Newbies need Lithium help please.

[John Williams]

Hi Corrigano

Thought I would give you our experience. Have had our boat for 11 years. Last year upgraded to LFP. I talk on the basis that getting it done properly is better than trying to get the cheapest deal. It all depends on your finances.

Simple answer is to find a good! marine electrician and just pay him/her to do it. Get quote first to make sure it is not cheaper to get them installed as an option with the boat manufacturer.

Engine batteries: just take whatever comes with the boat. No-one worries about car batteries! And that is all they are.

House batteries. We had two AGM deep discharge (not cold cranking) with 270 ah each. Total 540 ah. I was always worrying about the charge etc.

Bought a system recommended by our marine electrician and installed by him. One battery 300 ah. Would never go back. We have solar panels. If the sun shines (we are in Australia) then all good. If no sun we have to start the motor every second day. But we run an old freezer as well as everything else and the freezer uses a lot of amps. The system has all these chargers, regulators etc (don't ask me about them but one is an MPPT) that allow us to charge from the motor, the solar panels and 240 volts shore power. I have to do nothing other than check the battery monitor and decide if we need to start the motor.

Cost? How long is a piece of string. We have a 41 foot mono. Run TV, lights, fridge and freezer and of course instruments including electric autopilot. Our system fully installed cost $8,500 AUD about 2 years ago.

Good luck

[ramblinrod]

Originally Posted by roland stockham

I would advise caution here. You state that you ar new to sailing and the electrical system on a modern boat is a complex and balanced system (or should be!). If you don't understand the system suficiently to be confident in what needs doing then you could find it is a lot more expensive to both fit and maintain. There is a lot of hype around lithium and for boats with a very high power consuption it does look like a good solution but that does not meen that flooded lead acid batteries are not still very practical as well as been far cheaper.

My advice would be to run the boat for a full season to get a good idea of your needs before deciding on the upgrade.

This one is really making me think twice.

I frequently advise people, especially newbies, buying a used boat, to do all repairs related to safety and boat integrity immediately, but to avoid modifying the original design until they have at least a year experience with it. (Some times the absolute brilliance of the original design may not be immediately apparent.)

A lot of times a newbie mod is ill conceived, simply because they do not have the experience to know better yet.

Additionally, I generally advise newbies not buy a new boat, as they may have insufficient experience to know they will even like boating in general, let alone every design variable, and mistakes in new build specification or selection, can be very expensive.

But this particular element, choosing FLA and changing to LFP a year later, would be a terrible idea IMHO.

When choosing a new boat design, it is fine to opt out of things that can be easily added later, but to remove and replace an electrical system for an alternate design, doesn’t really fit in this category.

It really comes down to risk tolerance. If a newbie is our and bent to buy a new boat, and the cost of the factory option is no real concern, (meaning one can afford it) and one wants it, (after careful evaluation) then I would say go for it.

The newbie has far more important things are to worry about , than if they could save a few bucks on the LFP option.

[MikeTC]

To add to that good advice, include plenty of solar as you have lots of realestate. We have been cruising livaboard for 5 years with 800W, it’s good, friends have 2000W fantastic. IMHO far more useful than big alternators.

[Hans V]

Originally Posted by ramblinrod

When choosing a new boat design, it is fine to opt out of things that can be easily added later, but to remove and replace an electrical system for an alternate design, doesn’t really fit in this category.

It really comes down to risk tolerance. If a newbie is our and bent to buy a new boat, and the cost of the factory option is no real concern, (meaning one can afford it) and one wants it, (after careful evaluation) then I would say go for it.

The newbie has far more important things are to worry about , than if they could save a few bucks on the LFP option.

IF the factory does know how to design and install a proper LFP setup that suits the buyer in the long term and IF it's only a matter of saving a few bucks then I agree.

But there are several misconceptions (or disagreements) about robust LFP setups and most boatbuilders have far more experience with traditional lead-acid setups (that are still factory installed in most of the series build boats). So throwing money at LFP in the factory is not a guarantee for a solid LFP setup and potentially one thing MORE to worry about for the owner when not done properly by the boatbuilder.

The experience TS will gain as a livaboard and the knowledge he can acquire in the mean time about LFP will IMO help him a lot to do the careful evaluation that you mention.

[boatpoker]

Originally Posted by Hans V

IF the factory does know how to design and install a proper LFP setup that suits the buyer in the long term and IF it's only a matter of saving a few bucks then I agree.

But there are several misconceptions (or disagreements) about robust LFP setups and most boatbuilders have far more experience with traditional lead-acid setups (that are still factory installed in most of the series build boats). So throwing money at LFP in the factory is not a guarantee for a solid LFP setup and potentially one thing MORE to worry about for the owner when not done properly by the boatbuilder.

The experience TS will gain as a livaboard and the knowledge he can acquire in the mean time about LFP will IMO help him a lot to do the careful evaluation that you mention.

Sharon and I survey 2-3 new boats per year. We find almost as much wrong as with 20 year old boats. LFP are complex systems and I would not trust the average builder to have staff on hand with the expertise required. Go very slowly on this. Price should not be the first question.

[Matt Johnson]

Originally Posted by Corrigano

That is 4 x Relion 300 AH batteries for the house bank and 2 x 100 AH batteries for the two engines.

1200 Ah is a massive house bank for this type of boat. That's seems to be a red flag already with the information you're receiving.

And before anyone asks- Yes, the Relion 300Ah is a 12v pack and not individual cells.


Matt

[sailjumanji]

Seawind is tied to Mastervolt systems and your boat wont be the first LFP system they or Mastervolt has put together. Plus if there are any issues, the manufacturer will deal with them. (Just as they did for us earlier this year, when Seawind changed out both defective AGM house batteries.) Do this on your own, and you are responsible. There's a lot that goes into system design, and it's not just batteries.

[alansmith]

Some things... there are a lot of very experienced people on here. So, use their knowledge but use it as just one of your tools to ‘discover’ what is best for your situation.

There is a fella on YouTube who is into educating the unwashed masses about solar power and Lithium technology. It is “ Will Prowse Off Grid Solar Power Channel”. He is infectious. RV and marine are very similar users of solar/Lithium setups. He shows a lot of details in his examinations of batteries and solar. He goes into great depth about connectors, shunts, battery management systems, wiring and blah blah blah.

There is a fella on this website who has a lot of followers to his installation of Lithium on his 40 foot cat. I feel it is a must read if you go Lithium/solar. His background shows he is quite an interesting guy. Go to the drop down menu titled Forums. Go the far right column names Engineering&Systems. Open up the link for Lithium Power Systems. Open up the thread titled Merged LiFePo4 1000 Ah Winston prismatic cells and all electric galley. You won’t be disappointed. He is not the only good author ... but one of the best. He tells you how he did it and why he did that way. Highly detailed with lots of pics. Excellent article.

First thing... be practical. You have started correctly by asking end users. It is kind of new technology and only a small portion of marine end users are on board with it. It is expensive technology. But it has so many pluses to it. Catamarans are sensitive to weight. Lithium is so energy dense compared to lead acid. Can discharge down to 20-30% versus 50-60% for lead acid. Longer life if treated properly. Weighs only 30-40% of lead acid. Can accept a much higher charge input than lead. Weight is evil on trimarans and catamarans.

You may already know this... but the first thing you do when picking an electrical system is figure out what will you be using it for. For example... basics like lighting, navigation, running personal electronics, charging propulsion, etc. What extra things would you like to have like water maker, electric galley, upgraded refrigeration, radar, upgraded displays in different locations for Nav gear. If you are into blogging and you edit for publishing on YouTube it takes a lot of ponies to pull that wagon. So... you design your electrical system around your “projected” needs.

You have lots of real estate for paneling you. Mono hulls are limited by lack of “where to put the darn things”. Personally I wouldn’t buy a new boat. You can save a truck load of money buying a well kept cat. There are hundreds available all over this blue planet. You will not take the hit of huge depreciation over the first 1-2 years. But if you do go ‘New’ my advise would be to get Seawind to set up the solar and Lithium from the start. They are in the business and they know how to do the installs. You just have to figure out the size of your bank you need and get the solar and generators lined up.

And you know there are some legitimate worries about lithium fires. Most of the documentation seems to see problems with unstable banks. But the battery management systems are designed to carefully monitor these situations. We had a terrible tragedy last month off of Ventura California where 34 people burned to death on a dive boat. All the crew escaped. Horrific situation. Paid passengers slept down below decks. No escape available. They think the lithium ion batteries caught on fire. Possibly due to so many personal phones and iPad type devices being charged overnight. It is still speculation and under intense investigation. The fire was so intense that dna had to be used to identify the charred bodies. The real cause may never be known due to tides and intense fire.

[alctel]

There are a few really detailed writeups of people who installed lifepo4 on their blogs - I would take a good look at them first. Things like Mainesail etc.

The information tends to be a lot more detailed and useful than you find on YouTube.

I did a DIY install on my boat 3 years ago I'm happy with but I did 6 months of reading and research first, it can get expensive if you screw up!

[Mike_Thor]

Hi Corrigano,
There is some excellent advice above particularly pertinent is 'roland', Auspicious' and ramblinrod'. Note already I can tell they have 'been there' (pS. LP, LIPO, LiFePo4 and 'Lithium' generally all mean the same thing). Concur if you are thinking LP for start batteries you are 'way behind the power knowledge curve'.

Firstly we are full time live-aboards our sailing catamaran (16+m); I am an electrical / avionics engineer; I have approx 40+ years of sailing. I am also a 'systems' engineer for military applications. That said let me say straight up that your situation is different and our history (our advice) is equally diverse.

Be aware that we know 'nothing' about you; your expectations, how long you will own the boat (investment payback etc); your budgets and your knowledge or your own 'use' profile. Fundamentally if you do not have a formal electrical training then you are going to rely on two (2) things: a. your innate 'logic' and b. others experience. You will need to understand 'others' logic and then to trust someone and to be frank I have found that very very (n*10) difficult even though I am electrically qualified. So all I can in this forum is to try to 'suggest' where you need to do your research.

1. System; the system is made up of three primary components; charging or generation; storage and consumption. As a 'system' all need to be matched or at least understood from the 'design' requirements aspect. e.g. No use having a gazillion AH of storage if you cannot effectively (time and diesel efficiency) charge it. I say to people that it is like having a million dollar credit limit on your AMEX; at some point you have to pay it back (recharge) it. My advice is that you can stage it; the implementation that is; but that the design objectives should be pretty well sorted before you start. Anything you redo after the boat is launched will cost you more money, simply if only about throwing away good gear.

MY ADVICE is only as good as my understanding of your needs and I know almost nothing; your background, your electrical demands (comfort, lifestyle, you or your wife's prepensity for microwave oven, induction cookers, coffee machines and washing machines). These are ALL part of the input and the 'design' requirements. Further I am not saying I am right; just that you WILL need to understand these for yourself if you want to end up with a reasonable set of compromises. What 'compromise'; let me say that I hate compromise but everything to do with a sailing catamaran (boat for that matter) is generally a compromise of some sort. Moving on....

So in order to 'assess' my input you will need to know a little about me. I have formal electrical and engineering training, I hate systems that do not work first time and every time, I am happy to pay for a 'top of the line' professional system (resale here also) which is well documented and able to be supported by the OEM or larger Supplier/installer. PS. I am a 'grizzly' old man getting grizzlier by the day regarding incomplete or inadequate information (and it relates to this topic) where so called experts only provide half an answer. That said we do not have enough space here to even moderately begin to address all your needs. Further there is ALWAYS some trade-off so ultimately you need to either understand yourself or know enough to 'trust' some well informed person.

TECHNOLOGY
We are talking two (2) technologies in respect of your objective; 1. Lead Acid (LA) and 2. Lithium Peroxide (LiFeP04, LP, LIPO, Lithium). Other forms of Lithium chemistry are on the market but are, in my opinion, not ready for a 'blue-ocean' sailing catamaran.

In very broad summary the LA solution is great for the engine start. Stick with it and do not change anything there. It is old, dirty (electrically) and heavy but it is reliable, easily supportable and does not need to affect or effect my 'house' installation. I did not want my 'other' electrical system reduce or complicate my 'engine start' or support capability so I decided to stick with the exact system designed and supplied by my engine manufacture (Yanmar in my case) with low amp alternators (60A not 110 or higher and their associated regulators) and stock standard large heavy 'crank' batteries. Do not confuse their needs with 'house' or deep cycle batteries.

LP is new, not so easily supportable but getting significantly better by the day, light and more expensive. There are a huge number of options on how to proceed but I went with a single OEM solution from beginning to end and it is all well documented. The installation was done by a qualified marine electrician (not just electrically) but understands 'sailing' cats not just boats and not certainly not power boats. We both worked on the design which was completed before we started on the install. This time was his 'marketing' cost in order to get the job (AU$35,000 approx).

Comparison (for house systems). This is highly dependent on you and your family needs. Also you need to understand what the 'life' of a battery is and how it is affected by your usage profile. If you don't then you can generally get away with some very sloppy (electrically) behaviour on LA and they can be recovered but with LP (LiPO) you cannot. Furthermore you can have a fire on board with both technologies but if you do not know what you are doing with LP you can end up with a fire and a need for new very expensive LP batts very quickly whereas most often LA just dies (and they are cheaper).

Facts are also a little bit of a mixed bag and the following is a big 'generally' (or nominally if you will); A LA deep cycle can only use approx 40% of the total capacity before you start to degrade the battery life. LA only accept low charge and discharge currents (compared to LP) and take a very long time to get to 100% charge (6-8 hours compared to 30 mins for 97% in LIPO eg.) LA do not like 'partial' charges.

We had 900 AH of 12 VDC LA resulting in 900*0.4=360 Amp Hours (AH) of usable energy. It is heavy and relatively bulky. They are also 'limited' in the maximum current they can supply (at 12 or 24 Volts) so are not ideal for mid-to large AC (240 Volt) inverter system. So in your case if you change 'technology' later on; can you batteries fit inside the space. Make sure that you get that done BEFORE the boat is painted. The 'wiring' is also minimal on the SeaWind when launched. It may not even comply to your 'country' requirements so you need to do some work here. Basically however anything that works for 12 VDC will work better for 24 VDC but the consumers may not. Know what you want or at least have dual voltage (12/24) system where possible.

For LiPo it is one of the exciting and 'bonus' outcomes with only two trade offs. LiPo4 has high power density (AH/square cm/inch), can handle huge input (charge) and huge output (inverter/consumer) and are lightweight. By using approx 80% (100% down to 20% SOC) of their total capacity you are actually increasing their life (or cycles). Furthermore and relevant to sailing boats, they are very content with partial incomplete charges; LA are not so. The trade-off are that they MUST have an 'extra' management system for each 'cell' and they are expensive (relative to LA). So using the above 360 available AH for LA we only need 360/0.80=450 AH of 12 v LiFeP04 not 900 AH LA in order to achieve the same available energy capacity. (do not start on the power vs energy debate here I am keeping this very 'high level').

Remember that we started off with the 'system' and we now come to that rub; Solar (or wind) are good ways to charge LA as they are low power systems and you can run them continuously for long periods thereby fully charging your LA system. LIPO is not the same. Whatever you end up with you need to understand that you need to run a generator for the period to charge a LP bank from say 20% SOC to 98% SOC daily. That the 'charger' needs to be sized to achieve this (whatever your tolerance is for running a generator) and that the generator needs to have a decent capacity to achieve this. I do not think you will be in a situation where you over specify the charger or the generator as the LP technology can handle 'huge' charge currents (e.g. for a typical 24 V 200AH unit you can charge at 100A each and up to 400 A if you really want to). For 2 batteries (200X2=400AH at 24 V you can very safely (extended life cycle) at 100A*2 (batt) so 200 Amps charger. 200A at 24 Volts = 4,800 Watt generator (big, heavy and expensive)....combined with a suitable 200 Amp (continuous rated) 24 v charger.

If your head is starting to spin let me say that it does not realistically get any easier.

GENERATION/CHARGING

2. On a cat you are starting off ahead of those with mono-hulls in that you 'generally' have more real-estate for 'solar' than others but it needs to be thought about. For us we have three large panels (nominal 1 KW) and this is not nearly enough to replace our 'consumption' (more on that below) and is simply not a good 'match' for LiPo in any case.

3. We have changed from a 2KW Honda (portable) to a 4.5 KVA Northern Lights simply in order to get enough 'capacity' and safety (running petrol and 240VAC out on the aft deck in the rain has already cost one friend his life). Do not even go there.

4. We compromised on the 'charger' (120 A at 24 Volts).... did I also say we swapped from 12 to 24 volt house as the existing wiring becomes less lossy, the battery power density is higher and the quantity of batteries is lower).... If you 'undersize' your generator or your charger you will be charging for longer. Again I do not know your 'usage' and if you are not even using 'mains' (we are 240VA Australia) then perhaps you do not even need LiPo and a good LA bank will do fine. Huge caution on the later 'swap over' however particularly regarding sunk investment and physical space to fit 'new' technologies (they are often higher (i.e. inches/cm).

We ultimately selected 'VICTRON' throughout and ended up with their newer 24 V 200 AH LiFePO4 batteries because they 'fitted' into the existing cabinetry. We needed a new 5000/120 inverter to 'match' the demand and the built-in charger (110 A/24 Volt). Note that the LI technology can take some 600-1000 AMPS (total) for our technology so this is again a 'trade-off'.

We selected the 4.5KvA Northern Lights generator (water cooled) as this was the smallest KVa generator that ran at the lower (1500 RPM) speeds. Higher speeds more noise and vibration. Remember the time charging issue and I wanted to get away from as much petrol as possible. Only the dingy outboard uses petrol.

A 120 A charger cannot fully utilise the 4.5KVa capacity therefore we also run the water maker (did I mention that series of options and tradeoffs) at the same time and swapped from a 12 VDC water maker (desalinator actually) to a 240 VAC 240 L/Hr mains one. We found that we were often in water that I would not run the water maker in so wanted one that could top up quickly whilst we were in clean water. Neither the generator nor the desalinator are in the above AU$34,000 Lithium upgrade.

It really comes back to your needs and your willingness to pay for it. When all said and done I believe that you need to thoroughly understand your needs; Can you live as you wish on board your nice new palace without AC or at least without high current AC. No microwave, no AC water maker, no big coffeemaker, no induction cooker (much more gas usage and slower). Can you remember to ensure that 'no one' (wife, kids, guests) turns on too much AC demand. The reason is that normally the 'inverter' can supply the demand (we had a 3kVA inverter (from 12 VDC). A 700W microwave combined with a 2,200 W induction cooker or an electric jug draws approx 3,000 watts (they cycle abruptly from 0 to full power to 'average' their use) so 3,000 w at 12 V = 250 Amps. You will 'kill' your LA battery very quickly if you do this to a 'deep cycle' battery every day.

Diesel is still your cheapest 'power' density medium. It is easily replenished and easily stored and relatively safe. I (We) could not even begin to generate an argument as to cost effective outcome for our install (swap) because $34,000 buys a heap of fuel.

We (read my better half) wanted convenience and I wanted a 'complete' bullet-proof system that was highly redundant and fully supported by the OEM and/or a qualified electrician. So we bit the bullet. PS. For your reference we made choices down the line to spend more in order to maximise the battery / technology investment which cost us more (i.e. the AU$12k for a new desalinator)....

So in summary heaps and heaps more I can waffle on about. Happy to give you more if you want including why I ended up with Victron. A great outcome by the way but I would certainly make sure you fully understand WHY you want Lithium and not just dump Lead Acid (in any of its packaging forms) simply because of the hype of LP.

[downunder]

Originally Posted by sailjumanji

Seawind is tied to Mastervolt systems and your boat wont be the first LFP system they or Mastervolt has put together. Plus if there are any issues, the manufacturer will deal with them. (Just as they did for us earlier this year, when Seawind changed out both defective AGM house batteries.) Do this on your own, and you are responsible. There's a lot that goes into system design, and it's not just batteries.

As suggested by sailjumanji speak with Seawind as they likely have done LFP systems for owners. Installed by the boatbuilder would be best and if they did not do that you can make sure they use LFP friendly components.

[smac999]

Lithium batteries are still Experimental as far as I’m concerned. To be used by experienced electrical people who can install , troubleshoot , and repair themselves. And only in 1st world ports where spare parts are fairly Accessible.

And I would always have the ability to switch the ships power to a backup agm / flooded bank.

[Mike_Thor]

I suggest you seriously research the features of Lead Acid - Flooded cell (i.e. liquid electrolyte) and Lead Acid - Absorbed Glass Mat (AGM) - Electrolyte absorbed into a mat and does not splash around nor does it gas (when charging within nominated parameters). See also Valve Regulated Lead Acid (VRLA) e.g. https://en.wikipedia.org/wiki/VRLA_battery

I cannot see why anyone would recommend flooded cells on a moving / rolling platform for either the electrolyte (highly corrosive) and the gassing (maintenance and highly explosive) issues. Not to mention the daily maintenance (check electrolyte levels) and removal of each cell cap in order to charge. The difference in price between FLA and AGM (one of the VRLA) simply does not approach the risk and increased management required of flooded cells.

Can someone explain why I have this all wrong? In all my experience for both aircraft (military) and commercial flying, 40 years 4WD vehicle, as well as 40+ years sailing I cannot recall a flooded cell being used on a mobile application in the last 30 years.

In my opinion a minimum of AGM and if you want some specific features that GEL LA offer then maybe but already referred to that in my previous comments.

In summary: research suggested on:

Lead Acid battery technology; in particular different configurations of Flooded (gassing), and VRLA of either AGM or GEL configuration;

Charging cycles and methods for all above.

Good hunting.... and trust you get into the cruising lifestyle as soon as you can. Best of luck.

[Mike_Thor]

I strongly recommend you talk to existing Seawind owners regarding this 'power' (electrical) requirements and get their opinion and ones that are sailing in the area that you are. Note that the factory is in Asia but their 'agents' are wide and varied and none (Seawind themselves) that I know of actually provide the electrical support which is subcontracted (as are almost all others) to their specialist supplier. i.e. we sail the East Coast of Australia / New Caledonia and Vanuatu this year.

[roland stockham]

Ok I will attempt to answer your question. First I am an advocate for sticking with FLA's on most but not all cruising boats and will explain why. There are som cases when I would suggest eithe sealed cells or lithium as the best option but they are special cases. For most boats FLA's will be the most economical and reliable option.


QUOTE=Mike_Thor;3028297]I suggest you seriously research the features of Lead Acid - Flooded cell (i.e. liquid electrolyte) and Lead Acid - Absorbed Glass Mat (AGM) - Electrolyte absorbed into a mat and does not splash around nor does it gas (when charging within nominated parameters). See also Valve Regulated Lead Acid (VRLA) e.g. https://en.wikipedia.org/wiki/VRLA_battery

I cannot see why anyone would recommend flooded cells on a moving / rolling platform for either the electrolyte (highly corrosive) and the gassing (maintenance and highly explosive) issues.



Good FLS's are woll sealed with only a small vent in the cap, they have a recombinant system built into the cap that further reduces leakage. Up to about 60deg they do not leak and that is side decks awash and boom in the water teritory. In a roll over or mast in the water yes ther will drip a few cc of acid but there is going to be so much water comming through vents and hatches it will not matter. In 20 years of sailing I have never had problems with leakage or corrosion. These are simply none issues on a cruising boat (but could be on some racers) Hydrogen is explosive yes but it is also light so redily dissipates however best practice is to mount batteries in a plastic box and attach a vent tube to deck level. This takes care of both gas and any acid drips.



Not to mention the daily maintenance (check electrolyte levels) and removal of each cell cap in order to charge.


This is not the normal or necessary maitainence system best practice for a heavily used system is the check levels monthly after a full charge and at the same time check electrolite SG to ensure full charge. For most cases however every 3 months is fine. I usually top cell up bi-anually when preping for winter and again in the spring. I have never needed to add water during the season as deep cycle cells have a large water reserve and use very little in normal opporation



The difference in price between FLA and AGM (one of the VRLA) simply does not approach the risk and increased management required of flooded cells.

The difference in lifetime cost is a factor of about 6. Even the cheapest sealed batteries are more that twice the price of FLA's and have an expected service life of 1/3 to 1/2 so that purcase cost difference will at least double or triple plus a factor for inflation


Can someone explain why I have this all wrong? In all my experience for both aircraft (military) and commercial flying, 40 years 4WD vehicle,



These examples are not relevent as they are all situation which have an engine running during normal opperation so batteries are there to give service when stopped, balance loads or start engines. It would be rare for discary cycles to exceed 10%



as well as 40+ years sailing I cannot recall a flooded cell being used on a mobile application in the last 30 years.


Flooded cells probably are now 'standard' on sailing boats because most of them are tied to a marina with power connected or on a mooring for most of there life. The lower self discharge rates in these cases outway the benifits FLA's have for cruising. For cruiser the ability to practically recharge hevely discharged banks without shore power is key


In my opinion a minimum of AGM and if you want some specific features that GEL LA offer then maybe but already referred to that in my previous comments.

In summary: research suggested on:

Lead Acid battery technology; in particular different configurations of Flooded (gassing), and VRLA of either AGM or GEL configuration;

Charging cycles and methods for all above.

The key factors in my view that goven selection of batter tech should be,
Cycle depth, anything more than 80% daily require dedicated deep cycle batteries, usually either at banks of 6 or 2v cells.
Cycling frequency and pattern. A boat that spends 3 days plus in a marina every couple of weeks can sucessfully use seald batteries because they will regularly be fully charged. Fully charging sealed cells without shore power rarly happen so cells die prematurly due to sulfation (I have seen it happen in one season and 3yrs life is common) Why? Because in order to seal a cell you have to ensure it does not gas. This is done by limiting the charge voltage to 14.4v. If you bulk charge a bank to 14.4 volts it will at best be 80% charged and your charge acceptance rate is down to around C20 and dropping. That means for a large cruising bank it is likely to take several hour to get from 80% to 100%. In practice it never does. If you leave a bank at 95% for a month you loose that 5% to sulfation, then next month loose anther 5% and so on. Increasing the voltage at the end of the bulk cycle not only means that you get up to 85% with a well balanced system but also increases the charge acceptance rate by a factor of about 3. The result is that a battery can be charge from 60% to 95% in 3hrs and topped up to 100% most sunny days through solar. With a large solar stup and reletively light use 100% can be achieved with just solar. This does not happen with sealed cells due to the low charge acceptace at hight states of SoG.


So I havent mentioned lithium. If you have a boat with very high demands you can find that a bank capable of meeting it becomes impractically large. Performance of any lead accid deep cycle battery drops off marckedly at discharge rates above C5 and has a bulk charge rate of between C5 and C10. Lithium does not have the limits and can charge and discharge at very high rates (but read the small print as this can substantially reduce servic life). So if you have massive demands like electric stoves, microwaves and A/C and don'want a generator running it can be done with lithum but is not practical with L/A . The penalty is very hige instalation cost (more tha 10x LA) and often reliability issues unless you are very up pn this tech. Most yards wont be so you have to be your own sevice person. On large boats with very high domestic demands some ecconomy can be made by reducing bank size. They can do this because in the event of a charging problem they can shut down domestic services and likely have enough reserve capacity to run for serveral days. In more modest boats cutting the bank size is potentially dangerouse as it leave insuficent reserve to run the boat in an emergency.


So in summwry FLA's are usually best forcruising boats spending most of there time away fro marinas and having normal or modest demands.

Sealed cells, good for boats left unattended for long periods or with a charging source available at the dock on a regular basis such as marina hopping or weekend sailing but have higher life cycle cost and are easily damaged


Lithium. Good for situation with very high daily and/or peak demands abouvr C5 but very expensive and requir special expertize to ensure reliable opperation. Still comewhat cutting edge but perhaps no longer experimental.


A tipycal instal cost for a 35-45ft boatvwill be under $2000 for FLA, 3-4000 for sealed but multiply that for the shorter life And probably around 10000 for lithium. The claim that lithium will last more than 15 years is still to be demontsrated so life cycle cost ar a bit of a guess but would need to be in the order of 30 to 50yrs for them to be cost effective unless no other tech will do the job.


Good hunting.... and trust you get into the cruising lifestyle as soon as you can. Best of luck.[/QUOTE]