Lithiums in winter

[<<B-Guy>>]

We are new to both Class B's and more specifically to ithium bateries and don't have either at present - but should have both by Fall this year!

I have been reading the manual for the PW Plateau and understand that it is not desirable to be charging lithiums when they are below freezing. The manual says to disconnect the charging line - presumably until the interior of the van warms up. Sounds easy enough and I will do that!

I am surprised that the BMS does not automatically provide such protection though - I guess it does not!

But the manual also says that if the unit is being stored outdoors in below freezing temperatures, it is recommended to remove the batteries and bring them indoors.

I am wondering how important that is for battery longevity and if folks in cooler parts of the country actually do that?

We normally head south from Canada in mid Feb each winter, so the van would be outdoors in potentially cold weather until then.

Where we live in Canada is not terribly cold - all relevant I suppose - but certainly temperature extremes in the 10-15 deg F range could be experienced.

Should the batteries be removed? Anyone live in similar locations and able to advise?

I am assuming that if I bring the batteries indoors I won't be able to charge them as I assume lithiums need special chargers?


Thanks ............ Brian.

[Reed]

We have 4.5 kW-hrs in our 190 Roadtrek. . Son designed and fabricated the solar LFP system. The battery suite, inverter, battery chargers et al are under the bed (we have just left it as a bed). He put in a “blower” the evacuated the air under the bed to the outside which draws in cabin air once the temperature drops below 40F (5 C or so). We have an Olympic Wave 3 heater mounted on closet door which keeps cabin in mid to high 40s F. Startled us the first time it came on at 2 am.

We also have a fifth wheel that we seem to alternate in going to Yucatan. We just disconnect the battery suite of vehicle not in use

[cruising7388]

Originally Posted by Wingeezer

I have been reading the manual for the PW Plateau and understand that it is not desirable to be charging lithiums when they are below freezing. The manual says to disconnect the charging line - presumably until the interior of the van warms up. Sounds easy enough and I will do that!

I am surprised that the BMS does not automatically provide such protection though - I guess it does not!

But the manual also says that if the unit is being stored outdoors in below freezing temperatures, it is recommended to remove the batteries and bring them indoors.

I am wondering how important that is for battery longevity and if folks in cooler parts of the country actually do that?

We normally head south from Canada in mid Feb each winter, so the van would be outdoors in potentially cold weather until then.

Where we live in Canada is not terribly cold - all relevant I suppose - but certainly temperature extremes in the 10-15 deg F range could be experienced.

Should the batteries be removed? Anyone live in similar locations and able to advise?

I am assuming that if I bring the batteries indoors I won't be able to charge them as I assume lithiums need special chargers?


Thanks ............ Brian.

I don't think it's a question of the BMS not controlling charging parameters. I don't there is a BMS at all.

At 400ah and higher battery capacity, I understand the advantages of lithiums rather AGMs. What I don't understand is the virtue of equipping a coach with a total of only 200ah in lithium. This could be just as well accomplished using AGMs for a hell of a lot less money and with no concern regarding freezing issues.

[<<B-Guy>>]

Originally Posted by cruising7388

I don't think it's a question of the BMS not controlling charging parameters. I don't there is a BMS at all.

At 400ah and higher battery capacity, I understand the advantages of lithiums rather AGMs. What I don't understand is the virtue of equipping a coach with a total of only 200ah in lithium. This could be just as well accomplished using AGMs for a hell of a lot less money and with no concern regarding freezing issues.

Maybe that is the answer!

But even if it is a much less sophisticated system, is there not still an advantage in that the lithium batteries hold their voltage much better as capacity is used up?

Brian.

[gregmchugh]

Originally Posted by Wingeezer

Maybe that is the answer!

But even if it is a much less sophisticated system, is there not still an advantage in that the lithium batteries hold their voltage much better as capacity is used up?

Brian.

Even the drop in replacement lithium batteries have a BMS to at least support cell balancing but the BMS may not have all the protection functions of the higher end systems. It may have protections to prevent overcharging and overdischarging the cells but may not have protections for low temperatures.

In addition to higher voltage during discharge, lithium advantages over AGM include savings in weight and volume, more usable capacity for a given number of amp hours, and the capability to take higher harge currents all the way up to full charge which avoids the several hour absorption charge phase of an AGM battery.

[Winston]

Originally Posted by Wingeezer

But the manual also says that if the unit is being stored outdoors in below freezing temperatures, it is recommended to remove the batteries and bring them indoors.

Where we live in Canada is not terribly cold . . . but certainly temperature extremes in the 10-15 deg F range could be experienced.

It doesn't seem that your basic inquiry has been addressed and, unfortunately, we're not going to be able to answer it either.

It had been our understanding that the 'freezing limitation' of lithium is related to charging but that lithium, otherwise, can be exposed to temperatures as low as -4 degrees Fahrenheit. Your "manual" is the first we've heard that it may not be good for lithium to store them at temperatures below 32F. We'd like to see some authority for that proposition.

There's one thing for certain, there's no way we're going to be shuttling our somewhat ungainly 500ah lithium pack 'in and out' from its installation point under the bed. Although we live in northern climates (Michigan and northern Illinois) we've been fortunate over the past two winters to be able to park our van 'inside'.

But we've considered the issue if for no other reason that there will likely be times when we're using the van in sub-freezing temperatures. The good news is that our batteries are housed inside the van and, more specifically, within a sub-compartment of the bed only slightly larger than the batteries themselves. We opine that we could keep this area heated with a comparatively low power electric source.

Hoping that someone has the answer to safe lithium storage temperatures.

[<<B-Guy>>]

Originally Posted by Winston

It doesn't seem that your basic inquiry has been addressed and, unfortunately, we're not going to be able to answer it either.

It had been our understanding that the 'freezing limitation' of lithium is related to charging but that lithium, otherwise, can be exposed to temperatures as low as -4 degrees Fahrenheit. Your "manual" is the first we've heard that it may not be good for lithium to store them at temperatures below 32F. We'd like to see some authority for that proposition.

There's one thing for certain, there's no way we're going to be shuttling our somewhat ungainly 500ah lithium pack 'in and out' from its installation point under the bed. Although we live in northern climates (Michigan and northern Illinois) we've been fortunate over the past two winters to be able to park our van 'inside'.

But we've considered the issue if for no other reason that there will likely be times when we're using the van in sub-freezing temperatures. The good news is that our batteries are housed inside the van and, more specifically, within a sub-compartment of the bed only slightly larger than the batteries themselves. We opine that we could keep this area heated with a comparatively low power electric source.

Hoping that someone has the answer to safe lithium storage temperatures.

Thanks Winston,

The way it is worded in the PW manual is more a recommendation than a firm "must do," and I was just wondering how important it might be. Our temps here near Toronto are likely similar to yours.

Our van also will have the batteries inside under the rear sofa. I hope we will be keeping in in our driveway over the winter, so I could put a small cube heater in there just to keep temps above freezing but nt sure if it would be just a waste of electricity.

Brian.

[Boxster1971]

Originally Posted by Wingeezer

... The manual says to disconnect the charging line - presumably until the interior of the van warms up. Sounds easy enough and I will do that! ...

... But the manual also says that if the unit is being stored outdoors in below freezing temperatures, it is recommended to remove the batteries and bring them indoors...

I'd do what the manual says at least while under warranty in case the batteries should go bad.

You could also ask Pleasure Way to clarify in detail what the manual says.

[Davydd]

There are two rules with lithium batteries of which there are several varieties.

1. None should accept a charge at below freezing. Ideally not below about 41F. That means the temperature of the battery, not the air temperature. Batteries in use charging and discharging could be 10-20F above ambient. The simplest way is to monitor the cell temperatures of the batteries and automatically disconnect from charging or you will forever worry, wonder and constantly monitor when on the road in transitional weather. If you don't want to disconnect charging, applying external heat to the batteries can do it. Inside batteries is easy underway when the van is occupied. External batteries can be insulated and electric resistant heating pads are the easiest way. In storage and unoccupied disconnecting is probably easiest. I suspect an electric cube heater on Pleasure-ways batteries would be satisfactory. Personally, I think it is stupid to depend on the cabin's heat to bring up the battery temperature when underway especially if they have no method of monitoring the cell temperature. It becomes a guessing game of how long and you can't charge during that time.

2. The batteries should not go below -4F while in storage. Again that is the battery cell temperature and not the air temperature but while in storage that cell temperature will seek balance with the air temperature. Toronto can get that low but I suspect an electric cube heater will suffice in a Pleasure-way applied directly on the battery case. With your Pleasure-way it probably is possible to store them inside but might be a pain in the ass. With other upfitter supplying 400ah and above battery systems in discrete block assemblies it probably is not practical to remove them. Removing them also disables the electrical functions of your coach and for the most of the winter you may desire that use.

There are some new chemistries in lithium batteries being offered, but still the no-no charging below freezing still applies but the batteries can withstand temperatures to -40F which is the same as AGMs. Those are LiFeMgPo4 batteries as opposed to LiFePo4 batteries. I think the Volta System batteries can withstand lower temperature as well.

[<<B-Guy>>]

Originally Posted by Davydd

There are two rules with lithium batteries of which there are several varieties.

1. None should accept a charge at below freezing. Ideally not below about 41F. That means the temperature of the battery, not the air temperature. Batteries in use charging and discharging could be 10-20F above ambient. The simplest way is to monitor the cell temperatures of the batteries and automatically disconnect from charging or you will forever worry, wonder and constantly monitor when on the road in transitional weather. If you don't want to disconnect charging, applying external heat to the batteries can do it. Inside batteries is easy underway when the van is occupied. External batteries can be insulated and electric resistant heating pads are the easiest way. In storage and unoccupied disconnecting is probably easiest. I suspect an electric cube heater on Pleasure-ways batteries would be satisfactory. Personally, I think it is stupid to depend on the cabin's heat to bring up the battery temperature when underway especially if they have no method of monitoring the cell temperature. It becomes a guessing game of how long and you can't charge during that time.

2. The batteries should not go below -4F while in storage. Again that is the battery cell temperature and not the air temperature but while in storage that cell temperature will seek balance with the air temperature. Toronto can get that low but I suspect an electric cube heater will suffice in a Pleasure-way applied directly on the battery case. With your Pleasure-way it probably is possible to store them inside but might be a pain in the ass. With other upfitter supplying 400ah and above battery systems in discrete block assemblies it probably is not practical to remove them. Removing them also disables the electrical functions of your coach and for the most of the winter you may desire that use.

There are some new chemistries in lithium batteries being offered, but still the no-no charging below freezing still applies but the batteries can withstand temperatures to -40F which is the same as AGMs. Those are LiFeMgPo4 batteries as opposed to LiFePo4 batteries. I think the Volta System batteries can withstand lower temperature as well.

Very specific and helpful information Davydd, Thank you!

I am hoping that we will be able to keep our trailer in our driveway year round. There is a local bylaw saying RV's only in driveways during the summer
months, (6 months actually) but wen I spoke with the bylaw officer he toldme that they only enforce it if they get complaints.I have spoken with neighbours and they all seem fine with it being in our drive - but you never know! As long as I can keep it at home I will just stick a cube heater in if temps are likely to be near the point of potential damage If I do ever need to put it in winter storage, I guess I had better remove them! Thx ........... Brian.

[Davydd]

I think the solution is an electric shore power connection and it doesn't have to be 30a. A simple 15a connection will do stored at your home or remote. I opted to buy a condo garage remote from our home (9 miles) that is both shore powered and heated.

Most upfitters dismissed the special protections for lithium ion batteries and think of them as any other battery (lead-acid wet cells or AGMs). But if you pay a premium for more amp hours than you can possibly get with lead-acid because of space and weight considerations and pretty much having the batteries for the life time of the van you would think they could provide automatic protection devices at a nominal cost of the overall premium. I don't think they have thought it through. Pleasure-way has just put their toe in the lithium water probably for marketing reasons because lithiums are the coming standard. At 200ah battery capacity AGMs still rule. But with knowledge and common sense you can over come the short sightedness of the upfitters.

[Winston]

Originally Posted by Davydd

The simplest way is to monitor the cell temperatures of the batteries . . . especially if they have no method of monitoring the cell temperature

And how, really, does one measure the cell temperature? Our BMS (an Elite) monitors each of the 20 cells 'temperature', but that monitoring is a thermister on a PC board mounted to the two terminals of each cell. We wonder if this isn't more of an 'ambient' temperature reading as opposed to the true temperature of the cell. Thoughts?

[Davydd]

Originally Posted by Winston

And how, really, does one measure the cell temperature? Our BMS (an Elite) monitors each of the 20 cells 'temperature', but that monitoring is a thermister on a PC board mounted to the two terminals of each cell. We wonder if this isn't more of an 'ambient' temperature reading as opposed to the true temperature of the cell. Thoughts?

This is how I know the cell temperatures through our Silverleaf readout. When this photo was taken the ambient temperature was in the teens as I remember. The heat button is active to come on as I know by the green handles. I know by the flame symbol that it is actually heating. Cell 1 and 2 are at the end of the bank and usually register the lowest because they are not fully covered by the electric resistant heating pad. That's why the other cells are at a higher temperature because the heating pad will heat until all cells reach 41F. Our batteries are in an insulated box under the floor.

We have 16 200ah 3.2 volt cells. 4 in series to make a 12v battery and then four in parallel to make a total of 800ah in a single block .

By observation when heating has not come on, I've noted that our lithium battery temperatures are anywhere from 10 to 20 degrees F. above ambient when being charged or in use discharging, and usually there is no call for heat until ambient temperatures drop to the low 20s.

I have two 12vdc 5 amp electric resistant heating pads sandwiched between the batteries for a total 10 amps. They are powered by the batteries. So in a 24 hour period that's a maximum of 240ah drain on the batteries. That can be replenished in about one hour of idling the engine with the second alternator. For one we never are on the road where we would need that maximum and two, we would drive just about every day when it is that cold outside mainly to get someplace warm. So really no idling is necessary. Plugged into shore power is a no-brainer at home and the batteries can stay topped off with heat and now that I have a heated garage I have the proverbial belt and suspenders.

[avanti]

I think the situation is pretty simple:
If you decide to go with lithium, and if you live in an area where there is ANY reasonable chance of getting to negative degrees F, then you are committing to either (a) carrying your batteries inside during winter storage or (b) plugging into shore power all winter.

From my perspective, the former is ridiculous and the latter is far from a "no brainer", as it would cost me a lot in both dollars and convenience. Consequently, I have chosen to soldier on with a mere 440Ah of AGM, which (combined with modest solar) permits me to completely forget about batteries for seven years or so at a stretch. I guess I am just a "no compromise" kind of guy, at least when it comes to taking on constant chores, needless expenses, and/or nagging worries. When I turn my van "off", I like it to be "off".

[Winston]

Originally Posted by Davydd

I have two 12vdc 5 amp electric resistant heating pads . . . So in a 24 hour period that's a maximum of 240ah drain on the batteries.

Let's see . . . that's ~3kwh/day => $0.30/day or $10/month.

Originally Posted by avanti

If you decide to go with lithium, and . . . chance of getting to negative degrees F, then you are committing to either (a) carrying your batteries inside during winter storage or (b) plugging into shore power all winter.
. . . as it would cost me a lot in both dollars and convenience. I guess I am just a "no compromise" kind of guy,

Or, the third option - - the one that we (and Davydd) are employing: keep the vehicle inside.

Avanti, we assume your parking spot does not have access to shore power. In our case we can easily drop an extension cord and for that $10/month for the couple of really cold months . . . not worry. That doesn't seem like much of a "compromise" to us. Indeed, don't AGM's come with their own set of compromises . . . including the recommendation not to fully discharge them, the need to maintain them at full charge, the need to charge them at a high current rate, not to mention their weight and size disadvantages?

[avanti]

Originally Posted by Winston

Let's see . . . that's ~3kwh/day => $0.30/day or $10/month.

Or, the third option - - the one that we (and Davydd) are employing: keep the vehicle inside.

Avanti, we assume your parking spot does not have access to shore power. In our case we can easily drop an extension cord and for that $10/month for the couple of really cold months . . . not worry. That doesn't seem like much of a "compromise" to us.

I honestly do not believe that you sincerely think that my "compromise" has anything to do with the cost of electricity. Your statement was an obvious straw man. The simple fact is that the storage facility where I keep my rig is exceedingly close to my home and costs maybe 20% of what folks who have quoted storage rates have been saying. I have kept both of my rigs there for 13 years. It would be a huge compromise along multiple dimensions to change just to accommodate a technology for which I find no compelling need. If you need or want all-night air conditioning without running a genset, then Li is your only current choice. But, if you can live within a 250Ah daily consumption budget, LI is not a rational choice IMO. Since I can do so without even thinking about it, AGM is the "no compromise" choice for me.

Indeed, don't AGM's come with their own set of compromises . . . including the recommendation not to fully discharge them, the need to maintain them at full charge, the need to charge them at a high current rate, not to mention their weight and size disadvantages?

Every technology that has not been universally adopted comes with compromises,
obviously. Otherwise it would be the only choice. But none of the ones you mention are relevant to me:
--The recommended minimum charge level and the size and weight were fully-dealt with when I sized my battery. My required battery easily fits. No compromise.
--My solar setup keeps them fully-charged without my attention. No compromise.
--I am unaware of a "high current rate" requirement. But in any event, my second-engine alternator meets any such alleged requirement. No compromise.

What you are calling "compromises" are actually technical limitations. As I say, ALL non-universally-adopted technologies have technical limitations. In applying a technology, one starts with requirements, examines the limitations of a given approach, and then deploys. The result may or may not involve "compromises".

I don't quite understand why you found my post offensive. I am making a simple claim: If you require more than roughly 250Ah of daily consumption (and have the means to replenish it), then you need Li, and will have to accept the stated compromises (which you may well find acceptable). If 250Ah or less is adequate for your needs, then your life will be simpler with AGM. I don't see where the controversy is.

[Davydd]

Originally Posted by Winston

Let's see . . . that's ~3kwh/day => $0.30/day or $10/month.



Or, the third option - - the one that we (and Davydd) are employing: keep the vehicle inside.

Avanti, we assume your parking spot does not have access to shore power. In our case we can easily drop an extension cord and for that $10/month for the couple of really cold months . . . not worry. That doesn't seem like much of a "compromise" to us. Indeed, don't AGM's come with their own set of compromises . . . including the recommendation not to fully discharge them, the need to maintain them at full charge, the need to charge them at a high current rate, not to mention their weight and size disadvantages?

I hadn't thought of it that way ($10/mo.) because I store inside in a heated garage now and keeping it plugged in is for convenience in my now mancave with lights, computer, cube heater, refrigerator for my beer, coffee brewing, water and toilet. However, I just got the bill for the year for gas heat in the garage and it came to $42. I keep the garage at 40F when unoccupied so most of the time it is not on and subsequently there is no heat called for in the van. I found that surrounded by other garages that in over 90F heat the garage has stayed a cool 70F. That, I am pleased. My gas bill will go up this winter because I am equipping the garage with woodworking tools and probably will be in there a lot more.

Of course the other benefit of storing it inside is no sap, pollen and leaf and twig debris to clean up. No worries about hale damage. No sun damage. That's a no-brainer.

[booster]

The "high rate charging requirement" likely is referring to Lifeline's recommended charge rate of at least .2C if the battery has been discharged over 50%. Most AGM systems are already there, as the very common 200ah systems nearly always use bigger than 40 amp chargers. The big AGM systems of 440ah are mostly using 100 amp chargers so also OK. IMO, pretty much a non to minimal consideration anyway, as long you get the batteries truly full when charge them.

[Winston]

Avanti, no . . . absolutely nothing offensive. We were just carrying-on a friendly, low-key banter examining these issues from slightly differing perspectives. We appreciate your view and response.

And, yes, Booster . . . that was our reference. We never met that 'suggested' charge level in our CaRV with its 245ah AGM battery (49 amps!) as, at that time, we'd not heard of that charge target. If we'd stuck with the AGM system we'd have researched it further.

[avanti]

Originally Posted by Winston

Avanti, no . . . absolutely nothing offensive. We were just carrying-on a friendly, low-key banter examining these issues from slightly differing perspectives. We appreciate your view and response.