LiFePO Batteries for Marine Use

Electrical and electronic topics for small boats
jimh
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LiFePO Batteries for Marine Use

Postby jimh » Sat Mar 26, 2016 11:34 am

As a replacement for the traditional lead-acid storage battery, there are many new battery technologies being developed and brought to market. Several of these are based on Lithium. Of the Lithium storage battery technologies, batteries are now available using a Lithium-Iron-Phosphate chemistry that have the favorable characteristics of higher energy storage per weight, while avoiding the problem of self-heating that is seen in other Lithium batteries. This technology has been around for a while, so it is not the absolute latest, cutting-edge, untested invention; if fact, some refer to it already as old-school.

A good article on Wikipedia explains the chemistry of the LiFePO or LiFePO4 battery. It discusses the advantages and disadvantages of LiFePO4 batteries compared to other chemistries. Inherent safety of the battery is often mentioned. This battery chemistry is not prone to the self-heating and thermal runaway problems seen in other chemistries using Lithium. Another interesting facet: the LiFePO4 material is a natural mineral compound; iron is, of course, abundant and low cost, and non-toxic.

The LiFePO battery would seem to be a possible choice for replacement of lead-acid batteries in marine applications. I made an attempt by searching to locate a suitable LiFePO battery that could be used to replace my Group-24 AGM battery. I could not find an equivalently rated battery in that size with LiFePO chemistry. I found some 40-Ah-rated LiFePO4 12-Volt batteries selling for about $235. Their peak current for short duration was rated 400-Amperes. That should start most outboard engines. I also found some more expensive LiFePO4 marine batteries that were $580 to $700, but again rated only to 400 to 500-Amperes maximum short duration current.

The general marketing of these more expensive LiFePO4 batteries as competitors to less expensive lead-acid batteries is with emphasis on the these advantages:

--perhaps ten times greater number of charge-discharge cycles possible (3,000 compared to 300);

--a significant reduction in weight (30-lbs compared to 80-lbs);

--a greater useable energy storage capacity for similar size (about 2:1);

--almost no drop in output voltage during discharge cycle;

--ability to tolerate very deep discharge without harm.

I am curious if any readers have experience with LiFePO batteries or may have purchased one for use in their boat. While their cost is greater than premium lead-acid AGM batteries, they appear to have several advantages that might be particularly useful in certain marine applications. For example, an electric trolling motor running from an LiFePO4 battery may be a very good application. A bow-mounted trolling motor with the battery close by would benefit from the significant weight reduction, the greater energy storage, and the ability to tolerate deep discharge-recharge cycling.

jimh
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Re: LiFePO Batteries for Marine Use

Postby jimh » Sat Mar 26, 2016 11:55 am

The size and weight of a battery as a function of its energy storage are measured by volumetric density and gravimetric density, perhaps two terms not familiar to all boaters. Wikipeda compares the LiFePO4 battery to lead-acid batteries on these parameters:

Gravimetric energy density (higher is better)
Lead-acid = 30 to 40 W-h/kg
LiFePO4 = 90 to 130 W-h/kg

Volumetric energy density (higher is better)
Lead-acid = 60 to 75 W-h/ dm³
LiFePO4 = 220 to 330 W-h/dm³

( A dm³ is more familiarly called a 1-liter volume; W-h is 1-Watt for 1-hour.)

fno
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Re: LiFePO Batteries for Marine Use

Postby fno » Mon Mar 28, 2016 10:20 pm

Lithium based batteries catch fire all the time and some burn with the intensity of magnesium. Not on my boat.

jimh
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Re: LiFePO Batteries for Marine Use

Postby jimh » Tue Mar 29, 2016 9:11 am

Frank--you must have missed an important point of my first article about LiFePO4 batteries. Please re-read the first article in the thread. You are not making a proper distinction between various battery chemistries involving Lithium. The Lithium-Iron-Phosphate chemistry is not prone self-heating and to thermal runaway. It is much safer than other Lithium battery chemistries.

jimh
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Re: LiFePO Batteries for Marine Use

Postby jimh » Fri Apr 08, 2016 1:04 pm

I came across a recently published article on LiFePO4 batteries. The article refers to them often with the acronym LFP. The article is quite detailed and offers a wealth of information on LiFePO4 batteries. See

http://www.pbase.com/mainecruising/lifepo4_on_boats

The article includes a link to a demonstration of attempts to cause a LiFePO4 battery to explode or ignite in flames. The test is quite aggressive in its methods. First, a handgun fires several rounds into the battery case while it sits in some dry grasses. There is lot of smoke as acid is released but no flames. Next a dead short is placed across a fully-charged cell. Again, some smoke but no explosion, no flames. The battery supplies 1,800-Amperes into the short circuit.

Test three involves lighting a fire in a large barrel with some wood and accelerants. Once the fire is burning strongly, a LiFePO4 cell is tossed into the barrel. There is no explosion. Later the fire is extinguished and we see the charred case of the battery in the barrel. The fourth test puts the LiFePO4 battery into an oven chamber, and heats it to 85°C or 185°F. There is no sign of any damage; the battery terminal voltage is measured and is still at full-chage.

Next the battery is placed in some testing apparatus which drops it onto a steel plate from about a 1-meter height several times. The battery appears to absorb this shock testing without damage. After that a crush-test is conducted using a calibrated machine. The cell appears to survive this treatment, too. A following test uses large spikes to penetrate the battery case. This test causes some smoke and probably releases some acid.

The final test appears to be connecting a battery to an enormous 500-Ampere resistive load. The battery supplies current to the load for quite a while, then its terminal voltage is measured. The voltage remains at almost the initial full-charge voltage.

The demonstration is completely narrated in a Chinese language and all graphics on screen are in a Chinese font, so most viewers in the USA won't be able to understand what is being said or written, but the pictures tell most of the story. Watch the presentation at

https://www.youtube.com/watch?v=aQs7L5L ... e=youtu.be

If anyone has any evidence to support the claim that LiFePO4 batteries "catch fire all the time" please comment and give a cite to your source.

jimh
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Re: LiFePO Batteries for Marine Use

Postby jimh » Wed Apr 13, 2016 10:20 am

Just when you thought it was safe to invest in LiFePO4 batteries, also sometimes referred to as LFP batteries, here comes some new technology start-up with something even better. That is "even better" in terms of better energy density and lower cost.

A company called BioSolar is promoting a new battery technology which will use their patent-pending technology, which they refer to with the descriptor "Super Cathode." The claimed advantages for the Super Cathode battery method are impressive. We compare with the LiFePO4 technology, which, until this new method appeared, looked to be quite an improvement itself compared to conventional lead-acid storage batteries.

ENERGY DENSITY

LiFePO4 = 72-Watt-hour / kilogram
SuperCathode = 459-Watt-hour / kilogram

COSTS

LiFePO4 = $403 / kW-h
SuperCathode = $54 (an estimate)

The SuperCathode battery has six times the energy density and its cost is only one-seventh of the LiFePO4 battery. Where do I get one? I don't think you can get one. The BioSolar company is just announcing their invention, and I don't believe they have any batteries for sale, nor are they likely to pursue actual manufacturing. I think they would like some big battery manufacturing companies to license their technology and bring to market a real battery that uses it. Read more at

http://www.biosolar.com/super_battery.php

If the BioSolar SuperCathode battery does make it to mass production and has the energy density and energy cost parameters that are stated by BioSolar, the founders of BioSolar should be very substantially compensated financially for their discovery, and the lead-acid storage battery market would quickly disintegrate.

Hoosier
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Re: LiFePO Batteries for Marine Use

Postby Hoosier » Wed Apr 13, 2016 8:04 pm

[The BioSolar SuperCathode Lithium Ion battery if ever made] could be great for trolling motor and house batteries. It'd be nice to be able to anchor out for a couple of days without having to run a generator.
1978 Outrage V20 with 2004 Suzuki DF-115. 1992 23 Walkaround with two 2010 Yamaha F-150s.

knothead
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Re: LiFePO Batteries for Marine Use

Postby knothead » Fri Apr 15, 2016 8:09 pm

I recently read an article on the website "Watts Up With That" that discusses the proposed [SuperCathode Lithium Ion] battery and BioSolar. I scrolled through the comments, some of which were written by people far smarter than me (kind of like this website), and concluded that the battery may be "a pie in the sky" deal to help pump up the stock price of BioSolar, which has fallen substantially.

I wish and hope that this battery technology would work, as it would mean a great deal to the future of stored electricity.

Hope it warms up up there.

regards---knothead

jimh
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Re: LiFePO Batteries for Marine Use

Postby jimh » Sat Apr 16, 2016 8:33 am

I browsed the "WhatsUpWithThat" website, and found it interesting. As I mentioned in my article, there are no SuperCathode batteries from BioSolar and they do not seem likely to ever make one.

There are real LiFePO4 batteries available to purchase, and they do seem to have advantages compared to existing batteries.

Hoosier
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Re: LiFePO Batteries for Marine Use

Postby Hoosier » Sun Aug 05, 2018 5:33 pm

Here's an update: I just finished a boat trip to the North Channel with the BWGLCC (viewtopic.php?f=8&t=3674) and at the overnight stop in Killarney, Ontario my house and starboard starting battery failed. Since we were at a marina I had connected the battery to shore power with a (kinda) smart battery maintainer. In the morning the entire house electrical system was dead and the charger's "Bad Battery" light was on.

One of the members of the group had a RELION BR 50 LiFePO4 12-Volt battery that he was willing to lend me. We pulled the bad lead acid battery, cleaned up some crappy wiring, and installed the RELION BR50 battery. I then proceeded to complete the 2018 BWGLCC North Channel cruise without a hiccup. The battery supported the whole house electrical load for two nights at anchorage and started the starboard 2010 Yamaha F150 immediately every time.

After returning to Michigan I stopped in at the RELION dealer in Lansing and discussed the RELION batteries. He had checked with the manufacturer and they do not recommend the BR50 as a starting battery. They have a new dual purpose 50-series battery coming out later this year that will fill both the starting and deep cycle roles.
1978 Outrage V20 with 2004 Suzuki DF-115. 1992 23 Walkaround with two 2010 Yamaha F-150s.

Jefecinco
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Re: LiFePO Batteries for Marine Use

Postby Jefecinco » Mon Aug 06, 2018 8:50 am

Dave,

I call that a very positive endorsement. Perhaps a RELION would be a good replacement for the old lead acid battery on our old Sport 13. The 13 gets little use and weight aft is undesirable. If the self discharge rate is equal, similar, or better than a typical AGM that would be pretty irresistible.

I'll have to look for a dealer in the Gulf Shores area. BTW, we moved here this Spring. We're on the GCIWW (??) sometimes called Portage Creek.
Butch

Jefecinco
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Re: LiFePO Batteries for Marine Use

Postby Jefecinco » Tue Aug 07, 2018 10:00 am

The closest Relion dealer to Gulf Shores, AL is located in Orange, TX. I guess I'll stick with AGM batteries for now.
Butch