Turning off the Charging Process

[obiwancanoli]

After accepting the Limitation that I can't - and shouldn't attempt - charging my new BB Lithium batteries, it occurred to me that a few of the places I might like to go could get to freezing, or below, and gee, I could just turn off, switch off, or otherwise disengage the charging system so that I don't fry my batteries (no pun intended) if they somehow found themselves trying to recharge (I have Solar, and a generator).

Is there a way I can easily disengage the charging process at will, and reinstate when temps rise?

[MrWizard]

PT
You did not
But is appears the OP did
First post says BB Lithium
I assume that means Battle Born lithium

[pianotuna]

FWC wrote:

pianotuna wrote:
There are devices that will measure temperature and turn on or off charging.

Of course, SiO2 do not need such devices.

OMG!

If you read the OP and the 3 posts above you, they already have lithium batteries, and the batteries have a low temperature cutoff built in.

And where did I mention the make of battery? Not all LiFePO4 come with a BMS.

[pianotuna]

phemens,

Sounds as if you did some good thinking!

[phemens]

With Lithium you should only be concerned with charging after the thermal mass of the batteries has dropped below the minimum mfg recommended temp - there is no issue with discharging lithiums in cold weather, in fact they generally outperform other technologies in that scenario. For me that's roughly 0C, so I set the limit at 5C to be safe. I installed a waste tank heating pad taped to an aluminum sheet and put that under the batteries. Kicks in at 5C and turns off at 12C, without intervention, but I put in a cutoff switch for warmer weather anyways. Draws about 6 amps per hr. Victron monitor and temp sensor give accurate reading on battery temp and prevent solar from charging below 5C. I am completely off grid and it works great.

[MEXICOWANDERER]

Pluses then Minuses

Turns out to be negative?

Then the decision to live with the negatives is an obsession not a rational conclusion.

[FWC]

pianotuna wrote:
There are devices that will measure temperature and turn on or off charging.

Of course, SiO2 do not need such devices.

OMG!

If you read the OP and the 3 posts above you, they already have lithium batteries, and the batteries have a low temperature cutoff built in.

[pianotuna]

There are devices that will measure temperature and turn on or off charging.

Of course, SiO2 do not need such devices.

[FWC]

Exactly right. You don't need to do anything. If the batteries think they are too cold to charge, they won't charge. It is controlled by the internal BMS.

Also realize it needs to be below 24F for a significant amount of time for the batteries to activate their low temperature charge protection, they have a lot of thermal mass.

jkwilson wrote:

Tom_M wrote:
Battle Born batteries have a built in BMS (Battery Management System) that prevents charging at temps below freezing. No need to disconnect battery. You can still discharge well below freezing.

X2. The whole purpose of the BMS is to keep things from happening to the battery that shouldn’t. A BMS isn’t required to charge a lithium battery. It’s what is needed to make an acceptable lithium battery for use by non-technical consumers.

[jkwilson]

Tom_M wrote:
Battle Born batteries have a built in BMS (Battery Management System) that prevents charging at temps below freezing. No need to disconnect battery. You can still discharge well below freezing.

X2. The whole purpose of the BMS is to keep things from happening to the battery that shouldn’t. A BMS isn’t required to charge a lithium battery. It’s what is needed to make an acceptable lithium battery for use by non-technical consumers.

[Tom_M1]

Battle Born batteries have a built in BMS (Battery Management System) that prevents charging at temps below freezing. No need to disconnect battery. You can still discharge well below freezing.

[MEXICOWANDERER]

Some body should ask Deka of they build their arms 100 % in house.

[time2roll]

What does Battle Born recommend? I thought you could charge them slow so maybe carry a 5 amp charger depending on specification and conditions.

[capacitor]

I’m still not following. If you are connected to shore power, turn off the battery isolator. If you are dry camping, you aren’t charging them. If you run the generator, once again isolate the battery. I’m unfamiliar with Li but how do you charge them, wait until it gets warm? When you are driving, the batteries are charging. How do you do that, isolate them?

[obiwancanoli]

BFL13 wrote:
What is the exact scenario?

If you disconnect the batteries from the charger when it gets cold, you still need 12v from somewhere. That would be the converter if you have shore power.

No shore power? No battery because it is too cold? Now you need another battery that does work in the cold. (SiO2 says PT 🙂 )

Is the battery able to discharge (run loads) in the cold but just can't be recharged in the cold? (I am unclear how that is with Li)

So what is the scenario? Some have avoided this whole thing with various types of heating for their Lis to keep them in their operational zones. Not sure how you power those heater things off-grid when the batts can't be run without them. Kind of confusing!

Up to you to better describe the worrisome scenario here.

No problem DIS-charging, as in supplying AC via converter... the issue is in RE-charging. The tank warmers were initially meant to be attached, via adhesive, to water and gray water tanks, but are easily adapted to the battery bay. Further, my research suggests minimal amp needs to keep them going, and these have an on/off switch. Of course, the batteries would remain connected, for they're needed to power not just the tank warmers, but everything else inside.... and I'm thinking there will be times I'm not connected to shore power.

Reality is, I was exploring possible solutions, and looking for experience. I chose Li's for a number of reasons, and recognized early on that charging in colder temps would be problematic, but y'all are more experienced than this rookie (3 years in), and my hope was to find options I hadn't considered...

Installing the batteries inside would be ideal but for the fact there's no place to hide them except the ward in the bedroom, or, the drawers under the dining bench seats - valuable storage to sacrifice...