LiFePO- now the cheaper option?

[Kelpie]

Thanks to a tip from someone on this forum, I have stumbled upon some very low priced LiFePO batteries:
https://www.ev-power.eu/LiFeYPO4-ba...Battery-12V-90Ah-WB-LP12V90AH.html?cur=1#tab1

That's a 90Ah 12v battery for around £420 (inc VAT, but plus delivery). So that's about £4.67 per Ah if you are able to use the whole capacity.

The usual choice for marine batteries is the Trojan T105. A pair of these will give you 12v and 225Ah, at a cost of £300. But being lead-acid you can't use anywhere close to the full capacity. Figures vary, but let's say 50% discharge, so that gives 112Ah, or £2.67/Ah.

But what swings things back towards the lithium battery is the life cycle costs. Trojan suggest 1200 cycles, whereas most lithium batteries are good for 3000 if not more. So the lithium batteries should last two and a half times longer than the Trojans, which more than wipes out the cost difference.

It's not a simple swap, of course. In favour of lithium is that the weight/volume of the batteries is about one eighth that of traditional batteries, and that charging efficiencies are far higher. In favour of lead-acid is that few or no changes will be needed to the charging regime, and that it is tried and trusted technology.

Has anybody on here made the jump to lithium yet? We're looking at installing a new battery bank in a couple of years time, by which time I expect that lithium will be looking even more compelling as prices continue to fall.

 

[macd]

Interesting, Kelpie. They're certainly the future, and not a very distant one. I suspect the lack of individual cell monitoring capability might be of concern to some. Also not suited to serial connection, so no good for 24V systems. I suspect that something more like the 3.2V options on this page might be more versatile and cheaper overall: https://www.ev-power.eu/Winston-40Ah-200Ah/?cur=1

Just for information regarding your comparison, T105s can be properly deep-cycled. Trojan even produces graphs of the effect of discharge depth on total lifetime Ah and although there is a penalty, it's small. To an approximation, they'll deliver the same lifetime Ah whether deep-cycled or not. The same would be true of any truly deep cycle/traction battery.

I suspect most liveaboards don't routinely cycle them down to anywhere near 10 or even 20%, but they have that capacity.

P.S. You've got me going now. Prague's only a day's drive...

 

[Malabar]

Might be worth checking out the "Important Information" at https://www.ev-power.eu/important-informations-for-batteries/. One thing it touches on is that if you run the battery down below a certain point you effectively write it off. If they are anything like LiPo batteries you have to be extremely careful when charging as they are prone to bursting into flames if not treated exactly in accordance with instructions.

 

[macd]

If they are anything like LiPo batteries you have to be extremely careful when charging as they are prone to bursting into flames if not treated exactly in accordance with instructions.

If by LiPo you mean lithium polymer, then LiFePO4 such as these are very different, with a much lower fire risk, at a cost of slightly less charge density. That's precisely why virtually every Li-based boat battery system uses them. Charging regimes do need to be tailored to them, which is why I mentioned that lack of a means of individual cell monitoring in my earlier post. Equally, that could be be obviated by using banks of 3.2V elements, as I also suggested.

(The "Po/PO" in the two types refers to very different things: the polymer electrolyte in one, the phosphorus and oxygen part of lithium ferrophosphate in the other.)

 

[macd]

Kelpie: sorry, but you asked for hands-on experience from anyone using LiFePO4 batteries. I doubt you'll get a lot on this side of The Pond, but there's rather more on the other. Cruisers Forum has been a good starting point for several years:

http://www.cruisersforum.com/forums...or-those-using-them-as-house-banks-65069.html
http://www.cruisersforum.com/forums/f13/lithium-batteries-for-dummies-205819.html

Beware: the first of those has over six thousand posts. Look forward to hearing from you again this time next year

 

[[3889]]

There's a guy on the Jeanneau Owners forum who swears by his 20ah LiFePo engine battery. No expert but I understand it has virtually zero internal resistance so ideal for short, high loading, can be mounted at weird angles in nooks and crannies and is very compact thus freeing up space for 'traditional' domestic batteries. Downside is it don't work below freezing so depends where you are, I suppose. There's always the option of relaying domestic to engine to get somewhere warm.

 

[KompetentKrew]

I thought it was uncontroversial that lithium was now cheaper than lead, if you're prepared to pay the up front costs.

I've read some very positive reviews of Firefly lithium-foam batteries, which are a different technology again. I think they're a drop in replacement for lead-acid, but are hard to get hold of.

 

[Kelpie]

Kelpie: sorry, but you asked for hands-on experience from anyone using LiFePO4 batteries. I doubt you'll get a lot on this side of The Pond, but there's rather more on the other. Cruisers Forum has been a good starting point for several years:

http://www.cruisersforum.com/forums...or-those-using-them-as-house-banks-65069.html
http://www.cruisersforum.com/forums/f13/lithium-batteries-for-dummies-205819.html

Beware: the first of those has over six thousand posts. Look forward to hearing from you again this time next year

Well I've had a skim of those threads and I'm not entirely sure I'm any the wiser for it

Clearly LiFePO4 is not a drop-in replacement. I could set up a standalone bank that is only powered by solar, which would simplify things a little bit, but that would miss out on a lot of the advantages.

I'll continue to watch how things develop in this area, as we have two years to make a decision. However my gut feeling at the moment is that I'd be afraid of putting up all that money up front when a faulty charging regime could destroy the whole lot.

 

[BigJoe]

Another way to look at it is what we do.

We have 1000 amp/hr of cheapes batteries we can find, (less than £1 per amp/hr) with 750 watts of solar, the big banks means we never really run down the batteries and the big solar array charges them back up in 2 to 3 hours on a sunny day, 4 to 5 on a cloudy day.

We are big consumers, 2 fridges, inverter, TV, fire stick Etc. and don't have any issues.

 

[Kelpie]

Another way to look at it is what we do.

We have 1000 amp/hr of cheapes batteries we can find, (less than £1 per amp/hr) with 750 watts of solar, the big banks means we never really run down the batteries and the big solar array charges them back up in 2 to 3 hours on a sunny day, 4 to 5 on a cloudy day.

We are big consumers, 2 fridges, inverter, TV, fire stick Etc. and don't have any issues.

I'm not sure the numbers really add up though.
A cheap leisure battery is around £70 for 110Ah at 12v. A pair of T-105s would give you 225Ah for about £300. So around twice the cost per Ah.
However the cheap batteries are rated at 120 cycles, or maybe 240 for better ones, whereas the Trojans are rated for 1200 cycles. So anywhere between five and ten times the number of cycles, which makes the Trojans the clear winners overall.

One worry with the cheap batteries is that it's hard to find information on the expected lifespan and number of cycles vs depth of discharge, which makes it hard to do an accurate comparison.

 

[Kelpie]

Diggin around for better prices has led me to these batteries:
https://www.tayna.co.uk/industrial-batteries/us-battery/us2000/

Which seem pretty reputable and are a wee bit cheaper per Ah than Trojans, with a cost of £1.11/Ah at 12v.
Compare with T-105s at (best price) £1.31 or cheap leisure batteries at 63p.

 

[BigJoe]

I'm not sure the numbers really add up though.
A cheap leisure battery is around £70 for 110Ah at 12v. A pair of T-105s would give you 225Ah for about £300. So around twice the cost per Ah.
However the cheap batteries are rated at 120 cycles, or maybe 240 for better ones, whereas the Trojans are rated for 1200 cycles. So anywhere between five and ten times the number of cycles, which makes the Trojans the clear winners overall.

One worry with the cheap batteries is that it's hard to find information on the expected lifespan and number of cycles vs depth of discharge, which makes it hard to do an accurate comparison.

You raise a couple of interesting points, however, as I said, with the large capacity, the battery bank doesn't really deep cycle, and our 1000 amp/hr bad boys are 6 years old.

Horses for courses

 

[Kelpie]

You raise a couple of interesting points, however, as I said, with the large capacity, the battery bank doesn't really deep cycle, and our 1000 amp/hr bad boys are 6 years old.

Horses for courses

I wish the manufacturers of the cheaper batteries would publish more information on the lifespan vs DOD.
There's certainly a strong argument in favour of cheaper batteries since even the best batteries will be killed very quickly by a short or other mistreatment. One of the main factors that puts me off lithium.

 

[GTom]

This one does 600 cycles 50% DoD. Calculating with the useful capacity, it costs 2.5£/usefulAh, tax and shipping included:

https://www.alpha-batteries.co.uk/12v-xtreme-110ah-agm-leisure-battery-xr1750/

 

[GHA]

This one does 600 cycles 50% DoD. Calculating with the useful capacity, it costs 2.5£/usefulAh, tax and shipping included:

https://www.alpha-batteries.co.uk/12v-xtreme-110ah-agm-leisure-battery-xr1750/

Bearing in mind thats the best you'll ever see in laboratory back to really fully charged straight away. On a boat most likely less, not many cruising boats get batteries really fully charged very often, certainly much less often than most owners think seeing the regulator go into float, takes a long time
LiFePo & Firefly are certinly interesting without the need to get back to fully charged so often to get best life. LiFePo too scary for cruising, for me anyway. One regulator slip and lost the lot with nowhere to get replacements for a few thousand miles..

 

[GTom]

Bearing in mind thats the best you'll ever see in laboratory back to really fully charged straight away. On a boat most likely less, not many cruising boats get batteries really fully charged very often, certainly much less often than most owners think seeing the regulator go into float, takes a long time
LiFePo & Firefly are certinly interesting without the need to get back to fully charged so often to get best life. LiFePo too scary for cruising, for me anyway. One regulator slip and lost the lot with nowhere to get replacements for a few thousand miles..

Cycle claims for lithium also come from labs, not daily abuse. But even half that figure, 300cycles are good enough for many cruisers. Liveaboards on the hook/swing mooring are a different matter.

 

[GHA]

Cycle claims for lithium also come from labs, not daily abuse. But even half that figure, 300cycles are good enough for many cruisers. Liveaboards on the hook/swing mooring are a different matter.

With a good BS can you abuse lithium? Not sure, but suspect with the precise management and cut off points from the BMS they will have a much happier life than lead acid.

Think our definitions of cruisers might be a little different 300 Cycles wouldn't last a normal year

But for the majority of plenty of weekends and a few weeks in the summer with enough cash for marinas quite often then yes.

 

[geem]

With a good BS can you abuse lithium? Not sure, but suspect with the precise management and cut off points from the BMS they will have a much happier life than lead acid.

Think our definitions of cruisers might be a little different 300 Cycles wouldn't last a normal year

But for the majority of plenty of weekends and a few weeks in the summer with enough cash for marinas quite often then yes.

My truck batteries have been installed almost three years. Probably rated for very few cycles but we have circa 1000 amp hr of capacity. They rarely get below 90% DOD. Since they never hit 50% DOD they last a lot longer. They get charged up every day on solar and wind and this is verified by hydrometer on occasion.

 

[Kelpie]

This one does 600 cycles 50% DoD. Calculating with the useful capacity, it costs 2.5£/usefulAh, tax and shipping included:

https://www.alpha-batteries.co.uk/12v-xtreme-110ah-agm-leisure-battery-xr1750/

vs. Trojan T-105 at £2.62

(based on 50% useful capacity, and best price of £590 for four batteries giving 450Ah at 12v)

The difference is that the Trojans are rated for 1200 cycles at 50% DOD, so they actually work out at about half the cost over their lifespan. Unless you accidentally fry them of course

 

[BigJoe]

My truck batteries have been installed almost three years. Probably rated for very few cycles but we have circa 1000 amp hr of capacity. They rarely get below 90% DOD. Since they never hit 50% DOD they last a lot longer. They get charged up every day on solar and wind and this is verified by hydrometer on occasion.

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