Freezing Concerns for LiFePO4 Batteries?

[rubicon327]

Originally Posted by beebobby

So if I'm reading the HubLion manual correctly, the charge temp range is -20 to 45c ( -4 to 113F) . They list the Storage Temp range as -5 to 35c (23 to 95f). 23F isn't very cold for here in mid-MO, but -4f is. My bluetooth Victron Connect app has been showing around 13v for weeks. We had a cold snap and temps have been in the teens. 2 days ago the app was at 11.37v. Yesterday it wouldn't pull up any data, so I assume that the batteries are pretty far down. Reading at the Zamp port is .17v. Could the temps have tripped a disconnect? 21C Single panel is covered, battery disconnect switch is in storage position.

With no charging source (solar or shore power) and cold temps the power consumed by the heating function will quickly take you down to low voltage cutoff (10V). According to the spec sheet the internal heater is on below 30F and will not turn off until the battery internals are above 40F. Attached is some info for a 100AH Batteborn heated lithium battery...should be pretty similar for any brand.

[John in Santa Cruz]

those heaters should not be using battery power, they are usually wired so they use your charging power.

[beebobby]

Don't have shore power to camper. Should I go ahead and give it shore power and flip the batt disconnect? If the battery heater needs shore power, will the batteries start charging once they get up to temp? Am I going to damage anything?

[John in Santa Cruz]

Originally Posted by beebobby

Don't have shore power to camper. Should I go ahead and give it shore power and flip the batt disconnect? If the battery heater needs shore power, will the batteries start charging once they get up to temp? Am I going to damage anything?

to accurately answer that would require knowing the specific battery and how its heater is wired and how its BMS operates, and also which side of things that battery disconnect switch is on.

[rubicon327]

Originally Posted by John in Santa Cruz

those heaters should not be using battery power, they are usually wired so they use your charging power.

John: I think that depends on the battery. Battle Born for example are not designed that way.

[Perry Butler]

Originally Posted by rubicon327

John: I think that depends on the battery. Battle Born for example are not designed that way.

Originally Posted by John in Santa Cruz

those heaters should not be using battery power, they are usually wired so they use your charging power.

Some like BattleBorn use battery power for heat, but others like SOK must have a charge source available for the heaters to work. Being SOK chose the available charge source route we chose not to get heated SOK batteries, but BattleBorns are too expensive for our taste.

__________________________________________________ ___________

We just spent two days without the portable charging, but getting 290 and 380 watts from the rooftop panel, those two days/nights we were down 50 ah’s. When we got to Gilbert Ray outside of Tucson, after plugging in, I pressed the Charge Wizard button on Progressive Dynamics 50 ah charger and noticed 20-25 amps at 14.45 volts going into our pair of 100 ah SOK’s. After being gone for 3-4 hours the one SOK had fully charged and the BMS turned charging off, and the other SOK’s BMS turned off about a 1/2 hour after returning. So I wasted money on a lithium specific charger, since it only took $15 to buy a Charge Wizard to charge the batteries. Since we’re hooked to a power pole here at Gilbert Ray, and the batteries are fully charged, I turned off the PD charger. The 160 watt panel on the roof will take care of our dc needs here.

Enjoy,

Perry

[rubicon327]

Originally Posted by beebobby

Don't have shore power to camper. Should I go ahead and give it shore power and flip the batt disconnect? If the battery heater needs shore power, will the batteries start charging once they get up to temp? Am I going to damage anything?

That sounds reasonable. If it is really cold you could also turn on a heat source in the trailer to help warm the batteries. I'm assuming with a 21C your batteries are in the stock location inside. The battery BMS should protect the battery from any damage. The real question is what do you do long term. If the battery uses its own power for the heater then you will be right back in the same situation again if the temperature remains cold. Lithiums don't like to be continuously on charge but I'm not sure I see an obvious solution other than providing shore power as needed. The lithium batteries with internal heaters seem to be a blessing and a curse depending on how they are engineered. I need to learn more but it appears that Battleborn will draw itself down to warm itself even without a charging source. It sounds based on your experience that the HubLion is similar to the BattleBorn.

[rubicon327]

Originally Posted by Perry Butler

Some like BattleBorn use battery power for heat, but others like SOK must have a charge source available for the heaters to work. Being SOK chose the available charge source route we chose not to get heated SOK batteries, but BattleBorns are too expensive for our taste.

Perry: Interested in your specific use case and thoughts on this. It seems that heated batteries like Battleborn that could take itself down to low voltage cutoff just keeping itself warm is a huge disadvantage. Unless there is a constant charging source they are going to run down quickly whether inside a cold trailer or outside. It seems that a sequence of the BMS recognizing a charging source, warming the battery and then charging would be preferred (especially if one has solar). If there is no charging source the heater would remain off. Maybe I'm missing something.

[Perry Butler]

Originally Posted by rubicon327

Perry: Interested in your specific use case and thoughts on this. It seems that heated batteries like Battleborn that could take itself down to low voltage cutoff just keeping itself warm is a huge disadvantage. Unless there is a constant charging source they are going to run down quickly whether inside a cold trailer or outside. It seems that a sequence of the BMS recognizing a charging source, warming the battery and then charging would be preferred (especially if one has solar). If there is no charging source the heater would remain off. Maybe I'm missing something.

I probably should have added we boondock, so no charge source. I’ll be locating our batteries underneath the dinette where they are easy to remove (not so with our 5.0) for Minnesota < -20 degree winters.

There are two different scenarios here:

• Using a charge source doesn’t work for us, since we boondock (SOK), but works for those at sites with electricity.
  
  
• Self heating would work, for boondockers, but Battle Born’s are too expensive for us and we can get by without.

People should understand the differences between the two choices.

Enjoy,

Perry

[beebobby]

Blew warm air into the batt compartment via ext hatch. When batt compartment got around 40F, flipped batt disconnect off and turned house breaker that feeds shore power to rv on. When surge protector cycled through, the Victron showed 5.3V. After cycling on/off a couple of times the Vic panel is showing 13.47V at 7.3 amps. 100% charge. I'm confused.

[beebobby]

I would pull the batteries, but it would be a real PITA (see picture).

[beebobby]

Just checked on things. BMV 712 is now cycling, starting at 12.4v and slowly coming up to about 13.4, then starting over. Showing 50A and 680 watts, 100% Still confused.

[rubicon327]

Originally Posted by beebobby

Just checked on things. BMV 712 is now cycling, starting at 12.4v and slowly coming up to about 13.4, then starting over. Showing 50A and 680 watts, 100% Still confused.

Not sure about the cycling but 50A would be about what the stock charger would be putting into the batteries. By the way Hub Power says “our batteries recognize when the cells are under temperature and when a charge source is applied, and then activate their heating circuit. The power for the heating is drawn only from the charge source. They will not self-consume for heating.” This is a good thing for your circumstances. Forget about the Victron for a moment. Can you turn off charging and put a multimeter across the pos and neg on each battery separately and read a voltage?

[beebobby]

Since the batts are paralleled, I would have to disconnect them from each other to test, Correct?

[NEWYORKHILLBILLY]

Originally Posted by beebobby

I would pull the batteries, but it would be a real PITA (see picture).

wow I don't like the factory install at all. as per cycling some of these converters will shut down and restart if they are pushed over the amp rating. I dont think the air you put in to 40 would raise the internal temp that quick.as Rubicon stated if these have protection you should be able to plug them in for the winter. off course that might be ideal state of charge for storage. if it was me, I remove them for winter and store at 50% charge. at this point being your already plugged in and know the heaters run off the charge current. I leave it plugged in overnight and check tomorrow. yes, you have to disconnect the batteries to check voltage of each battery. The factory install sure does not make it easy to remove batteries for the winter. does that mounting board just sit in there or is bolted down?

[beebobby]

Just kind of sitting there. Seems to be stuck down along one edge on the shunt side, but wiring is so tight, it can't move much.

[beebobby]

It got to 50F today and it's going down to 10F tonight. Gonna leave it plugged in tonight and monitor it.

[John in Santa Cruz]

a 50A charge cycle of a 50% discharged 400AH Lithium looks like this...



the power was turned on where the voltage jumps from ~ 12.5V to 13.5V and current jumps from 0 to 45-50A, at about 12:00. The current bounces around 45-50 amps until the voltage climbs up to about 13.8V and the batteries are like 95% charged, then the current drops while the voltage shoots up to 14.6V. the spikes after the voltage hits 14.6V are the SOK Battery's BMS doing cell equalization.

here is the same time span showing state of charge adn voiltage.



here is the last hour of charging with those BMS cell equalization pulses expanded.

[beebobby]

Just received the temp probe for the Victron. PV is covered, but have not put the PV disconnect in yet. Shore power breaker in the house is off. Batt disconn switch is in the storage position. Can I install the new lug connection without a spark?
Thanks.

[John in Santa Cruz]

long as there's no large battery current, you should be fine to remove the cable to install the temp probe. If you have a victron smartsolar mppt, you can shut it off with the victron app.

bonus, once the shunt is configured to read the temps, you can link the smartsolar to it, and the solar controller will track the battery temp and tweak its voltages suitably. probably more important for lead acid than lithium