Price Point of lifepo4 batterys.

[hendorog]

Is your spot price list for your network node? I think that is important as I think the price for each node can go up due to local effects as well as regional and national effects.

So if its just a regional price then you might be missing some spikes.

I'm no power expert though.

[mrpackethead]

Its the actual price paid at my location.

[NorthGuy]

Conclusion: putting a battery in byitself to round off the peak power prices, has negetive economic benefit.

And you haven't even factored in Inverter/Charger losses.

[mrpackethead]

I had included them in the life time of the battery, but had'nt added the energy cost for the 'lost' energy. Its almost a moot point, becuase there is'tn much of a way of paying for it.

As a bit of an exercise i wondered what would happen if i moved the point at which i cut over to batterys higher, so i only chopped off the more expensive peaks.  As you can see from teh histogram those just get less and less, and even though you need a smaller battery, the payback doe'snt get any better.

I need to remodel this with solar, which i expect will actually change the game plan.    Since i have my actual historical data of useage and the actual pricing, i probably can model this quite well. My gut feeling is that with solar i might be slightly up, but not so much that it would be worth the effort to do.
 

[hendorog]

Rough is this fesible math.

Heres the 1/2 hour spot market price sorted into price bins of sorts..
 
At USD $400/kwH for batterys,  lets assume 3000 cycles to 80%,  we can get 20,000kWh out of a 10kWh battery pack over its life. .  Thats goign to cost me $NZD 0.10c per unit for the battery.

There is no savings to be made by using the battery to provide power until the unit cost of power is > average + 0.10c   or in our case;  16.7c units.       We should never charge the batterys if power is greater than average cost;

The average cost of 'peak priced power ) is 24.8c

There were 974 hours over the dataset that exceeded that ( 1489 days )..  or 2.7% of the time. 87% of the peaks that are greater than 16.7c are less than 2 hours wide.   My household use does tend to use power in line with the peaks, and i use 1.4kWhr/hrs on average during the peak.  ( i already ditch non essential loads ).       5kWh of storage probably will suffice, which will cost me about $2000USD ( $2800 NZD )

My potnetial savings over a year,  are 236hours * 1.4kW ( 24.8 - 6.7c )  =  $59.80!!!!    Factor in the 'cost' of the battery.. its just $26.76 per year im ahead.        If i factor in cost of money at say 4.9%,,  ( 2800 * 4.95 ) = $138 / year.  I'm down $110 a year for the hassle.

I'm not convinced the logic is correct. I think you need to work out the cost of each peak and sum them up. The average won't work. I have had massive peaks which have cost $20 or more on their own just for an hour or two of power. I am pretty sure that your maths will not account for those peaks, and those are the ones which will pay for the system if they are frequent enough. AFAIK there is no price cap on a spike so the system is also cheap insurance against a crazy bill.

Also consider that you will only be using 330 odd kWh of 'battery life' in a year. So your battery will last for 60 years at that rate.
Also $400/20000kWh = USD 2c per unit, which is NZD 3c not 10c, and  80% of 3000*10kWh is 24000kWh not 20000.

[Mr.B]

Following.

[mrpackethead]

Rough is this fesible math.

Heres the 1/2 hour spot market price sorted into price bins of sorts..
 
At USD $400/kwH for batterys,  lets assume 3000 cycles to 80%,  we can get 20,000kWh out of a 10kWh battery pack over its life. .  Thats goign to cost me $NZD 0.10c per unit for the battery.

There is no savings to be made by using the battery to provide power until the unit cost of power is > average + 0.10c   or in our case;  16.7c units.       We should never charge the batterys if power is greater than average cost;

The average cost of 'peak priced power ) is 24.8c

There were 974 hours over the dataset that exceeded that ( 1489 days )..  or 2.7% of the time. 87% of the peaks that are greater than 16.7c are less than 2 hours wide.   My household use does tend to use power in line with the peaks, and i use 1.4kWhr/hrs on average during the peak.  ( i already ditch non essential loads ).       5kWh of storage probably will suffice, which will cost me about $2000USD ( $2800 NZD )

My potnetial savings over a year,  are 236hours * 1.4kW ( 24.8 - 6.7c )  =  $59.80!!!!    Factor in the 'cost' of the battery.. its just $26.76 per year im ahead.        If i factor in cost of money at say 4.9%,,  ( 2800 * 4.95 ) = $138 / year.  I'm down $110 a year for the hassle.

I'm not convinced the logic is correct. I think you need to work out the cost of each peak and sum them up. The average won't work. I have had massive peaks which have cost $20 or more on their own just for an hour or two of power. I am pretty sure that your maths will not account for those peaks, and those are the ones which will pay for the system if they are frequent enough. AFAIK there is no price cap on a spike so the system is also cheap insurance against a crazy bill.

Also consider that you will only be using 330 odd kWh of 'battery life' in a year. So your battery will last for 60 years at that rate.
Also $400/20000kWh = USD 2c per unit, which is NZD 3c not 10c, and  80% of 3000*10kWh is 24000kWh not 20000.

$4000 for 20,000kW But my math was wrong as well. Its much more than 10c!    ( the 20,000 factored in some loss at the inverter and converio )

Add up the peaks, and sum them..  sounds like an average. :-)

[NorthGuy]

I had included them in the life time of the battery, but had'nt added the energy cost for the 'lost' energy. Its almost a moot point, becuase there is'tn much of a way of paying for it.

You just calculate that you need to buy more energy to recharge the battery.

With solar there are also different pathways, with different losses, such as:

Solar->Inverter->House - requires 1.10kWh per kWh used
Solar->Charger->Battery->Inverter->House - 1.35kWh
Generator->House - 1.0kWh
Generator->Charger->Battery->Inverter->House - 1.45 kWh

So, you can choose your pathways by timing loads. If the sun is shining or the generator is working, using energy is much cheaper because it doesn't go through batteries. It also saves battery life. That's how I save energy.

Also, you can wait with recharging your battery until the price is really low. This will increase your savings - buy low sell high.

[hendorog]

Rough is this fesible math.

Heres the 1/2 hour spot market price sorted into price bins of sorts..
 
At USD $400/kwH for batterys,  lets assume 3000 cycles to 80%,  we can get 20,000kWh out of a 10kWh battery pack over its life. .  Thats goign to cost me $NZD 0.10c per unit for the battery.

There is no savings to be made by using the battery to provide power until the unit cost of power is > average + 0.10c   or in our case;  16.7c units.       We should never charge the batterys if power is greater than average cost;

The average cost of 'peak priced power ) is 24.8c

There were 974 hours over the dataset that exceeded that ( 1489 days )..  or 2.7% of the time. 87% of the peaks that are greater than 16.7c are less than 2 hours wide.   My household use does tend to use power in line with the peaks, and i use 1.4kWhr/hrs on average during the peak.  ( i already ditch non essential loads ).       5kWh of storage probably will suffice, which will cost me about $2000USD ( $2800 NZD )

My potnetial savings over a year,  are 236hours * 1.4kW ( 24.8 - 6.7c )  =  $59.80!!!!    Factor in the 'cost' of the battery.. its just $26.76 per year im ahead.        If i factor in cost of money at say 4.9%,,  ( 2800 * 4.95 ) = $138 / year.  I'm down $110 a year for the hassle.

I'm not convinced the logic is correct. I think you need to work out the cost of each peak and sum them up. The average won't work. I have had massive peaks which have cost $20 or more on their own just for an hour or two of power. I am pretty sure that your maths will not account for those peaks, and those are the ones which will pay for the system if they are frequent enough. AFAIK there is no price cap on a spike so the system is also cheap insurance against a crazy bill.

Also consider that you will only be using 330 odd kWh of 'battery life' in a year. So your battery will last for 60 years at that rate.
Also $400/20000kWh = USD 2c per unit, which is NZD 3c not 10c, and  80% of 3000*10kWh is 24000kWh not 20000.

$4000 for 20,000kW But my math was wrong as well. Its much more than 10c!    ( the 20,000 factored in some loss at the inverter and converio )

Add up the peaks, and sum them..  sounds like an average. :-)

Ah of course, I screwed up the total price.

However I still think the average method is wrong. You are averaging all of the peaks and then averaging all of the usage, and then multiplying those together to get the final answer.
However I think you need to work out the cost of each peak (usage x price) and then sum those to get a correct answer.
Consider if in one hour you used 2kW of power at a very high rate of $50/kWh. The cost of that hour could be $100, but you are only multiplying the average usage (1.4kW) by the average peak price for the entire year - of say 20c - so that hour looks like it something like 28c.

Where did you get the spot pricing data from? I will download mine and try and have a work out. The Flick website has gone to crap for historical data older than about a year, so I can't scrape much data from them.

[a59d1]

Some people in this thread are being way too picky about using secondhand lithium cells. You will certainly lose some of the capacity with a used cell, but "most of the usable capacity"? No. The worst degradation ever seen on a Leaf pack is something like 65% after 7 years, meaning you've lost 35% of the capacity. Most likely you'll be getting 75-90% of the original capacity at a cartoonish discount. If your BMS is properly designed, this should never be a problem.

And if you're annoyed about having to use someone's old cells, get real. Stationary storage is not (and won't be for the foreseeable future) a primary consumer of new cells due to the fact that energy mass and volumetric density doesn't matter as much when your battery is sitting in a basement or warehouse vs. strapped to the bottom of a moving car.

If you're almost willing to pay $380/kWh to your current supplier for 10kWh, and you can get Leaf cells for less than $200/kWh, you're making money if the cells have anything more than 53% of their original capacity left.

And for the record, it is literally impossible to buy new cells or packs for less than $100/kWh. There are rumors that Tesla may have beaten that number internally, but they're sure as shit not selling their batteries at cost to anybody.

Even better: if you hold on and wait a year or two, you'll start to see the supply of recovered (undamaged, mind you) batteries from crashed electric vehicles grow dramatically, and prices will drop proportionately. Right now, there is simply way more demand than supply.

As an addendum, note that this was written from a US-centric perspective, as was NiHaoMike's. Having batteries shipped to Australia from the US, especially 10 kWh of them (!) is an absolute nightmare when they're not already installed in a vehicle.

[NiHaoMike]

The question still unanswered is what residential load is using 2kW for at least 5 hours on a regular basis? There's probably a better solution like thermal storage rather than using batteries.

[woodchips]

As has been mentioned, surely a diesel generator is much the cheapest way to generate electricity?

Can buy a 10-15kVA 3ph 400V genny for about £3k, $4k.

These are probably 80% efficient, and if you can use the cooling water as well then that is over 90%. Diesel costs about £0.70 litre, $0.90, and you get 10kW litre.

To store electricity then fork lift batteries are the best choice. Could even make the batteries yourself out of lead sheet formed into a Vee shape either side to maximise area. A static system has no real limits on size or weight, so the Lithium advantages are null and void. Need a large container, lots of battery grade acid, and significant energy to form the battery, a one off job.

It has been pointed out, Matsch - Capacitor, Magnetic Circuits & Transformers, that the energy stored in 1lb, 454g, coal is about the same as a flywheel 9' in diameter, weighing 1 ton and rotating at 3,600rpm. And the flywheel would need to be in a vacuum. Similarly a 6V 100 Ah battery (this is 1964 so LA) gives 600Wh or 2,180,000J or about 14% of 1lb coal. Oil, hydrocarbons, are about 11.5/8 kWh per kg.

I too have had zero luck in finding these wonderful cheap lithium batteries, and this is just s few to replace the Ni-Cds in my drill.

[splin]

As has been mentioned, surely a diesel generator is much the cheapest way to generate electricity?

These are probably 80% efficient, and if you can use the cooling water as well then that is over 90%.

The massive two stroke diesels used in large container ships can reach 56% efficiency or more. Car engines can achieve around 42% but a cheap diesel generator probably won't do much better than 30 to 35% average, especially given that it probably won't be running at peak efficiency much of the time.

Older Lister diesels, much loved by many UK off-gridders, whilst very simple and reliable probably only run around 20 to 25% efficient.

If you can use the heat then the overall efficiency could approach 90% but it is usually very difficult to match the heat and electrical loads over the course of a year so the average seasonal efficiency will be much lower.

I too have had zero luck in finding these wonderful cheap lithium batteries, and this is just s few to replace the Ni-Cds in my drill.

I'm pretty sure they don't exist in the retail market. LiFePO4 don't seem to have come down in price at all in the last 10 years, and whilst Li-on cells may have reduced in price over the years, they are still expensive for retail customers and lead acid are still the most economical for most.

[tytower]

I just read briefly through this thread and all i can say is there is a load of BS in there posted by people sitting in chairs that know very little about Lithium Iron Phosphate . LFP or LiFePo4.

Firstly.. this is not Lithium Ion technology
Second... LiFePo4 does not explode or burn .
Third ..You can expect to use these batteries from full charge down to 20% of charge left or less every day.
Fourth... You are likely to be able to do this on the same set of batteries 5000 times or better.
Fifth ..100 amp hour cells can be had for USD $ 90 atm approx from China ..Check the weight though.
Sixth.. LiFePo4 cells sit at 3.2V for most of their cycle and only fall below 2.5 volts at the very end of their capacity.
Seventh..LiFePo4 cells jump quickly to 3.55Volts which my manufacturer says is full.
Eigth....A BMS (Battery Management System is essential to stay inside these limits.
Ninth..They have aluminium cases these days and
Tenth.. Lead acid AGM etc only last 3 or so years and that only if you don't discharge them below 50% of their capacity. If you get better than than that great for you but don't try to convince me.

That said  can you see the value in going LFP now ?
10 Years you will get out of them and you only need a third of the capacity you are using now ....and you dont have all the fiddling with 18650 little battery systems and the like.

You need a controller for solar that just feeds in current at a reasonable voltage for a reasonable time to recharge.
 Here is a good site to start learning https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery

[a59d1]

Fifth ..100 amp hour cells can be had for USD $ 90 atm approx from China ..Check the weight though.

$900/kWh is not particularly competitive. LiFePO4 fires are also not unknown, but they are much less common than lithium ion fires.

[splin]

Fifth ..100 amp hour cells can be had for USD $ 90 atm approx from China ..Check the weight though.

$900/kWh is not particularly competitive. LiFePO4 fires are also not unknown, but they are much less common than lithium ion fires.

That's $900 for 1000Ah which is 3.2kWh or $281/kWh. Still expensive though and, unlike Li-ion, they have barely come down in price - 10 years ago they were around $100 for a 100Ah cell.

[mtdoc]

Eigth....A BMS (Battery Management System is essential to stay inside these limits.

No. If you know what you’re doing, bottom balancing and no BMS (but proper charge controller settings, LVCO, etc) is a better, safer option.  Otherwise, then sure, a good BMS would be a ood idea.

Ninth..They have aluminium cases these days

Some do, some don’t.

. Lead acid AGM etc only last 3 or so years and that only if you don't discharge them below 50% of their capacity.

Utter nonsense. As long as you don’t do something stupid, quality deep cycle FLA will last 10- 15 years (large traction batteries longer) and AGM 8-10 years in daily cycling applications.

Yes, LFP make good sense and are financially competitive with LA when one considers lifetime costs. But don’t oversell them, they are not always the best option.

[mrpackethead]

Best thing i can do to chop off the peaks, is to install a Natural Gas Powered gen set.    Can buy natural gas at about 5c/kwH.  Conversion to electricty is about 25% efficent.  so, give or take it costs 20c/kWh.     

[Eka]

So, how do the numbers come out when you make the system 5X the size you need and sell back some of it when prices are high?

[mrpackethead]

They would say you would loose money.

[tautech]

You can take a look there: http://www.batteryspace.com/96v-lifepo4-battery-packs.aspx
You have to ask for a quote i think.

For 10 kWh, it's most likely going to be over $5000.
Ouch.

i can buy 10kW for $3800 without any trouble... Still too high a price point i think.

Have a look at what these guys have to offer:
http://en.winston-battery.com/index.php/products/power-battery

With a bit of a hunt you can find suppliers.
Guy I know has banks of them for his off the grid house giving him 22 KWh of storage.

EDIT
Link updated

[f4eru]

Eigth....A BMS (Battery Management System is essential to stay inside these limits.

No. If you know what you’re doing, bottom balancing and no BMS (but proper charge controller settings, LVCO, etc) is a better, safer option.  Otherwise, then sure, a good BMS would be a ood idea.

What do you mean by " bottom balancing" ? Manually controlling the individual cell voltages when discharged ? That kind of "human BMS" sounds like fun and completely error free

[electrodacus]

I have huge experience with energy storage as this is my hobby for the past 6 to 7 years and I currently live in an offgrid net zero energy house powered 100% by solar that means electricity and heating and it is the most cost effective solution possible.
My small house energy requirements are as follows peak month January requires 1000kWh for heating and 120kWh as electricity for appliances most of that electric cooking the 120kWh is included in the 1000kWh heating as any energy you use inside the house ends up as heat.
Heating season here in Saskatchewan Canada is about 7 months per year so total energy needed for heating is around 5000kWh to 6000kWh (depends on how cold it is in a particular year) and average of 120kWh/month as electricity that is  about 1400kWh/year thus total energy requirement 5000kWh + 1400kWh = 6400kWh

My system is made out of a 10kWp PV array (can produce in a year about 14000kWh) so less than half of available energy is used but this makes sense as it is designed to use almost all available energy in winter and there is up to 90% unused energy in summer that makes perfect economic sense and will explain later.
There is a large thermal storage 158kWh capacity made of 97kWh 14m^3 concrete floor and a water storage tank 1500liter 61kWh capacity then for electricty I use a 5kWh LiFePO4 battery just enough for 24h autonomy as the huge PV array can produce worst case the minimum energy required about 4kWh in worst overcast day.

Total cost of the system $15K and expected life of the system at least 30 year thus $15000/30years/12month = $42/month total energy bill for heating and electricity.
Put this in another way $500/year / 6400kWh = 7.8cent/kWh but is not quite a fair representation as the energy used for heating is at around 5cent/kWh while the one used for appliances is around 18 cent/kWh

Thus heating with PV solar is the most effective heating option even cheaper than the next option natural gas.

Now with this out of the way I want to give you some numbers for perspective very relevant to this tread

Cost amortization for different elements sort of best case
PV panels cost amortization 2 cent/kWh
Thermal storage as low as 1 cent/kWh
LiFePO4 around 15 to 20 cent/kWh (best option but still not a good solution for grid energy storage so do not add a battery to your grid connected house just have a grid connected PV array if you care about costs and is valid anywhere in the world).
Tesla PowerWall or similar storage devices at least 40 cent/kWh very bad investment if you care about savings and not just want an UPS and do not care about costs.
Lead Acid 60 cent/kWh up to over $1/kWh depending on battery used and in what conditions still very bad for energy storage applications.
Car alternator or small gasoline or diesel generator at least $1/kWh so extremely bad idea in most cases.

This is a bit of advertising but for details about my open source devices making my house solution possible see the documentation in my Kickstarter campaign description.

[hendorog]

Total cost of the system $15K and expected life of the system at least 30 year thus $15000/30years/12month = $42/month total energy bill for heating and electricity.

Not to mention you have probably added at least that to the value of your house.

Many would happily spend $15K on a new bathroom with earns nothing, but complain that a solar system because it is not profitable enough.

[tytower]

. Lead acid AGM etc only last 3 or so years and that only if you don't discharge them below 50% of their capacity.

Utter nonsense. As long as you don’t do something stupid, quality deep cycle FLA will last 10- 15 years (large traction batteries longer) and AGM 8-10 years in daily cycling applications.

Have a look on utube or search DIY Will Prowse. Look for his video comparing lead acid cost to LFP. His statement about Lead acid  " if you get better than 3 years then you are not using them" rings strong with me . After all thats whhat lead acid batteries were designed originally for . Quick discharge for a short time and then immediate recharge for auto use . Storage batteries in lead don't work that well in that situation as you well know.