SOK Auto-Shutdown If Low?

[porkchopmountain]

I'm new to LiFePO4 batteries and I have my eye on the SOK 12V100Ah LiFePO4 Battery Bluetooth & Built-in heater battery. I've read that if you run the battery down to 0%, then it damages them.

Does the BMS protect against this and would it shut the SOK battery down before it gets low enough to damage it? Is this called the "BMS Low-Voltage Disconnect"? Do all SOK batteries come with this?

Thank You!

 

[LithiumSolar]

Yes, the SOK battery includes low-voltage disconnect around 10.4V (per their product page). The only pre-built LiFePO4 batteries I have ever seen that do not include this protection are those designed for engine starting.

 

[RVLiFe]

I'm new to LiFePO4 batteries and I have my eye on the SOK 12V100Ah LiFePO4 Battery Bluetooth & Built-in heater battery. I've read that if you run the battery down to 0%, then it damages them.

Does the BMS protect against this and would it shut the SOK battery down before it gets low enough to damage it? Is this called the "BMS Low-Voltage Disconnect"? Do all SOK batteries come with this?

Thank You!

The answers to your questions are Yes and Yes.
All BMS’s offer a low voltage disconnect that protect against low voltage but I would not want to rely on the BMS to do what you should be doing yourself. I feel a BMS is there as an insurance policy if something goes wrong but you should be monitoring your batteries voltage yourself and make sure it doesn’t get low in the first place. Please don’t think that you don’t need other forms of battery monitoring just because the battery has a safety protocol built in. I don’t have a built in Bluetooth in my SOK so maybe I’m just being paranoid? Maybe if mine had Bluetooth built in then I’d think differently.

 

[rmaddy]

Keep in mind that while the SOK's BMS will shutdown when the voltage gets really low, you should setup your other stuff to shutdown before the BMS needs to kick in. For example, a good inverter lets you set a specific low voltage disconnect. DC loads can be shutdown using something like Victron's Battery Protect, for example.

 

[porkchopmountain]

Keep in mind that while the SOK's BMS will shutdown when the voltage gets really low, you should setup your other stuff to shutdown before the BMS needs to kick in. For example, a good inverter lets you set a specific low voltage disconnect. DC loads can be shutdown using something like Victron's Battery Protect, for example.

It seems like the more I read, the more things I need to buy!

I read a little about the Victron's Battery Protect. It says for Li-Ion, to connect "the load disconnect output of the VE. Bus BMS to Pin 2-1". As far as I know, the SOK just has the two battery lugs up on top. How does one connect the SOK to the Victron Battery Protect if the VE. BUS BMS output doesn't exist?

 

[LithiumSolar]

It seems like the more I read, the more things I need to buy!

What inverter are you using? If it's programmable (like an MPP Solar or Growatt) you can configure the voltage at which it shuts down, thus eliminating the need for the Victron product.

 

[porkchopmountain]

What inverter are you using? If it's programmable (like an MPP Solar or Growatt) you can configure the voltage at which it shuts down, thus eliminating the need for the Victron product.

I'm not using an inverter. For now, I am just using 12v.

I suppose I should step back and give you some background on my setup/idea. I have a 12v fridge (uses ~.8Ah) that I would like to power when I'm in my trailer for the weekend. Long-term, I would like to add a few lights around the trailer too, but those would be powered by 12v as well. I don't have any plans to do anything with 120v. I also am thinking about adding a DC to DC charger so my vehicle can charge the batter, if needed. Or maybe add a solar panel so I can charge the battery in the middle of nowhere.

I'm getting a 100ah battery because I *think* it will be able to power the fridge for a weekend without a charge.

Thanks!

 

[rmaddy]

What inverter are you using? If it's programmable (like an MPP Solar or Growatt) you can configure the voltage at which it shuts down, thus eliminating the need for the Victron product.

The Victron Battery Protect must never be used directly for an inverter (or anything with big capacitors).

The Battery Protect would be wired between the bus bars and a DC fuse box. It would be there to prevent your DC loads from over discharging the battery.

The Battery Protect does have a relay. If you had an inverter with a remote on/off connection and the inverter did not let you set a specific LVD, then you could wire the Battery Protect's relay to the inverter's remote on/off. But again you must never directly wire a Battery Protect directly on the DC wire to the inverter.

I read a little about the Victron's Battery Protect. It says for Li-Ion, to connect "the load disconnect output of the VE. Bus BMS to Pin 2-1". As far as I know, the SOK just has the two battery lugs up on top. How does one connect the SOK to the Victron Battery Protect if the VE. BUS BMS output doesn't exist?

That's assuming you were using Victron's Lithium batteries. That would not apply in your case. Your only use of the Battery Protect would be to put it between your battery and your DC fuse box (which the fridge and lights go through) to prevent the DC loads from over discharging the battery.

If all you have is a fridge and some lights that you run only on weekends then this is probably overkill. Start with a full battery. Do your weekend trip, and you will be fine. As long as your battery can easily provide enough power for those few loads for your trip then adding a Battery Protect probably isn't useful. If your setup could over discharge the battery nearly every trip then adding one would be useful.

 

[MT_Mike]

I have two SOK 100AH batteries for our 20' travel trailer. I have my system set up with a heavy duty batter switch with one SOK permanently mounted and the other as a portable battery for external camp use or for trolling motor use. When boondocking I get 3 nights/days with one 100AH battery running lights, propane heater & refrigerator, and running 2 two C-pap machines. Two 100AH batteries support 6-7 days with the same amperage load. If I use a separate 96 AH battery for the C-PAPs I can run the trailer for more than two weeks with out recharging using both 100AH batteries. For our energy use, a portable 200w solar system will keep everything topped off nicely when boondocking for a week or two in one spot. I also installed a Victron 30 amp DC-DC charger and have a a 2AWG DC WARN winch connection (truck battery/alternator to back of the truck) to connect directly to the Victron charger which keeps one or both SOKs fully charged as we drive. This setup worked very well traveling to Alaska for 2 months this summer and I never needed to use the the portable solar charger or the 2KW generator the entire trip. The propane heater use was minimal as needed in the morning and evening. I am very happy with the performance of the SOKs. I will be installing external 25w heater pads with external temp relay controllers on both batteries too support low temp charging and battery using during fall hunting/fishing trips and winter travel between Montana and south west. The best diagnostic tools for my trailer is a good quality digital Volt/Ohm meter and clamp on AC/DC amp meter.