Batteries: Li-on v. LiFePO4 - Slightly offtopic

[ChuckD]

Hi,
This is about the relative merits between these two chemistries, but for the purposes of home power backup. But I figured there's some overlap, and some here might have a different insight, and more honest, than the industry itself.
I'm actually looking for a definitive comparison. I'm looking for storage on the order of 16 to 22 kWh.
Any thoughts on the plusses and minuses of either?

 

[vicv]

It really comes down to two things. Much better cycle life for the lifePO4. Much better capacity for size for the regular lithium ion

 

[ChuckD]

It really comes down to two things. Much better cycle life for the lifePO4. Much better capacity for size for the regular lithium ion

That's kinda what I thought based on personal experience with much smaller versions. LG clearly is biased toward Lithium ion, who I know as an otherwise reputable company.

 

[vicv]

How does LG figure into this? And what do you mean otherwise it a reputable company? I'm kind of confused that you threw that in there

 

[ChuckD]

How does LG figure into this? And what do you mean otherwise it a reputable company? I'm kind of confused that you threw that in there

Sorry, we're currently designing a solar PV system with battery backup for our home. A contractor we're working with sells LG batteries. He seems like a good guy. I have several LG products, including on my 3rd LG phone and am inclined to go with him. But then I see the specs LG lists for their batteries and their verbiage on battery chemistry shows a clear bias for Lithium ion and specifically not for LiFePO4.

 

[vicv]

Oh ya. Too bad about their mobile phone division. They make very good cells. Unfortunately lifePO4 has kind of been given up on and none of the big players are making them that I know of. So 18650s are still under 2000mah

 

[Nocturrne]

Hi,
This is about the relative merits between these two chemistries, but for the purposes of home power backup. But I figured there's some overlap, and some here might have a different insight, and more honest, than the industry itself.
I'm actually looking for a definitive comparison. I'm looking for storage on the order of 16 to 22 kWh.
Any thoughts on the plusses and minuses of either?

I prefer lifePO4 batteries for storage due to their relative safety - they are less likely to explode or ignite like li-ion. The dendrite formation in traditional li-ion batteries is unavoidable - it will happen eventually. If I used li-ion for storage, I would want them to be in a structure separate from my house, with active heating and cooling, similar to a Tesla liquid thermal regulation system.

 

[vicv]

I think people worry about batteries more than is necessary. I've gone out of my way to make lithium ion batteries explode. It requires gross negligence to do so.
All battery powered vehicles are using the same type of lithium ion batteries as we do. The high capacity type which are the most dangerous chemistry. And you don't see customers and Chevy volts exploding all over the place. They have 10-year warranties on the battery. I'm not saying that lifepo4 doesn't have some advantagements as it certainly does. I love the nimh/nicd like safety and flat regulation but with more voltage.
But regular lithium ion batteries are perfectly safe as long as the circuity is well engineered and built, and good cells are used.

 

[ikanode]

I wouldn't use Li-ion anyplace unless Weight is a major factor Because of safety problems.

Re: Chevy

GM recalls every Chevy Bolt ever made, blames LG for faulty batteries

Two simultaneously occurring defects will cost $1.8 billion to fix.

arstechnica.com

 

[idleprocess]

If I used li-ion for storage, I would want them to be in a structure separate from my house, with active heating and cooling, similar to a Tesla liquid thermal regulation system.

One thing I considered when I was contemplating a DIY large-scale energy storage system using Li-ion cells was simply burying the thing in a suitable metal container with an overpressure vent. My thinking was that soil would provide a decent heatsink on the external surfaces while a gravel or sand fill around the overpressure vent would allow for the sudden release of gas without major disruption of the terrain.

 

[ChuckD]

I think people worry about batteries more than is necessary. I've gone out of my way to make lithium ion batteries explode. It requires gross negligence to do so.
All battery powered vehicles are using the same type of lithium ion batteries as we do. The high capacity type which are the most dangerous chemistry. And you don't see customers and Chevy volts exploding all over the place. They have 10-year warranties on the battery. I'm not saying that lifepo4 doesn't have some advantagements as it certainly does. I love the nimh/nicd like safety and flat regulation but with more voltage.
But regular lithium ion batteries are perfectly safe as long as the circuity is well engineered and built, and good cells are used.

Then you may have missed this:

Fire risk causes GM to recall Chevy Bolt worldwide

General Motors has recalled its Chevy Bolt globally due to concerns that the electric car’s battery could pose a fire risk. The automaker noted a pair of manufacturing defects that could in r…

www.nydailynews.com

General Motors has recalled its Chevy Bolt globally due to concerns that the electric car's battery could pose a fire risk.
The automaker noted a pair of manufacturing defects that could in rare cases be problematic.
Friday's recall adds roughly 73,000 Bolts sold in 2019 through 2022 to a previous recall of 69,000 earlier model Bolts. Ford, BMW and Hyundai have also recently recalled cars that use lithium ion batteries.

 

[ChuckD]

One thing I considered when I was contemplating a DIY large-scale energy storage system using Li-ion cells was simply burying the thing in a suitable metal container with an overpressure vent. My thinking was that soil would provide a decent heatsink on the external surfaces while a gravel or sand fill around the overpressure vent would allow for the sudden release of gas without major disruption of the terrain.

Sound arguments for wanting to go with an LiFePO4 system like the Encharge that I can just mount on the wall in the basement.
Thanks.

 

[vicv]

Then you may have missed this:

Fire risk causes GM to recall Chevy Bolt worldwide

General Motors has recalled its Chevy Bolt globally due to concerns that the electric car’s battery could pose a fire risk. The automaker noted a pair of manufacturing defects that could in r…

www.nydailynews.com

General Motors has recalled its Chevy Bolt globally due to concerns that the electric car's battery could pose a fire risk.
The automaker noted a pair of manufacturing defects that could in rare cases be problematic.
Friday's recall adds roughly 73,000 Bolts sold in 2019 through 2022 to a previous recall of 69,000 earlier model Bolts. Ford, BMW and Hyundai have also recently recalled cars that use lithium ion batteries.

Oh I didn't miss it. If you read, that's a manufacturing defect. Not a lithium ion battery problem.
Tesla power walls are mounted in people's homes. I've charged thousands of cells. Never a fire, explosion, vent, anything.
Engines blow up sometimes. Are they dangerous? A mouse trap could hit your finger while setting it. Should those be kept out of the house? Anything can be dangerous.

 

[idleprocess]

Sound arguments for wanting to go with an LiFePO4 system like the Encharge that I can just mount on the wall in the basement.
Thanks.

The cycle life argument is a bit more compelling when it comes to actual professionally-engineered products. Although I've seen more than a few YOLO homebrew 18650 battery banks that I wouldn't want anywhere on my property, such is their lack of regard for safety - li-ion nor LiFePO4.

 

[orbital]

+

I looked into some LiFePO4 for my solar setup & couldn't believe the prices.
200Ah @ 24V was like $1700 or more

Very hard to justify that over standard lead acid.... just make sure you have a hand truck.

The voltage was another issue, really not standard voltage///tricky,
hard to get 29VDC spot on for charging from solar.
Not sure how much I'd trust the 'V Controller ' to give that number perfectly.

Don't mean to sound negative because I may look at it again later, if prices relax some.

 

[vicv]

Should always use a charge controller. And they will provide proper charging voltage

 

[idleprocess]

I looked into some LiFePO4 for my solar setup & I couldn't believe the prices.
200Ah @ 24V was like $1700 or more

Very hard to justify that over standard lead acid.... just make sure you have a hand truck.

Upfront cost per Wh for Li* chemistries is more than the faceplate ratings for lead-acid for sure. But there are at least two offsetting advantages for lithium chemistry I can think of offhand:

1. Li* chemistry can be discharged flat without impacting cycle life as opposed to lead-acid which might handle 50% depth-of-discharge
2. LiFePO4 will last far longer - maintenance free - than lead-acid

I also believe that the charging efficiency for Li* chemistry is roughly double that of lead-acid.

 

[orbital]

+

Had 720W of panels running today, this is nothing for some, I get it.
One thing that's a concern is trickle charging,, this will ruin AGM batteries with certainty, and Li-Ion should never be in a stand-by/trickle mode , that'll ruin them also.
Understanding LiFePO4 are different, the trickle charge (depending on weather) is a concern for longevity for something relatively uncheap
Lead acid may be less efficient, but there is no worry, none & it's not like getting a couple more is hard.

Really wanted to dive into LiFePO4, but I'm just not feeling it yet.
.......maybe next week lol

 

[idleprocess]

Understanding LiFePO4 are different, the trickle charge (depending on weather) is a concern for longevity for something relatively uncheap
Lead acid may be less efficient, but there is no worry, none & it's not like getting a couple more is hard.

As I understand it, lead-acid/SLA-replacement LiFePO4 batteries with onboard BMS can be treated like lead-acid with some penalty to lifespan. But I also gather that's for stable grid power. For a solar application you're apt to want to use a chemistry-specific charge controller.

 

[orbital]

.. For a solar application you're apt to want to use a chemistry-specific charge controller.

+

Solar panels are just a type of charger.

Regardless of the listed battery chemistry on the charger/maintainer/controller (or price $$$) if you try to trickle/maintain an AGM, it will ruin it.
Doesn't matter what the controller/charger/maintainer says. Trust me.

I fought AGM chemistry
My father fought AGM
My brother with his stupid $$$$$ charger/maintainer, fought AGM

All ended up an expensive hassle/failure.

Other than old fashion lead, most current batteries want to be fully charged quickly, then any charger taken off, disconnected fully.
From the smallest Li-Ion battery for your light, to some giant unit, leaving Li-Ion/poly on a charger will terminally damage them.

Invested in two Pecron E1000 units, they will run just about anything in my house, they take series voltage of 40V connected directly to the solar panels. The most Watts I'm seen them absorbing is 259W,, they can even do more than that!
They go out only when it's mostly sunny & put those to work daily running whatever I can
= bit of a chore/hobby and that's ok.

Also have a Samlex 24V inverter setup and a Samlex Europe solar controller w/ 2 lead acid.


Always nice to know I can EASILY fire up my little gas generator if I need to charge my E1000s' using gasoline ( via AC charger), when there is no sun. It's charger is more like a computer power supply, not just a 'brick'.