Where there is smoke, there is Fire

[awpatterson217]

It sounds like there was an internal short in one of the cells. Perhaps unsuitable wires/connections were used in an effort to save money and one took a while to fail. Considering the batteries were in storage, this doesn't sound like user error. Give the OP a break.

 

[MurphyGuy]

Your battery experienced a geography problem called China.

 

[wattmatters]

can eco worthy be connected in series?

Yes, at least according to advertised specs, up to four in series:

LiFePO4 12V 8Ah 24Ah 100Ah 150Ah Lithium Iron Phosphate Battery

ECO-WORTHY LiFePO4 12V Lithium Iron Phosphate Battery has twice the power, half the weight, and lasts 8 times longer than a sealed lead acid battery, no maintenance, extremely safe and very low toxicity for environment. Our line of LiFePO4 offer a solution to demanding applications that require...

www.eco-worthy.com

 

[HowlerMonkey]

What if one of the two paralleled batteries was highly discharged and the other fully charged and then put in parallel.

 

[Supervstech]

What if one of the two paralleled batteries was highly discharged and the other fully charged and then put in parallel.

Who are you directing this question to?

 

[HowlerMonkey]

Since you answered, then I guess the question is for you.

 

[curiouscarbon]

What if one of the two paralleled batteries was highly discharged and the other fully charged and then put in parallel.

The fully charged battery will charge the highly discharged battery. The number of amps will be directly determined by the internal resistance of the two batteries.

Many battery available today have an internal resistance that is low enough that the high number of amperes (amps) will result in some degree of damage to one battery or the other.

Lower internal resistance will result in higher amps. Higher internal resistance will result in lower amps.

Hope this helps, happy to try to address any follow up questions.

 

[HowlerMonkey]

That was my angle but was posted as a question rather than the hint it was.

 

[Leeds]

Two batteries wired in series, connected to two other batteries wired in series

So with four batteries in series you were setting this up to be a 48v system?

It seems likely that the damage occurred the last time you charged it.

 

[Geoff-AU]

One of the insidious failure modes of lithium batteries is being over-discharged. If you discharge a cell below 2V, the copper current collector(s) start dissolving in the electrolyte. The copper can then plate out later when the battery is charged, and possibly form an internal short. If the battery is charged when the short happens, up it goes.

It's also possible that a BMS component failed. The "disconnect" MOSFET needs to withstand the voltage rating of the entire pack which is why some batteries can't be put in series, and some can only be put in series up to say 40-60V. Depends on the MOSFET rating. MOSFETs usually die short circuit, which means you have no protection any more and the pack can then be easily overcharged or over-discharged, leading to the failure mode above.

Certainly there's a strong argument for only buying good quality LiFePO4 batteries. This is not an area where shortcuts are well tolerated, and there are a TON of power tool batteries around with very very cheaply designed internals (I've seen enough to be concerned). My neighbour's had one of his power tool packs catch fire in the middle of the night. Kinda scary!

 

[Skypower]

I wanted an early warning so I added these two to the hardwire of the whole house. One is a heat detector and the other is a combination photo/ionizing detector. I got these and 14/3(3+ground) Romex at Lowe’s.
Since there’s no internal combustion engine in the garage I’m not worried about false alarms. It is sensitive, 7 feet below I was heat shrinking 32 balance leads with an heat gun and I guess the adhesive lined tubing emitted some fumes I couldn’t smell. Well, every cat in the house thought the world was ending. Yah, the system works.

 

[curiouscarbon]

love the sensors approach!