Advice on buying Lithium Batteries

[PaulRainbow]

From your perspective I can see that - however the way you use your boat is so very different from the majority for all the reasons you seem to ignore. If lithium does indeed become a straight swap (phone call and a undoing a few terminals) then you are right, BUT it is not and never will be for most boats. There is little advantage available to justify the cost of the change. The "last battery you ever buy" only holds water if you keep the boat for ever OR like you have a pattern of usage that means either you will use up LAs quickly or won't be able to consume electricity in the way you can now. Most boats change hands in much less than the lifetime of AGMs so many owners will never have to replace batteries. Same with cars now. The average life of cars is 14 years, but ownership typically 3 years. My wife's car is 19 years old, had it from new and just had its second replacement battery. My stop start C max is 7 years old and still on the original battery. My Morgan battery was changed after 19 years.

Boat batteries like engines die from misuse and neglect and there is no reason why 10 years is the minimum life expectancy which is pretty long term for most weekend type sailors.

I agree with much of what you say, Lithiums make sense for a few, but not for most small yacht/weekend users.

As much as your AGM "argument" makes sense for some, it also makes no sense for many others, using the same arguments that you use for your Lithium vs AGM argument.

For many, a couple of £80 - £100 "leisure batteries fulfil their needs.

My Merc battery is the original AGM at 6 years old. Boat SLA's still perfectly OK at 5 years. Who knows when either will dies, but the Merc looks after its own batteries, i have to look after the boat batteries, if i get it wrong, they die early. Equally, if i fit Lithiums and get it wrong, they die early.

 

[dune16]

I'm going lithium. I've just ordered 2 x 300ah lifepo batteries (from Vatrer) to replace 4 x 140ah agm's. Got the batteries on a prime day deal, paid just over £1200 for both delivered to Croatia. My boat already has chargers and mppt that can switch to lifepo4 profiles, alternators are temperature regulated and the 2 starter batteries (agm's and will not be changed) are connected with the domestic bank via argofet isolators. This means if the bms on the 2 lifepos cut off then the starter agms remain connected to protect the alternator. I'm making the change mainly due to us regularly running the current agm bank down to 50% when anchored overnight with fridges etc on and this is only doing them harm. With the 600ah bank of lifepos I'll have pretty much double the usable capacity of the existing 560ah agm bank and save about 130kg in weight. They'll also last much longer. It's a no brainer for us in the way we use our boat.

 

[xyachtdave]

Out of interest Sea Sense, what does your boat weigh?

Will a 100kg shaved off the total make a difference to the performance?

 

[geem]

I'm going lithium. I've just ordered 2 x 300ah lifepo batteries (from Vatrer) to replace 4 x 140ah agm's. Got the batteries on a prime day deal, paid just over £1200 for both delivered to Croatia. My boat already has chargers and mppt that can switch to lifepo4 profiles, alternators are temperature regulated and the 2 starter batteries (agm's and will not be changed) are connected with the domestic bank via argofet isolators. This means if the bms on the 2 lifepos cut off then the starter agms remain connected to protect the alternator. I'm making the change mainly due to us regularly running the current agm bank down to 50% when anchored overnight with fridges etc on and this is only doing them harm. With the 600ah bank of lifepos I'll have pretty much double the usable capacity of the existing 560ah agm bank and save about 130kg in weight. They'll also last much longer. It's a no brainer for us in the way we use our boat.

Comparing with cars is very misleading. Cars don't cycle their batteries. Anybody with a fridge and anchor light on at night and maybe the heater sat at anchor cycles the batteries. (A completely different issue if you never leave the marina, where any battery will do.) Cycling lead acid batteries quickly reduces their life. The more time you spend at anchor or on a mooring without access to shore power the more relevant the switch to lithium becomes.
We will never agree with each other, it seems, but hopefully a few more open minded cruising types that spend some time at anchor/ on a mooring will understand the benefits of this superior battery chemistry and they will be able to reap the benefits. They won't have to worry about getting their batteries to float, or whether the beer will be cold. They can use almost all of their battery capacity over the weekend sailing and let the solar charge it back up during the week when they are back at work. Even the tiniest cruiser with an outboard, would benefit from a small lithium battery where the solar would be more effective by about 20% compared to lead. The weight/space saving would be appreciable as well
Edit: this post wasn't aimed at you. My apologies.

 

[B27]

I'm going lithium. I've just ordered 2 x 300ah lifepo batteries (from Vatrer) to replace 4 x 140ah agm's. Got the batteries on a prime day deal, paid just over £1200 for both delivered to Croatia. My boat already has chargers and mppt that can switch to lifepo4 profiles, alternators are temperature regulated and the 2 starter batteries (agm's and will not be changed) are connected with the domestic bank via argofet isolators. This means if the bms on the 2 lifepos cut off then the starter agms remain connected to protect the alternator. I'm making the change mainly due to us regularly running the current agm bank down to 50% when anchored overnight with fridges etc on and this is only doing them harm. With the 600ah bank of lifepos I'll have pretty much double the usable capacity of the existing 560ah agm bank and save about 130kg in weight. They'll also last much longer. It's a no brainer for us in the way we use our boat.

If you're running down 4 x 140Ah to 50% overnight some might say you have a consumption problem rather than a battery problem.
280Ah is a lot of energy to reliably find in a day, either solar or motoring.

 

[B27]

........ Even the tiniest cruiser with an outboard, would benefit from a small lithium battery where the solar would be more effective by about 20% compared to lead. The weight/space saving would be appreciable as well

That's true.
The tiniest cruiser with an outboard can lose the requirement for the house battery to be the back-up engine battery.
You can move into a world of power banks to charge phones, rechargeable lights each with their own Li cell, and it's nice to have light 12V power bank to carry home to charge. In fact I know people who not only do this but their outboard is a Torqeedo which also gets charged at home, or sometimes a pub ashore.

Someone will be along dreckly to suggest we don't need electricity anyway, candles and paraffin are fine.

 

[dune16]

If you're running down 4 x 140Ah to 50% overnight some might say you have a consumption problem rather than a battery problem.
280Ah is a lot of energy to reliably find in a day, either solar or motoring.

We could definitely be more frugal with power but with 6 onboard we have 3 fridges running, a freezer etc etc. Also I suspect the agm's are a bit tired hence the decision to switch to lifepo4. We have 840w of solar and are generally back to fully charged by 11am in the summer

 

[Tranona]

Comparing with cars is very misleading. Cars don't cycle their batteries. Anybody with a fridge and anchor light on at night and maybe the heater sat at anchor cycles the batteries. (A completely different issue if you never leave the marina, where any battery will do.) Cycling lead acid batteries quickly reduces their life. The more time you spend at anchor or on a mooring without access to shore power the more relevant the switch to lithium becomes.
We will never agree with each other, it seems, but hopefully a few more open minded cruising types that spend some time at anchor/ on a mooring will understand the benefits of this superior battery chemistry and they will be able to reap the benefits. They won't have to worry about getting their batteries to float, or whether the beer will be cold. They can use almost all of their battery capacity over the weekend sailing and let the solar charge it back up during the week when they are back at work. Even the tiniest cruiser with an outboard, would benefit from a small lithium battery where the solar would be more effective by about 20% compared to lead. The weight/space saving would be appreciable as well
Edit: this post wasn't aimed at you. My apologies.

I know you are replying to me. The point about car batteries is to illustrate how far conventional LA batteries have advanced over the years. I use the Morgan as an example because its usage pattern is very much like a weekend sailors boat - long periods of inactivity followed by short periods of intensive activity. The long life comes partly from the type of battery and partly from the use of a trickle charger when the car is not used for a few weeks.

One of the reasons we will never agree is because you keep moving the goalposts to suit your argument. You immediately start talking about changing patterns of usage - staying free of shorepower (and presumably adding solar). The OP was not suggesting doing that, nor do the vast majority of marina based cruisers. It is not closed minded to recognise that if usage patterns change then so might your energy strategy (remind me how many times I have said this - if you bother to read).

Why are you suddenly talking about small outboard powered yachts? Nobody on this thread has mentioned this - and of course if somebody with a boat like that and that pattern of usage sought advice on batteries, lithium would be a serious option.

It all gets back to a needs assessment NOT a discussion on properties of a particular type of product. Choice of product comes out of the assessment taking into account your starting point with the existing system if you have one. As Paul points out in post#41 for many cheap leisure batteries are the choice and even my argument for spending more to get longer life from AGMs does not cut it. Our club has something like 350 active cruising and racing boats in the 30-40' range. You can almost count on your fingers the number that have significant solar or wind, and I bet virtually none will have lithium. It is simply not necessary as there is shorepower in the marina. As has been demonstrated many times including in this thread a domestic bank of 3-400Ah is perfectly adequate for the type of sailing most coastal sailors do. Typically 40% of cruising time is under engine and access to shorepower is readily available at overnight stops. Modern boats aimed at this market are designed for that usage pattern - My Bavaria 33 had a domestic bank of 3*95 and dedicated start and thruster/windlass batteries. Never any worries about insufficient capacity and they were still going strong when I sold the boat after 6 years.

 

[geem]

I know you are replying to me. The point about car batteries is to illustrate how far conventional LA batteries have advanced over the years. I use the Morgan as an example because its usage pattern is very much like a weekend sailors boat - long periods of inactivity followed by short periods of intensive activity. The long life comes partly from the type of battery and partly from the use of a trickle charger when the car is not used for a few weeks.

One of the reasons we will never agree is because you keep moving the goalposts to suit your argument. You immediately start talking about changing patterns of usage - staying free of shorepower (and presumably adding solar). The OP was not suggesting doing that, nor do the vast majority of marina based cruisers. It is not closed minded to recognise that if usage patterns change then so might your energy strategy (remind me how many times I have said this - if you bother to read).

Why are you suddenly talking about small outboard powered yachts? Nobody on this thread has mentioned this - and of course if somebody with a boat like that and that pattern of usage sought advice on batteries, lithium would be a serious option.

It all gets back to a needs assessment NOT a discussion on properties of a particular type of product. Choice of product comes out of the assessment taking into account your starting point with the existing system if you have one. As Paul points out in post#41 for many cheap leisure batteries are the choice and even my argument for spending more to get longer life from AGMs does not cut it. Our club has something like 350 active cruising and racing boats in the 30-40' range. You can almost count on your fingers the number that have significant solar or wind, and I bet virtually none will have lithium. It is simply not necessary as there is shorepower in the marina. As has been demonstrated many times including in this thread a domestic bank of 3-400Ah is perfectly adequate for the type of sailing most coastal sailors do. Typically 40% of cruising time is under engine and access to shorepower is readily available at overnight stops. Modern boats aimed at this market are designed for that usage pattern - My Bavaria 33 had a domestic bank of 3*95 and dedicated start and thruster/windlass batteries. Never any worries about insufficient capacity and they were still going strong when I sold the boat after 6 years.

I had my last boat with a set of lead batteries that lasted 7 years. I was very pleased that they did. You miss the point. Lithium is simply far better. You can keep your lead. I would never ever go back to lead for the domestic battery on any boat I will own in the future. It is so antiquated and a poor choice for deep cycle use.
If you never leave the marina you could run on a watch battery but if you want to use the boat. Anchor over night or live on a mooring, lithium is better in every way. There is simply no comparison.

 

[geem]

That's true.
The tiniest cruiser with an outboard can lose the requirement for the house battery to be the back-up engine battery.
You can move into a world of power banks to charge phones, rechargeable lights each with their own Li cell, and it's nice to have light 12V power bank to carry home to charge. In fact I know people who not only do this but their outboard is a Torqeedo which also gets charged at home, or sometimes a pub ashore.

Someone will be along dreckly to suggest we don't need electricity anyway, candles and paraffin are fine.

My very first boat had a 4 stroke outboard with some charging output. A small solar panel and two batteries. One for the engine starting and the domestic battery. I look back now and think what a game changer it would have been if the domestic battery was lithium. We didn't have much space and we were always short of power. That would have been a thing of the past with lithium.

 

[B27]

My very first boat had a 4 stroke outboard with some charging output. A small solar panel and two batteries. One for the engine starting and the domestic battery. I look back now and think what a game changer it would have been if the domestic battery was lithium. We didn't have much space and we were always short of power. That would have been a thing of the past with lithium.

The game changer for small boats compared to 30 years ago is solar.
It's cheap and easy now to harvest enough power to run a fridge plus the essentials, at least in the Summer.
Lithium would not have made much difference to us 30 years ago, except carrying batteries home from a mooring, they'd have been lighter I suppose.
Also LEDs have changed things, lighting in small boats was pretty dismal last century. And our nav lights ate half the battery on an overnight race.
Storing the power was not the problem, generating it was.
Hence many people spent a lot of cash on wind generators for a measly output and a lot of noise.

In winter, my mooring doesn't get much sun, so a portable lithium pack I could charge a home would be of interest.
But this needs to be a portable self-contained thing like a 'drop in' battery, not something significantly integrated with the boat's systems.

 

[geem]

The game changer for small boats compared to 30 years ago is solar.
It's cheap and easy now to harvest enough power to run a fridge plus the essentials, at least in the Summer.
Lithium would not have made much difference to us 30 years ago, except carrying batteries home from a mooring, they'd have been lighter I suppose.
Also LEDs have changed things, lighting in small boats was pretty dismal last century. And our nav lights ate half the battery on an overnight race.
Storing the power was not the problem, generating it was.
Hence many people spent a lot of cash on wind generators for a measly output and a lot of noise.

In winter, my mooring doesn't get much sun, so a portable lithium pack I could charge a home would be of interest.
But this needs to be a portable self-contained thing like a 'drop in' battery, not something significantly integrated with the boat's systems.

You can buy empty battery boxes and still build your own battery. My pal did this on his cat. You don't need to buy cheap drop in lithium with cells from an unknown source and quality. Spend a little more and get a far better product. You can locate the cells, bms and shunt in the battery box and take that home with you. When you are charging at home, you will know the SOC from the bluetooth shunt and you will be able to see the individual cell voltages from the Bluetooth BMS on your phone. If you want a 105Ah 12v portable lithium battery, the cells weigh 2kg each. You need 4 cells so 8kg. Add in 0.5kg for the BMS, similar for the shunt, some ply end plates and some threaded rod, battery box and cell seperstors and you might be at 13kg all in, probably less. A 100ah lead battery will weigh 28/30kg and have half the useful Ah.
This would be plenty for a small weekend cruiser and not a big weight to lug home for charging

 

[B27]

You can buy empty battery boxes and still build your own battery. My pal did this on his cat. You don't need to buy cheap drop in lithium with cells from an unknown source and quality. Spend a little more and get a far better product. You can locate the cells, bms and shunt in the battery box and take that home with you. When you are charging at home, you will know the SOC from the bluetooth shunt and you will be able to see the individual cell voltages from the Bluetooth BMS on your phone. If you want a 105Ah 12v portable lithium battery, the cells weigh 2kg each. You need 4 cells so 8kg. Add in 0.5kg for the BMS, similar for the shunt, some ply end plates and some threaded rod, battery box and cell seperstors and you might be at 13kg all in, probably less. A 100ah lead battery will weigh 28/30kg and have half the useful Ah.
This would be plenty for a small weekend cruiser and not a big weight to lug home for charging

For 'domestic purposes' I don't need 105Ah, 30Ah and a lot lighter would be nice.
However, what you describe is pretty close to my thoughts for a trolling motor pack.

 

[GHA]

Lithium would not have made much difference to us 30 years ago,

imho that's ignoring what game changer having batteries which don't fairly quickly die if you don't get them the really 100% soc pretty regularly.
From a cruising perspective that's one of, or maybe the top benefit. All the rest wouldn't matter if they were like lead acid & needed a really good charge to 100% once a week or so when in use.

 

[B27]

Sure, in the old days, a 'domestic' battery on a yacht often only lasted two or three years, and in the second year it had lost a chunk of capacity, but I think car batteries were cheaper then and we just got on with it.
Cars used to get through more batteries too?
People with more budget used shore power in their marina, and serious cruisers had generators.
Those of us in the cheap end of the market had no energy source other than the engine alternator.
Most boats had a 1-Both-2 switch, so you could disconnect either battery relatively easily to take it home for a proper charge.
One boat I raced on, we were often swapping batteries before a race.

Not sure what year it was when we started getting affordable solar panels of a few watts to keep up with self-discharge, which gradually grew into panels which would put back what you'd used on a weekend of night channel crossings over the working week.

It would have been little consolation that your battery wasn't being damaged by being left part-charged, the problem was always about the power to charge it. If it was simple to take big charging currents direct from the alternator, that would have been valued, as it was, people were playing with alternator boosters to cram charge into LA batteries.

While some people are surprised about the low enthusiasm level for lithium batteries in some quarters, I'm surprised to still see so many yachts on moorings with little or no solar. Motorboats too come to that.

 

[geem]

Sure, in the old days, a 'domestic' battery on a yacht often only lasted two or three years, and in the second year it had lost a chunk of capacity, but I think car batteries were cheaper then and we just got on with it.
Cars used to get through more batteries too?
People with more budget used shore power in their marina, and serious cruisers had generators.
Those of us in the cheap end of the market had no energy source other than the engine alternator.
Most boats had a 1-Both-2 switch, so you could disconnect either battery relatively easily to take it home for a proper charge.
One boat I raced on, we were often swapping batteries before a race.

Not sure what year it was when we started getting affordable solar panels of a few watts to keep up with self-discharge, which gradually grew into panels which would put back what you'd used on a weekend of night channel crossings over the working week.

It would have been little consolation that your battery wasn't being damaged by being left part-charged, the problem was always about the power to charge it. If it was simple to take big charging currents direct from the alternator, that would have been valued, as it was, people were playing with alternator boosters to cram charge into LA batteries.

While some people are surprised about the low enthusiasm level for lithium batteries in some quarters, I'm surprised to still see so many yachts on moorings with little or no solar. Motorboats too come to that.

Have a look at this. The lithium market is maturing. Batteries are improving in quality even at the cheap end. Add a Victron smart shunt to something like this and you could have a reasonable set up on a very small boat

 

[GHA]

It would have been little consolation that your battery wasn't being damaged by being left part-charged, the problem was always about the power to charge it.

I went nearly 6 months over the winter never getting to 100% soc & not bothered a bit. It was a massive consolation over previous years pre LiFePo4 which meant having to run a genny for hours on end once a week or so trying to get lead acid back up to 100%. Cruisers would have sold a kidney (maybe not their own ) to get batteries like lifepo4 in years gone by. Exactly because charging was so difficult.

 

[fredrussell]

I reckon in ten years time most boat owners will have a lithium house bank, and in twenty years time ALL cruising boats will have one. Why? Because lead acid batteries to buy new will be rare as hens teeth by then, for the same reason it’s damn hard to find a blank VHS tape these days. The technology moves on, and becomes cheaper.
Put it this way: of the two types of battery technologies we are discussing, which do you think the Chinese (who have cornered the market in lithium power) will be more keen to export worldwide? Nice light product, or the far heavier product?

 

[B27]

I reckon in ten years time most boat owners will have a lithium house bank, and in twenty years time ALL cruising boats will have one. Why? Because lead acid batteries to buy new will be rare as hens teeth by then, for the same reason it’s damn hard to find a blank VHS tape these days. The technology moves on, and becomes cheaper.
Put it this way: of the two types of battery technologies we are discussing, which do you think the Chinese (who have cornered the market in lithium power) will be more keen to export worldwide? Nice light product, or the far heavier product?

Possibly so, but it might take longer than 10 years.
New cars are still leaving the factory with LA batteries
Even many (most?) EVs have an LA battery for certain functions.

There might be a turning point when there are alternators readily available which charge a lithium battery with no intervening complication.
There's a backlog of 35 million IC vehicles in the UK alone, all with lead acid batteries.
How many people do you know who changed their petrol or diesel car to a lithium battery?
I know a few who've fitted Li batteries to motorbikes, so it's starting to creep in, but very slowly.

Possibly in the next few years, the peripheral bits like smart shunts and MPPT's and alternator adaptors will become cheap and that will create a turning point. But for the foreseeable, people are still buying lead batteries by the million.

 

[geem]

Possibly so, but it might take longer than 10 years.
New cars are still leaving the factory with LA batteries
Even many (most?) EVs have an LA battery for certain functions.

There might be a turning point when there are alternators readily available which charge a lithium battery with no intervening complication.
There's a backlog of 35 million IC vehicles in the UK alone, all with lead acid batteries.
How many people do you know who changed their petrol or diesel car to a lithium battery?
I know a few who've fitted Li batteries to motorbikes, so it's starting to creep in, but very slowly.

Possibly in the next few years, the peripheral bits like smart shunts and MPPT's and alternator adaptors will become cheap and that will create a turning point. But for the foreseeable, people are still buying lead batteries by the million.

He said lithium house banks. I see no advantage in lithium starter batteries. Its an ideal application for lead. Top end production boats are starting to be sold with house lithium banks now so the move to lithium is going to happen