Do I remove my batteries for winter

[booster]

Originally Posted by jakegw2

They are fine down to -4 deg F. Note that getting the battery to this temperature would require more than just dipping below that temp overnight, it would require a day or two of consistently below -4 deg temperature. In PA I would just take my chances, probably 8 out of 10 winters will not have a cold stretch cold enough for it to be an issue.

If you have the time and inclination you can add heating pads to your batteries. It isn't that hard and will give you peace of mind no matter the weather. I did this because I lived in MA, but as it turned out we never had an extended cold snap long enough to truly need it for battery protection. The heating pads did end up being very useful however, as the batteries cannot take a charge below freezing, so having them heated allowed us to use the camper in winter weather, which we do regularly.

l will point out as I have in the past that it is highly unlikely that any of the temp good/bad points are really good/bad at that point like water freezing is.


I think this is pointed out be the sliding scale of storage time at reduced temps, with "allowable" time decreasing at each step colder and the point that the "optimum storage temp is quite far above -4* for most manufacturers that list that spec.

The guess, for me anyway, would be that there is a constant curve of damage per time period that starts around +70* and ends at -45*F. The line is likely not linear and is a curve the gets progressively steeper as the coldest temps are nearing -45*.

The recommended temp specs at face value would seem to indicate to most people that if your batteries are at 0* for months you are just fine, no damage. If you are at -4* for a week they are severely damaged. I would bet a large sum that is not the case and that the long time at zero would cause more damage than the short time at -4*.

The cutoffs are probably set based on the "acceptable" damage done vs length of time expected for the batteries to get that cold, plus the elephant in the room for this kind of stuff, marketing and warranty consequences.

If the above is correct, that would indicate that comparing life at +4,0, and -4* is not what you want to do and make decisions on. What you would need to test was the difference between them and "optimal" storage temp of 50-70* depending on who you believe for the optimal.

As mentioned, we don't know any real data on that, at least that I know of, but manufacturers of batteries would not be putting the recommended cold temp specs if they didn't feel that they were causing to much warranty issues without the specs.

[Snowy]

Originally Posted by avanti

Victron says that my batteries are OK to store down to -45°C, and I sort of trust them, so I am not going to lose much sleep over this issue.

When i first read this i thought that Victron must be using some other chemistry. I looked up the data sheet and found to my surprise that they are using a LFP chemistry. Now i wonder if there is a range of LFP chemistries with different cold-weather performance. It seems doubtful that one LFP chemistry can do -45 (at that T, F and C are about the same) and all the others can only do -4F, but anything is possible i guess.

[avanti]

Originally Posted by Snowy

When i first read this i thought that Victron must be using some other chemistry. I looked up the data sheet and found to my surprise that they are using a LFP chemistry. Now i wonder if there is a range of LFP chemistries with different cold-weather performance. It seems doubtful that one LFP chemistry can do -45 (at that T, F and C are about the same) and all the others can only do -4F, but anything is possible i guess.

I am no expert, but I suspect that there are factors beyond the chemistry that affect temperature robustness. One can certainly imagine that physical construction may matter.

[booster]

Originally Posted by avanti

I am no expert, but I suspect that there are factors beyond the chemistry that affect temperature robustness. One can certainly imagine that physical construction may matter.

Very possible as temp issues often include expansion and contraction induced problems.


I would, though, wonder about it in this case for one reason if it still applies.


My understanding from past reading indicated the Victron was using Winston cells, which many consider to be the best of the best in lithium, it appears.


Other high end batteries use Winston cells also and don't make the temp claims that I know of anyway.

[Snowy]

Originally Posted by booster

Very possible as temp issues often include expansion and contraction induced problems.

I would, though, wonder about it in this case for one reason if it still applies.

My understanding from past reading indicated the Victron was using Winston cells, which many consider to be the best of the best in lithium, it appears.

Other high end batteries use Winston cells also and don't make the temp claims that I know of anyway.

This explains somethings. Winston cells have Yttrium in them, which may explain all or part of their better low-T performance. The first couple of sites that came up showed *operating* (charge and discharge) temperatures from -45℃～85℃! I doubt that these values are correct for charge and discharge, but maybe for storage.

[GLW]

can we discuss what parts you used with battery heating via a private chat or direct me to where a "kit" or individual parts could be purchased... that would be very helpful. Also where do you go "camping" during winter as I'd be interested in those options, what do you do without water if the camper is winterized?

[Snowy]

Your batteries may have internal or external heaters already installed, i don't know. I would contact Pleasure-Way to determine of you have any heaters already installed or for their recommendations about how to install some sort of battery heater if your batteries lack internal heaters. Outside of that, google "battery blanket lithium" and see where that takes you.

There are many ways to deal with cold when camping. It depends on how cold it is, how private your campsite is, whether you have shore power, etc. If you don't have power to plug into, and it is not that cold, and you know you can find a dump station, then you can use tank heaters and/or antifreeze to keep things going. This is what a lot of snow machiners do. If you are a guy, you can piss outside. If you can't find an open dump station and you have privacy, i actually find pooping in a 5 gallon bucket lined with a plastic bag not bad at all - if it is cold out everything freezes solid so no mess or smell. Then you bring the frozen poop bag back to town and throw it in a dumpster. You can disassemble your sink piping so the sink drains directly into a 5-gallon "slop" bucket, which you can throw out on the ground if you are not in some concentrated camping area. For water, i find it easier to use 5 gallon jugs, the kind with a spout attached, on the counter near the sink to work well either draining into a plastic basin in the sink or into a slop bucket beneath the sink.