Might be a bit over the top, but it would help. Options for extending the banks could be to put 2x extra 24v bank batteries in the aft clothes locker beside the bank or put them beside the nav station on the floor. Putting that extra pair should be fine as long as all the wires running to the unswitched distribution block from all the pairs are of equal length. That way they will all charge and discharge the same.  
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com