LiFePO Batteries ???

[tpenfield]

Greetings,

My boat (Cruisers Yacht 338) has 7 (seven) 31M-AGM batteries, which spec at 72 lbs. each. The batteries are isolated into 4 banks (4 for the inverter, 1 house, port engine, starboard engine). The boat is now 7 years old and I expect to be replacing batteries over the next few years. The boat also has a weight problem (well not really, but it is more heavy than it would like and as such is a bit thirsty).

A fellow boating buddy with the same boat has recently swapped out the heavy AGM batteries for the new-fangled LiFePO batteries to reduce the weight. I believe he used DC/DC converters to regulate the current draw from the alternators and shore power chargers.

My understanding is that the LiFePO batteries are much safer than the Lithium-ion batteries that like to catch on fire (aka thermal runway).

I have not seen much on boating forums about the LiFePO batteries, so wondering if folks here have some insight into the viability of using these instead of traditional batteries?

I figure if I replaced all 4 banks with liFePO batteries, I'd only need 5 batteries, instead of 7, since you can draw the LiFePO batteries down much more than AGM batteries. So, the inverter bank would only have 2 batteries instead of 4. (all the batteries are currently 100Ah rated)

Cost wise . . .

The 31M-AGM (Interstate) price out at about $400 each = $2,800

The LiFePO batteries are about $700 each, depending on brand/Ah rating. So, call it $3,500

Weight savings :
AGM
7 x 72 = 504 lbs.

LiFePo
5 x 28 = 140 lbs.

Saving about 364 lbs +/-

If I wanted to reduce weight even more, I could possibly go with 4 LiFePO instead of 5, which would bring the costs in line and bring the weight savings up to almost 400 lbs.

Thoughts on the LiFePO batteries and use in a boat/vehicle, etc.?

TIA for your comments

 

[dubs283]

it is more heavy than it would like and as such is a bit thirsty..........

Saving about 364 lbs +/-

My go to is if fuel economy is a concern for you then boating is not your hobby

Guessing with twins and an inverter your boat is in at least the 30-40 foot class so 364 lbs (average weight of 2-3 adults) is a drop in a bucket comparatively. You will notice little to zero change in fuel consumption

I'm not familiar with LifePo batteries but knowing the durability of interstate batteries it is the only brand I recommend/use. Given the boat (guessing) was rigged with interstate agm batteries they are the intended batteries for your vessel.

If the batteries are original seven years on batteries is impressive, consider yourself fortunate to have achieved the milestone. My recommendation is to stick with the interstate agm 31's and keep boating

 

[tpenfield]

Thanks @dubs283 . . . not overly concerned about the cost of fuel, just thinking shedding 400 lbs. of weight reduction might help time-to-plane and boat balance.

The dry weight of the boat is 11,300 lbs +/-, so 400 lbs is not a game-changer, but something to consider.

Wondering if the LiFePO technology is solid enough, since much of the information online is more of an advertising nature.

 

[909]

Yes generally speaking Lithium Iron Phosphate batteries have some advantages over other Lithium Ion . Not to say Lithium Ion isn't safe . I use Lithium Ion because they are generally very safe , unless you do something incredibly stupid . They are practically in every cordless device , power tool, electronics, you name it. They are currently the most affordable. Especially if you recycle cells ( approx $2 per pound ) they are in fact incredibly affordable. And when they are not overcharged , undercharged, stored in normal temperature , not too hot , not too cold, they should easily provide a decade of service.

You mentioned you needed 140 lbs of batteries. Can you imagine outfitting your boat's battery requirements for under $300 and a bit of DIY work ? Totally possible !

Lithium Iron Phosphate will do all these things, but better . It will just will cost a bit more . And you'll likely have to buy new . As these gain popularity they will eventually be viable on the recycled market but not at the moment .

In regards to your question, yes they are an incredibly solid option , but your best bet for a reliable source of info would be to visit the battery version of Iboats :

Lithium Iron Phosphate Batteries

Discuss any aspect of Lithium Iron Phosphate batteries (LiFePO4/LFP)

secondlifestorage.com

 

[909]

Batteryhookup would probably be the most reputable used battery source for Lithium Iron Phosphate :

Genuine Lithium Batteries for DIY Projects

Battery Hookup

batteryhookup.com

When recylcing Lithium Ion , I just go to my local scrapyard . One who collects Electronic waste aka E-waste.

When buying new you can always use Amazon / Aliexpress / Alibaba . And no matter where you source it from, they will almost always come from China. But ideally you would want to purchase one that's been reviewed on YouTube or similar with Charge / Discharge Capacity benchmark tests performed . These battery retailers like to bs about their numbers and make incredible claims. Often the reviewers will also tear down a battery so you can see what's inside, so at least you'll know exactly what you're getting if you order the same battery.

 

[tpenfield]

You mentioned you needed 140 lbs of batteries. Can you imagine outfitting your boat's battery requirements for under $300 and a bit of DIY work ? Totally possible !

OK, I'm listening . . .

I'm also concerned about the charge rate of the LFP batteries and the need to regulate charging current. Although my friend added a dc/dc converter to his battery conversion, he 'mysteriously' blew out the ProNautic 1230 shorepower charger. I'm thinking that the LFP battery charging was a bit too much for the ProNautic (30 amp rated), but just a guess on my part.

 

[tpenfield]

@909 Thanks for the links. I was thinking about Dakota Lithium as the battery brand. I believe they are made in the USA flag-waving

 

[909]

I'm not familiar with Dakota , but here's the first video that popped up:

 

[909]

OK, I'm listening . . .

I'm also concerned about the charge rate of the LFP batteries and the need to regulate charging current. Although my friend added a dc/dc converter to his battery conversion, he 'mysteriously' blew out the ProNautic 1230 shorepower charger. I'm thinking that the LFP battery charging was a bit too much for the ProNautic (30 amp rated), but just a guess on my part.

The way I built my battery was simple. I bought discarded laptop cells. I disassembled the packs and tested each one. Then I re-assembled the good ones. Look for your local scrapyards that collect electronic waste ( not all scrap metal buyers have the proper license to collect E-waste ) . You can expect to pay $2 per pound for used Lithium Ion cells. You can also buy new cells but the price goes up exponentially

In regards to your friend's blown setup . He probably made a mistake setting up his system. Your best bet for getting solid advice would be to make a post here and get honest experienced opinions on how best to setup your system :

DIY Battery Project Builds

Share and document your powerwall build journey in a project thread

secondlifestorage.com

 

[909]

This is just one of the tiny trolling motor batteries I built from discarded latop cells.
I used an ammo box from Bass Pro as a case . It's mostly waterproof.
This battery is 50 AH . It can drain from 100% to 0 % unlike regular batteries ( regular batteries stop at 50% )
I can honestly troll for a weekend ( my boat is light ) , and it's never died on me.
It weighs 11lbs. Cost about $25 to make.
It should last a decade. I've had it for a few years now.
Notice the unused green cells in the back. That's what the individual cells look like when you disassemble them.

 

[dingbat]

Couldn’t pay me to install lithium ion on a boat.

Have seen two melt down in lap tops in the past 3 weeks.

Dakota batteries have support/supply chain issues..ie Chinese components

Dakota Lithium Batteries | Complaints | Better Business Bureau® Profile

View customer complaints of Dakota Lithium Batteries, BBB helps resolve disputes with the services or products a business provides.

www.bbb.org

 

[tpenfield]

Couldn’t pay me to install lithium ion on a boat.

Have seen two melt down in lap tops in the past 3 weeks.

Dakota batteries have support/supply chain issues..ie Chinese components

Thanks for the link on Dakota Lithium . . .

To be clear, it is "Lithium Iron Phosphate" (not the standard Lithium ion) . . .

https://elcanindustries.com/toll-pr...phosphate-batteries-vs-lithium-ion-batteries/

Just not a lot of folks using them in boats at this point, it seems.

 

[sam am I]

Lithium iron phosphate (LiFePO4) battery

Trying to skip/avoid the opinion/hearsay mongers here as much as possible............ Thinking I might make the jump this next year (other than my Dewalt's and B&D's) so specifically, anyone ACTUALLY running/ran one in their Boat/RV? If so...... House? Crank? Like it? What manu? Is/has...

forums.iboats.com

 

[airshot]

Lifepo4 are a great choice but....they need to be handled without mistakes!! Lipo batteries have no forgivness, one mistake and poof...all gone !! Lifepo4 are more forgiving but..you still havevto do things right!! Cant stress that enough !! They MUST be hooked up correctly, they MUST have the proper charger, you can't mishandle them in any way !! If properly handled they are great, but you can't make any mistakes or " lets try this and see what happens". Those kinds of things will get you into big trouble. When it is time to replace my 31 batteries, I will go lifepo4 batteries, but I will take all necessary precautions !!! Also...check to see what tyoe fire extinguisher would be needed...don't believe a standard dry chemical will put out a lithium battery fire!
And check with you insurance company, some will not cover fire from lithium batteries.

 

[tpenfield]

Thanks for the additional comments and links . . . @sam am I sounds like you were a very early adopter, or as least thinking about it.

One concern is the charge rate and limiting the amperage to be compatible with alternators.

In my boat there are all kinds of battery isolators and I have a solar charging system with a charging regulator and battery isolator. I'm also wondering about the shorepower battery charger, if that will regulate the current or possibly be overload in rapid charging situations. Then there is the Inverter, which charges its own battery bank if AC power is available.

I'll have to research how these charging devices handle high current situations. I've seen the ProNautic (charger) go to 30 amps and the Xantrex (inverter) go to 40 amps. . . . but wondering if/when the LiFePO battery(ies) want 60+ amps for a certain amount of time . . .

 

[airshot]

From my experience with lipo batteries, they do not want high charge rates...that is one of the past problems.. My chargers use a steady rate and taper down as needed. Another reason to have the proper charger. I would never charge directly of an alternator, to much variation, a good seperate charger should be able to control what is needed for the battery.. One of my lipo chargers has a connection to a car battery/ altenator, but the charger itself controls the output to the battery. Sorry, not an electrician, so better terms might be explained by others.

 

[dubs283]

You want to spend less and save weight on batteries only to have to add/change accessories to allow the batteries to work properly and you are unsure of what/how to set them up?

Not sure if you're speculating here or are absolutely sold on the idea but based on your first post the current system you have in place works as designed and has no issues.

Go boating, monitor your current system and enjoy!

.02

 

[tpenfield]

Quick Update . . .

Reaching out to my friend who has the same boat as I; it turns out that he swapped out to the LiFePO batteries and then installed a seakeeper system, which negated any weight savings. So, no good comparisons on the weight reduction.

I have the wiring diagram from the factory, so I'll spend some time planning out what would be needed for an LiFePO swap . . . maybe next year's improvement list . . . got to save up my weekly allowance.

 

[tpenfield]

After some discussion with an electrical engineering buddy of mine, I am getting closer to a final design of the electrical system.

One important aspect with LiFePo (LFP) conversions is the protection of the alternators. The LFP batteries have an electronic management system 'BMS' that can/does shut the battery off in certain situations. The alternators don't like that . . . it basically turns the alternator into an ignition system . . . nothing good happens at that point.

I know there are some work-around solutions, but it adds complexity.

Anyway . . . looks like I'll be keeping the engine batteries as AGM and everything else as LFP. Weight savings would be more in the 300 lb range, yet there still will be more room for me in the engine compartment, as it is currently filled with batteries

 

[flashback]

I always follow your threads with interest, and here again I think you mis titled your previously posted thread "My boat is being a boat" would make more sense to me as "my computer is being a boat". Just sayin..