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LiFePO4 Battery Warmer Install

Yeah I agree, you just need to make sure that the charge controller is a type which has low temp cutoff (with battery temp probe), or the BMS has a low temp charging cutoff (with battery temp probe) so any charging isn't allowed on the circuit below freezing temp. That would be your only safeguard. Even a manual battery disconnect you shut off when you button up the place and leave it for Winter til Spring...
If the battery will not be charged and is "without any load", why heat it? It should be fine to sit in storage.

Aha, so the battery can be stored at low temperatures?

It’s not super important, but I have a little dream to have a web camera going over the winter.

I’ve also been contemplating setting up a generator with auto start. But it’s risky since it’s out on an island and when the ice forms in the fall and when it goes in the spring, there can easily be 2 months at the time when nobody can get there…
 
Aha, so the battery can be stored at low temperatures?

It’s not super important, but I have a little dream to have a web camera going over the winter.

I’ve also been contemplating setting up a generator with auto start. But it’s risky since it’s out on an island and when the ice forms in the fall and when it goes in the spring, there can easily be 2 months at the time when nobody can get there…

Well as HRTKD said last post before yours, he looked up the storage sitting temp on that and it said -20° C so if it goes lower than that then not sure how bad that would be for the battery. It may or may not be 'super bad' or not, just you'd be testing to see what the actual life would be I guess.

What about what he said about just trucking the batteries out of there with you when you leave?

Or other option of course is you could just put some AGM batteries out there but they might not last either because they would eventually drain low volts without good float on them, and kill them prematurely (based on that minimal Sun you get)...

BTW, beautiful pictures, the sunset is cool right on the horizon...

I still would prefer the method of just trucking the batteries out of there when you button the place up and batten down the hatches...
 
Each of my batteries (4s 280Ah) uses two pads, one on other either of the long sides. Each pad is rated for 1 amp @ 12v, so ~24 watts total. For my RV trailer, it turned out just right. The batteries stay in the 34° F to 45° F range and the impact on the battery state of charge is small enough that I don't worry about it any more. My trailer would have to be without sun for a week before I would begin to be concerned.
As to the 24W I'm wondering where the bank is in your trailer and how much heat they may have from the furnace?

One thought I have is using more wattage and controlling it with a rheostat so the cells don't get cooked.

I may run a duct from the furnace but that would be back up and only used when the trailer is occupied.
 
As to the 24W I'm wondering where the bank is in your trailer and how much heat they may have from the furnace?

One thought I have is using more wattage and controlling it with a rheostat so the cells don't get cooked.

I may run a duct from the furnace but that would be back up and only used when the trailer is occupied.

The compartment is below a cabinet in the bathroom. The compartment itself is not directly heated, but a furnace vent does go through the compartment. It stays warm enough when the furnace is active that I usually turn off the warming pads. When the furnace is off the pads are on.
 
Well as HRTKD said last post before yours, he looked up the storage sitting temp on that and it said -20° C so if it goes lower than that then not sure how bad that would be for the battery. It may or may not be 'super bad' or not, just you'd be testing to see what the actual life would be I guess.

What about what he said about just trucking the batteries out of there with you when you leave?

Or other option of course is you could just put some AGM batteries out there but they might not last either because they would eventually drain low volts without good float on them, and kill them prematurely (based on that minimal Sun you get)...

BTW, beautiful pictures, the sunset is cool right on the horizon...

I still would prefer the method of just trucking the batteries out of there when you button the place up and batten down the hatches...

Thanks!

It’s in the archipelago, but I can take them by boat in the fall. At least the first year or two when I get to know them and figure out what can be done from an heating perspective.

It’s windy out there so one alternative is to get a mid sized wind turbine. But at the same time, I fear that they need a little maintainable every now and then…

Another is to just have an automatic generator that starts by itself and fills up the battery, if it’s enough to do it once or twice per winter.

I recon it ultimately depends on what type of isolation factor I get from the storage. We have a lot of time on our hands when we are out there, I could dig down and cast something under the house.
 
Thanks!

It’s in the archipelago, but I can take them by boat in the fall. At least the first year or two when I get to know them and figure out what can be done from an heating perspective.

It’s windy out there so one alternative is to get a mid sized wind turbine. But at the same time, I fear that they need a little maintainable every now and then…

Another is to just have an automatic generator that starts by itself and fills up the battery, if it’s enough to do it once or twice per winter.

I recon it ultimately depends on what type of isolation factor I get from the storage. We have a lot of time on our hands when we are out there, I could dig down and cast something under the house.
I'd skip solar up there.

Maybe wind, or an autostart generator. NREL doesn't even rate the solar insolation.

Even in July, you're bordering on minimal solar.
 
The autostart generator may work, but what if it doesn't?

A neighbor near our cabin was sold an AGS solution that would keep their solar running over the winter when no on was there. AGS didn't work, and $2000 of AGM batteries went to zero.

I think AGS is an OK thing to have for convenience, when you don't want to interrupt the poker game to start the generator. For dead winter when no one is around, don't use an AGS. You need a different solution engineered into your design, like shutdown. Just sayin'.
 
I would give the AGS a go. Two generators could be used if critical. Small wind would not hurt either. System should be designed to just shut down if support fails. I assume human life is not in jeopardy here. OK you could kill the battery and require replacement next year. Some data may not be collected. Is there communication to send a signal if a failure sequence has begun?
 
Many thanks guys for all valuable input!

It is interesting, we have an ice cellar that is about 6 feets under ground and about as much over it (built in a slope). I opened the roof of it today so that it can be filled with snow, and the temperature was above zero despite November and December being really cold.

My plan will be to first set up the system to get it up and running but to bring in the batteries next fall, and then in the future add both a turbine and a generator with auto-start while also exploring building some kind of isolated storage.

The Cabin is in the very north of Sweden close to the Finish border (see red X down to the right), so we get a ton of sun in the summer (almost 24/7) but no sun winter time:
1640708408584.png
 
Anyone have experience of using a wind turbine in winter conditions? Does it require a lot of maintainance?
 
It is interesting, we have an ice cellar that is about 6 feets under ground and about as much over it (built in a slope). I opened the roof of it today so that it can be filled with snow, and the temperature was above zero despite November and December being really cold.
If you could put your batteries below the frost line - like your cellar - your problem would be solved. No wind turbine, generator, AGS.... If the subsurface earth is keeping your batteries warm enough, you don't have to worry about something breaking down.

I realize this may not be possible, but it would be a way better solution if it is possible.
 
Anyone have experience of using a wind turbine in winter conditions? Does it require a lot of maintainance?

Years ago I saw a vertical shaft turbine running when there was 2' of snow on the ground. Don't know if someone cleaned it off.
 
It’s not super important, but I have a little dream to have a web camera going over the winter.
Maybe downsize your power needs? Instead of a web camera with live data/communications, could you add trail/game cameras? I have them for photos that last the winter on a set of AA batteries. You would save to memory cards and get them in the spring. For me, it's exciting to drive to camp to see what happened over the winter.

Another option would be a batch upload. You'd need a smarter camera, but could turn on every xxx days and upload to the web. That would be more power, but maybe you could do a weekly wake up, transmit the images, then go to sleep for another week. You could possible have enough battery storage for 6 months or so without charging. I haven't looked to see what's out there. Thinking about a small PC that has the script to upload from the memory disks when it's booted up. Maybe a raspberry pi could do the job?

You could use a timer for weekly bootup, or possibly sense power charging source to upload when there's a charge?

It's sometimes easier to live within your means (power wise) instead of increasing everything to meet your wants.

Here is an article on cellular phone based trail cameras. It mentions the standby mode is about .025a. I assume that's for 6VDC as the camera can run on 4 AA batteries. 12VDC could be almost .0125A.


Figuring on 12VDC, .025A, that would be about 5 months on a 100AH battery. This is a really small load. You may get by with a deep cycle lead acid battery and avoid the freezing problems of LiFePO4's.

At my camp, I do have some old deep cycle lead acid batteries for a horse fence charger 24/7, 365 days per year (Mouse deterrent). I power a small PWM solar charger off the campers power (LiFePO4) to trickle charge the lead acids. If the main camp LiFePO4's shut off due to cold/ low voltage/no charging possible, the lead acids will run the fence for a year without charging.

I understand this is heading off topic from heating LiFePO4's. This can be moved to another topic if there are issues.
 
Many thanks to this forum, a wonderful source of informtion and discussion. I installed a pair of Battleborn LiFePO batteries in my RV several years ago, and paired them up with heating pads for the winter. I never could get the heating circuit to work. Frustrated with Annod's 'Abeyant Temp Sensor,' this forum pointed me to digital temperature controllers. Just received and installed the XH-W3001! WOW! Accurate control AND power ON indication. So happy, especially since the tempareture is supposed to drop to the low teens tonight.
XH-W3001 Temp controller installed.jpgXH-W3001 Wiring diagram for Digital Temperature Controller_1.jpg
 
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Got a 48v 280ah battery to build for an off grid setup i plan to build when all the parts arrive. I will install heating pads somewhere as well. Need a circuit to supply power to heating pads only when an external power source is present such as geanerator or PV. Looks like some great workmaship by you all. I look forward to reading this entire post in greater detail.
 
Got a 48v 280ah battery to build for an off grid setup i plan to build when all the parts arrive. I will install heating pads somewhere as well. Need a circuit to supply power to heating pads only when an external power source is present such as geanerator or PV. Looks like some great workmaship by you all. I look forward to reading this entire post in greater detail.
A relatively simple solution: Buy the smallest Victron Battery Protect (60A or something like that. Have the output of that power your heating pads when needed. Set the cutoff of the Battery Protect at just below the Bulk / Absorption charge voltage of your battery. That way the heating will only have power when a charge voltage is present.
 
A relatively simple solution: Buy the smallest Victron Battery Protect (60A or something like that. Have the output of that power your heating pads when needed. Set the cutoff of the Battery Protect at just below the Bulk / Absorption charge voltage of your battery. That way the heating will only have power when a charge voltage is present.
I like it! Thank you.
 
Got a 48v 280ah battery to build for an off grid setup i plan to build when all the parts arrive. I will install heating pads somewhere as well. Need a circuit to supply power to heating pads only when an external power source is present such as geanerator or PV. Looks like some great workmaship by you all. I look forward to reading this entire post in greater detail.

Some of the Victron solar charge controllers have a Load port that be programmed.

 
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