Are LFP prices artificially high?

A.Justice

Swears he didn't start that fire.
Cost is irrelevant to sale price.

market value is king.


profit drawn from building, marketing, future sale reduction pricing, etc.
I would be EXTREMELY surprised if sales were anywhere close to material and labor and manufacturing costs...
It's like the cannabis market. It costs MAYBE $50 to grow a pound of very high quality buds, and that pound can sell for $3k- $5k. People always complain about the markup of weed, but still pay high prices.

Why would a dealer charge less for a product that people will pay more for?
 

Hedges

I See Electromagnetic Fields!
For grid tied I think that's a bit optimistic.

I think it is reasonable for LiFePO4 (give or take a factor of 2, depending on brand/quality/compression)

With grid tie you would do a full cycle daily, subject of course to available sun. Undersize PV means more shallow cycles some days. Maybe battery lasts longer than 10 years? Oversize PV means full cycles, 90% or whatever you set to avoid knee of curve. Additional PV production goes straight to grid and doesn't get time-shifted to peak rate hours. Summer/winter PV production vary considerably.
If capacity does decline, you still use all it has to offer within voltage limits.

Off grid is where utilization is affected by matching of production and consumption. All power is use it/store it/lose it.

But maybe you're right. I was looking for test results, found one guy who said his 2000 cycle batteries dropped to 50% capacity after 6 years and 400 cycles:


If anyone here lost half capacity in 18 months and 400 cycles I think we'd be hearing about it. Maybe his conditions were more abusive.

Promotional brochure reports 2500 cycles 100% DoD at 1C dropping to 81% capacity.
Also, "0.3C charge/discharge @ 80% DOD achieved 6,000 cycles @ 80% nominal capacity" which would be equal to or greater total Wh compred to 3800 full cycles.


I'd like to see reports of independent testing.

Treating the cells gently, low charge rate and moderate temperature, together with staying between knees of curve should give long life. That's not the ideal usage model for EV applications, but for grid tied peak shaving, 0.2C (5 hour) charge and discharge of batteries kept climate-controlled would be typical.
 

wattmatters

Solar Addict
With grid tie you would do a full cycle daily, subject of course to available sun.
That's not what happens in reality. Daily capacity utilisation of a typical Powerwall 2 is about 60-70%. If you have two it'll be under 50%. A while back I surveyed a group of PW2 owners and the average capacity utilisation was a bit over 60%. No one was over 80%.

It would be rare that a battery of that size is cycled, on average, 100% every day. There are just too many days where inadequate solar charge is available, and days when the energy demand is low (e.g. occupants not home). Which all means it unlikely such a battery experiences a full charge/discharge cycle, on average, every day.

I'm not saying it's impossible, just unlikely.
 

wattmatters

Solar Addict
Undersize PV means more shallow cycles some days. Maybe battery lasts longer than 10 years?
Yes but you then run into other ageing effects. One might hope >10 years things are still good, but how much longer can one expect?

I'd like to see reports of independent testing.
There is the battery test centre in Australia:

Latest report, #10 in the series:

They cycle the batteries pretty hard, 2-3 cycles/day, so it's a form of accelerated stress testing, take that into account.

The outcomes on commercial battery reliability are woeful though.
 

Hedges

I See Electromagnetic Fields!
Yes but you then run into other ageing effects. One might hope >10 years things are still good, but how much longer can one expect?


There is the battery test centre in Australia:

Latest report, #10 in the series:

They cycle the batteries pretty hard, 2-3 cycles/day, so it's a form of accelerated stress testing, take that into account.

The outcomes on commercial battery reliability are woeful though.

Thanks.
They say some brands hold up well, while others show capacity fade, e.g. LG RESU-U "The data suggests a SOH of ~80% after ~1,430 cycles."
Sony doing better: "Capacity appears to have decreased linearly over time with a SOH of ~84% after ~2,965 cycles"

Even 3 cycles per day could be 0.25C charge and discharge, should be so stressing.
 

Hedges

I See Electromagnetic Fields!
It would be rare that a battery of that size is cycled, on average, 100% every day. There are just too many days where inadequate solar charge is available, and days when the energy demand is low (e.g. occupants not home). Which all means it unlikely such a battery experiences a full charge/discharge cycle, on average, every day.

I was thinking of a usage model where it discharges 100% (or whatever max/min you selected to avoid excessive degradation) by dumping into the grid. So not dependent on demand.
The usage model here is to store energy when produced by PV, deliver to grid during peak rate hours. Put 100% of PV into battery (unless it becomes full), then discharge all to grid.
 

wattmatters

Solar Addict
The usage model here is to store energy when produced by PV, deliver to grid during peak rate hours.
I see. Hence why you see value in arbitrage. Very uncommon here in Australia. Certainly no commercial battery permits this natively, only when part of a VPP with discharge controlled by the VPP operator.
 

12VoltInstalls

Solar Addict
It's like the cannabis market. It costs MAYBE $50 to grow a pound of very high quality buds, and that pound can sell for $3k- $5k. People always complain about the markup of weed, but still pay high prices.

Why would a dealer charge less for a product that people will pay more for?
That’s a little bit an ok analogy. But tunnel vision on the other hand.

Tunnel vision? Yes. Your analogy assigned an assumed needs/value to cannabis without reflecting cultural bias, addiction draw, and lifestyle factors.

The construct of needing batteries and objecting to our perceived over-margining of these batteries is a little different. For another angle, when I use my solar produced electricity I’m not looking for a box of snacks, bag of chips, or calling out for pizza…
 

Hedges

I See Electromagnetic Fields!
Yes but you then run into other ageing effects. One might hope >10 years things are still good, but how much longer can one expect?


There is the battery test centre in Australia:

Latest report, #10 in the series:

They cycle the batteries pretty hard, 2-3 cycles/day, so it's a form of accelerated stress testing, take that into account.

The outcomes on commercial battery reliability are woeful though.

Page 9 is a sea of red ink (battery failures.) Only a small fraction of the brands made it to test completion.

With so many single samples failing, we don't know if those which completed cycle testing just got lucky or that brand delivers consistently reliable product. Need results from a quantity of batteries to know MTBF. Or reports from all users, or a statistically valid sample.

Looks like lithium batteries for home use are a bleeding-edge product. Or many fly by night vendors.
Compare to EV, where a limited number of brands have relatively large number of cars on the road. Apparently their battery packs are mostly if not all good.

Regarding Samsung battery (which worked well up to almost 2800 cycles), "ITP believes that the SOC recalculation during the discharge cycle triggers standby mode and expects that these issues are due to cell voltage imbalances, which are typically exacerbated by aging."
People on this forum have said high balancing currents aren't needed, very slow active balancing is sufficient. Looks like higher rate balancing attempted to get more total Wh from batteries, but algorithm became unstable. Cells may have a cycle life and degradation in testing, but battery is a system that also has to work well.

"Redflow" flow battery - that's the sort I would hope could provide large capacity long term storage, because energy is stored in the electrolyte, in a tank. Similar to concept of a fuel cell, there is a component that allows chemical reaction and produces electricity, fed by storage of arbitrarily large capacity. But this one failed repeadly.

BYD: "In late August 2020, the battery’s internal DC breaker tripped during normal cycling and continued to trip after only a few minutes after reconnection to the SMA Sunny Boy inverter. BYD concluded that the battery stopped working due to the Sunny Boy Storage firmware being out of date and incompatible with the HVM battery. SMA and BYD were helpful and provided support to get the battery cycling again in November 2020. Since then, the battery has been cycling reliably."
I hate software.
My car has never experienced software incompatibility. Occasionally reports a failing sensor.
Interfaces between electronic boxes should use a communication protocol independent of software revision and backwards compatible, never breaking something that previously worked.

For grid tied I think that's a bit optimistic.

I would adjust it accounting for:
- portion of capacity that's sensibly useable
- reality that not every day will a battery go through a full cycle (low solar charge days, days not there etc), 60-70% is probably more realistic
- capacity will decline with age so and will creep up before getting 3500 cycles in

What you say is certainly supported by these test results.
Only the best of the batteries tested show they can reach the equivalent of 3500, 100% (original capacity) cycles (with capacity decline reducing actual cycle Wh)


The lithium batteries are showing round-trip efficiencies of 85% to 95%. Not as much higher than lead-acid as I expected, but this was at high C rates. Possibly lead-acid would perform even worse at those rates due to higher internal resistance. But June 2019 report says, "Round-trip efficiency between 85-95% had been observed for both the lead-acid and lithium-ion technologies, while linear extrapolation of capacity retention to date suggested that between 2,000-6,000 cycles could be delivered by properly functioning lithium-ion battery packs."


Prices in recent years for the batteries they tested have been $500 to $1000 per kWh, down from $2000 in 2015.
Compare the ~ $100/kWh for grade-B LiFePO4 individual cells bought by forum members.
If the DIY battery gave 3500 equivalent cycles, cost is $0.029/kWh, vs. commercial battery $0.145 to $0.29/kWh
That's about the price of wholesale utility generation vs. expensive market retail in the U.S.


"The capability of the manufacturer to diagnose faults remotely has proven valuable for some batteries. Ideally, this would not be required, but faults have proven common throughout the trial."
That makes you quite dependent on others, unless you can swap BMS and cells yourself.

Seems to me hot swapping of redundant battery assemblies is needed for reliability. Unless a brand is rock solid.
September 2019: "While some battery packs had experienced faults and/or failed prematurely, the Sony, Samsung, Tesla Powerwall 1, BYD, Pylontech, and GNB Lithium battery packs had generally demonstrated high reliability, with minimal issues encountered throughout the testing period."
April 2020, "The Sony and Samsung battery packs from Phase 1 have proven reliable, alongside the Pylontech and GNB Lithium battery packs from Phase 2."
 

A.Justice

Swears he didn't start that fire.
...."The capability of the manufacturer to diagnose faults remotely has proven valuable for some batteries. Ideally, this would not be required, but faults have proven common throughout the trial."
That makes you quite dependent on others, unless you can swap BMS and cells yourself.

Seems to me hot swapping of redundant battery assemblies is needed for reliability.
As much as I like the idea of remote diagnostic access, it scares me on some level, especially when dealing with a critical power system.

We have all seen what happened with the oil pipeline. The SolarWinds government hacks' seriousness was overlooked by many, if the government's servers aren't secure, not much actually is. People loose all their data (and business data) every day from malicious exploits.

Imagine a security breach at the battery company. Ransomware designed to shut off (or destroy, BMS settings could be altered to fry the batteries) the users power untill it's paid. Even on a smaller level, if the company can access your equipment remotely, so can someone else. Some f**k-boy neighborhood kid with a bit of tech savvy could potentially mess with your power system. There are people out there who do that kind of thing for kicks, and would love to cause some havoc.

Other than user-access system monitoring (no actual control) of systems, I wouldn't ever keep my batteries / equipment "on-line". I even disconnect my Bluetooth module from my JBD BMS when I'm done programming it.

Hot-swappable parts should be more or less standard on commercially available products anyway. I cringe every time I see Will Prowse having to cut into battery assemblies just to access the BMS or other small part. The ability to buy extra parts, and to repair at home are HUGE selling points for me. In most cases I would rather attempt to repair units quickly at home, rather than deal with a warranty, even if it's free.
 

wattmatters

Solar Addict
"Redflow" flow battery - that's the sort I would hope could provide large capacity long term storage, because energy is stored in the electrolyte, in a tank. Similar to concept of a fuel cell, there is a component that allows chemical reaction and produces electricity, fed by storage of arbitrarily large capacity. But this one failed repeadly.
I get the sense that more recent versions have improved on this. The issue for me with flow batteries is the low round trip efficiency. If RTE doesn't matter, e.g. you have so much solar it's going to waste anyway, then it's fine. But in a grid tied scenario where excess solar PV can be exported for at least some income, then diverting it to charge a battery and losing 40% of the energy along the way really hurts battery economics.

In Australia commercial residential batteries are far too expensive to make financial sense. The cost per kWh cycled is way more than the price differential between import and export tariffs. It's just cheaper to buy from the grid. There is an early adopter market of course, there always is, people who are less concerned with the money side and want the backup, the cachet, a sense of grid independence. In a couple of locations there are incentives to reduce the up front cost.
 

wattmatters

Solar Addict
Compare to EV, where a limited number of brands have relatively large number of cars on the road. Apparently their battery packs are mostly if not all good.
Just a comment on this. It might seem counterintuitive, but a cell in a typical residential battery is worked nearly an order of magnitude harder over its life compared with its cousin sitting in an EV battery pack.

What do I mean?

A typical cell in a residential battery might be cycled, on average, 70% daily. e.g. 10kWh battery, averages 7kWh cycled daily. 60-70% capacity utilisation is pretty typical for grid tied residential batteries in Australia. If you have sufficiently favourable grid arbitrage where you are, you might push that to 100%.

An EV on the other hand might be averaging 40km/day approximately while its battery pack has a range of 300-500km. On average, the EV is only cycling through 10% of its capacity daily.
 
Top