Date   

Re: anods unusual wearout

Mark Erdos
 

 Bill K, Not all Amels were made with the MAS system installed.

 

With best regards,

 

Mark

 

Skipper

Sailing Vessel - Cream Puff - SM2K - #275

Currently cruising - French Polynesia

www.creampuff.us

 


On 5/4/2022 2:18 AM, Bill Kinney wrote:

Greg,

You have a serious stray current problem if your anodes are disappearing that quickly. This is very important to fix. Once your anodes are destroyed, the next thing to go will be other underwater metals. If there is enough current flow, very serious damage can occur very quickly (in weeks, not months!). Ordinary galvanic corrosion is a slow process.  Stray currents accelerate this by many orders of magnitude.

Somewhere on the boat you have an electrical connection between the battery and the bonding system that should not be there. Amel installed the "MAS" light to help find this problem.

The anode on the bowthruster that was not destroyed is not properly connected to the bonding system, but should be.  

Bill Kinney
SM160, Harmonie
Simpson Bay, Sint Maarten


Re: Martinique to Newport

Ken Smith
 

Email sent.

Regards,
Ken Smith
M202 Bon Edda


On May 5, 2022, at 7:59 PM, Miles <milesbid@...> wrote:

Hello all,
Once again Ladybug will be sailing from Martinique to Newport, RI.  I plan to leave Martinique on the 20th May, and I would like one more crew person.  The other crew person has made this trip with me several times. If you would like to join me on this voyage, please send an email tp milesbid at gmail.com.

Miles

S/Y Ladybug,,SM 216,  le Marin, Martinique


Re: Stress crack main sheet boom attachment Maramu

karkauai
 

Kristy is an SM, her forwardmost attachment point on the boom is where a line goes from the base of the mast to the boom. It's where a vang would be attached and is there I presume to keep the boom from lifting in an accidental jybe.
--
Kent & Iris
KRISTY
SM243


Re: Amel lost its mast - D1?

Bob Grey
 

Hmm, happened to me just after I brought Renaissance 3, the fitted Genaker Halyard (still after 7 years,I  have never raised this sail) came loose and wrapped around the Genoa as I was furling, by the time the fuse stopped the motor, the fore stay was badly birdcaged  and I replaced it. So it can happen, the Genaker halyard is still fitted but only used as a backup climbing halyard. I check it’s tension often as not to repeat my expensive mistake.


Bob Grey

Renaissance 3
Amell 55 #25


Re: Worldwide insurance

Dean Gillies
 
Edited

Bob,
You might want to try Topsail Insurance. Stella is Australian registered and we found Charlotte Fenn from Topsail to be very helpful for insurance coverage in Europe.

 

Sydney
43 Baroona Road, Northbridge. NSW 2063

Phone:             02 9188 7828

Email:               charlotte@...

Website:           www.topsailinsurance.com.au

 

Cheers
--
Dean Gillies
SV Stella *****,  Amel 54-154

PS: Pantaneius also offered coverage for Australian Registered vessels, but their pricing and restrictions were less attractive for us. Maybe they are better for world-wide coverage options.


Worldwide insurance

Bob Grey
 

Hi Guys, covid is over, borders are opening, so I start my circumnavigation of the globe this Sunday from Melbourne, my current Australian insurer won’t entertain more than 200 miles from Australian waters (Club Marine) so who do we Amelians recommend? 

Bob Grey
Renaissance 3
Amel 55 #25.


Re: drop LiFePo4 batteries vs LiFePo4 cells in a bundled pack #solution

Dean Gillies
 

Hi Scott,
Wading into the weeds ... :-)

Hitting the 4V limit is even more curious.

You are correct that the LFP cells will "limit" current as they approach a full charge... however they do not cut this off completely and will continue to accept charge (and increase voltage) beyond your 3.55V absorption voltage per cell setting. This is what pushes their voltage up towards the 4V HV disconnect. The job of the BMS is to make sure this does not happen ... so why is it happening? My per-cell absorption voltage set point is 3.58V and I have never had a cell rise above this level during balancing (with DVCC active). 

It seems that your cell balancers are not providing sufficient bleed-off to stop the voltage of the highest cell from rising further? The (passive) cell balancing circuits provide a bypass current path for those cells which have reached the high voltage set point. You are relying on the cell-pack to self-limit current, maybe with its cell-balancers that's not enough and so the highest cell voltage continues to rise?  7 cells with an average of 3.48V and one cell at 4V is still under the 28.4V shutdown. Maybe Victron realised that and introduced DVCC to address the issue? 

Also I don't know enough detail about the Victron BMS to understand exactly how it deals with batteries in series, but could it be possible that it does not deal with imbalance in series pairs?  What does the BMS do when it finds one battery at 14.8V  and the other at 13.75V? Does it simply shut down the charging? What is the function of the daisy-chain connections between batteries? Is it monitoring only or is it controlling the balancing?

Sorry I don't know enough detail about how the Victron BMS operates so I've got more questions than answers, but hopefully the questions are food for thought.  Personally, I wouldn't be comfortable with a system which activated high-voltage disconnects in the normal course of charging. 

Cheers

--
Dean Gillies
SV Stella *****,  Amel 54-154


Re: drop LiFePo4 batteries vs LiFePo4 cells in a bundled pack #solution

Dean Gillies
 

Hi Jose,
Great advice, the 24V batteries are much preferable to the 12V batteries.  The balancing process (I don't like using the term 'equalisation' in connection with LFP batteries!) is simpler and more reliable as you describe, also they provide better redundancy. If you use 12V batteries to make a 24V/400Ah bank then you have 4 strings (4x series-connected pairs). Any battery disconnecting will cause a 25% reduction in capacity, whereas a 24V/400Ah bank using 8x24V batteries to get the same capacity will lose only 12.5% capacity when one battery disconnects.

I know that Battleborn and Relion both produce 24V/50Ah batteries.  Last time I checked, Transporter (who rebadge Battleborn batteries for the EU market) had not obtained certification in Europe for the 24V/50A model. They may now have done that.  There are many other "manufacturers" since "drop-in" LFP batteries are very easy to assemble. There are only a handful of cell manufacturers (all Chinese) and a whole range of BMS options available to build in.  However sticking with the reputable manufacturers should give confidence that the batteries have been assembled with components (internal wiring, terminals etc) correctly rated for the product.

Cheers
Dean Gillies
SV Stella *****,  Amel 54-154


Re: AML 54 fridge cooling

David Crisp
 

Ian, Judy,
I'm suspecting my refrigeration cooling circuit needs a clean out.  Can you buy Rydlyme in Greece?  I'm currently in Preveza.
--
David Crisp
SV Wilna Grace
Amel 54 #58


Re: drop LiFePo4 batteries vs LiFePo4 cells in a bundled pack #solution

David Vogel
 

Re: power produced by wind generators

Our actual stats - Rutland1200 (400W) - since installation SXM: 17,443Ah (at nominal 24v) produced in 24,113 operating hours || ~420kWh produced.

Which is, to be honest, somewhat less than what I thought we'd see long-term. However, I think this is the result of the wind-gens' MPPT throttling output when the solar MPPT is putting out at bulk/absorption voltages (or when the same happens using the genset/shore-power->battery chargers, or the engine-driven high-output alternator).

In any event, with our cost of ~USD2,500- installed, the resulting cost of wind-produced electricity is running at ~$6- per kWh (and slowly falling).

Nevertheless, I am glad to have installed the windgen as, with windspeeds >15kts apparent (which typically coincides with grey/overcast conditions and reduced production from the solar array), the windgen starts to produce enough to offset the additional 'underway' loads of A/P and N2K sensors/AIS/VHF/Radar & chartplotter. On the recent passage Fiji to NZ, with 8 days of overcast @ AWS>22knots, we didn’t need to run the genset at all; although did so nevertheless every 24-48 hours when in continuous large seas, in order to reduce the potential for issues arising from possible water entry via the exhaust.

Best,

David
SM#396, Perigee
Whangarei, NZ


From: <main@AmelYachtOwners.groups.io> on behalf of Alan Leslie <s.v.elyse@...>
Reply to: <main@AmelYachtOwners.groups.io>
Date: Friday, 6 May 2022 at 1:35 pm
To: <main@AmelYachtOwners.groups.io>
Subject: Re: [AmelYachtOwners] drop LiFePo4 batteries vs LiFePo4 cells in a bundled pack #solution

Thank you very much Jose!
Your post , I think, answers all my questions, in a very well sorted manner.
My key concerns are answered by using the Victron monitor to turn the battery charger on and off, and the alternator protector, which I was unaware of.
Many thanks
Cheers
Alan

Elyse SM437


Re: drop LiFePo4 batteries vs LiFePo4 cells in a bundled pack #solution

Alan Leslie
 

Thank you very much Jose!
Your post , I think, answers all my questions, in a very well sorted manner.
My key concerns are answered by using the Victron monitor to turn the battery charger on and off, and the alternator protector, which I was unaware of.
Many thanks
Cheers
Alan
 
Elyse SM437


Re: drop LiFePo4 batteries vs LiFePo4 cells in a bundled pack #solution

Jose Venegas
 

Scott,
I agree that this is the kind of project that needs a good understanding of the system before jumping into it.  As far as I know, each drop-in Battleborn battery has its own BMS that works independently of the rest batteries in the bank.  In a series-parallel array as in most AMELS if one of the batteries shuts down it affects the other battery in series and transfers the current to the other 3 sets of series batteries.   I don't know how to detect such an event other than by noting a reduction 0f 25% in the amount of amps-hour that you can introduced into the system from a discharged state to full charge.
This brings however something relevant for those considering drop-in batteries.  As in your system, a period of equalization at high voltage is required to bring all the cells of a battery to the max degree of charge.  However, any given battery (drop-in or not) has always several cells in series to generate the desired voltage.   If the cells in each path are not carefully selected to have similar characteristics, as Battleborn does,   during equilibration the cells with higher internal resistance could be exposed to a higher voltage than others. So, even if the total equilibration voltage does not exceed the recommended one, over time this could result in the early failure of those cells.  It is for that reason that Battleborn creates its batteries selecting cells with similar internal resistance for each series pathway.
The issue also occurs if the 12-volt batteries you put in series have different internal resistance.  When you try to equilibrate the batteries at 28.4 volts one of them may have, say 15 volts and the other one 13.4 volts and eventually the BMS of one of them will shut down preventing the second one from equilibrating.    The smart BMV 712 has an input that you can use to measure the voltage between the two batteries and evaluate the difference in charging voltage, giving an alarm if it exceed a given %.  By the way, this is a problem of any kind of battery but is more critical for lithium than acid-lead batteries which don't need a BMS.  In fact, Victron makes a gadget ( Battery Balancer) that at high levels of charge it shunts current to the less charged battery when the difference in voltage between them exceeds a certain percentage.  I had purchased one of them and was using it with my previous set of AGMs batteries when it alerted me when one of the batteries in the bank went bad.
Now, when I was buying my set of lithium batteries I was asked if I wanted the units of 24 volts 50 amp-hours or those of 12 volts 100 amp-hours.  I did not think about this problem at the time and bought the 12 volts to be able to use the same cables I had and avoid the extra cost of buying new ones.    Initially, I connected the BMV 712 to measure the middle voltage in one set of series batteries.   To my surprise, I noted that at the end of a fast charge, (with 160 amp) as the total accepted current by the bank dropped a difference in voltage developed between the two monitored batteries.  Alarmed I call Battleborn and showed them the problem. They suggested that I tried to pair the batteries in series to have similarly charged voltage.  I did so and asked if it was worth using the Battery Balancer that I was originally told I did not need in lithium batteries because they had a balancer in the BMS.  After some research, they said it was OK to use it, which I did.  For a set of 4 battery branches in parallel, they recommend either buying one Balancer for each parallel branch or connecting all middle points together and having the balancer take care of monitoring and maintaining this voltage.  Effectively having the 4 lower batteries in parallel and connected to the 4 upper batteries also in parallel.  I have been using this for a couple of months and noted during the first equalization the balancer was working hard to keep the middle voltage in the middle.  Since then, the middle voltage has deviated less and less and It seems the system is now back in balance.
IN CONCLUSION:  when buying a new set of drop-in batteries it is best to buy the 24 volts and put them in parallel.  Since during manufacture each series of cells are preselected, the system will not have the unbalance problem I observed.  However, if you don't want to spend the extra money of making new cables, I recommend that you select pairs of batteries that match their charge and install a battery Balancer!
Hope this helps and is not too confusing. 

To your second question, the answer depends on where your boat is.  When Ipanema was in Bocas del Toro, Panama, I got nothing out of it.  However, when we were in San Andres, where it always blows over 20 knots, the superwind made a difference on rainy days.  Here in Cartagena, it is rare when it blows more than 15 knots but in the Rosario islands (3 hours south of Cartagena) it can blow over twenty all afternoon and part of the night.  I just noted that  23 knots give only 160 wats and I have the wind generator on top of my mizzen mast!  So, knowing what I know now, I would not recommend buying one unless you are in a  place like Sand Andres.

Jose Gabriel Venegas
Ipanema SM2K 278
Cartagena, Colombia

 


Martinique to Newport

Miles
 

Hello all,
Once again Ladybug will be sailing from Martinique to Newport, RI.  I plan to leave Martinique on the 20th May, and I would like one more crew person.  The other crew person has made this trip with me several times. If you would like to join me on this voyage, please send an email tp milesbid at gmail.com.

Miles

S/Y Ladybug,,SM 216,  le Marin, Martinique


Re: drop LiFePo4 batteries vs LiFePo4 cells in a bundled pack #solution

Peter Luke
 

Scott,

Small detail, but I think you misspoke. :-)

"So as the batteries approach 100% SOC, the batteries naturally take less current."

I think you meant "So as the batteries approach absorption charge voltage, the batteries naturally take less current."

Without DVCC or some other SOC current limiting device/software, charging is based on a voltage level generated by a charger.

BTW - love your work.

Regards,
Peter

On 2022-05-06 4:12 am, Scott SV Tengah wrote:

Dean, small detail, but I misspoke - high voltage disconnect occurs at 4v per cell. Further, I only charge to 28.4v, so 3.55V per cell. Victron seems to believe the additional capacity above that voltage level is not worth the stress on the batteries.

I do not use the DVCC but rather simply a VeBUS BMS with the Victron Smart batteries. I installed my system in 2018 so I'm not sure DVCC was available then? 

In any event, here's what I think happens. Please correct me if I'm wrong. The lifepo4 batteries draw as much current as necessary to charge themselves. So as the batteries approach 100% SOC, the batteries naturally take less current. In other words, even when my 200amp chargers are connected to a nearly fully charged Victron Smart lithium battery that is going into top balance mode, the batteries only demand 1-3 amps and I can see, through bluetooth, that the batteries are being balanced. This can continue for hours. But usually if I want to top balance, I'll run the generator for a bit to take the batteries to 90-95% and let the Victron MPPT do the rest. No use in running in the generator to provide 25-50watts of power!

I don't know what is going on behind the scenes, but my ve-bus BMS is connected to my Quattro charger via ethernet. With respect to my other charging sources (Skylla-i 80amp, Victron MPPT and Mastervolt 110amp alternator), the ve-bus BMS, through an on-off signal, turns off charging in a safe manner. I reiterate, for others, that it does not disconnect the batteries from the charging source, but rather turns off the chargers safely.

As aside, for my MV alternator, I have it set at a very low absorption voltage. This is for two reasons (1) prevent holding the batteries at high SOC if I am motoring for a long time (2) let my solar do its work as a I have an aversion to "wasting" solar energy. To be honest, more often than not, I turn off my alternator because we simply don't need that charging source. This is done through an additional manual switch installed inline with the "reg-on" wire.


On Thu, May 5, 2022 at 03:53 AM, Dean Gillies wrote:


Scott,
You mentioned about charging at 200A causing your overvoltage protection to trigger at 3.7V. Does your system use Victron's DVCC?  This allows your BMS to control the charging voltage and current directly, and is particularly important in the situation you mention.  By way of example, my BMS disables my alternator and Mastervolt charger when the SOC reaches 95%. That leaves my Victron MP and MPPT as the only charging sources when the system is above 95%.  The BMS then uses DVCC to exert fine control over the charging voltage and current at the top-end.  When the first cell reaches 3.45V, the total charge current is reduced significantly by the BMS which starts to balance the cells in a controlled manner using DVCC to control the MP and MPPT.  As the cell voltages increase and come into balance then the charging current is ramped down and reaches zero when the cells are all at 3,58V.  Balancing currents are small, in the order of 1A, I don't believe you can effectively balance a LFP battery with a free-running 200A charger.  Maybe your Victron BMS can do more for you?

On the subject of alternator protection, my system turns-off the alternator (Using the RegON signal) whenever the SOC exceeds 95% and turns it on again when it drops below 90%. My Mastervolt charger is also controlled in this way. So my normal operation is to cycle the charging.  If all that fails then my AGM batteries will act as a fail-safe sink as you mentioned.

Dean
SV Stella
A54-154
(Trapani, Sicily)


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


Re: Stress crack main sheet boom attachment Maramu

Dennis Johns
 

Glad it's not cracked.  Don't have a photo of my boom -sorry.

How far is the first ring from the mast?  Perhaps it can do double-duty as a purchase point for your main sheet and for your preventer?

Dennis

On Thu, May 5, 2022 at 12:28 PM Alex BAIZEAU <alexandre.baizeau@...> wrote:
Thanks for the replies, I ended up grinding a little bit more paint and it seems that the metal, is not cracked.

Hopefully our boom doesn’t break in half, do you have any pictures of your third attachement point?

There seems to be a thick layer of fairing/padding to make the weld look smoother, it has the consistency and is white and Grey like rusting aluminium so it made me believe that the crack was in the metal but it’s not the case

Our boom has 4 rings/eyes and starting from the mast we use the second one for our preventer when going downwind.

Alex 

On Thu, May 5, 2022 at 7:11 PM Dennis Johns <sbmesasailor@...> wrote:
Ours was worse than that.  The single purchase to the middle of the boom resulted in metal fatigue and our boom actually broke in half.  We now have three purchase points on a new boom.  I would recommend you do the same to further distribute the energy.

Dennis Johns
Libertad
Maramu 121

On Thu, May 5, 2022 at 10:31 AM Alex BAIZEAU <alexandre.baizeau@...> wrote:

Hello Everyone, during a routine inspection we notice a couple of stress cracks where the main sheet connects to the boom on our Nirvana boom, Maramu 86.

See attached pictures. 


Is it something that has happened to anyone else? I’m wondering if someone already had this fixed and how.



Thanks for your input!

Alex Baizeau

Maramu #207, 1986 


Re: drop LiFePo4 batteries vs LiFePo4 cells in a bundled pack #solution

Scott SV Tengah
 

Michael,

 

On a Victron charger / BMS / battery system, additional balancing devices are not needed, but you do need to take the battery up to absorption voltages for a few hours now and then. I try to do it at least once every two weeks since we get carried away and find ourselves using two induction plates, boiler and toaster at the same time, certainly qualifying as a system that has high discharge currents.

 

 

How to ensure that the battery remains balanced

A 2-hour fixed absorption period is recommended for lithium batteries, so that there is enough time for cell balancing to take place. It is important to regularly fully charge the battery. This so that the battery spends enough time in the absorption stage. A full charge once a month should be sufficient. However, there are some applications where the battery cells will become quicker unbalanced than usual. This is the case when the system is intensively used, or if the battery bank consists of multiple batteries in series. To ensure a well balanced battery a weekly full charge is required for:

  • Systems with a battery bank that contains batteries that are connected in series.
  • Systems that are charged/discharged every day or a few times per week.
  • Systems that have high discharge currents.
  • Systems that have short charge periods or low charge voltages.

 

 

https://www.victronenergy.com/media/pg/Lithium_Battery_Smart/en/operation.html

 

If you don’t balance, all that happens is that one cell hits 4v earlier than others and the BMS tells the chargers to stop charging. That causes a TEMPORARY loss of capacity, fixed once you balance them.

 

Hope this clarifies things, at least with respect to how Victron does it.

 

From: "main@AmelYachtOwners.groups.io" <main@AmelYachtOwners.groups.io> on behalf of Michael Fuchs <fuchsmi@...>
Reply-To: "main@AmelYachtOwners.groups.io" <main@AmelYachtOwners.groups.io>
Date: Thursday, May 5, 2022 at 10:28 AM
To: "main@AmelYachtOwners.groups.io Group Moderators" <main@AmelYachtOwners.groups.io>
Subject: Re: [AmelYachtOwners] drop LiFePo4 batteries vs LiFePo4 cells in a bundled pack #solution

 

Scott,

I appreciate your knowledge and based on your documentation I'm currently planning an Amel 54 Victron setup.

 

I'm confused regarding the need of balancing the Victron Smart Lithium Batteries. In the datasheet it states:

" Our LFP batteries have integrated cell balancing and cell monitoring. Up to 5 batteries can be paralleled and up to four 12V batteries or two 24V batteries can be series connected, so that a 48V battery bank of up to 1500Ah can be assembled. The cell balancing/monitoring cables can be daisy-chained and must be connected to a Battery Management System (BMS)."

 

So the daisy-chained cables from the Smart Batteries should eliminate any additional balancing device or manual balancing as you discribe.

 

Michael

 

On Thu, 5 May 2022 at 20:12, Scott SV Tengah <Scott.nguyen@...> wrote:

Dean, small detail, but I misspoke - high voltage disconnect occurs at 4v per cell. Further, I only charge to 28.4v, so 3.55V per cell. Victron seems to believe the additional capacity above that voltage level is not worth the stress on the batteries.

I do not use the DVCC but rather simply a VeBUS BMS with the Victron Smart batteries. I installed my system in 2018 so I'm not sure DVCC was available then? 

In any event, here's what I think happens. Please correct me if I'm wrong. The lifepo4 batteries draw as much current as necessary to charge themselves. So as the batteries approach 100% SOC, the batteries naturally take less current. In other words, even when my 200amp chargers are connected to a nearly fully charged Victron Smart lithium battery that is going into top balance mode, the batteries only demand 1-3 amps and I can see, through bluetooth, that the batteries are being balanced. This can continue for hours. But usually if I want to top balance, I'll run the generator for a bit to take the batteries to 90-95% and let the Victron MPPT do the rest. No use in running in the generator to provide 25-50watts of power!

I don't know what is going on behind the scenes, but my ve-bus BMS is connected to my Quattro charger via ethernet. With respect to my other charging sources (Skylla-i 80amp, Victron MPPT and Mastervolt 110amp alternator), the ve-bus BMS, through an on-off signal, turns off charging in a safe manner. I reiterate, for others, that it does not disconnect the batteries from the charging source, but rather turns off the chargers safely.

As aside, for my MV alternator, I have it set at a very low absorption voltage. This is for two reasons (1) prevent holding the batteries at high SOC if I am motoring for a long time (2) let my solar do its work as a I have an aversion to "wasting" solar energy. To be honest, more often than not, I turn off my alternator because we simply don't need that charging source. This is done through an additional manual switch installed inline with the "reg-on" wire.


On Thu, May 5, 2022 at 03:53 AM, Dean Gillies wrote:



Scott,
You mentioned about charging at 200A causing your overvoltage protection to trigger at 3.7V. Does your system use Victron's DVCC?  This allows your BMS to control the charging voltage and current directly, and is particularly important in the situation you mention.  By way of example, my BMS disables my alternator and Mastervolt charger when the SOC reaches 95%. That leaves my Victron MP and MPPT as the only charging sources when the system is above 95%.  The BMS then uses DVCC to exert fine control over the charging voltage and current at the top-end.  When the first cell reaches 3.45V, the total charge current is reduced significantly by the BMS which starts to balance the cells in a controlled manner using DVCC to control the MP and MPPT.  As the cell voltages increase and come into balance then the charging current is ramped down and reaches zero when the cells are all at 3,58V.  Balancing currents are small, in the order of 1A, I don't believe you can effectively balance a LFP battery with a free-running 200A charger.  Maybe your Victron BMS can do more for you?

On the subject of alternator protection, my system turns-off the alternator (Using the RegON signal) whenever the SOC exceeds 95% and turns it on again when it drops below 90%. My Mastervolt charger is also controlled in this way. So my normal operation is to cycle the charging.  If all that fails then my AGM batteries will act as a fail-safe sink as you mentioned.

Dean
SV Stella
A54-154
(Trapani, Sicily)


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


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


Re: drop LiFePo4 batteries vs LiFePo4 cells in a bundled pack #solution

Michael Fuchs
 

Scott,
I appreciate your knowledge and based on your documentation I'm currently planning an Amel 54 Victron setup.

I'm confused regarding the need of balancing the Victron Smart Lithium Batteries. In the datasheet it states:
" Our LFP batteries have integrated cell balancing and cell monitoring. Up to 5 batteries can be paralleled and up to four 12V batteries or two 24V batteries can be series connected, so that a 48V battery bank of up to 1500Ah can be assembled. The cell balancing/monitoring cables can be daisy-chained and must be connected to a Battery Management System (BMS)."

So the daisy-chained cables from the Smart Batteries should eliminate any additional balancing device or manual balancing as you discribe.

Michael

On Thu, 5 May 2022 at 20:12, Scott SV Tengah <Scott.nguyen@...> wrote:
Dean, small detail, but I misspoke - high voltage disconnect occurs at 4v per cell. Further, I only charge to 28.4v, so 3.55V per cell. Victron seems to believe the additional capacity above that voltage level is not worth the stress on the batteries.

I do not use the DVCC but rather simply a VeBUS BMS with the Victron Smart batteries. I installed my system in 2018 so I'm not sure DVCC was available then? 

In any event, here's what I think happens. Please correct me if I'm wrong. The lifepo4 batteries draw as much current as necessary to charge themselves. So as the batteries approach 100% SOC, the batteries naturally take less current. In other words, even when my 200amp chargers are connected to a nearly fully charged Victron Smart lithium battery that is going into top balance mode, the batteries only demand 1-3 amps and I can see, through bluetooth, that the batteries are being balanced. This can continue for hours. But usually if I want to top balance, I'll run the generator for a bit to take the batteries to 90-95% and let the Victron MPPT do the rest. No use in running in the generator to provide 25-50watts of power!

I don't know what is going on behind the scenes, but my ve-bus BMS is connected to my Quattro charger via ethernet. With respect to my other charging sources (Skylla-i 80amp, Victron MPPT and Mastervolt 110amp alternator), the ve-bus BMS, through an on-off signal, turns off charging in a safe manner. I reiterate, for others, that it does not disconnect the batteries from the charging source, but rather turns off the chargers safely.

As aside, for my MV alternator, I have it set at a very low absorption voltage. This is for two reasons (1) prevent holding the batteries at high SOC if I am motoring for a long time (2) let my solar do its work as a I have an aversion to "wasting" solar energy. To be honest, more often than not, I turn off my alternator because we simply don't need that charging source. This is done through an additional manual switch installed inline with the "reg-on" wire.


On Thu, May 5, 2022 at 03:53 AM, Dean Gillies wrote:


Scott,
You mentioned about charging at 200A causing your overvoltage protection to trigger at 3.7V. Does your system use Victron's DVCC?  This allows your BMS to control the charging voltage and current directly, and is particularly important in the situation you mention.  By way of example, my BMS disables my alternator and Mastervolt charger when the SOC reaches 95%. That leaves my Victron MP and MPPT as the only charging sources when the system is above 95%.  The BMS then uses DVCC to exert fine control over the charging voltage and current at the top-end.  When the first cell reaches 3.45V, the total charge current is reduced significantly by the BMS which starts to balance the cells in a controlled manner using DVCC to control the MP and MPPT.  As the cell voltages increase and come into balance then the charging current is ramped down and reaches zero when the cells are all at 3,58V.  Balancing currents are small, in the order of 1A, I don't believe you can effectively balance a LFP battery with a free-running 200A charger.  Maybe your Victron BMS can do more for you?

On the subject of alternator protection, my system turns-off the alternator (Using the RegON signal) whenever the SOC exceeds 95% and turns it on again when it drops below 90%. My Mastervolt charger is also controlled in this way. So my normal operation is to cycle the charging.  If all that fails then my AGM batteries will act as a fail-safe sink as you mentioned.

Dean
SV Stella
A54-154
(Trapani, Sicily)


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


Re: modified stern railing on 54 to carry line drums

Danny and Yvonne SIMMS
 

Hi all, We sailed from Florida to the top of  Maine and back down, through Long Island sound and New York to the Chesapeake, then to the Caribbean and Panama, Galapagos, Marquesas, French Polynesia and various Pacific Islands and Home to NZ. Then numerous cruises to the Pacific islands and much cruising around NZ. Used a stern anchor once in Hiva Oa where all the boats were in perfect line. We just used our second primary anchor and chain. A bit cumbersome, but once in 14 years, I don't think it justifies a dedicated anchor
Kind regards
Danny
SM 299
Ocean Pearl

On 05/05/2022 11:04 CW Bill Rouse <brouse@...> wrote:


We used the stern anchor in those two places on our circle around the world:

The Galapagos and Hiva Oa in the Marquesas, and both due to restricted space and wanting to point the bow to the ocean swell. We had a 15kg Spade with 4 or 5 meters of 10mm chain connected to a nylon 3-strand rode.

Bill

CW Bill Rouse Amel Owners Yacht School

720 Winnie, Galveston Island, Texas 77550 
   

On Wed, May 4, 2022 at 1:46 PM Peter Forbes <ppsforbes@...> wrote:
Scott,

We used our stern anchor in 2 places - the Galapagos and Hiva Oa in the Marquesas. Both due anchorages with restricted space and lots of boats which also had stern anchors. Other than that never used - but I guess if you need it once it is enough to carry one.

Peter Forbes
CARANGO 
Amel 54 035
Lymington UK
07836 209730

On 4 May 2022, at 18:48, Scott SV Tengah <Scott.nguyen@...> wrote:

Thanks Martin. We finally had to use a stern anchor after 4 years cruising. We deployed the port anchor (Delta, believe 31kg!) as a stern anchor using the dinghy. Not a pleasant experience and we have not yet tried to retrieve it. By the way, the rode is attached to the stern cleat but chafes on the stainless rub rail and on the hull as the boat moves around. Have you solved this?

I am considering getting a dedicated Fortress stern anchor, but wondering how much I will use it. Other than Patagonia, where do you anticipate needing it?

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




Re: Stress crack main sheet boom attachment Maramu

Alex BAIZEAU
 

Thanks for the replies, I ended up grinding a little bit more paint and it seems that the metal, is not cracked.

Hopefully our boom doesn’t break in half, do you have any pictures of your third attachement point?

There seems to be a thick layer of fairing/padding to make the weld look smoother, it has the consistency and is white and Grey like rusting aluminium so it made me believe that the crack was in the metal but it’s not the case

Our boom has 4 rings/eyes and starting from the mast we use the second one for our preventer when going downwind.

Alex 

On Thu, May 5, 2022 at 7:11 PM Dennis Johns <sbmesasailor@...> wrote:
Ours was worse than that.  The single purchase to the middle of the boom resulted in metal fatigue and our boom actually broke in half.  We now have three purchase points on a new boom.  I would recommend you do the same to further distribute the energy.

Dennis Johns
Libertad
Maramu 121

On Thu, May 5, 2022 at 10:31 AM Alex BAIZEAU <alexandre.baizeau@...> wrote:

Hello Everyone, during a routine inspection we notice a couple of stress cracks where the main sheet connects to the boom on our Nirvana boom, Maramu 86.

See attached pictures. 


Is it something that has happened to anyone else? I’m wondering if someone already had this fixed and how.



Thanks for your input!

Alex Baizeau

Maramu #207, 1986 


Re: modified stern railing on 54 to carry line drums

Scott SV Tengah
 

Thanks for the detailed response Martin. This is the most advanced stern anchor system I've seen on an Amel by far. 

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

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