Lithium iron phosphate the choice for home solar?

softdown

We mostly hear about Li-ion. However I have concluded that LiFePo4 is the far superior battery for most home solar installations. This is why:
1) Uses iron instead of cobalt. Iron is much cheaper and far more environmentally friendly. Cobalt is not recyclable. 
2) Does not use nickel - which can experience unstoppable thermal runaway. Thermal runaway causes fires and the fumes are toxic when colbalt is part of the battery make-up.
3) Much greater cycle life. Roughly four times greater on average it seems. This is simplified but Li-ion is generally rated at 500 cycles while LiFePo4 is generally rated at 2000 cycles. 
4) Cheaper to make and buy. Iron is far, far cheaper than nickel and especially cobalt.
5) Much safer. Thermal runaway risk hardly exists. The toxicity of cobalt fumes are also eliminated.
6) Lower voltage translates to excellent mimicry of lead acid voltage. At 3.2 volts cell they are literally drop in replacements for lead acid batteries. 

They are much larger and much heavier than similar Li-ion batteries. Yet still much lighter and smaller than lead acid batteries. I don't see their increased size and weight as a major issue for the majority of home solar installations. 

**We will continue to be barraged by Li-ion. It is the best chemistry for laptops, smartphones, tool batteries, drones, and RC cars. Any place where high energy, and light weight in a small size are required. The ubiquitous 18650 cylindrical cell with Li-ion chemistry is unlikely to see anything but increasing usage in the market place. You can recognize this battery by its similarity to the AA battery though it is larger at 18mm x 65mm. Hence the 18650 designation. Recognize the Li-ion is also used in many other configurations such as prismatic (rectangular box configurations) and pouches. As well as AA sized all the up to cylindrical sizes that weight a few pounds each. 

For home solar? Many of us seek safety, longevity and economy. LiFePo4 offers those characteristics with a significant margin over Li-ion. 

softdown

After all the talk of lithium this and lithium that, the discussion should have been nickel and cobalt high performance batteries vs. the safety and longevity of iron batteries. 

Remember that poster that used to say we need to re-visit the merits of iron batteries? 

MichaelK

No thank you.  I'm already planning my next battery purchase.  They will be Rolls lead-acid.

mike95490

softdown said:

.......

Remember that poster that used to say we need to re-visit the merits of iron batteries? 

you mean the 50 year Nickle-Iron batteries  (NiFe) (that need an electrolyte change out every 10 years) or the Li-Iron batteries that are fire resistant ( LFP )

softdown

mike95490 said:

softdown said:

.......

Remember that poster that used to say we need to re-visit the merits of iron batteries? 

you mean the 50 year Nickle-Iron batteries  (NiFe) (that need an electrolyte change out every 10 years) or the Li-Iron batteries that are fire resistant ( LFP )

Both really. I had no idea that iron is the core material in LFP batteries until last week. Basically I knew about squat. LFP is a great solar storage chemistry when more size and weight are acceptable. What it loses in performance it gives back in safety and longevity. 

When talking lithium I think most are talking about 18650 NMC Li-ion. Nickel manganese cobalt is super high performance but there is good reason that Tesla fuses each cell. 

LFP are pretty darn safe unless someone does something stupid - same can be said for lead acid. 

Subwayman701

i bought 4  12v 200ah lfp batteries and working great so far.

mike95490

Subwayman701 said:

i bought 4  12v 200ah lfp batteries and working great so far.

Wired how ?  Series  Parallel  ?

Ampster

I just replaced a pack of used Nissan Leaf modules with 28 kWh of LFP. Cost about $125 / kWh. Wired 2P16S.

softdown

Used batteries are cheap! I'd have done that but I am prepping for ~20 years of not being able to buy in the marketplace. Rational would very likely get deleted. 

I'm building some of own - another couple were just priced too low to resist. 

If not prepping - I'd have stayed with lead. It works fine if not discharged too heavily and kept somewhat coolish (below 75F or better).

Ampster

softdown said:

I'm building some of own - another couple were just priced too low to resist. 

How much are those 18650s costing per kWh?

Dave Angelini

Doubting the softdown cares about having an insured structure for insurance. Many of us do not care offgrid, especially out west in wildfire prone areas where it is too expensive. Many put the insurance money into hardening for this.

For those who do care, be very careful with any of the lithium batteries. Inform your insurance company or take the chance they will cover you. It is not just the cell that must meet UL standards BTW. The whole battery must meet UL 1973 and UL 9540. Just went thru this with a local AHJ.

Batteries such as Tesla powerwall, LG chem, and a few others do meet these standards and also meet UN 38.3 for safe transport. 

Would be a real bummer if one of the 500 fires in this state right now caused a total loss and ....

Red flag is raised for the next few days due to dry lightning, high wind, and low humidity.

softdown

I'll  see that and raise it. The thing that stopped me from totally dropping out of this crazy society and living in Siberia is the expense of cargo boats. Modern society is  - enough to scare me into the dark woods of Siberia. That is as about as far from modern civilization as I can go. 

Why? Getting robbed every time I turn around for years and years has a lot to do with it. Now I am making Escalade payments for a contractor in Florida and being told to pay a $700 water bill - due to a leaky toilet? Another year of losses from hell - S. Florida landlord. 

Could be worse though. Could be a 2020 resident of Cali. 

Dave Angelini

We both love where we live in the State of Jefferson !   It must suck to have your problems. Good Luck !

softdown

Dave Angelini said:

We both love where we live in the State of Jefferson !   It must suck to have your problems. Good Luck !

Have not been robbed in the mountains in a bit. There is that. But S Florida is just killing me. Which it has been for years now. Cali is still a great state - geographically. Out of staters tend to only hear of fkd up politics and fiscal disarray. Fires, poop on the streets, Hollywood pedo's, high tech commies, water problems, mass exodus, Gov. Gruesome and the SF political Gambino crime syndicate - to name a few. I'd like to see it turn around myself, Cali stole my heart may times. I have vacationed there so very many times.

You are far removed from most of the problems. Glad you like it.

I'll stay in Colo if my neighbor doesn't decide to circumvent my electric fence. In fact my brother wants to move in with me. I have three "empty" bedrooms in the east wing - it might work.

jmb

I switched from Lead AGM to LiFePO4 this spring and so far I have zero regrets!  I have 4 24V 200 AH battery assemblies hooked parallel and in the mornings with fans and CPAP running all night I am usually about 85% full according to my Classic CC.  In the spring when no fans were running overnight I was usually in the low 90% range.

softdown

jmb said:

I switched from Lead AGM to LiFePO4 this spring and so far I have zero regrets!  I have 4 24V 200 AH battery assemblies hooked parallel and in the mornings with fans and CPAP running all night I am usually about 85% full according to my Classic CC.  In the spring when no fans were running overnight I was usually in the low 90% range.

What is CPAP?

Very powerful battery system you invested in. How much? Know the kWh rating? 

706jim

CPAP is a breathing device that helps people with sleep apnea, a condition where a person momentarily stops breathing while asleep. Hard on the heart.

jmb

Soft - I guess 800 AH would roughly work out to around 20 KWh and I have a little over $8k invested.

softdown

jmb said:

Soft - I guess 800 AH would roughly work out to around 20 KWh and I have a little over $8k invested.

Some people fail to adjust for moves to 12V and 24V etc, 20 kWh is huge in my book. I decided that my freshly ordered 5 kWh was not enough and bumped it to 10 kWh. Which is kind of like 16 kWh with LA since we can freely operate between 10% and 90% instead of 50% to 100%.

Nevertheless I'd have stayed with lead but these batteries will likely be stored 3-4 years until my LA expire. I am, perhaps foolishly, preparing for major disruptions in the supply chain. And an inability to purchase in the marketplace with the "biochip".