This is the the top page of my last page re the E-Ray 12 volt Li-Ion battery Doc. It was posted by Bear who lives in NH. It appears to me his contacts opened because of the Cold Protective Value in the BMS.
As noted he recorded the Voltage with time. 12.74 volts does not appear to me that would open the contacts:

What if the Battery Voltage Gets TOO LOW or Perhaps TOO
COLD Opening the Internal Contactors?
The Charger Instructions state this prevents the Charger from detecting there is
a battery connected. The Charger needs to RESET the UVP (Under Voltage
Protection.) Pressing the large RED Rest Button for 10 seconds should open the
UVP. Once open, the charger automatically starts the charging cycle.
A Forum Member recorded these values or his Stored E-Ray in Cold NH, no
charger:
December 2 = 13.30 volts
January 2 = 13.12 volts
February 6 = 12.99 Volts
March 11 = 12.74 volts: It went into Under Voltage Battery Protection. My
thought: My a combo low voltage and lower temperature that caused
the BMS to open contacts. All 12-volt Li-Ion batteries will open contacts and
disconnect the battery to protect it at some temperature.

He stated the Dealer tech said once started the battery was fine.

SIDEBAR:
Note, the minimum Cold Temp to open contacts can be freezing 32F. GM does not say.

Asked Google AI what the typical minimum voltage that would open contacts:
For a 12-volt Li-ion (specifically LiFePO₄) car starter battery, the Battery Management System (BMS) typically opens the circuit (disconnects) when the voltage drops to 10V–11V to prevent damaging the cells. This, commonly referred to as the low voltage disconnect (LVD).

 

can you say more about "any little bit of power" by using the override button??? I would think a voltmeter on the battery and connected in parallel to the NOCO box while in "override" would force an open circuit voltage of about 14-16 volts across the battery... Also, did you happen to ever measure the voltage (at say the frunk connector) at any time over your winter storage??? Still sounds like a battery that perhaps saw too low a voltage at some point and went into "under voltage protection (UVP)"...

Chevrolet has shared so little information about this battery... I've never even heard for sure that is of the LiFePO4) (Lithium Iron Phosphate) chemistry though most "think" it likely is... And built by??? Maybe by Chevrolet in their own battery factory??? One rumor...

So any feedback you can offer about the battery voltage at any time over the winter??? Or when the jump box was across the battery and in "override"???? thanks...

 

I dont see how its not covered by the bumper to bumper. Ill dig into that myself. Curious.


Operator error.

I exited my car in the garage in shuttle mode and never turned off the ignition is my best guess.

When i pulled the panel jumped mine with the noco in manual override it showed 11.3v so imo the bms opens the contacts around that figure.

 

OP

Did they pull the cowl panel and put the jump box to the battery AND MANUAL OVERRIDE it?

I wish I took video of when I did it but I was in a rush. It's so easy.

Can't imagine it's the actual 12v battery.

If you dont override these newer smart jump boxes they read zero volts and provide no power.

 

Yeah with the Noco jumpbox connected directly to the battery using the manual override it would give some power to the dash and turn the lights on for a short time before it will drain a fully charged jumpbox.

 

Understood about the shuttle mode... I understand it's your "guess" but very likely a good one...

And when you then used the NOCO across your battery, you simply went into "override" mode that forces the box to output voltage, then got in the car and simply started it, correct???

Just to say it, a guy "Bear" noted during his tests to see how low the battery could go in a cold climate before it quit, his shutdown at around 11.7 volts one day while he was sitting in the car. Had to use the mechancal door release to get out... He tried to wake his battery with two different, small CTEK chargers and neither worked... But when a tow driver came out with a large DeWalt jump box, that started his car immediately... Just reporting...

 

Any chance the battery tender might have been without power for some extended period of time over the winter???

 

True... My NOCO GBX75 says it "must see at least 3 volts" as a load or it will output ZERO unless and until you press and hold the "override" button for something like 10 seconds... Then it will force a 12+ volt output (and it warns that safety features like reverse polarity and so forth are disabled while in override)...

 

Getting nervous reading the posts about the 12V battery failure. I just picked up my new Eray this week. I did order the CTEK GM charger with the car. Plan to use it all winter. My car is stored in an unheated garage, can get to minus 8C some days in the winter. My question is, as long as the battery tender is being used all winter, will the cold temp still cause the battery to shutdown? Should not, is my opinion, with the tender working all winter and checked regularly. My 2003 had a regular battery and I never had an issue with in the same conditions, but I can see this new style battery is a different animal.
Thx for the input from a C8 newbie..

 

^^^
Good question. GM gives zero info on minimum temperature. Might be smart to use a small heater when getting near 0C!

Check out my Doc with more info than probably needed, but better than worrying!
https://netwelding.com/E-Ray_12_Volt_Battery.pdf

Think I would buy a car battery heater. This on Amazon is $24. OR buy a Jump Start Box for whatever reason the internal Contacts open!

 

Welcome and congratulations on your new Eray... Hope you enjoy your's like I've enjoyed my 25 Eray... As JerryU points out, GM has offered almost no information on the 12 volt battery other than it's a Lithium based battery... I don't think we even know for sure if it's LiFePO4 (Lithium Iron Phosphate) or some other Lithium chemistry but the best goes is yes, it is LiFePO4... And exactly how the Battery Control system works either inside or connected to this battery, we just don't know. I agree with Jerry that keeping the battery not only on a smart charger such as the GM supplied charger it sound like you bought but also with some sort of heater when stored in winter would seem to make sense... The battery might be monitored such that it might open the internal contactors and send the battery voltage to zero if it gets too cold... But we've never seen those specs so we just don't know for sure....

I own both the GM supplied (CTEK made) "1090 Corvette" charger. I also own the CTEK "Lithium-US" charger... I've used the 1090 charger a number of times but, based on input from others here, have never used the "Lithium-US" charger... For a while I was charging the battery to 100% every week with the 1090 charger... But I stopped that when some on here described the Lithium battery as having the longest life if maintained more at 80% charge... And for a LiFePO4 battery (assumption that's what we have) that is at 13.30 volts... That's where I find my Eray's voltage to be pretty much every time I check it... It sits day by day at 13.28 - 13.32 volts after letting it sit overnight... When I have put my battery on the 1090 charger, it comes up three the first three lights within one minute. Then it would typically take 3-4 hours to get to the 100% (4th light)... If you're going to store the car, that would mean you're going to be keeping it at 100% on the charger... Perhaps not the optimum voltage but still good and sort of your only (and best) choice for storing the car over a winter...

I'm considering contacting GM to see if they could/would give us some actual specs on this battery including how its battery management system works...

 

Any jump pack or any other 12v battery with 12 volts (ie a charged one) hooked direct to the battery + and - will get the battery out if uvp. Think of it like resetting a tripped breaker.

It's not that long maybe 5 seconds.

 

^^^^
With the two reports of the CTEK chargers (both GM Sold and dedicated for Li-Ion batteries) stated procedure NOT working to close open contacts on an E-Ray 12 volt Li-Ion battery, asked Google what pulse voltage/current is required. GM provides no guidance.

Google AI answer:
The activation pulse current required to wake a Battery Management System (BMS) typically ranges from a very low 0.07A to a minimum threshold of 2A, depending on the specific BMS model and manufacturer.

Common Activation Current Standards

• Minimum Threshold: Many popular smart BMS units require a detected charge current of at least 2A to trigger a wake-up state.
• Low-Current Pulses: Specialized "Recovery" or "Rescue" modes on smart chargers may use much smaller pulses, alternating between roughly 0.07A and 0.8A, to gently revive deeply discharged batteries without overwhelming the protection circuit.

Additional Requirements for Successful Wake-Up
Beyond the current, the charger must also meet specific voltage criteria to trigger the BMS:

• Voltage Differential: For charging activation, the charger's input voltage must often be at least 2V higher than the current battery pack voltage.

• Nominal Detection: Some BMS units need to detect a charging voltage near the battery's nominal voltage (e.g., ~14.4V for a 12V system) before they will allow the internal MOSFETs to reconnect.

 

to it it sounds like you got scammed

 

I sure feel like I got scammed. I had to use a towing company outside of the roadside assitance included with the factory warranty to get my car towed because the towing companies they sent wouldn't take car out of garage.

it's coming up on 1 month since the 12v battery has been ordered still with no updates.

I paid for towing and battery not covered under warranty. Was recently told they still have to make the battery.

 

I dont think it should take that long for a battery to come.
Also, did you get like something like a tracking code for it? Because if not, I'm 99 proc. sure you did get scammed

 

No tracking number I do have a case still open with GM care and they can't give me any information or timeline either. They are not even allowed to tell me who makes the battery for them and where it is coming from for me to contact myself.

 

Sorry you're still in this seemingly stuck place... Don't recall if you said before but did you or any tech ever just put a voltmeter across your 12 v starter battery to see what it reads??? 0?? Or maybe some low but still not zero voltage??? Zero would imply the internal contactors are likely open. Other voltages might suggest other situations... Do you know that value??? Be interested to hear...


Regarding the battery itself, I've also tried, without success, to get more information about the battery, even to try to confirm if the Lithium chemistry of this battery is LiFePO4 (Lithium Iron Phosphate) (what most guess it is) or something else.. For instance I bought the "Lithium-US" CTEK charger but I've never used it for a couple of reasons. For one, right on the first page of the manual, it says...

[size=13px]"The LITHIUM US charger model is designed for Lithium-ion batteries using LiFePO4 technology only. Please check with the battery manufacturer for details. Do not use the LITHIUM US charger for any other battery technology."

Also, several folks here suggested reasons for using, instead, the "Corvette (1090)" charger that GM sells as an accessory that I bought with the car... I've used it on my Eray but nothing else...

I think GM owes us more information about this battery, such as who makes it, what is the chemistry and whose Lithium cells are used internally... But, so far, nothing... [/size]