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-   -   Storing boats with lithium batteries in cold climates (https://www.walleyecentral.com/forums/showthread.php?t=723834)

gbin 05-30-2021 03:22 PM

Storing boats with lithium batteries in cold climates
 
Recent discussions here and elsewhere have prompted me to study up a bit on lithium batteries for boats. As on so many subjects, I've found some of the best explanations of various things right here at WC! :thumbsup:

I've been left with a few questions, though, particularly in the area of storing boats with lithium batteries in cold climates, so I thought I'd see if devoting a thread here to that specific area would help improve my education. Many thanks in advance to all who respond with knowledge/experience and on topic!

Background: Here are the minimum storage temperatures - mind you, I'm NOT talking about minimum discharge or charge temperatures - I found stipulated by a few of the more frequently discussed lithium boat battery manufacturers:[INDENT][LIST][*]Battle Born -10F[/LIST][/INDENT][INDENT][LIST][*]RELiON/Tracker 23F[/LIST][/INDENT][INDENT][LIST][*]Ionic not specified anywhere that I can find[/LIST][/INDENT]My questions:

- What does it really mean to say that one of these batteries has a minimum storage temperature? That is, what happens to the battery if it's stored below that temperature, and in principle how serious a matter could it be (other than possibly cracking the battery's housing if it gets cold enough)?

- Why does the minimum storage temperature vary so much from one manufacturer to another?

- In practice rather than principle, what are folks who live in cold climates and have switched to lithiums to power their trolling motors and maybe their main motor doing to store their batteries in the winter? Just leaving them in the boat with everything shut down and not worrying about it, so far with no apparent harmful effect? Taking the batteries out in the fall so they can be kept someplace at least somewhat climate-controlled for the winter before reinstalling them in the spring? Or ...?

In my case, I use an unheated barn for winter storage of my boat, and there's definitely plenty of time out there every year below 23F; there are always at least occasional days, sometimes spans of days, below -10F, too. Right now I have all lead-acid batteries which I leave in place and on a charger, but it's not at all clear to me what I would best do if I switch to LiFePO. And I'd like to make that switch at some point, maybe soon, so these aren't just academic questions for me.

Thanks again!

Gerry

Ozark Bob 05-30-2021 06:38 PM

-40 is what I have seen. I will look for a source. The numbers you have been looking at are from lab testing for either minimum operating temp or minimum charging temps. Lab results are different and probably should be. I doubt there is regulation involved other than possible safety issues. Bob
PS your search should include LiFePO4. Each lithium chemistry has different stat's

Ozark Bob 05-30-2021 06:55 PM

This is something I have offered up before. [url]https://www.solacity.com/how-to-keep-lifepo4-lithium-ion-batteries-happy/[/url]
This is part of it.

Storing Lithium-Ion Batteries
The very low self-discharge rate makes it easy to store LFP batteries, even for longer periods. It is no problem to put a lithium-ion battery away for a year, just make sure there is some charge in it before placing it in storage. Something between 50% 60% is ideal, that will give the battery a very long time before self-discharge brings the Voltage close to the danger point.

Storing batteries below freezing is fine, even at very low temperatures such as -40 Centigrade (that is the same in Fahrenheit), or even less! The electrolyte in LiFePO4 cells does not contain any water, so even when it freezes (which happens around -40 Centigrade, depending on the particular formulation) it does not expand, and does not damage the cells. Just let the battery warm up a bit before you start discharging it again, which is OK at -20 Centigrade and above. You will see an apparent loss of capacity when discharging at below-freezing temperatures that reverses when the battery gets above freezing, and there is a slightly accelerated effect on aging. Storing them at low temperatures is certainly much better than storage at high temperatures: Calendar aging slows down dramatically at low temperatures. Try to avoid storing them at 45 Centigrade and above, and try to avoid storing them completely full if possible (or nearly empty).

If you need to store batteries for longer periods, be sure to simply disconnect all wires from them. That way there can not be any stray loads that slowly discharge the batteries.

gbin 05-30-2021 07:58 PM

[QUOTE=Ozark Bob;6564916]This is something I have offered up before. [URL]https://www.solacity.com/how-to-keep-lifepo4-lithium-ion-batteries-happy/[/URL]
This is part of it.

Storing Lithium-Ion Batteries
The very low self-discharge rate makes it easy to store LFP batteries, even for longer periods. It is no problem to put a lithium-ion battery away for a year, just make sure there is some charge in it before placing it in storage. Something between 50% – 60% is ideal, that will give the battery a very long time before self-discharge brings the Voltage close to the danger point.

Storing batteries below freezing is fine, even at very low temperatures such as -40 Centigrade (that is the same in Fahrenheit), or even less! The electrolyte in LiFePO4 cells does not contain any water, so even when it freezes (which happens around -40 Centigrade, depending on the particular formulation) it does not expand, and does not damage the cells. Just let the battery warm up a bit before you start discharging it again, which is OK at -20 Centigrade and above. You will see an apparent loss of capacity when discharging at below-freezing temperatures that reverses when the battery gets above freezing, and there is a slightly accelerated effect on aging. Storing them at low temperatures is certainly much better than storage at high temperatures: Calendar aging slows down dramatically at low temperatures. Try to avoid storing them at 45 Centigrade and above, and try to avoid storing them completely full if possible (or nearly empty).

If you need to store batteries for longer periods, be sure to simply disconnect all wires from them. That way there can not be any stray loads that slowly discharge the batteries.[/QUOTE]

That's what I originally thought, Bob, and though I have no real background in this stuff, it made sense to me. But I've definitely been focusing on LiFePO4 batteries (specifically 100Ah 12V Deep Cycle LiFePO4 batteries for marine use), and the numbers I stated above are definitely what the manufacturers have to say about minimum storage temperatures, not minimum discharging or charging temperatures.

From Battle Born:

[quote]The storage temperature range is -10F to 140F (-23C to 60C)...

Battle Born Batteries... won’t accept a charge once the internal cell temperature drops to 24F. At this point they will continue to discharge even down to -4F.[/quote]From RELiON/Tracker:

[quote]Temperature Specifications
Discharge Temperature -4 to 140 F (-20 to 60 C)
Charge Temperature* -4 to 113 F (-20 to 45 C)
Storage Temperature 23 to 95 F (-5 to 35 C)[/quote] So I'm hoping you and other folks here can help me work through the questions I asked.

Gerry

Ozark Bob 05-30-2021 08:14 PM

[QUOTE=gbin;6564922]That's what I originally thought, Bob, and though I have no real background in this stuff, it made sense to me. But I've definitely been focusing on LiFePO4 batteries (specifically 100Ah 12V Deep Cycle LiFePO4 batteries for marine use), and the numbers I stated above are definitely what the manufacturers have to say about minimum storage temperatures, not minimum discharging or charging temperatures.

From Battle Born:

From RELiON/Tracker:

So I'm hoping you and other folks here can help me work through the questions I asked.

Gerry[/QUOTE] Those are the numbers. What the marketing and stated stats are from individual companies is going to very. If you tell company "A" that company "B" says about there battery says theirs is ok in colder temp the will then tell you theirs will do the same so they don't lose a sale. Maybe you, as a scientist should read the technical white papers out there to get the real story.

gbin 05-31-2021 08:00 AM

[QUOTE=Ozark Bob;6564926]Those are the numbers. What the marketing and stated stats are from individual companies is going to very. If you tell company "A" that company "B" says about there battery says theirs is ok in colder temp the will then tell you theirs will do the same so they don't lose a sale. Maybe you, as a scientist should read the technical white papers out there to get the real story.[/QUOTE]

Maybe so, amigo. But if folks here can straighten me out on this stuff, I figure I'll have an easier time understanding y'all than I will those technical papers. It's decidedly not my field!

Gerry

Ozark Bob 05-31-2021 11:08 AM

[QUOTE=gbin;6565004]Maybe so, amigo. But if folks here can straighten me out on this stuff, I figure I'll have an easier time understanding y'all than I will those technical papers. It's decidedly not my field!

Gerry[/QUOTE] That's why I hate them! Spend half my time looking up meanings of words. But hearsay and advertising is not as reliable.

gbin 06-15-2021 07:01 PM

Had a chance to talk with a guy at RELiON today, and the 23F minimum storage temperature of their LiFePO4 batteries is one of the things I asked him about. He said that's their specification because there's a risk that the computers in their batteries will be damaged by temperatures colder than that, and he recommended that folks such as myself who live where it gets colder than that either remove the batteries for storage someplace warmer or buy one or more heating blankets suitable for use with batteries.

I mentioned that Battle Born specifies a much more accommodating -10F minimum storage temperature for their LiFePO4 batteries, and he said that's the point at which the cells in any such batteries would start to be damaged by the cold. He suggested that Battle Born's in-battery computers may be at just as much risk to damage from temperatures below 23F as are RELiON's, but Battle Born may have decided that the risk is small enough to be worth taking so they can advertise that much lower minimum storage temperature.

Gerry

Ozark Bob 06-15-2021 07:51 PM

So, What have you gleaned from that? I am seeing a CYA and the hint he thought the batteries are the same, but the language was different? I also heard no statement about any warrantee issues. I guess I am just not able to decipher the corporate lingo. Bob

Yellow Fever 06-16-2021 05:14 AM

Ozark Bob always does great research. What i get from this is that the anglers that fish till freeze up, ( and we frequently fish that at Quinte) possibly should not be using these batteries if you don't have a shop to put your boat in at the end of the day so you can charge the batteries. Am i right?


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