What leisure battery and what capacity?

Dockhead

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Despite claims from many sellers, the vast majority of "leisure" batteries are not deep cycle. As you have noted, true deep cycle are expensive. I would go with Trojan for deep cycle, but i would question the need for deep cycle on such a boat.
"Leisure batteries" and deep cycle batteries are mutually exclusive terms. Avoid leisure batteries on boats. The best cheap lead-acid solution is 6v golf cart batteries like Trojan T105 -- wire them in series to get 12v. That is a true deep cycle battery which works well on a boat. Otherwise, LiFePo4 is really the best solution, but you may need to do some modifications to your electrical system.
 

Dockhead

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I would love to be able to buy "12V 100Ah LiFePO4" for 50 quid ... please where are you buying at that price ? Plus its interesting that you choose to quote a Lead Acid of higher price than I see on the shelf !! Selective comparison if ever there was !!

And please can you not bulls*** about it being 200A/Hr equivalent ... you are trying to say that a Lead Acid delivering 50% capacity as per advised max ... and that your LiFePo is delivering 100% ???

I have been using Lithium batterys of many different formats ... LiCo .. LiPo .. LifePo4 .. LiIon and all would suffer damage if discharged 100% .. and that damage is accumulative each time you do it ... doesn't matter whether big or small batterys .. the chemistry is same for per type.

Cycle life is bulls*** as well .. as most batterys live a life of perpetual high charge state ...
Well, you're right about no 100% discharge but LiFePo4 batteries are very happy to go down to 20% or even 10%, and if properly regulated (an external BMS may be required), outlast a "leisure battery" at least 10x, and proper deep cycle lead batteries probably 4x or 5x. So it's not bull**** that they have more USABLE capacity as a percentage of nominal capacity than lead. Maybe not 2x, but certainly 1.5x or 1.6x. And they are vastly longer lived if properly regulated. A good LiFePo4 setup will be cheaper in the long run, than any kind of lead battery.
 

Refueler

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"Leisure batteries" and deep cycle batteries are mutually exclusive terms. Avoid leisure batteries on boats. The best cheap lead-acid solution is 6v golf cart batteries like Trojan T105 -- wire them in series to get 12v. That is a true deep cycle battery which works well on a boat. Otherwise, LiFePo4 is really the best solution, but you may need to do some modifications to your electrical system.

Sorry but Golf Cart batterys are NOT true Deep Cycle ... where you get that idea from ???

Golf Cart batterys are literally 6V versions of the general purpose Truck batterys that start engines as well as power hydraulic tail lifts etc.

Golf Cart batterys nearest equivalent for boat ? Leisure batterys in fact .. where plates are hard enough to withstand short spell high amp draw - but also able to deliver 50 - 55% of capacity.
 

migs

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My post said that I could build a 100Ah LiFePO4 battery with BMS for £50. That’s £34 for the batteries (Alibaba DTP delivered price), £10 for the BMS (the cost of the parts) and £6 for the compression housing.

‘I would love to be able to buy "12V 100Ah LiFePO4" for 50 quid’

Not everybody is a chartered electronic engineer; sadly most people are exposed to the greed of the marine industry…

As for comparative costs, let’s not spit hairs like 90% etc. The arguments for Lithium are so compelling that in a few years lead-acid batteries will most likely have disappeared in same way as Kodak film cameras.
 

Tranona

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'OP' can have multiple repeats of Lead Acid over the life he owns the boat for 350 quid !!'

Well, let’s compare like-with-like. A 12V 100Ah LiFePO4 (200Ah lead equivalent) would cost me about £50 at current prices. A 120Ah Numax lead acid from Tayna is £150.

The LFP battery will last 4000 cycles to 80% SoH, whereas you might get 400 from the lead acid. That makes the LFP battery 50 times cheaper in Ah time / £ … ;)
A typical small yacht like the OPs may get used less than 50 days a year. 15 weekends and a 2 week holiday is generous. Typical energy usage maybe 25Ah a day. A basic AGM has 600+ cycles, so well over 10 years use. Your 4000 cycles with lithium is totally irrelevant for most leisure sailors. The challenge with small boats is not battery capacity but maintenance of charge and now with low cost solar that is much easier as even in the UK a 100ah battery can be kept on float with a modest solar panel.

Too many people who advocate lithium tend to do what you have just done - talk about the properties they have rather than whether those properties are of value to the individual and his situation. choice of batteries starts from an analysis of consumption and generation and if you do that for most small coastal cruising yachts LA is usually the preferred choice.

As to what happens in the future you may well be right that lithium (or even something better) will push LA out. However we are in the present day and lithium is still in the "early adopters" stage where a small part of the market is populated by people who can take advantage of the different properties but for the vast majority there is no benefit. Remember small yachts are just a tiny part of the battery market and their needs are easily met by existing technology which is largely derived from the automotive and industrial market. The transition will be far slower than one imagines because of the long life of the product. Users are typically faced with a replacement every 10 years or even longer (the Red Flash in my Morgan lasted 19 years) and there is no need to rush and replace a functioning battery. For replacements now in this scenario it is difficult to justify going lithium particularly if it means revising charging arrangements.
 
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B27

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'OP' can have multiple repeats of Lead Acid over the life he owns the boat for 350 quid !!'

Well, let’s compare like-with-like. A 12V 100Ah LiFePO4 (200Ah lead equivalent) would cost me about £50 at current prices. A 120Ah Numax lead acid from Tayna is £150.

The LFP battery will last 4000 cycles to 80% SoH, whereas you might get 400 from the lead acid. That makes the LFP battery 50 times cheaper in Ah time / £ … ;)
That's a lot cheaper than I've seen, once you include shipping to the UK.
Also all the cell maker data I've seen suggests safe limits for Lifepo4 is in the 1C region, so if you're talking about running a bow thruster or backup starting a diesel, it sounds like the BMS might be a bit suspect?
 

B27

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A typical small yacht like the OPs may get used less than 50 days a year. 15 weekends and a 2 week holiday is generous. Typical energy usage maybe 25Ah a day......
To paraphrase a bloke in my club, there are a lot of yacht sailors who 'sail like trawlerman', on with the autopilot and the stereo before they've cleared the breakwater.
Not everyone can live on 25Ah a day.
 

fredrussell

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That SUPPORTS my post ...

Read my post again ... I was remarking about LiFe batterys that are sold WITHOUT BMS .... they are out there and they are not the best solution for the uninitiated…
Can you post a link to a 12v 100a/h lithium battery without BMS please. I couldn’t find any.
 
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Tranona

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To paraphrase a bloke in my club, there are a lot of yacht sailors who 'sail like trawlerman', on with the autopilot and the stereo before they've cleared the breakwater.
Not everyone can live on 25Ah a day.
I know. In which case they should do the sums and equip their boat with the most appropriate power supply.

The OP like thousands of others IS in the 25Ah a day category so does not need the same as your "trawlerman" or to feed a bowthruster and windlass, radar, sail long distances at night, run a big fridge, nor live off grid for days or weeks at a time. he just needs enough capacity for his modest demands and a reliable way of keeping it charged.

As ever focus on the question that was asked not on what the question might be or how a different question was answered.
 

Refueler

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My post said that I could build a 100Ah LiFePO4 battery with BMS for £50. That’s £34 for the batteries (Alibaba DTP delivered price), £10 for the BMS (the cost of the parts) and £6 for the compression housing.

‘I would love to be able to buy "12V 100Ah LiFePO4" for 50 quid’

Not everybody is a chartered electronic engineer; sadly most people are exposed to the greed of the marine industry…

As for comparative costs, let’s not spit hairs like 90% etc. The arguments for Lithium are so compelling that in a few years lead-acid batteries will most likely have disappeared in same way as Kodak film cameras.

You have just proven my point about the 50 quid ... making your original post irrelevant to the usual punter ...

The average price for LiFePo4 vs Lead Acid - is still in favour of the Lead Acid.
 

Refueler

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I know. In which case they should do the sums and equip their boat with the most appropriate power supply.

The OP like thousands of others IS in the 25Ah a day category so does not need the same as your "trawlerman" or to feed a bowthruster and windlass, radar, sail long distances at night, run a big fridge, nor live off grid for days or weeks at a time. he just needs enough capacity for his modest demands and a reliable way of keeping it charged.

As ever focus on the question that was asked not on what the question might be or how a different question was answered.

As with every thread ... they wander off based on one ore more persons view on the wider subject .. focus gets lost.
 

fredrussell

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Sorry but Golf Cart batterys are NOT true Deep Cycle ... where you get that idea from ???

Golf Cart batterys are literally 6V versions of the general purpose Truck batterys that start engines as well as power hydraulic tail lifts etc.

Golf Cart batterys nearest equivalent for boat ? Leisure batterys in fact .. where plates are hard enough to withstand short spell high amp draw - but also able to deliver 50 - 55% of capacity.
Once again you’re making no sense. Trojan T105 6v batteries are used primarily in golf carts and are a ‘true’ deep cycle battery. They’re NOT just the 6v version of a truck battery and the manufacturer strongly recommends they NOT be used for engine starting.

From their website: “Trojan's deep-cycle flooded batteries are the flagship of Trojan's product portfolio. Engineered to provide rugged durability, outstanding performance and long life, Trojan's deep-cycle flooded batteries are perfectly suited for use in a variety of golf and electric vehicles.
 

Refueler

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Once again you’re making no sense. Trojan T105 6v batteries are used primarily in golf carts and are a ‘true’ deep cycle battery. They’re NOT just the 6v version of a truck battery and the manufacturer strongly recommends they NOT be used for engine starting.

From their website: “Trojan's deep-cycle flooded batteries are the flagship of Trojan's product portfolio. Engineered to provide rugged durability, outstanding performance and long life, Trojan's deep-cycle flooded batteries are perfectly suited for use in a variety of golf and electric vehicles.

This really gets my goat ... so you pick a particular brand - you think all are same as that ?

I'm trying to stay generic and I get bombed by picking a particular brand ...
 

Refueler

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Apols - typo. I meant to say can you provide a link to a 12v lithium leisure battery WITHOUT a BMS. You said that many don’t have them - I was querying that.

Even with correction - you are asking wrong question as this is what I posted :

"I find it interesting and TBH - worrying that so many post that Lithium can be taken all way down and not worry ! mmmmm do it without BMS looking after the battery and you'll be out of pocket quick.
BMS is there for two equally important main reasons ... to prevent overcharging and to prevent over discharge.

There are many Li batterys out there that are not fitted with BMS - so you as buyer will have to sort that out. ... but those with good BMS will be of course more expensive."


Please highlight where I say Lithium Leisure battery ...

There are many people out there that are not aware of the various formats and designs / styles of batterys .. Lithium in fact have so many that without taking time to explore the information - people could have expensive mistakes.

Dear ol' migs - who you should've directed to goes on to describe his constructing his Li bank ....

Case Closed.
 

fredrussell

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This really gets my goat ... so you pick a particular brand - you think all are same as that ?

I'm trying to stay generic and I get bombed by picking a particular brand ...
All I’m trying to say is that golf cart batteries ARE deep cycle. You said:
Sorry but Golf Cart batterys are NOT true Deep Cycle ... where you get that idea from ???

Golf Cart batterys are literally 6V versions of the general purpose Truck batterys that start engines as well as power hydraulic tail lifts etc.

That is incorrect. Golf cart batteries- all of them - are deep cycle. The reason being, golf carts don’t have starter motors and therefore their batteries are never required to belt out upwards of 300 amps turning an engine over. Two of the biggest brands of golf cart batteries are Trojan (T105) and US Battery. Both of those advise against using their deep cycle batteries as a ‘starter’ battery. These batteries are not “literally 6V versions of the general purpose Truck batterys that start engines” as you state.
 
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