Freeze protection BMS?

[pretzel]

I have a 4s LFP in an RV. Looking for a BMS with separate charging input and low-temperature protection.

Any Suggestions?

[Here is my long winded legacy post:]
>>>
I have a DIY LFP battery made of A123 cells and a 100w solar panel in a Westie camper.

I'm concerned when it gets close to freezing, the battery might be damaged.

I do have a 12v resistance heating pad salvaged from a seat heater, and maybe could fashion a simple thermostat to power up the heater when the temperature drops.
One failsafe might be to power the heater directly from the solar using a thermostat circuit, thus not pulling down the battery.

Already sounding a bit complex and prone to failure.


Starting to think it's simpler to have an automatic thermal cutoff to the solar circuit (and alternator feed)
and maybe a manual switch to the heater pad so I could warm up the battery manually if necessary

What are the best approaches to automatic cutoff?
I don't currently have a BMS since all my loads are running through a Victron solar controller load output (and inverter with it's own low-cutoff protection)

So maybe add a BMS with separate charging input. Bonus if the BMS has temperature sensing cutoff, too!
System maximum draw is probably around 50A (but realistically closer to 30A)

Suggestions for a 4s LFP thermal sensing / protected separate charging port, BMS?
Thoughts?
<<<

 

[Johnny]

Hi Pretzel,

I can't answer your question about BMS as I don't have sufficient knowledge, but recently I needed a device that would turn on fans when a certain temperature had been reached, you could use something similar to turn on your heat pad. The link below is a 12v version but they also have AC mains versions as well. There are many other types of these devices as well that have AC sockets integrated.

Temperature 12v Controller
Temperature AC Controller

John

 

[Offgrid97]

I have a 4s LFP in an RV. Looking for a BMS with separate charging input and low-temperature protection.

Any Suggestions?

[Here is my long winded legacy post:]
>>>
I have a DIY LFP battery made of A123 cells and a 100w solar panel in a Westie camper.

I'm concerned when it gets close to freezing, the battery might be damaged.

I do have a 12v resistance heating pad salvaged from a seat heater, and maybe could fashion a simple thermostat to power up the heater when the temperature drops.
One failsafe might be to power the heater directly from the solar using a thermostat circuit, thus not pulling down the battery.

Already sounding a bit complex and prone to failure.


Starting to think it's simpler to have an automatic thermal cutoff to the solar circuit (and alternator feed)
and maybe a manual switch to the heater pad so I could warm up the battery manually if necessary

What are the best approaches to automatic cutoff?
I don't currently have a BMS since all my loads are running through a Victron solar controller load output (and inverter with it's own low-cutoff protection)

So maybe add a BMS with separate charging input. Bonus if the BMS has temperature sensing cutoff, too!
System maximum draw is probably around 50A (but realistically closer to 30A)

Suggestions for a 4s LFP thermal sensing / protected separate charging port, BMS?
Thoughts?
<<<

Battery Controller S516 150A/750A | Energus Power Solutions

Battery Management System. Compact, yet powerful and feature-rich. Cell voltages, temperature, current and logs are available over communication line.

www.energusps.com

Here is a BMS that does exactly what you are looking for. Pretty pricey but a ton of features.