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


EricOpdeweegh
 

Dear Amelians.

We are considering to buy a bundled pack of LiFePo4 cells vs  the drop-in ready batteries (like the ones from Battle Born,Transport Energy or Victron).

Based on the beautiful battery compartment on the Super Maramu's that can be closed and is sealed pretty wellwith a separate ventilation duct. (This could even be improved to the max)
In our point of view it would be a difficult task to get this GPR battery compartment full with water. If it does we would be in a liftraft already I think. 

What would be the reason to have the LiFePo4 cells in a HDP or some sort of other casing? 

We found a supplier that clamps the individual cells together in a pack of 40 kg with pressure plates and strips (under pressure). So a pack of  2x 300Ah /24V at total 15kWh (2x8 cells 2P8S) can be made with a dimension of 650x340x230 mm (80kg). The battery pack is supplied with its own BMS that moitors and reglates over-, under charge , temp and balancing of the individual cells.
Based on these dimensions we would in theory even be able to get 2x sets of 650 x340x 230 ( or 12kwh in the compartment AND the starter battery ( our compartment is 1610 x390x 252 mm)

The question is why would we still need a HDP Casing with this type of LiDePo4 cells? 

We are very interested to hear the various opinions about this..

Best Regards and Fair Winds
Eric Opdeweegh
sv Abayomi 
SM 158
Currently in Holland 


Matt & Michelle
 

Eric,
This should be a fun thread to watch replies.....:)

Making a move to LFP requires you to think a bit differently and be prepared to significantly change your boat systems.  Make sure to read Scott's and Bill's previous posts on LFP installs and trades in the process (that may steer you away from the battery technology...ref Bill's commentary).

First, if you are trying to fill the battery box to capacity, you are thinking with a lead-acid design mindset.  Each Group 27/31 battery will give you roughly 30-40% more capacity.  Going from 400Ah to 800Ah may sound magical, but you still have to charge them.  And if you are not exercising the batteries, you cannot expect the advertised life.  One really needs to look at these batteries from a system design perspective...like Henry did when putting in the lead acid batteries.

LFP batteries can swell as part of the charging process (or as they break down) and emit heat.  Strapping them together can lead to battery rupture or thermal runaway.  I would urge you to use caution, or forego any idea of strapping the cells together.    

The HDP case performs multiple functions, but two specific to your proposal.  It provides the space necessary for thermal expansion and contains the electrolyte from rupturing a cell(s).  The electrolyte is toxic as hell.

LFP works safe and well when installed on a boat systematically.  We made the intentional decision to put a Victron system in the boat and all the rewiring that it requires.  It was absurdly expensive, but we have significantly limited our risk of thermal runaway with multiple paths of redundancy.  You can do that same system approach with SuperBee, MasterVolt, etc.  I would have little hesitation building batteries for a home installation on land, but in harsh environment and on open water, I would council caution.


Bruno COTTE
 

First of all I would choose a well known brand with BMS insinbedded
2/ your alternator and your regulator must be adapted to LIPO batteries ( lot of charge , lot of heat risk of fire in the engine room 
3/ have in mind that the battery charge curve is different . LIPO accept a lot of charge up to full . 
4/ your chargers must be adapted also 
Each battery mus have its own fuse and it’s own breaker . 
A global interface system following all these points is a plus ( Mastervolt data bus , Victron … ) 
If you add a good fan in the battery room as well as an automatic fire extinguisher you do everything ok . Have in mind that in the Amel 50/60 the 24v 5500 MLI 200A batteries are fixed together and no problem if all above rules are respected 

Envoyé de mon iPhone

Le 5 avr. 2022 à 15:36, Matt & Michelle <charlesmatthewday@...> a écrit :

Eric,
This should be a fun thread to watch replies.....:)

Making a move to LFP requires you to think a bit differently and be prepared to significantly change your boat systems.  Make sure to read Scott's and Bill's previous posts on LFP installs and trades in the process (that may steer you away from the battery technology...ref Bill's commentary).

First, if you are trying to fill the battery box to capacity, you are thinking with a lead-acid design mindset.  Each Group 27/31 battery will give you roughly 30-40% more capacity.  Going from 400Ah to 800Ah may sound magical, but you still have to charge them.  And if you are not exercising the batteries, you cannot expect the advertised life.  One really needs to look at these batteries from a system design perspective...like Henry did when putting in the lead acid batteries.

LFP batteries can swell as part of the charging process (or as they break down) and emit heat.  Strapping them together can lead to battery rupture or thermal runaway.  I would urge you to use caution, or forego any idea of strapping the cells together.    

The HDP case performs multiple functions, but two specific to your proposal.  It provides the space necessary for thermal expansion and contains the electrolyte from rupturing a cell(s).  The electrolyte is toxic as hell.

LFP works safe and well when installed on a boat systematically.  We made the intentional decision to put a Victron system in the boat and all the rewiring that it requires.  It was absurdly expensive, but we have significantly limited our risk of thermal runaway with multiple paths of redundancy.  You can do that same system approach with SuperBee, MasterVolt, etc.  I would have little hesitation building batteries for a home installation on land, but in harsh environment and on open water, I would council caution.


Germain Jean-Pierre
 

Unfortunately, no one has yet mentioned the many restrictions brought into the discussion by insurance companies. 

They may not approve or insure your installation plan. 

Check with them first!!

Jean-Pierre Germain, former ownerEleuthera, SM007. 


On 5/04/2022, at 08:20, Bruno COTTE <cotte.bruno@...> wrote:

First of all I would choose a well known brand with BMS insinbedded
2/ your alternator and your regulator must be adapted to LIPO batteries ( lot of charge , lot of heat risk of fire in the engine room 
3/ have in mind that the battery charge curve is different . LIPO accept a lot of charge up to full . 
4/ your chargers must be adapted also 
Each battery mus have its own fuse and it’s own breaker . 
A global interface system following all these points is a plus ( Mastervolt data bus , Victron … ) 
If you add a good fan in the battery room as well as an automatic fire extinguisher you do everything ok . Have in mind that in the Amel 50/60 the 24v 5500 MLI 200A batteries are fixed together and no problem if all above rules are respected 

Envoyé de mon iPhone

Le 5 avr. 2022 à 15:36, Matt & Michelle <charlesmatthewday@...> a écrit :

Eric,
This should be a fun thread to watch replies.....:)

Making a move to LFP requires you to think a bit differently and be prepared to significantly change your boat systems.  Make sure to read Scott's and Bill's previous posts on LFP installs and trades in the process (that may steer you away from the battery technology...ref Bill's commentary).

First, if you are trying to fill the battery box to capacity, you are thinking with a lead-acid design mindset.  Each Group 27/31 battery will give you roughly 30-40% more capacity.  Going from 400Ah to 800Ah may sound magical, but you still have to charge them.  And if you are not exercising the batteries, you cannot expect the advertised life.  One really needs to look at these batteries from a system design perspective...like Henry did when putting in the lead acid batteries.

LFP batteries can swell as part of the charging process (or as they break down) and emit heat.  Strapping them together can lead to battery rupture or thermal runaway.  I would urge you to use caution, or forego any idea of strapping the cells together.    

The HDP case performs multiple functions, but two specific to your proposal.  It provides the space necessary for thermal expansion and contains the electrolyte from rupturing a cell(s).  The electrolyte is toxic as hell.

LFP works safe and well when installed on a boat systematically.  We made the intentional decision to put a Victron system in the boat and all the rewiring that it requires.  It was absurdly expensive, but we have significantly limited our risk of thermal runaway with multiple paths of redundancy.  You can do that same system approach with SuperBee, MasterVolt, etc.  I would have little hesitation building batteries for a home installation on land, but in harsh environment and on open water, I would council caution.


EricOpdeweegh
 

Hi Matt & Michelle

 

Thanks for your quick reply. And sure hope we get a lot of replies. The opinions are very far apart.

 

Sure we are not just replacing the Gel batteries by LiFePo4. We are about to change the whole system and make it lithium prove, more or less with Victron equipment and all installed by certified well experienced electricians.

We sure are looking at the charge side too. We will start with 1000W and may extent to 1400W solar + a 400W wind gen for the night sailing

 

We are about to go for 600AH liFePo4 (2P8S), but if the price is right a little higher to 900. If we run all the systems, cook induction and use an airco this gives enough juice with a Quattro 5000W.

If we go for 600AH lifePo4 without a casing system this will only need 650 mm in length of our 1610 mm long battery compartment. So even space for the starter battery and even 2x 100AH redundancy lead acid batteries.

We have a SM and not a SM2K so the  battery compartment is smaller and only fits 8 x 100AH /12 V batteries.

If I understand correctly it is not so much the LiFePo4 cells but the fuses, BMS and equipment around them that you need to be very specific about for safety on a SM.

 

LiFePo4 Victron batteries would limit us to less AH, not enough to run without generator for 3 days. And They are way too expensive. Also we have an older Onan that we like to spare as much as possible.

 

Your pro- and cons on the HDP casing well noted. Will look more into your comments on that.

For as far as I am informed now the suppliers of the block of LiFePo4 cells have the block well strapped under tension with separation plates. No danger for explosion, if the right fuses and BMS are used off course.

Additionally the battery compartment itself is one of Henry Amels super design ideas and suppose to be water and airtight if I am correct. It has its own ventilation.

 

I might be wrong on some points so anyone who likes to fire at me, please do.

 

Soonest we have all figured out safely we will post our findings for review again.

 

Thanks again for your quick reply. Well appreciated.

 

Eric Opdeweegh

Sv Abayomi SM 158

Currently in Holland

 

Van: main@AmelYachtOwners.groups.io <main@AmelYachtOwners.groups.io> Namens Matt & Michelle
Verzonden: dinsdag 5 april 2022 15:37
Aan: main@AmelYachtOwners.groups.io
Onderwerp: Re: [AmelYachtOwners] drop LiFePo4 batteries vs LiFePo4 cells in a bundled pack #solution

 

Eric,
This should be a fun thread to watch replies.....:)

Making a move to LFP requires you to think a bit differently and be prepared to significantly change your boat systems.  Make sure to read Scott's and Bill's previous posts on LFP installs and trades in the process (that may steer you away from the battery technology...ref Bill's commentary).

First, if you are trying to fill the battery box to capacity, you are thinking with a lead-acid design mindset.  Each Group 27/31 battery will give you roughly 30-40% more capacity.  Going from 400Ah to 800Ah may sound magical, but you still have to charge them.  And if you are not exercising the batteries, you cannot expect the advertised life.  One really needs to look at these batteries from a system design perspective...like Henry did when putting in the lead acid batteries.

LFP batteries can swell as part of the charging process (or as they break down) and emit heat.  Strapping them together can lead to battery rupture or thermal runaway.  I would urge you to use caution, or forego any idea of strapping the cells together.    

The HDP case performs multiple functions, but two specific to your proposal.  It provides the space necessary for thermal expansion and contains the electrolyte from rupturing a cell(s).  The electrolyte is toxic as hell.

LFP works safe and well when installed on a boat systematically.  We made the intentional decision to put a Victron system in the boat and all the rewiring that it requires.  It was absurdly expensive, but we have significantly limited our risk of thermal runaway with multiple paths of redundancy.  You can do that same system approach with SuperBee, MasterVolt, etc.  I would have little hesitation building batteries for a home installation on land, but in harsh environment and on open water, I would council caution.


EricOpdeweegh
 

Hi Bruno,

 

Thanks for your reply. Much , Much appreciated. Really great to receive all this feedback. I should maybe have been a little more clear about all the things we are changing before asking this specific question about the HDP casing or not.

 

Our whole system will be modernized and made future prove for lithium, most with Victron equipment. We are preparing a full new electrical system diagram but can not release it yet because it’s not fool prove yet.

Let me reply to your comments and questions in your mail.

 

Thanks and Rgrds

Eric SM 158 sv Abayomi

 

 

Van: main@AmelYachtOwners.groups.io <main@AmelYachtOwners.groups.io> Namens Bruno COTTE
Verzonden: dinsdag 5 april 2022 16:20
Aan: main@amelyachtowners.groups.io
Onderwerp: Re: [AmelYachtOwners] drop LiFePo4 batteries vs LiFePo4 cells in a bundled pack #solution

 

First of all I would choose a well known brand with BMS insinbedded

2/ your alternator and your regulator must be adapted to LIPO batteries ( lot of charge , lot of heat risk of fire in the engine room 

Check . We will use the Sterling regulator

3/ have in mind that the battery charge curve is different . LIPO accept a lot of charge up to full . 

Check. The complete support system will be Victron including VE Bus / Quattro/ shunts  and Cerbo GX

4/ your chargers must be adapted also 

Each battery mus have its own fuse and it’s own breaker . 

Check, each battery  will be fused including 2 battery Protectors to the equipment

A global interface system following all these points is a plus ( Mastervolt data bus , Victron … ) 

 

If you add a good fan in the battery room as well as an automatic fire extinguisher you do everything ok . Have in mind that in the Amel 50/60 the 24v 5500 MLI 200A batteries are fixed together and no problem if all above rules are respected 

Adding a fan and automatic ( LIFEPO4) extinguisher is a good idea, thanks

Can you explain a little more about the Amel 50/60 24V 5000 MLi 200A ? Is that idividual cells in a block too without a HDP box?

 

Envoyé de mon iPhone



Le 5 avr. 2022 à 15:36, Matt & Michelle <charlesmatthewday@...> a écrit :

Eric,
This should be a fun thread to watch replies.....:)

Making a move to LFP requires you to think a bit differently and be prepared to significantly change your boat systems.  Make sure to read Scott's and Bill's previous posts on LFP installs and trades in the process (that may steer you away from the battery technology...ref Bill's commentary).

First, if you are trying to fill the battery box to capacity, you are thinking with a lead-acid design mindset.  Each Group 27/31 battery will give you roughly 30-40% more capacity.  Going from 400Ah to 800Ah may sound magical, but you still have to charge them.  And if you are not exercising the batteries, you cannot expect the advertised life.  One really needs to look at these batteries from a system design perspective...like Henry did when putting in the lead acid batteries.

LFP batteries can swell as part of the charging process (or as they break down) and emit heat.  Strapping them together can lead to battery rupture or thermal runaway.  I would urge you to use caution, or forego any idea of strapping the cells together.    

The HDP case performs multiple functions, but two specific to your proposal.  It provides the space necessary for thermal expansion and contains the electrolyte from rupturing a cell(s).  The electrolyte is toxic as hell.

LFP works safe and well when installed on a boat systematically.  We made the intentional decision to put a Victron system in the boat and all the rewiring that it requires.  It was absurdly expensive, but we have significantly limited our risk of thermal runaway with multiple paths of redundancy.  You can do that same system approach with SuperBee, MasterVolt, etc.  I would have little hesitation building batteries for a home installation on land, but in harsh environment and on open water, I would council caution.


EricOpdeweegh
 

Hi Jean Pierre,

 

Thanks for the warning. We are aware of the issues with insurance.

Will sure do check with them as soon as we have all plans and diagrams ready for sure.

 

Rgrds

Eric

SM 158

Sv Abayomi

 

Van: main@AmelYachtOwners.groups.io <main@AmelYachtOwners.groups.io> Namens Germain Jean-Pierre
Verzonden: dinsdag 5 april 2022 17:34
Aan: main@amelyachtowners.groups.io
Onderwerp: Re: [AmelYachtOwners] drop LiFePo4 batteries vs LiFePo4 cells in a bundled pack #solution

 

Unfortunately, no one has yet mentioned the many restrictions brought into the discussion by insurance companies. 

 

They may not approve or insure your installation plan. 

 

Check with them first!!

 

Jean-Pierre Germain, former ownerEleuthera, SM007. 



On 5/04/2022, at 08:20, Bruno COTTE <cotte.bruno@...> wrote:

First of all I would choose a well known brand with BMS insinbedded

2/ your alternator and your regulator must be adapted to LIPO batteries ( lot of charge , lot of heat risk of fire in the engine room 

3/ have in mind that the battery charge curve is different . LIPO accept a lot of charge up to full . 

4/ your chargers must be adapted also 

Each battery mus have its own fuse and it’s own breaker . 

A global interface system following all these points is a plus ( Mastervolt data bus , Victron … ) 

If you add a good fan in the battery room as well as an automatic fire extinguisher you do everything ok . Have in mind that in the Amel 50/60 the 24v 5500 MLI 200A batteries are fixed together and no problem if all above rules are respected 

Envoyé de mon iPhone



Le 5 avr. 2022 à 15:36, Matt & Michelle <charlesmatthewday@...> a écrit :

Eric,
This should be a fun thread to watch replies.....:)

Making a move to LFP requires you to think a bit differently and be prepared to significantly change your boat systems.  Make sure to read Scott's and Bill's previous posts on LFP installs and trades in the process (that may steer you away from the battery technology...ref Bill's commentary).

First, if you are trying to fill the battery box to capacity, you are thinking with a lead-acid design mindset.  Each Group 27/31 battery will give you roughly 30-40% more capacity.  Going from 400Ah to 800Ah may sound magical, but you still have to charge them.  And if you are not exercising the batteries, you cannot expect the advertised life.  One really needs to look at these batteries from a system design perspective...like Henry did when putting in the lead acid batteries.

LFP batteries can swell as part of the charging process (or as they break down) and emit heat.  Strapping them together can lead to battery rupture or thermal runaway.  I would urge you to use caution, or forego any idea of strapping the cells together.    

The HDP case performs multiple functions, but two specific to your proposal.  It provides the space necessary for thermal expansion and contains the electrolyte from rupturing a cell(s).  The electrolyte is toxic as hell.

LFP works safe and well when installed on a boat systematically.  We made the intentional decision to put a Victron system in the boat and all the rewiring that it requires.  It was absurdly expensive, but we have significantly limited our risk of thermal runaway with multiple paths of redundancy.  You can do that same system approach with SuperBee, MasterVolt, etc.  I would have little hesitation building batteries for a home installation on land, but in harsh environment and on open water, I would council caution.


Matt & Michelle
 

Eric,

Sounds like great fun.  We used the Victron 200Ah prismatic cells in a 2P6S with 1140W of surface mount solar.  We are on hull 209, so similar 8 cell limitation.  With the remaining space we were able to install our fusing, MMPTs, CERBO, BMS in the battery compartment.  Likewise, we installed the 5kW Quattro, VE isolation transformer (in aft lazarette), 120v Phoenix Inverter (Americans...), and two back-up Skylla 65A chargers (just in case....cheap, networked and reliable).  I also installed a 24V/12V charger for the starter battery (the reasoning becomes apparent below).

You might want to reach out to John at ElectroMaax to discuss your engine charge options.  I banged my head for days trying to find an acceptable high capacity alternator with an isolated ground.  They have a couple of options you might find intriguing.  I will be installing a 165A/24V IG unit with a remote rectifier and BT controller that integrates directly with the Victron BMS.  I have the option to add a second alternator to replace the 12V unit installed, in which case I theoretically could replace my genset.  I don't have the nerve to pull the trigger on that one yet.      

Matt & Michelle
SV Talia SM#209
Hampton, VA


Wolfgang Weber
 

Changing to Lithium batteries is not a do-it-yourself job !
It is only 24 Volt - but a lot of amperes !
Ask your insurance !
The realistic costs for changing to lithium batteries is 20-30t € by professional installation. This is not much for a Amel 50 or 60 for 1.3-2.6 m €, but a lot of money for a Amel 100-200 t€.
Make a good decision  ! - what ever it is .
Wolfgang Weber SY Elise Amel 54#162 - Complete Mastervolt Lithium System 400 AH


EricOpdeweegh
 

Hi Wollfgang and other Amelians,

 

Thank you for your concerns.

It is sure not a do it yourself job we are intending to do.

We have taken a certified electrician in hand experienced in this type of refit of electrical systems, working with Victron equipment and we are in the end process of redesigning the complete electrical diagram for future proof solar based system. This will need to be supported by the insurance offcource.

It is not cheap as you and others can confirm but we think this ship is worth it for the future. Once we have the system design ready to be implemented we will share on this forum. (Only the professional design already costed Euro 1000,-)

Furthermore we like to improve the Amel design without fuses on the Bowtruster etc. So all will need to be fused properly.

 

All said, we are now in the process of decision making regarding the LiFePo4 batteries themselves and not yet convinced.

Based on the beautiful designed battery compartment of our Amel SM 1996 ( with limited space : 1610x390x250-290 mm) we see an ideal option to fit the cells (in a pressured block with separation plates and active BMS of 2P8S) without the HDP casings.

 

This option will allow us to fit at least 600Ah or even 900AH instead of 400AH with the traditional available drop-in batteries.

It will allow the need of the Onan genset (we like to cut down the use) only once every 3 days (in the tropics), cook on induction, run one airco unit at night, partly run the watermaker  (on the Victron Quattro -II 5000W inverter) and would be a major cutdown in purchase costs of at least  Euro 4000 or even more.  Last but not least we would even be able to place 2x100AH gel or lead acid batteries in the battery compartment as a backup redundancy system if the BMS system of the LiFePo4 system fails.

 

Suggestions and comments so far

  • Check with your insurance!
  • Add a mechanical ventilation
  • Add an automatic extinguisher ( fit for LiFePo4)
  • HDP case said to provide better protection. The HDP case provides the space necessary for thermal expansion and contains the electrolyte from rupturing a cell(s).  The electrolyte is toxic as hell.

 

 

So the question still stands for more pro’s and cons. What are the downsides of a block of LiFePo4 cells in watertight and airtight Amel battery compartment vs drop-in batteries?

Will this be a safe and good option?

 

In our opinion once green water reaches this part of the boat we will likely be in a life raft 😊

 

Any other (good or bad) experiences or well-founded opinions with other Amel SM owners ?

 

Looking forward to the reactions

 

Fair winds and enjoy

 

Eric Opdeweegh

Sv Abayomi SM 158

Phone  +31621240217

Email     sv.abayomi@...

 

Van: main@AmelYachtOwners.groups.io <main@AmelYachtOwners.groups.io> Namens Wolfgang Weber
Verzonden: dinsdag 5 april 2022 23:32
Aan: main@AmelYachtOwners.groups.io Group Moderators <main@amelyachtowners.groups.io>
Onderwerp: Re: [AmelYachtOwners] drop LiFePo4 batteries vs LiFePo4 cells in a bundled pack #solution

 

Changing to Lithium batteries is not a do-it-yourself job !

It is only 24 Volt - but a lot of amperes !

Ask your insurance !

The realistic costs for changing to lithium batteries is 20-30t € by professional installation. This is not much for a Amel 50 or 60 for 1.3-2.6 m €, but a lot of money for a Amel 100-200 t€.

Make a good decision  ! - what ever it is .

Wolfgang Weber SY Elise Amel 54#162 - Complete Mastervolt Lithium System 400 AH

 


Paul Osterberg
 

We installed DIY Li cells last winter 2P8S in total 540 Ah, I made a “compression” case by two pieces of 18 mm plywood, took threaded rods to keep adequate pressure to the cells. A BMS from MasterLi who can control charging via a relay or signal to control alternator, Victron MultiPlus etc. we use our MultiPlus and the old Dolphins charger to charge the battery pack. The alternator already had a Balmar regulator so easy to control that as well, we only added a temp sensor to the alternator. The two relays for chargin and load are good for 750 A continues. After cá 18 month of operation we are very please with the installation. To charge we mainly use solar 1160 w, on passage also a hydro generator. This season we are “ fully electrical” ie make our food on induction, bake bread with baking machine and as oven we use an air fryer. Event though only early April yet, we have had no need to use the Onan generator or shore power. Highly recommend to convert 
Paul on SY Kerpa SM#259 currently in Galicia Spain on route to Lofoten 


EricOpdeweegh
 

Hi Paul,

 

Hope you and your wife are doing fine and enjoying the cruising. Are you going back to Norway (Lofoten)? Let me know when you are in the area and stop by in Holland (Zeeland)

 

Thanks for your positive reaction.  That is what I am aiming for too.

 

Be carefull with the selfmade compression. Have a look at PureAcell.nl.

https://www.pureacell.nl/webshop/accessoires/detail/33/cellen-opspannen-met-drukplaten.html. They have special sets for the compression which needs at least 300kg pressure. Also to optimize and increase the lifecycles.

Trust you can translate the Dutch in English or Norwegian. Tell him I gave you his details.

 

I will have a professional electician design, guide and assist me in the installation but that is just because I am not experienced enough to do it on my own.  In the end however I will have to do the maintenance myself in the open ocean😊

 

Fair Winds

Eric Opdeweegh

Sv Abayomi SM 158

Phone  +31621240217

Email     sv.abayomi@...

 

 

Van: main@AmelYachtOwners.groups.io <main@AmelYachtOwners.groups.io> Namens Paul Osterberg
Verzonden: woensdag 6 april 2022 13:51
Aan: main@AmelYachtOwners.groups.io
Onderwerp: Re: [AmelYachtOwners] drop LiFePo4 batteries vs LiFePo4 cells in a bundled pack #solution

 

We installed DIY Li cells last winter 2P8S in total 540 Ah, I made a “compression” case by two pieces of 18 mm plywood, took threaded rods to keep adequate pressure to the cells. A BMS from MasterLi who can control charging via a relay or signal to control alternator, Victron MultiPlus etc. we use our MultiPlus and the old Dolphins charger to charge the battery pack. The alternator already had a Balmar regulator so easy to control that as well, we only added a temp sensor to the alternator. The two relays for chargin and load are good for 750 A continues. After cá 18 month of operation we are very please with the installation. To charge we mainly use solar 1160 w, on passage also a hydro generator. This season we are “ fully electrical” ie make our food on induction, bake bread with baking machine and as oven we use an air fryer. Event though only early April yet, we have had no need to use the Onan generator or shore power. Highly recommend to convert 
Paul on SY Kerpa SM#259 currently in Galicia Spain on route to Lofoten 


Paul Osterberg
 

Eric
We might pas Holland on our way back next year, now we will hopefully go direct from >Coruna to Cork Ireland, but weather does not cooperate now so we might go via Brest before continue to Ireland for further passage to Lofoten. Aim to be there around mid June
Paul SM#259 


Dean Gillies
 

Matt and Michelle,
Ok,  curiosity got the better of me !!
You said " We used the Victron 200Ah prismatic cells in a 2P6S with 1140W of surface mount solar.", with the emphasis on "6".
Go on, I'm sure you know why I ask... ??  :-)

Dean
SV Stella
A54-154


Matt & Michelle
 

Dean,

Very fair question.  I hope I did not add confusion.  In normal lead acid thinking, "more is better" makes sense when you have a battery with 50% usable capacity.  You can witness this constraint in the original AMEL system design of the SM (8-LA-batteries; 24V/400Ah; w/200Ah usable) transition to the SM2k (12-LA-batteries; 24V/600Ah; w/300Ah usable).  The power usage and generation systems and redundancy in the design are well balanced, containing risk.

This is one reason why I made my sarcastic comment at the beginning of this string.  It is easy to look at the LA vs LFP battery debate as binary ("we are all going to die because of LFP" vs "LFP will save us all from the Kraken").  The reality is the system changes are a practical undertaking of managing risk, especially if you do your best to follow the Amel design path.  Both battery chemistries by definition are stored energy and therefore dangerous....etc etc etc....blah blah blah 

We chose to install 6 Victron LFP prismatic batteries.  The result was a battery bank (for SM#209) that went from (8-LA-batteries; 24V/400Ah; w/200Ah usable) to (6-LFP-batteries; 24V/600Ah; w/~500Ah), or lets assume 200% of original usable energy storage.  To maintain the robust design philosophy, I have to assume (based on LFP chemistry) that this energy can be discharged at an extraordinary rate.  I therefore had to change fusing, breakers and most of the main leads.  This was a royal PITA as you well know, especially getting through to the engine bay.

The power generation sources have limited capability matched to our system needs...with margin to give and redundancy.  I can generate enough power daily for our typical needs with wind/solar, and supplement with dinosaur juice.

We could have added an additional 24V/200Ah of capacity, but the knock-on effects are not worth it.  I add greater energy storage on the boat that is a risk, and I will have limited use with the system design.  The batteries are expensive, the oversized wiring gets prohibitive monetarily and physically.  We did not want the added risk or system cost.

For us the time horizon of usage is fairly long and we could justify the system changes/costs.  If your time horizon is short, that is a horse of a different color.  Bill Kinney's write-up of FireFly batteries is a solid discussion of the risk/cost challenges.

Sorry for bloviating....

Matt & Michelle
SV Talia (Sm#209)
Hampton, VA
 


Dominique Sery
 

Matt,

Totally agree with you, I followed the same approach and installed a full Victron set (24v 600Ah).
It's night and day with the old system. It's only the price that can make you hesitate. 

Dominique
Irko (A54#16)


 

Matt,

Very, very clear. I totally agree. 

Some Amel owners are aware that any battery bank can be the source of a hot fire, and lead-acid batteries can be the source of a hydrogen fueled explosion.

Best,

CW Bill Rouse 
Amel Owners Yacht School
+1 832-380-4970 | brouse@...
720 Winnie, Galveston Island, Texas 77550 
www.AmelOwnersYachtSchool.com 
Yacht School Calendar: www.preparetocastoff.blogspot.com/p/calendar.html


   


On Thu, Apr 7, 2022, 12:10 Dominique Sery via groups.io <dominiquesery=me.com@groups.io> wrote:
Matt,

Totally agree with you, I followed the same approach and installed a full Victron set (24v 600Ah).
It's night and day with the old system. It's only the price that can make you hesitate. 

Dominique
Irko (A54#16)


Nick Newington
 

I agree with Dean. The hybrid solution makes a lot of sense. The lithium keep the AGM at float until it doesn’t.  You then either charge or start drawing down on the AGM part of the bank.
I have not yet installed a lithium but more than just mulling it over.
Nick
S/Y Amelia
Amel 54/019
Leros


On 7 Apr 2022, at 18:51, CW Bill Rouse <brouse@...> wrote:


Matt,

Very, very clear. I totally agree. 

Some Amel owners are aware that any battery bank can be the source of a hot fire, and lead-acid batteries can be the source of a hydrogen fueled explosion.

Best,

CW Bill Rouse 
Amel Owners Yacht School
+1 832-380-4970 | brouse@...
720 Winnie, Galveston Island, Texas 77550 
www.AmelOwnersYachtSchool.com 
Yacht School Calendar: www.preparetocastoff.blogspot.com/p/calendar.html


   

On Thu, Apr 7, 2022, 12:10 Dominique Sery via groups.io <dominiquesery=me.com@groups.io> wrote:
Matt,

Totally agree with you, I followed the same approach and installed a full Victron set (24v 600Ah).
It's night and day with the old system. It's only the price that can make you hesitate. 

Dominique
Irko (A54#16)


Dean Gillies
 

Hi Matt,
Thanks for clearing that up. I agree entirely with your analysis, and it doesn't sound like "bloviating", more like music to my ears :)

The reason for my original question was that the terminology "2p6s" or "2p8s" is normally used to describe the topology of batteries which are made up of multiple cells. The "p" refers to parallel, and the "s" refers to series.  So a 2p6s battery would be comprised of 6 pairs of paralleled cells where all 6 pairs are connected in series.  A "2p8s" would thus be a series string of 8x paralleled pairs (which is what I installed for the LiFePO4 part of my battery bank ... 16x 270Ah cells in a 2p8S configuration, giving 540Ah/25.6V)). 

For LiFePO4 200Ah prismatic cells with a nominal voltage of 3.2V, then a cell topology of 2p6s would result in a 400Ah/19.2V battery!! Whereas if you were referring to a set of Victron 200Ah/12.8V "batteries" in a "2p6s" configuration then that would be 400Ah/76.8V!  

In the normal terminology, I suspect you have a 8s3p configuration of cells (which you could also describe as a 2s3p configuration of "batteries", i.e. 3x strings of 2 batteries in series and all three strings connected in parallel).

Normally I would have put the "6" down to a typo that should have been "8", but your emphasis was on the "6" so I reckoned that you really meant "6" ... and that was interesting lol.

Dean
SV Stella
A54-154


Matt & Michelle
 

Dean,

Well damn...Many thanks for the clarity of the nomenclature.  Great information, and a fun learning opportunity.

Matt