Advice on buying Lithium Batteries

[Sea Change]

I changed all of my batteries to AGMs

I considered AGM but they were out of budget.
I went DIY lithium instead, hundreds of pounds cheaper in my case.

 

[xyachtdave]

Errrrr. Batteries like to be used.

Errrrr. Batteries like to be charged too!

 

[B27]

I considered AGM but they were out of budget.
I went DIY lithium instead, hundreds of pounds cheaper in my case.

Ever decent Lithium installation I've seen has involved some sort of expensive charger, whether DC/DC or some other 'box', plus a significant spend on wiring and hardware. Then you've got cells and BMS .
You can buy a fair amount of lead-acid for the same or less.
It seems to me that while long term 12 months of the year liveaboards with big electrical needs will get a good payback, many people will not.

Running a fridge 24/7 is mostly a question of generation rather than storage in most cases.
Now that solar is so cheap, a lot of yachts might be able to get by with smaller house banks.

 

[Sea Change]

Ever decent Lithium installation I've seen has involved some sort of expensive charger, whether DC/DC or some other 'box',

My 'expensive charger' was my pair of MPPTs, which I would have needed to buy regardless of the battery choice.
My shore power charger was a little bit expensive than it would otherwise have been, to ensure lithium compatibility. Maybe an extra £50 or so.

The bit that can get expensive and complicated is when you want to use your alternator to charge the lithium. I simply ignored that, and charged off solar only. But you can add a DC-DC charger for about £150, or you can buy a new alternator if you want to turn your engine on to the most effective generator possible. Which most people don't really need.

Then you've got cells and BMS .

Otherwise known as the battery. If chosen with a little care, this part is now significantly cheaper than AGMs or deep cycle batteries.

 

[Sea_Sense]

My 'expensive charger' was my pair of MPPTs, which I would have needed to buy regardless of the battery choice.
My shore power charger was a little bit expensive than it would otherwise have been, to ensure lithium compatibility. Maybe an extra £50 or so.

The bit that can get expensive and complicated is when you want to use your alternator to charge the lithium. I simply ignored that, and charged off solar only. But you can add a DC-DC charger for about £150, or you can buy a new alternator if you want to turn your engine on to the most effective generator possible. Which most people don't really need.


Otherwise known as the battery. If chosen with a little care, this part is now significantly cheaper than AGMs or deep cycle batteries

What lithium battery did you end up fitting? What brands should I look out for that provide reasonable price and reliable lithium batteries?

 

[Sea Change]

What lithium battery did you end up fitting? What brands should I look out for that provide reasonable price and reliable lithium batteries?

I've built two, with cells and BMS sourced from China. One uses Lishen cells and other is EVE. Both use the JBD BMS, although today I would choose the JK because it has better features for similar money.
It's definitely a wee bit of a project, but you don't need an engineering or electrical background- just a bit of time and a curious mind.

 

[geem]

Ever decent Lithium installation I've seen has involved some sort of expensive charger, whether DC/DC or some other 'box', plus a significant spend on wiring and hardware. Then you've got cells and BMS .
You can buy a fair amount of lead-acid for the same or less.
It seems to me that while long term 12 months of the year liveaboards with big electrical needs will get a good payback, many people will not.

Running a fridge 24/7 is mostly a question of generation rather than storage in most cases.
Now that solar is so cheap, a lot of yachts might be able to get by with smaller house banks.

It's interesting that people seem to think AGMs are cheaper than lithium. What deep cycle AGMs are people buying that are cheaper than lithium?
A quick look online suggests you can build a 305Ah lithium battery for £105/cell. These are grade A. You need four cells so £420 gets you the battery plus some bits of threaded rod and plywood to compress them. Add in a JK BMS with 2A active balancer for another £100 so call it £550. Compare this with a lead battery where you can only usefully use 50% of the battery capacity so let's say conservatively, the lithium battery is equivalent of 500Ah of lead battery capacity. How much does 500Ah of AGM deep cycle battery capacity cost?
With lithium you are likely to add in a smart shunt at £100 and a DC/DC at £180 but you can expect far, far longer battery life, faster charging and all the other benefits I listed in my posts above.
If you are happy to build a battery with grade B cells, you can buy 280Ah cells for £65 each. The battery all in will then cost you about £380 for an equivalent of about 450Ah of lead. The grade B cells are likely to outlive even the most expensive AGM batteries by several years.
If you are happy to buy the cheapest lead batteries (not true deep cycle) then you can of course do this, but life expectancy and reliability are vastly reduced. The deeper you discharge them, the less the life expectancy.
Have a look at Fogstar lithium batteries. They do a good range at reasonable price or buy their cells and build your own. It's really not hard

 

[Sea Change]

@geem I would suggest that your lithium cell prices are on the high side.
My first 280Ah battery cost me £407 precisely, delivered to my door, including BMS. And that was early 2021. Prices have fallen substantially since then. I used grade A cells.
My more recent battery cost a bit more than that, but that was because of the cost of shipping in to Grenada.

 

[geem]

@geem I would suggest that your lithium cell prices are on the high side.
My first 280Ah battery cost me £407 precisely, delivered to my door, including BMS. And that was early 2021. Prices have fallen substantially since then. I used grade A cells.
My more recent battery cost a bit more than that, but that was because of the cost of shipping in to Grenada.

Agreed, but I priced them from a reputable UK supplier so that there is no argument. The prices were direct from the Fogstar website.

 

[Graham376]

It's interesting that people seem to think AGMs are cheaper than lithium. What deep cycle AGMs are people buying that are cheaper than lithium?

Leaving out building them, when I've browsed prices, the cost of buying off the shelf lithium, plus dc/dc charger and mains charger, to replace 4 x Trojan, is far higher, particularly in EU.

 

[geem]

Leaving out building them, when I've browsed prices, the cost of buying off the shelf lithium, plus dc/dc charger and mains charger, to replace 4 x Trojan, is far higher, particularly in EU.

Why do you need a mains charger? You spend all your time at anchor. How long do your Trojans last? 4x Trojan T105s are £670 @Tanya. That buys you 450Ah.

 

[Graham376]

Why do you need a mains charger? You spend all your time at anchor. How long do your Trojans last? 4x Trojan T105s are £670 @Tanya. That buys you 450Ah.

450AH of Trojans works well for us but at some time will need replacing, last ones came from Tayna before Brexit but, in common with most things, UK supply now out of the question. Very rare we're on shore power (except when in Bruce's), but sometimes use generator to top up after prolonged cloudy periods, usually autumn through to spring when heater regularly in use.

 

[B27]

If you really need hundreds of Ah, then lithium becomes competitive.
Many people don't actually need that much storage.
People expect 3 or 4 leisure batteries in a 40ft yacht, because that's what people used to need with poor fridges and tungsten lighting, if they wanted to be away from shore power for a week. Now with a bit of solar and efficient systems, people can live happily on a lot less Ah.
So the baseline is £200 for a couple of leisure batteries for many people.

I'm not saying that's enough for everyone, some people will make use of the kind of system I'm intending to fit to my house.

Personally, SeaChange's system with no alternator charging would be a significant disadvantage, so I'd want to add on some sort of B to B charger. In Summer I could probably live without alternator charging, but pushing the season into UK Autumn, I'm not convinced.

I'm starting to find some good deals on smaller Lifepo4 cells though.
~£20 plus taxes for 4off 15Ah cells could make a useful power pack.

 

[geem]

If you really need hundreds of Ah, then lithium becomes competitive.
Many people don't actually need that much storage.
People expect 3 or 4 leisure batteries in a 40ft yacht, because that's what people used to need with poor fridges and tungsten lighting, if they wanted to be away from shore power for a week. Now with a bit of solar and efficient systems, people can live happily on a lot less Ah.
So the baseline is £200 for a couple of leisure batteries for many people.

I'm not saying that's enough for everyone, some people will make use of the kind of system I'm intending to fit to my house.

Personally, SeaChange's system with no alternator charging would be a significant disadvantage, so I'd want to add on some sort of B to B charger. In Summer I could probably live without alternator charging, but pushing the season into UK Autumn, I'm not convinced.

I'm starting to find some good deals on smaller Lifepo4 cells though.
~£20 plus taxes for 4off 15Ah cells could make a useful power pack.

You only need a power pack if you have lead domestic batteries

 

[Graham376]

If you really need hundreds of Ah, then lithium becomes competitive.

I still don't see it. Say 450ah fla (225ah max usable) to be replaced by 225ah off the shelf lithium + B to B + shore power charger, still a lot more expensive.

 

[Sea Change]

Leaving out building them, when I've browsed prices, the cost of buying off the shelf lithium, plus dc/dc charger and mains charger, to replace 4 x Trojan, is far higher, particularly in EU.

For off the shelf, you're probably right.
When I built my first DIY battery, for the same useable capacity Trojans would have been around £260 more expensive.
That quite easily buys a moderately sized DC-DC and leaves a bit left over for the other upgrades.
The price difference between Trojans and DIY lithium will be significantly greater now.

 

[Tranona]

It's interesting that people seem to think AGMs are cheaper than lithium. What deep cycle AGMs are people buying that are cheaper than lithium?
A quick look online suggests you can build a 305Ah lithium battery for £105/cell. These are grade A. You need four cells so £420 gets you the battery plus some bits of threaded rod and plywood to compress them. Add in a JK BMS with 2A active balancer for another £100 so call it £550. Compare this with a lead battery where you can only usefully use 50% of the battery capacity so let's say conservatively, the lithium battery is equivalent of 500Ah of lead battery capacity. How much does 500Ah of AGM deep cycle battery capacity cost?
With lithium you are likely to add in a smart shunt at £100 and a DC/DC at £180 but you can expect far, far longer battery life, faster charging and all the other benefits I listed in my posts above.
If you are happy to build a battery with grade B cells, you can buy 280Ah cells for £65 each. The battery all in will then cost you about £380 for an equivalent of about 450Ah of lead. The grade B cells are likely to outlive even the most expensive AGM batteries by several years.
If you are happy to buy the cheapest lead batteries (not true deep cycle) then you can of course do this, but life expectancy and reliability are vastly reduced. The deeper you discharge them, the less the life expectancy.
Have a look at Fogstar lithium batteries. They do a good range at reasonable price or buy their cells and build your own. It's really not hard

It is not helpful to highlight extremes such as this. Thousands of N European cruisers in modest (30-45') boats manage just fine with LA batteries. That is what the boats are designed to use. Unless the pattern of usage changes when it comes to replacement there is really little need to consider going any further than basic AGMs for the extended life. Most owners are not like you who live and breathe their boats but have busy lives to support their fun boating. Replacement batteries are just a phone call and a couple of hours taking the old batteries out and new ones in - then nothing more required for the next 10 or 15 years by which time the boat has moved on anyway. It doesn't take any specialist knowledge to work this out - even a lowly social scientist like me can do it.

I think the situation is unlikely to change in the near future no matter what happens to the cost of lithium or any other new technology. The benefits of changing just are not there for most people and the vast stock of boats (and cars) that are designed to use LA batteries will ensure a good supply of batteries long into the future. New mass production boats are still designed to use LA because for their main market that is the most appropriate technology.

So, while it is interesting to see how others in different situations use the technology to meet their needs, or more likely extend their use of electric power, for the majority in practical terms it is irrelevant.

 

[geem]

It is not helpful to highlight extremes such as this. Thousands of N European cruisers in modest (30-45') boats manage just fine with LA batteries. That is what the boats are designed to use. Unless the pattern of usage changes when it comes to replacement there is really little need to consider going any further than basic AGMs for the extended life. Most owners are not like you who live and breathe their boats but have busy lives to support their fun boating. Replacement batteries are just a phone call and a couple of hours taking the old batteries out and new ones in - then nothing more required for the next 10 or 15 years by which time the boat has moved on anyway. It doesn't take any specialist knowledge to work this out - even a lowly social scientist like me can do it.

I think the situation is unlikely to change in the near future no matter what happens to the cost of lithium or any other new technology. The benefits of changing just are not there for most people and the vast stock of boats (and cars) that are designed to use LA batteries will ensure a good supply of batteries long into the future. New mass production boats are still designed to use LA because for their main market that is the most appropriate technology.

So, while it is interesting to see how others in different situations use the technology to meet their needs, or more likely extend their use of electric power, for the majority in practical terms it is irrelevant.

I used to think like you. I just couldn't see the advantages. The reality is that compare life expantancy of lithium and lead and the lithium battery may be the last battery you ever buy. You can't say this of lead. Yes you can think of it as the long game compared to lead but as lithium gets cheaper all the time, the price difference will become even more in favour of lithium.
When everybody fits lithium it will be the norm and those using lead will be left in the dark

 

[B27]

I still don't see it. Say 450ah fla (225ah max usable) to be replaced by 225ah off the shelf lithium + B to B + shore power charger, still a lot more expensive.

Some heavy users might get a lot more cycles out of LiFePO4..
If you are cycling the system every day, 365 days of the year, like in a house system or in industry, it's a different game.
Trojan sell a lot of lithium into industry now!

Also it depends on your loads or applications.
Heavy current continuous stuff like traction, inverters, lithium is more efficient.

 

[Tranona]

I used to think like you. I just couldn't see the advantages. The reality is that compare life expantancy of lithium and lead and the lithium battery may be the last battery you ever buy. You can't say this of lead. Yes you can think of it as the long game compared to lead but as lithium gets cheaper all the time, the price difference will become even more in favour of lithium.
When everybody fits lithium it will be the norm and those using lead will be left in the dark

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.