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?

Simple switch would do it. However solar likes to have a battery connected. Panels need to be switched off.

Prior to any disconnect from the controller or the batteries I’d suggest covering the solar panels so they make no, or little, power.

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.

Could just keep the battery warm.

Turning off the Charging Process | Good Sam Community

22 Replies

MrWizard
Moderator
Nov 09, 2020
PT
You did not
But is appears the OP did
First post says BB Lithium
I assume that means Battle Born lithium
pianotuna
Nomad III
Nov 08, 2020
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
Nomad III
Nov 08, 2020
phemens,

Sounds as if you did some good thinking!
phemens
Explorer
Nov 08, 2020
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
Explorer
Nov 08, 2020
Pluses then Minuses

Turns out to be negative?

Then the decision to live with the negatives is an obsession not a rational conclusion.
FWC
Explorer
Nov 08, 2020
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
Nomad III
Nov 08, 2020
There are devices that will measure temperature and turn on or off charging.

Of course, SiO2 do not need such devices.
FWC
Explorer
Nov 08, 2020
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
Explorer III
Nov 08, 2020
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
Explorer
Nov 08, 2020
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.