Drop-In LiFePO4 Batteries – Be an Educated Consumer

[DArcy]

I've done some lithium battery testing but only on primary cells, not rechargeable. I can tell you things get interesting very fast when you abuse some of those batteries. The batteries I tested are Lithium-Thionyl chloride (Li-SOCl2), non-rechargeable, high energy density. One type was vented cells, the other was non-vented. The vented cells are not as bad but if you can get them over about 180°C they very quickly burn and exceed 800°C. The non-vented cells get a little more exciting. The 4 C-cell pack blew the door off the test chamber and the shock wave aggressively rattled the door to the room the test chamber was in during a partial short circuit test. This long duration over current (but under the fuse rating current) was introduced due to the Boeing 787 ELT fire which had a partial short circuit.

I only point this out to demonstrate the difference between these Li-SOCl2 cells and the much safer LiFePO4 rechargeable cells.

The US DOT conducted an investigation into hazards associated with plug in vehicle battery fires (DOT HS 812 418). A general conclusion was "The propensity and severity of fires and explosions from the accidental ignition of flammable electrolytic solvents used in Li-ion battery systems are anticipated to be somewhat comparable to or perhaps slightly less than those for gasoline or diesel vehicular fuels, with the overall consequences for Li-ion batteries also expected to be less because of the much lower amounts of flammable solvent released and burning." This is for rechargeable lithium batteries in general. This report also indicates for LiFePO4 batteries "For a significant improvement in safety in a positive electrode material, it has been suggested to move away from oxide materials to ones based on phosphates. Phosphate bonds are much stronger than those in oxides, with the result that when abusively overcharged, LiFePO4 cells release very little energy. "

Lithium batteries got a bad wrap early on but are much safer now than they were originally. Lithium is flammable, lead is not, so there is a slight increase in the risk of fire however modern BMS and the use of phosphor makes this risk easily manageable. You would need to expose the batteries to greater than 180°C (255°F) to get them to burn and by then you probably have other things to worry about.

 

[DCGULL]

LiFePO4 batteries- all manufactured in China- have gone through an almost 'normal' cycle of new, learning curve, take risks & buy now, to 'sticker appliers' (we are HERE now) to genuinely meeting needs of niche markets (sailboats). Note: rack battery manufacturers are applying 'what we need' to very well built systems now. Note: EG4 (formerly Gyll batteries) is building H2Oproof batteries with tested & matched cells with appropriate internal wiring than are only missing on FETs so far as I can see.
At this point, your 'average Joe' like me knows just enough about the properties of LiFePO4 that we can tell when improvements in BMS, internal wiring, cell balancing & matching are happening. Soon, additions like carbon sheets (Graphene) will increase storage, charge/Discharge(C) rates and BMS's will be developed & normalized that can accept broader voltage/current ranges within tolerances. But, as far as I can see- these are not in place yet.
The problem is that no one (self included) are asking: which FET's are you using & what can they handle? The BMS 'information out' sharing already exists, but- few users are asking for more data than is required by a nice cell phone app. I can get individual cell SOCs, but- I bet dollars to donuts that most guys don't know what it means outside of mv variances between them. The ability to take a 'battery' out of the pack temporarily because several cells are dangerously close to damaging overcharge status is NOT available to the average user.
The cells are improving because of advancements like graphene, but manufacturers have issues with QC and I think that will never change. It takes legitimate companies to test each cell, and develop answers to ABYC recommendations (MasterVolt, Victron...)
Currently (electric joke!) these are cost prohibitive but over time- they'll make it into 'obtainium' like pricing. Probably not within a year or two, but I could see 5 years? Seems far away and there are those who are risking life & limb today with Tesla batteries, SOC batteries & sticker applier batteries. I have no idea of whether they are insured or not. If it's part of the failure, they will be denied coverage. If not....

 

[Maine Sail]

You cant compare fork truck batteries(real deep-cycle batteries) to the typical lead acid batteries used on boats. Some Fork truck batteries claim 5000 cycles so 1200-1500 is not so good. The cycle life data comes from over 20 years of capacity testing "marine" batteries. The vast majority never break 150 cycles..

 

[walt]

My experience with Lithium batteries is with an electric bike but it brings up a "management " issue that Im wondering how you would deal with on a sailboat.

BU-808: How to Prolong Lithium-based Batteries Take a look at table 3 in the link which shows that Li batteries last longer when left only partially charged. For example, at 25C, the battery has 96 percent of capacity after one year when left at 40 percent charge but the capacity drops to 80 percent if left at 100 percent charge. Ie, the battery retains capacity longer if left at a 40 percent charge rather than 100 percent charge.

If you are using the boat such as living on it or daily use with heavy discharge and charge, the above doesn't matter. But in my particular case with the boat in a slip for four months of the year, I have a solar panel that keeps my Lead acid batteries topped up nearly 100 percent of the time. I like this as when I go to use the boat for an overnight outing, the batteries are conveniently fully charged. When the boat is not in the slip for the rest of the year, the solar also keeps the batteries at 100 percent charge.

Keeping the batteries fully charged is good for Lead Acid. But apparently its not so good for Li.

 

[JamesG161]

Guess what is the major source of Lithium?

Ocean Water that was/is Solar Dried in Salt beds.

Go Chile Go!!
Jim...

 

[jviss]

My experience with Lithium batteries is with an electric bike but it brings up a "management " issue that Im wondering how you would deal with on a sailboat.

BU-808: How to Prolong Lithium-based Batteries Take a look at table 3 in the link which shows that Li batteries last longer when left only partially charged. For example, at 25C, the battery has 96 percent of capacity after one year when left at 40 percent charge but the capacity drops to 80 percent if left at 100 percent charge. Ie, the battery retains capacity longer if left at a 40 percent charge rather than 100 percent charge.

If you are using the boat such as living on it or daily use with heavy discharge and charge, the above doesn't matter. But in my particular case with the boat in a slip for four months of the year, I have a solar panel that keeps my Lead acid batteries topped up nearly 100 percent of the time. I like this as when I go to use the boat for an overnight outing, the batteries are conveniently fully charged. When the boat is not in the slip for the rest of the year, the solar also keeps the batteries at 100 percent charge.

Keeping the batteries fully charged is good for Lead Acid. But apparently its not so good for Li.

Yes, this is an issue, and an opportunity. I've been thinking about it a lot. I'd like to have a system where I can tell it to go to a particular state of charge, maybe pre-programmed ones like 80% for storage and 100% for anticipated need; and also, like my Macbook, have some intelligence that can track my usage patterns, knows the date and time, and can put the batteries in an appropriate SOC. Maybe even have a cellular network interface so you can remotely command it to various states. You'd need a place to dump charge: maybe the water heater. And also a source of charge: shore power, solar, automatic generator, etc.

I don't anticipate the marine market getting here anytime soon.

 

[smokey73]

Please don't turn this thread into an argument over EV's vs. ICEs, etc. Start a new thread in Sails Call or something, "The place for non-sailing related posts that aren't political or religious." Oh, wait - maybe star a thread on another site and let us know where it is.

p.s. I agree with you, I just don't think this is the forum for that debate.

Agreed - I'll delete. Don't feel like stating another thread. Thanks though.

 

[smokey73]

Agreed - I'll delete. Don't feel like stating another thread. Thanks though.

@jviss You may need to delete you're post about not hijacking the thread. With my quote in there it is still available by the link. It doesn't automatically delete the quote. Being there it might get brought back up.

 

[DCGULL]

Well written, considered & appropriate. For another thread. AND, I agree with you. Thanks for the rant. Off topic (ish). Besides, we're very busy trying to fit a round peg into a square hull with LiFePO4.

 

[jviss]

Besides, we're very busy trying to fit a round peg into a square hull with LiFePO4.

I'd like to understand what you mean by that. I think LFP is a revolutionary - not evolutionary - development for remote power: boats, rv's, off-grid. A flooded lead-acid bank on a sailboat on a mooring, now, that's a square peg, round hole situation!

 

[DCGULL]

Sorry, it COULD be taken wrong. I love LiFePO4- because of the 4 x's storage capacity in 1/2 the weight and 30%+ smaller size. But, at present- everyone is being QC for the manufacturers (you, me, Victron, Mastervolt, Dakota Lithium...) and the controls needed are getting closer to being in place for us to use them consistently & safely. What the industry is doing today will change at a wholesale level in the next few years. That's what I mean.
I'm very excited about the near future of this storage solution for sailors.

 

[DArcy]

My experience with Lithium batteries is with an electric bike but it brings up a "management " issue that Im wondering how you would deal with on a sailboat.

BU-808: How to Prolong Lithium-based Batteries Take a look at table 3 in the link which shows that Li batteries last longer when left only partially charged. For example, at 25C, the battery has 96 percent of capacity after one year when left at 40 percent charge but the capacity drops to 80 percent if left at 100 percent charge. Ie, the battery retains capacity longer if left at a 40 percent charge rather than 100 percent charge.

If you are using the boat such as living on it or daily use with heavy discharge and charge, the above doesn't matter. But in my particular case with the boat in a slip for four months of the year, I have a solar panel that keeps my Lead acid batteries topped up nearly 100 percent of the time. I like this as when I go to use the boat for an overnight outing, the batteries are conveniently fully charged. When the boat is not in the slip for the rest of the year, the solar also keeps the batteries at 100 percent charge.

Keeping the batteries fully charged is good for Lead Acid. But apparently its not so good for Li.

A buddy with a Tesla says they take care of this with an app. It's going to be a while before boat charges get to this point. The Tesla chargers keep track of state of charge and will charge up to a set point (say 80%) overnight. If you need more, you plan your route through the app, which connects with your car and the charger and automatically gives you more charge if the route you plan is longer than the 80% can accommodate.

For a sailboat you would just need to have your boat charger (which, of course, controls your solar, shore, generator... charging) connected to the internet and you tell it you will be heading out Friday evening for a weekend at anchor so it tops up the batteries Thursday night for you before you get there. It also chills the wine and turns on the AC for you . Isn't the future beautiful?

 

[Johann]

For a sailboat you would just need to have your boat charger (which, of course, controls your solar, shore, generator... charging) connected to the internet and you tell it you will be heading out Friday evening for a weekend at anchor so it tops up the batteries Thursday night for you before you get there. It also chills the wine and turns on the AC for you . Isn't the future beautiful?

Future? This is pretty much exactly what I do now. The day before heading out I connect to VRM and select full charge profile on my solar and inverter/charger. As far as chilling drinks, the fridge is always on, but I could use one of the Victron relays… now if only my ACs would come out with the WiFi module they promised was on the way…‍

 

[jviss]

I connect to VRM

What's VRM?

 

[Johann]

What's VRM?

Sorry. Victron Remote Management. Free internet access and control of your system when it is managed by a Victron GX device.

 

[jviss]

Sorry. Victron Remote Management. Free internet access and control of your system when it is managed by a Victron GX device.

Interesting! Beware Russian hackers!

 

[thinwater]

You cant compare fork truck batteries(real deep-cycle batteries) to the typical lead acid batteries used on boats. Some Fork truck batteries claim 5000 cycles so 1200-1500 is not so good. The cycle life data comes from over 20 years of capacity testing "marine" batteries. The vast majority never break 150 cycles..

Yes, I said they were abused. Some of the smaller trucks run the same 6 V batteries people use in boats. I've never gotten less than 7 years and from the cheapest deep cycle batteries, and up to about 700 cruising nights, though not all of the boats were cruised that much, and very few are. I think I'm reasonably good about recharging, but I ignore them a good bit too. The thing is, I've never gotten much more than 7 years of good service from a lithium battery either. Phone. Power tools.

I'm not sayin' that lithium is not going to become the smart choice for full time cruisers who use the full capabilities of their batteries every night. I'm pretty sure it already is. My cell phone gets cycled every day, and power tools need to be light and powerful. I'm saying 98% of sailors don't spend enough time of the hook for the advantages of lithium to be so black and white. At 7 years or so they are going to get new batteries, either way.

As for an ap to monitor batteries (not your posts), I've got to believe 99% of boaters couldn't care less. They want to ignore everything about the battery system other than a simple SOC number. Not the people on this thread, perhaps, but me and 99% of boaters. This parcially explains a lot of FLA batteries not living long. But I doubt a simple 5-7 year replacement cycle bothers them much either. That's what they do with their cars.

I can see this all changing if OEMs start installing them or if drop-in replacements include more features that could make them truely drop-in. Perhaps an external black box. Or is there a hole in my logic?

 

[jviss]

I'm saying 98% of sailors don't spend enough time of the hook for the advantages of lithium to be so black and white.

I asume you mean "on the hook?" If so, that means your assumption is that 98% of sailors are at docks, plugged in to shore power? That's just not so where I am, the vast majority of sailboats are at moorings. For that use case, LiFePo4 is vastly superior to lead-acid.

I can see this all changing if OEMs start installing them or if drop-in replacments include more features that could make them truely drop-in. Perhaps an external black box. Or is there a hole in my logic?

"Drop-in" is a stop-gap measure because boat electrical systems assume lead-acid. Once boat systems are designed from the ground up for LiFePo4, including integrated BMS's, charging regulators, and intelligent controls, so called drop-ins won't be necessary or desirable. But, this won't happen anytime soon. It would be cool if someone would develop a BMS for LFP that would make it appear as a LA battery, and fool existing systems into thinking it was a LA, all the while treating the LFP properly.

 

[Hayden Watson]

A buddy with a Tesla says they take care of this with an app. It's going to be a while before boat charges get to this point. The Tesla chargers keep track of state of charge and will charge up to a set point (say 80%) overnight. If you need more, you plan your route through the app, which connects with your car and the charger and automatically gives you more charge if the route you plan is longer than the 80% can accommodate.

For a sailboat you would just need to have your boat charger (which, of course, controls your solar, shore, generator... charging) connected to the internet and you tell it you will be heading out Friday evening for a weekend at anchor so it tops up the batteries Thursday night for you before you get there. It also chills the wine and turns on the AC for you . Isn't the future beautiful?

I have been looking into the Samlex Evo series of inverter / chargers and while it does not work from an app, it does have the most controllability of any charger that I am aware of. One of the programable charge settings allows you to go to whatever voltage you want and then off, no absorb, no float, just off. It does not restart until the bank drops down to an restart voltage. This would cover the 80% while in storage on shore power. Another nice feature is that it also has a DC passthrough input which will allow it to control the charge current from other sources so you can get the same bulk/off/restart from your solar.
According to the spec sheet it is ABYC A31 & E11 compliant. surprisingly, I could not find a similar statement about ABYC compliance anywhere on the Victron site or spec sheets. I am looking at the EVO-1212HW because I don't have any high demand AC stuff but the 60A charger (+50A pass-through) would be nice on the charging side.

 

[tfox2069]

Future? This is pretty much exactly what I do now. The day before heading out I connect to VRM and select full charge profile on my solar and inverter/charger. As far as chilling drinks, the fridge is always on, but I could use one of the Victron relays… now if only my ACs would come out with the WiFi module they promised was on the way…‍

I use a Victron solar controller and BMV-712 BMS on my boat and have been looking at the Victron CerboGX to monitor my batteries and charging system while I'm away.. And while you can monitor and manipulate your connected systems remotely (e.g. turning off solar power), it doesn't appear there's any new functionality. So, for example, I cannot now tell my shore charging system to charge my batteries to 80% and stop. VRM doesn't change that for my existing system, but please set me straight if that's not the case. I've tried to read a lot on VRM, but aside from the rather general literature I haven't run across any practical use cases that illuminate the VRM capability all that well. i'm sure I'm missing a lot.

Perhaps a LifePO BMS is much more functional, like my Tesla which (as has been pointed out) has an app which allows me to see the state of charge of my battery, start or stop charging manually, set a charging % limit, direct it to charge during low grid load periods, or even set a departure time so the car charges in time to be ready when I'm headed out the door. I've owned three electric cars since 2012, and this tech has been around since the first one I owned, a Nissan Leaf.