Lithium Batteries and Cold Snap

KC_Camps

We have a 2022 320S. We replaced the lead acid battery in the tongue tub with a marine grade, 206 amp hour lithium battery. On a 3-week trip we camped between 4,500 and 8,000 ft. (Eastern Sierra’s). A short colder system came through and the temperatures dropped to cold rain 1night, then an overnight 2inches of snow. The Alde and fridge shut off in the middle of the snowy night, and we realized the battery was not working. Thankfully the 320 only dropped to 58 degrees inside. The storm was short lived, but our next campsite was still dropping to 31 at night. All day Solar was not bringing it back. It would try, but would shut off in just several seconds turning the water pump on. Another night without heat. We drove home 8 hrs, and the battery went up to 13.1V. Then we plugged it in at home, before taking another trip at sea level and no colder than 48degrees. The Alde and fridge  worked fine. We are thinking that the solar is not giving us a full charge. We already have shoved packing foam around the battery thinking it would help insulate it from cold. Since this didn’t work, what else can we do? We are not capable of moving it inside ourselves. Before we decide to pay someone to move it, what suggestions are out there? We’re thinking about adding some kind of heating, maybe a pad. Sounds like the propane tank would like to be warmed too. Anyone else solving this dilemma?

Grumpy_G

You might be conflating two things here, the fact that the battery ran empty and the cold temperatures. While LiFePo batteries do not like being charged at freezing temperatures they typically deliver power down to -4F. The power loss was more likely due to the battery just not getting recharged enough/not at all by solar. I'd start looking there first, before adding heating which just drains the battery even more.

Yoshi_TAB

Hi,

A couple of questions if you happen to know;  1.  Was your battery fully charged when you left on your trip?  2.  How many days into your trip was it when the Alde and fridge shut off? 3.   What was the outside temperature during your trip before you lost power?  Depending on your battery BMS, it may have shutdown charging if the temp. was below the shutoff threshold.  At that point, you would not get any charge from the solar, even if there was full sun.   4. Do you have a smart shunt and can provide any historical data up until you lost power?  Can you provide any screen shots from the solar history ?

As @Grumpy_G, says, adding heat wraps is easy, but any device that produces heat, especially electrical heat (either 12V or 110) will be a energy hog.

Horigan

Also, was the charging profile for the shore power charger and solar charger changed to the LiFe profile?  If not, that would prevent being able to fully charge the battery. 

WayneW

I suspect @Grumpy_G is on to the cause.  The solar angle this time of year is quite low and even with full sun you would likely not get the full capability of the solar panels.  You were probably in a deficit situation from the start and the batteries finally got so low that the BMS shut things down.  A heating pad would only consume more power, making things worse.

We recently camped at about 7000ft with lows in the 30s.  One night it got down to 20.  I have a Victron Battery Sense on our 100 ah Lithium battery that is in the front tub in a lightly insulated box.  The lowest temp the battery ever got was 3 deg C (37 deg F).  I doubt your BMS hit the low temp cutoff, and even if it did, it would have warmed up enough during the day to allow the solar panels to charge.  But again, with the low solar angle you probably never gained back what you lost.  And the Victron solar controller requires the solar output of the panel to be at least 5 volts more than the battery to kick in so that was likely a limiting factor as well.

You could get more solar capacity, like a portable suitcase, or perhaps a small generator.  I have a DC-DC charger mounted in the tub and I could hook it up to my truck and run it for a while if need be.  It's a challenge to go on a 3 week trip and keep everything going - even more so this time of year!

pthomas745

You need to be specific about your battery.  If the battery reached its "low discharge cutoff", it may have just cut off.  If it has a "low temp charging protection" it may not have charged below a certain temperature. You do not mention a Victron app, a multimeter, etc.

Some details on the battery will help.  Details from your Victron will be useful: are your settings correct for a lithium battery?  Are your panels actually working? 

And: what exact battery is it? 

Marceline

Grumpy_G said:

You might be conflating two things here, the fact that the battery ran empty and the cold temperatures. While LiFePo batteries do not like being charged at freezing temperatures they typically deliver power down to -4F. The power loss was more likely due to the battery just not getting recharged enough/not at all by solar. I'd start looking there first, before adding heating which just drains the battery even more.

I agree with Grumpy. I camp year round in California, but from September to April you have to carefully monitor your battery. If you have a 2022 I assume that you have the Victron SmartShunt or BMV 712. You need to use it to watch how much power is going into the battery and how much power you are using. It's really easy to fall behind when there's less sunshine. If you did 3 weeks in the Eastern Sierra and you never plugged into shore power you were probably running a bit of a deficit every day and it finally caught up with you. 

otr_320

Agree with @pthomas745, basic battery/system data is needed to move forward with your core problem, @KC_Camps.  Without it, you're operating, troubleshooting blind.  Data from a bluetooth capable BMS/battery, a battery shunt, or a few strategic before & after voltage/current checks would be very helpful in this regard.

@KC_Camps, you asked about heating pads.  Heating the exterior of a lifepo4 battery case with small silicone heating pads is a very viable option.  We used to have a 200ah lifepo4 battery we exposed regularly to sub-freezing temps.  Heated this battery using 4, 80x100mm 24w silicone pads wired series/parallel so they only drew 2a/12vdc (24w) of total current. They were able to maintain the battery/cells between 45-50f (via thermostat) when exposed to ambient temps as low as 0f.  For what it's worth, 2a (24w) is the typical parasitic/no-load current for many 2000-3000w inverters, so a very low draw comparatively speaking.  Also, keep in mind the pads would not operate on a 100% duty cycle (2ah consumption) unless ambient temps were near 0f.  With higher ambient temps (i.e., 15-20f), overall consumption would typically drop below 1ah---roughly equivalent to turning on a couple of lights inside our 320.

If there hadn't been available space in our '23 320's passenger-side wheel well, we wouldn't have hesitated using heating pads to keep our new 304ah lifepo4 battery warm in the front tub.  However, for us, relocating the battery to the passenger-side wheel well offered a number of advantages that went beyond just protecting the battery from extreme temperatures.  It:  1) lowered our tongue weight, 2) provided the opportunity to replace/shorten the excessively long OEM battery/battery-disconnect/power-center/converter wire run---significantly reducing voltage drop, and 3) allowed the battery to be located next to our inverter/charger significantly reducing cable length and costs.  Even with the battery located inside our 320 . . . we still installed heating pads just to cover every eventuality.

bjn2

I'm in the process of moving our 100AH battery inside the trailer. As you noted, the temp inside the trailer likely stays above freezing just from body heat. Our battery protection cuts off charging at 32 deg. F, and will deliver power until temps hit 14 deg. F. You could look at using a portable solar panel that you can orient toward the Sun for better power capture in the winter to supplement the built-in solar. 

KC_Camps

Thank you for all the helpful comments. We are in such a steep learning curve! We think the battery was full before the 3-week trip, but did not have the Smart Shunt yet. We see what you mean about Fall camping in the Eastern Sierras and we were in canyons and next to 10,000-12,000 ft mountains. We do have a Rockport portable solar panel to charge a battery like a Jackery, (Wattfun). I thought we could plug it into the battery via the extra plug supplied, but then think we were told by Nucamp we would need another converter? That was too confusing, so we dropped it for the time being. We got a Shunt and started learning, but after a big rainy storm, it quit working. It’s in the front bin, but not in any covering, so maybe got too wet? We will reread all your comments many times and try to get a better handle on how to use the battery, understand BMS, And the Shunt. We are thinking that stopping for a day or two at a campground with shorepower and a great idea. Our battery is a

Marine Grade 12V 206Ah LiFePO4 Battery,Sealed Plastic Box

sorry about font, I copied it from website. Bought it from Will Prouse after watching a bunch of his videos. Those guys will talk to us over the phone, so will ask them about BMS and the Smart Shunt and maintaining battery over 3-week camping vacations. Will gave specs on the Victron App settings, so we will check and make sure what they are and if we have them correct. The DC-DC generator idea is way over our heads at this point, but much appreciated. Helpful points about battery heat pads. Moving the battery and Shunt inside seems like a good idea. We will look into cost. We have a real good RV Maintenance shop that is expensive ($85/hr) but hasn’t gouged us and has been helpful in some trouble shooting things we can do ourselves. Thank you to everyone! 

Sharon_is_SAM

@KC_Camps - your shunt issue sounds familiar.  Ours went out after heavy rain and we found the fuse on the shunt battery supply was wet and corroded.  See here:  https://tab-rv.vanillacommunity.com/discussion/7396/victron-bmv-700-battery-monitor-display-troubleshooting

pthomas745

@KC_Camps yes, the learning curve, especially jumping into the "battery experience" part of the curve with a lithium battery is a shock.

Looks like you have the SOK 206AH battery, which many owners have purchased after a dose of Will Prowse.
One of the "learning curve" items is the fact that a lithium battery will be damaged if you try to charge the battery when the actual physical battery cells are below 32F.  The SOK has a "low temperature charging protection" circuit on the battery that will shut down charging when the battery reaches 32F.  That may have been one issue on your inability to charge.  Your idea of insulating the battery is a good one.  It will help.

There are many moving parts to your solar setup. 

You have a Victron Solar controller, and that provides access to the Victron App.  The App is the gateway to all things battery: battery state of charge, solar controller settings, charging history, etc.  You mentioned a state of charge of "13.1", but don't say where that number comes from.  A multimeter? The app? What tool did you use to get that voltage number?

The shunt is certainly nice, but if you don't have access to the controller via the App, there is no telling if your battery is actually charging.  There is a specific way a battery must be installed into a solar setup:  the battery must be connected to the solar controller before the solar panel is connected. 

So: we need to know if you have the Victron Connect app. (Sounds like you do) We can help with all of the setup needs on the controller and the shunt.  If you could show us the Status page (with the panels in the sun, at least) and the settings page, we will be able to tell right away what might need to be done.

https://www.victronenergy.com/panel-systems-remote-monitoring/victronconnect

And, of course, a multimeter is still a good tool for any battery situation like this. Yes, you can get battery voltage status.  In the absence of an app or a shunt, a multimeter is a perfectly good tool.  But, yes, more learning curve.

Your "extra" solar panel will need its own solar controller to connect to the battery for charging.  The "batteries in a box" can be used to connect to your trailer, but you would need to know: does your Rockport panel have a solar controller connected to the panel?  If not, then there are adapters that can be used to connect the panel to  a stand alone solar controller that would then enable you to connect the controller to the battery. 

Don't feel bad about being lost in a sea of jargon and bafflegab.  Everyone (well, me) started out without any experience with the actual job of maintaining a battery so it does what you need it to do.  Plenty of owners have gotten help in this group with the battery setup issues. 

rcarlson1957

@otr_320 - agree with you on heating pads. They work fine and aren't a terrible draw. I installed a 7x24 inch 12v pad and it's 78 watts. Only time it would be a problem if doing long boondocking and not much sun. Plus, gives me piece of mind when camping in shoulder season and you run into those unexpected overnight freezes. 

otr_320

rcarlson1957 said:

@otr_320 - agree with you on heating pads. They work fine and aren't a terrible draw. I installed a 7x24 inch 12v pad and it's 78 watts. Only time it would be a problem if doing long boondocking and not much sun. Plus, gives me piece of mind when camping in shoulder season and you run into those unexpected overnight freezes. 

If you're heating the battery case directly, 78w may overheat the cells (unless you're camping in sub-zero temps).  May want to consider using a thermostat.  We find 24w is enough to heat 4 304ah cells to approx. 50f with ambient temps as low as 0-5f.