As some have stated it really depends on how you actually use your boat.
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Remember that for every trawler there are at least a dozen sail boats, and it is them that are driving this push to LiFeP04 as they fit the mold better than a power boat as having long periods with little or no charging source.
The more I look at MY preferred cruising habits the more I realize that increasing my recharge capability both on generator and underway along with some solar creates a system where LiFeP04 technology is not cost justified.
The price for LFP has definitely been coming down. But it also depends on where you are in the world. It seems that AGMs are unusually expensive in your area, while for me, they're definitely cheaper than LFP. If I wanted to go for FLA, that would be even cheaper.
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A good quality traction battery from Rolls or Hoppecke will last a very long time, and with the price difference one can built a bigger house bank. .
We sure as heck would not put one of the Lithium power walls on the house due to the fire risk.
I would love to see the maths on that one
Considerably heavier battery as well so the freight would be diabolical
And you shouldn't put it in a boat for the same reason
But you do realise they are different chemistry to lifepo4 right?
Off the top of my head, I don't have the spreadsheet in front of me, the lead acid batteries from Rolls were $500 for a 410AH@6v battery. So $1,000 for a usable 200ish AH@12v. A Mastervolt LiFePo 180 AH@12v was $3,500ish. There were all internet prices from a few years ago so who knows what the prices are now. I saw LiFePo batteries drop greatly in price but then go up a bit.
If we confine the discussion to LFP, the one common theme to horror stories is $000's down the drain due to gross over/discharging.s. This is typically caused by considerable human or design errors but it is true that if voltages are maintained wildly out of spec the damage is permanent and irreversible.
https://youtu.be/0j0zcRXTDRk
The majority of other stories are either different chemistries or simply misinformed
wath i did not now was that when lithium cells are charged they need a resting period to ceep there lifespan,
@DiverDave, yours is certainly one answer, by that is coming from a tech guy with a catamaran.
The view might be different from the perspective of a guy with a 100,000 lb trawler who has a generator and needs to run it once a week. Also, powerboats with fly bridges often have much less horizontal area to mount solar panels than a cat as well.
This thread has been very helpful to me as it’s given some various perspectives to consider.
Most know that i am currently driving an all electric boat. (Duffy 22' Cuddy) I have had 10 diesel powered boats since 1995 and all kinds of batteries. For my electric boat with 16-6 volt batteries, it's going to be LIFEPO4s in the future. I've spent more time that I care to admit researching battery chemistry and it's no contest, LIFEPO4s are the clear winner. Cost be damned! It's a boat & I want the best!Interesting discussion,
It seems the common reasons that most won't recommend LiFePo is the initial price or unfamiliarity with the technology.
The benefits though seem to far outweigh this,
Weight, less than 50% per useable Ah (how ready are you to swap out 8D 200lb LA batteries from the bilge vs 80lb LiFePo or maybe 2 smaller size for same Ah)
Actual power, LiFePo batteries can discharge at far more varied conditions and still get rated capacity. LA can lose up to 50% of rated output based on temp and current flow. In head to head testing posted online, LA batteries almost never meet their labeled output.
Most LiFePo batteries have a BMS that prevents damage from overcharge or discharge. With LiFePo, the rate of output doesn't significantly affect the total output, it does significantly affect LA output.
Something I haven't seen commented on, especially with solar users is the charging difference. LiFePo batteries will charge much faster as the can charge up to 90% capacity at a .5C rate as opposed to LA with a short bulk charge at .2C, then a lower second stage, then float.
Most quality inverter/chargers can be easily set to LiFePo charging profile.
Many of the reason to disqualify LiFePo are just not correct.
No more fire risk than LA. In fact LiFePo batteries are totally sealed so can be installed in enclosed areas. No so with any LA batteries.
No more complicating to charge LA. In fact LA charging profile and directions to fully recharge after each use is not needed with LiFePo
Far more charge cycles in lifespan than LA. While there are many claims it is generally up to 5 times the lifespan.
LiFePo batteries will provide power at cold temps, you can not charge them below 20deg. LA must be charged to store at cold temps or they freeze, also provide as little as 20% of rated output.
No more likely to be damaged by incorrect installation LA. I will agree it is more expensive to brick a LiFePo than a LA of equal size.
One place a LA battery excels vs LiFePo is as a starting battery. Large, short discharge followed by proper charging.
Everything being equal if you are looking to keep your boat for a few years AND you spend some time on the hook, LiFePo battery system should be seriously considered. Generally in most installations, over the lifespan of LiFePo batteries the upfront cost will be less expensive than the overall cost of LA batteries in the same timeframe.
Interesting discussion,
It seems the common reasons that most won't recommend LiFePo is the initial price or unfamiliarity with the technology.
The benefits though seem to far outweigh this,
Weight, less than 50% per useable Ah (how ready are you to swap out 8D 200lb LA batteries from the bilge vs 80lb LiFePo or maybe 2 smaller size for same Ah)
Actual power, LiFePo batteries can discharge at far more varied conditions and still get rated capacity. LA can lose up to 50% of rated output based on temp and current flow. In head to head testing posted online, LA batteries almost never meet their labeled output.
Most LiFePo batteries have a BMS that prevents damage from overcharge or discharge. With LiFePo, the rate of output doesn't significantly affect the total output, it does significantly affect LA output.
Something I haven't seen commented on, especially with solar users is the charging difference. LiFePo batteries will charge much faster as the can charge up to 90% capacity at a .5C rate as opposed to LA with a short bulk charge at .2C, then a lower second stage, then float.
Most quality inverter/chargers can be easily set to LiFePo charging profile.
Many of the reason to disqualify LiFePo are just not correct.
No more fire risk than LA. In fact LiFePo batteries are totally sealed so can be installed in enclosed areas. No so with any LA batteries.
No more complicating to charge LA. In fact LA charging profile and directions to fully recharge after each use is not needed with LiFePo
Far more charge cycles in lifespan than LA. While there are many claims it is generally up to 5 times the lifespan.
LiFePo batteries will provide power at cold temps, you can not charge them below 20deg. LA must be charged to store at cold temps or they freeze, also provide as little as 20% of rated output.
No more likely to be damaged by incorrect installation LA. I will agree it is more expensive to brick a LiFePo than a LA of equal size.
One place a LA battery excels vs LiFePo is as a starting battery. Large, short discharge followed by proper charging.
Everything being equal if you are looking to keep your boat for a few years AND you spend some time on the hook, LiFePo battery system should be seriously considered. Generally in most installations, over the lifespan of LiFePo batteries the upfront cost will be less expensive than the overall cost of LA batteries in the same timeframe.
No, sir, not even close, not a few years, more like 36 years to break even if one considers the time value of money. In my example that follows, even after 24 years, you would be $3,000 in the hole. Even using a straight-line projection, the break-even point would be 24 years.
An LFP purchaser has a lot of money tied in an asset of depleting value. It is actually quite easy to make a cost comparison with a few reasonable assumptions. There are just three that are required: (1) cost; (2) expected number of cycles; (3) useable amp-hours.
FLA 6V Golf Car - $150 each, 2 required, 115 amp-hours usable, 500 cycles (East Penn/Deka, price found locally)
BattleBorn 12V, 100-amp - $1,000 with shipping, 90 amp-hours useable, 3,000 - 5,000 cycles
So, a Deka FLA bank of eight will cost $1,200 and provide 460 amp-hours depleted to 50%. A BattleBorn bank of five will cost $5,000 and provide 450 amp-hours depleted to 90%.
Assuming that a FLA bank lasts six years, a conservative assumption, one must factor in the lost earnings from the up-front $5,400 investment in LFP versus FLA. Here is the investment cost.
1. Period 1 - $5,000 - $1,200 = $3,800. Invested at a 4% rate of return, for six years, compounded monthly yields $1,029 in lost interest.
2. Period 2 - $5,000 - $2,400 + $1,029 = $3,629. Invested at the same rate and term, this yields $983 in lost interest.
3. Period 3 - $5,000 - $3,600 + $983 = $2,383. Invested it yields $645.
4. Period 4 - $5,000 - $4,800 + $645 = $845. Invested, it yields $229.
So, after 24 years in place, the real cost of that LFP bank is the $5,000 of capital investment, plus $2,886 of forgone interest for a total cost of $7,886. That’s for 2,000 cycles.
5. Period 6 - $5,000 – 6,000 + $229 = ($771). Invested yields $209 to the good.
6. Period 7 - $5000 - $7,200 + $209 = ($1,991). Invested it yields $539.
After 36 years, the LFP cost is $5,000 plus a net of $2,138 of forgone interest ($2,886 - $209 - $539) for a total cost of $7,138 compared to $7,200 for six FLA banks. The BREAK-EVEN point for the LFP bank is 3,000 cycles and 36 years in the boat. Even after 24 years, you are under water by $3,000. Battle Born estimates 3,000 – 5000 cycles and warrants their batteries for 10 years and also stating that their batteries will last 10 - 15 years. Dakota estimates their batteries will last 2,000 cycles and warrants them for 11 years. The break-even point assumes that the Battle Born batteries make it to 3,000 cycles and we don’t know for certain that they will. We do know, however, that FLA batteries last six-to-nine years. This analysis has assumed a conservative useful period of six years. If a FLA lasts longer than that, then the break-even point would be 42 – 48 years.
So,yes, LFP works, they are not dangerous, and if one is paying attention, they should not be murdered prematurely but cost is just not a reason to go with LFP. The technology may get better with time and/or the cost will decrease but, until then, cost savings are a myth. But, as always, your boat, your money, and your choice is the right choice for you. And I ask you, who among us will even be still be boating 36 years or even alive?
My conclusion: LFP is not cost-effective, not even close. However, there are other good reasons to go with LFP.
I am looking into a boat with a questionable solar installation, 4 300w panels trying to charge 10 AGM 8D batteries. So I have been doing a great deal of research as to upgrading to LiFePo. Too much weight, to little charging time with solar. Owner wanted to run AC while on the hook, but after a couple days the solar system can't put enough power back to last the night.
Something to ponder LiFePo4 batteries and quality:
"1, Rebranded generic made in China batteries like the Chins batteries, which seem to be relabeled and sold under a number of brand names.
2, Customized built to spec made in China batteries, like the ReBel batteries I recently bought, where the seller specifies all sorts of details about the construction of the battery pack, size and gauge of wire used inside, brand and model of BMS, type of cells, and even how they are secured internally, and the thread size of the terminal screws.
3, Custom designed, or exclusively distributed made in China batteries, the Renogy smart batteries with the RS485 port on top are probably a good example of these.
4, Premium assembled in North America (or Europe) batteries such as Battle Born.
What each person has to decide is where do they choose to strike the balance between cost, build quality, warranty and support. Do you mind buying from a fly by night, no name brand with no contact information in the US for warranty claims, if they even have a warranty. How about the small shop, one man show selling customized batteries, do you prefer a bigger company like Renogy who has been active in the US selling solar panels and other solar accessories for about a decade, or maybe you prefer a dedicated LiFePo4 premium brand with premium level of support and very long warranty like Battleborn, that is somewhere between a one man shop, and a big company."
Most know that i am currently driving an all electric boat. (Duffy 22' Cuddy) I have had 10 diesel powered boats since 1995 and all kinds of batteries. For my electric boat with 16-6 volt batteries, it's going to be LIFEPO4s in the future. I've spent more time that I care to admit researching battery chemistry and it's no contest, LIFEPO4s are the clear winner. Cost be damned! It's a boat & I want the best!
True; my argument becomes somewhat flawed on boats that dont get used much. But not the case with this audience, correct?.
[emoji41]
Lots of threads would be likewise affected. Oil type, engine type, hull design, antenna height. LOL.
My conclusion: LFP is not cost-effective, not even close. However, there are other good reasons to go with LFP.
Back to the title of the thread, I think the only “stupid” thing you could do in a new build is to not consider LFP and make an informed decision based on your own planned use of the boat.