LiFePO4 - The future for off-grid battery banks?

[steveg]

I saw the Latronics inverter in your picture and thought, here is yet another system in Australia or New Zealand.
As PNJunction said, thanks for the update. Your system is the oldest that I have seen an update on.


Looks like a perfectly sized LFP battery if you are running a generator with just over one days storage capacity (~15kWh). I would be interested to know how often you have to run your generator.

We have a smaller system and requirements, we have 1140W of solar panels, 360Ah@24volts LFP battery(~9kWh around three days storage capacity) installed in April 2013, 4kW inverter and no generator. Our winter requirements are ~2.5-3kWh and summer ~5-6kWh. Like you, cooking is done on induction hotplate and electric oven in summer and wood stove in winter.

If one didn't want to run a generator, now that solar panels are so cheap I would look at oversizing the solar array and decreasing the battery to maybe two days storage capacity.

If the battery lasts ten years I have calculated that the cost of storing power in our battery will be ~$0.40-$0.50/kWh, for your system I calculate around $0.30/kWh assuming you are storing around half you daily consumption.

Simon

Hi Simon,

Yeah system works well still - 6+ years in. Generator runs are only really in winter, and not every day. On a nice crisp day in winter we still get 12-14kWh power - anything less than around 7kwh the day previous then we would start the generator the next day. So in summer : we would only run generator say 2-3 times on horrible cloudy days - most cloudy days give us 8-12kWh ('summer' starting late August through early May) 8 months of the year.

Batteries have only been deep cycled (power dropped out) a handful of times say 20? maybe - otherwise everything well.

Our 'otherwise' cost would be NZ$0.30/kWh + NZ$1.00 per day connection fee - 10yrs 13kWh/day = NZ$3650 connection fee + NZ$14235 power ... nice.

So far it's been 6 (and a bit) years...

[miahallen]

steveg, thank you for staying active in this thread

[steveg]

Hi All,

Well it's almost been 12 years now - thought I'd update in my System and the LiFePO4 cells.

So our original solar panels were getting old so I sold them locally , and used the cash to offset new set of panels - so now have 6200W. Got an extra 60A MPPT regulator, so I have 2 banks of solar with a regulator on each in parallel charging batteries. Haven't used the generator in ages for charge as I now charge when I need to from my Leaf - I can give details if you are interested, but suffice to say the 12V battery in the car is in parallel with a DC-DC converter with the main traction cells and you can draw1700W ish out if you want to.

Still same LiFePO4 cells so the lifetime is great - IO remember folks had said it was untested technology etc but honestly the data at the beginning spoke for itself as being superior in every way to PbA.

Anyways - I hope all is well out there to anyone still watching this thread!

Regards,

Steve.

[plateauhops]

Hi All,

Well it's almost been 12 years now - thought I'd update in my System and the LiFePO4 cells.

So our original solar panels were getting old so I sold them locally , and used the cash to offset new set of panels - so now have 6200W. Got an extra 60A MPPT regulator, so I have 2 banks of solar with a regulator on each in parallel charging batteries. Haven't used the generator in ages for charge as I now charge when I need to from my Leaf - I can give details if you are interested, but suffice to say the 12V battery in the car is in parallel with a DC-DC converter with the main traction cells and you can draw1700W ish out if you want to.

Still same LiFePO4 cells so the lifetime is great - IO remember folks had said it was untested technology etc but honestly the data at the beginning spoke for itself as being superior in every way to PbA.

Anyways - I hope all is well out there to anyone still watching this thread!

Regards,

Steve.

Hi Steve,

I just logged in for the first time in around a year, but I recall LifePO4 being next- gen back in 2010. I still think they are a lot "greener" than Lead-acid, but recently my local utility company co-op sent me in their newsletter an article about "iron-air batteries". Some major companies like Amazon are investing in this. The idea of batteries being 10x as dense as they are seems like a game changer. While I think there are benefits to buying LifePO4 battery banks (if the budget can allow it), there are a lot of reasons where it may not yet be economically feasible, nor able to store enough power to run certain things like heating and AC. But what if energy storage could be so dense as to be able to accomplish full home heating and cooling? Some homes are relatively energy efficient, but in northern climates they still require a lot of energy to heat via electric (oil/space heaters) (or heat pumps which have a co-efficiency of performance of 3x the former). It would be nice to have an energy storage medium capable of converting both solar thermal panels water- and photovoltaic into usable heat- but storing it may not be necessarily more efficient by converting it into a battery than a water heater using sunlight to warm water- to an extent. I am thinking https://en.wikipedia.org/wiki/Thermal_energy_storage may have some residential applications, perhaps hybridizing both solar thermal and solar photovolatics into some usable energy that is not just heat. for example, if warm weather causes an excess of heat, that heat could be stored and converted into electric power using a tubine. But in colder weather, having only sunlight might limit the amount of power a thermal energy storage system could provide, thus a PV system would need to be quite adequate. Maybe PVs already do this, but may need 60 panels to product 20kwh in northern climates.

[Ampster]

Thanks for the update and for bumping this thread. It is interesting to reflect how the technology has evolved. I have not stayed with the same LFP cells in 12 years but have continued to believe it provides the best long term value for energy storage despite the continued scepticism. The EV conversion community saw this value equation twelve years ago.

[travissand]

Thanks for that update, that's completely awesome. There's still so many people out there who think this chemistry isn't proven. My LifePO4 batteries are also 12 years old and still holding 96% of their original rating. These things are truly a dream compared to the other chemistries.

[SunEagle]

Thanks for that update, that's completely awesome. There's still so many people out there who think this chemistry isn't proven. My LifePO4 batteries are also 12 years old and still holding 96% of their original rating. These things are truly a dream compared to the other chemistries.

IMO any battery chemistry that includes Lithium will last longer then FLA type. What I have said in the past and repeat now is you have to weigh in the cost of Li chemistry against FLA type to see which is more cost affective for you. The last time I compared them the Li was still much more expensive for the kWh it could produce in it's life then a quality FLA battery.

As Li chemistry batteries improve I believe the cost per kWh will come down and they will be very competitive to FLA type.

[travissand]

IMO any battery chemistry that includes Lithium will last longer then FLA type. What I have said in the past and repeat now is you have to weigh in the cost of Li chemistry against FLA type to see which is more cost affective for you. The last time I compared them the Li was still much more expensive for the kWh it could produce in it's life then a quality FLA battery.

As Li chemistry batteries improve I believe the cost per kWh will come down and they will be very competitive to FLA type.

The cost per kwh fully depends on your ability to find the deal. My cost was unheard of cheap. I bought 700kwh and more but you can get brand new cells straight from China for a dang good deal which makes fla a thing of the past.

[jflorey2]

The last time I compared them the Li was still much more expensive for the kWh it could produce in it's life then a quality FLA battery.

I figured I'd check this against some available batteries out there.

EG4 LFP: $1500 for 5kwhr, 4kwhr usable: $375/kwhr
-Lifetime ~5000 cycles, cost per lifetime kwhr $0.08

Costco T105: $130 for 1.3kwhr, .6kwhr usable: $216/kwhr
-Lifetime ~500 cycles, cost per lifetime kwhr $0.43

Rolls S6 L16: $395 2.6kwhr 1.3kwhr usable: $303/kwhr
-Lifetime ~1900 cycles, cost per lifetime kwhr $0.16

[SunEagle]

I figured I'd check this against some available batteries out there.

EG4 LFP: $1500 for 5kwhr, 4kwhr usable: $375/kwhr
-Lifetime ~5000 cycles, cost per lifetime kwhr $0.08

Costco T105: $130 for 1.3kwhr, .6kwhr usable: $216/kwhr
-Lifetime ~500 cycles, cost per lifetime kwhr $0.43

Rolls S6 L16: $395 2.6kwhr 1.3kwhr usable: $303/kwhr
-Lifetime ~1900 cycles, cost per lifetime kwhr $0.16

Well I guess FLA is no longer cost effective compared to Li chemistry batteries. Good to know. Thanks for the work

[Ampster]

Well I guess FLA is no longer cost effective compared to Li chemistry batteries. Good to know. Thanks for the work

That has been my opinion for some time. Glad to see you have an open mind. Also glad to see this forum is open to current realities. There is a reason why commercial energy storage has been using Lithium chemistry.

[solardreamer]

I figured I'd check this against some available batteries out there.

EG4 LFP: $1500 for 5kwhr, 4kwhr usable: $375/kwhr
-Lifetime ~5000 cycles, cost per lifetime kwhr $0.08

Costco T105: $130 for 1.3kwhr, .6kwhr usable: $216/kwhr
-Lifetime ~500 cycles, cost per lifetime kwhr $0.43

Rolls S6 L16: $395 2.6kwhr 1.3kwhr usable: $303/kwhr
-Lifetime ~1900 cycles, cost per lifetime kwhr $0.16

LFP battery costs have certainly dropped but don't think you can put EG4 in the same tier as Rolls. It would be more appropriate to compare Battleborn with Rolls. Battleborn LFP battery prices are much higher than EG4 and other similar tier brands (e.g. SOK, etc.).

[SunEagle]

That has been my opinion for some time. Glad to see you have an open mind. Also glad to see this forum is open to current realities. There is a reason why commercial energy storage has been using Lithium chemistry.

Well I feel the main reason for the POCO's using Li chemistry is because the Li battery manufacturers were trying to get a larger share of the market. They almost gave away the first set knowing that they can increase their charge for the next set the POCO has to purchase.

But that has really nothing to do with a homeowner going with Li chemistry.

[Ampster]

Well I feel the main reason for the POCO's using Li chemistry is because the Li battery manufacturers were trying to get a larger share of the market. They almost gave away the first set knowing that they can increase their charge for the next set the POCO has to purchase.

But that has really nothing to do with a homeowner going with Li chemistry.

Economics should drive most rational decision making. Scale does favor the larger facilities, but as demonstrated above, the economics are still there at small scale for those with a long term view. I don't know of any examples of Li manufacturers almost giving away their products. Do you?

[jflorey2]

LFP battery costs have certainly dropped but don't think you can put EG4 in the same tier as Rolls.

Agreed - which is why I included Costco T105's as a better comparison against a bottom-tier LFP battery.

Battleborn, Renogy, Discover, SimpliPhi and a few other LFP batteries are strangely expensive. For a better comparison you could look at Pylontech which have been doing very well in tests. Now that they have gone to 16S they are much easier to use as well. So for those:

Pylontech US3000C: $1757 3.5kwhr 2.8kwhr usable: $627/kwhr
-Lifetime 4000 cycles, cost per lifetime kwhr $0.15