Price Point of lifepo4 batterys.

[NorthGuy]

I don't think trying to include cycle life across different chemistries yields a clearer picture.

Cycle life is the most important thing. That's what you're paying for. The battery which would last 3000 cycles in your application is 3 times more valuable than the battery which lasts 1000 cycles. The chemistry is secondary. That's why big FLA batteries beat GC by huge margin. That's why buying Chinese LiFePO4 with generally unknown/unpredictable cycle life is a bad idea.

[john61ct]

Bad idea for yourself, according to your priorities & prejudices, aversion to risk, level of knowledge and experience, attachment to money or joy in discovery.

We each have our differences in those and many other areas.

[mrpackethead]

Bad idea for yourself, according to your priorities & prejudices, aversion to risk, level of knowledge and experience, attachment to money or joy in discovery.

We each have our differences in those and many other areas.

As a sub-100 poster, you need to earn some creditability before we'll take you seriously as well.

[john61ct]

I'm just here to learn and to help if I can.

No interest in any damn pecking order.

[f4eru]

Pb FLA with 3000 cycles ?
That´s quite unlikely, and even if perhaps atteinable under ideal conditions, it will need regular maintenance, which is then a bigger cost than the battery itself.

-> reasonnable quality (chinese) LiFePo4 beat this setup economically.
They last the same 3000 cycles, but with less risk of not making those, and with zero maintenance.

[Red Squirrel]

FLA maintenance is fairly cheap just need distilled water.   If you have a lot of em then it even pays to get a water ionizer/distiller to make your own distilled water.  That's what they do here at work for CO batteries.   There's also VRLA and AGM which are maintenance free but not a fan of those as they tend to not last very long and are 3x the price.  You get maybe 1-2 deep discharges from them and they're toast.   May as well try to source out lithium based at that price point. (whether it's lithium ion or lifepo4).   lifepo4 is probably best bet for stationary but as discussed it's sourcing them that's hard but same goes for lithium ion.  There's vape shops I guess but don't think they do any kind of bulk orders.   Would be nice if places like Digikey sold them but they don't seem to have much.
 

[NorthGuy]

Pb FLA with 3000 cycles ?
That´s quite unlikely, and even if perhaps atteinable under ideal conditions, it will need regular maintenance, which is then a bigger cost than the battery itself.

The bigger the battery, the longer it lasts. This is because thicker plates take longer to corrode.

The only maintenance I do is measure SG and add water twice a year. The whole procedure takes 1/2 hour, so it's 1 hour per year.

[f4eru]

Nice if it works out for you.
Also, factor in cost of training, because if the guy doing it makes mistakes, it may cost a few tenths of thousands in downtime and replacements.
Not a risk with LiFePo4.

[john61ct]

It is **much** easier to murder an LFP bank if you don't have the correct gear and knowledge to care for them properly, build the failsafe protection systems at bothe the cell and pack levels,, constantly monitor, periodically test and balance the cells etc.

If all goes well depending on the use case, especially temperatures and C-rates, yes LFP can last a **very** long time - 3000 cycles barely broken in, and maybe end up cheaper than lead.

But the up-front investment in not just top quality cells but all that infrastructure, maybe 5-10x the cost of a good FLA bank - depends on your local market conditions

makes getting that ROI very risky financially.

The most compelling reason to pay so much more are use cases where the much higher C-rates, both in and out, are required, aka power density.

Or where half the weight and volume - energy density - adds a lot of value, e.g. racing yacht, small camping van. . .

[f4eru]

maybe 5-10x the cost of a good FLA bank

I don't think that ratio of 5-10x is correct.
Perhaps you have only BMS available with heavy gold plating, costing 10x the price of hte battery, but in the real wold, for any commercial application, automating away battery maintenance to a good and cheap BMS makes the most sense.

[Red Squirrel]

Nice if it works out for you.
Also, factor in cost of training, because if the guy doing it makes mistakes, it may cost a few tenths of thousands in downtime and replacements.
Not a risk with LiFePo4.

Why would you hire someone for that?  It only really needs to be done once or twice a year.  Even if it had to be done more often it makes no sense to hire someone for that.   

[tytower]

It seems to be human nature to interfere in things that they just don't know sufficiently about. A little knowledge can be a dangerous thing.

I frequently get people telling me that LiFePo4 can be charged to 4.2v which of course they cannot. They must not go above 3.6V. Different technology to Lithium Ion but people get on and start flaming the thread before they accept they are wrong and fade away without retracting the silly stuff.

The difficulty seems to me to be caused by people with a little knowledge not reading the posts properly first.
Don't have a suggestion on how to avoid that except perhaps " Read Well".

Now on suppliers I have not taken the risk to buy any larger cells from china. It seems that there is a seller on every street corner selling these now and when you talk to them they are the big main manufacturing plant. There seems to be no way , short of going to china, to ensure you are dealing with an honourable truthful factory, They all claim to be that.

I took the chance and got 8 Lifepo4 cells of 50Ah to test about 2 years ago now from Shenzen OHC factory supposedly and they have been going well to date with a $30 BMS and a $20 Cellog8 and recently an active cell balancer for $17. They cost about $550 AUD landed at my door.

I decided to fein a battery cell breakdown and see if their promised warranty of 6 years had any backing. After many ,many emails to almost anyone who seemed likely to listen including Ali Express with all its security claims and promises , I have not been able to get even one reply ! Just completely ignored and without recourse.

So I guess before I buy the bigger capacity cells that I need and want now, I will have to wait until an Australian reseller appears that offers a warranty , and that means they will be expensive. I see that Amazon in the states is giving some good prices to the yanks but have not seen any on australian amazon and they will not ship from the states to here.

[tytower]

Even for a much smaller bank, the delivery cost alone is usually $600+
Keep in mind they're Hazmat, and Trumps's tariffs may have an impact any day now.  Actually from China LFP is not Hazmat for Air Freight now. Mine came with no problems from door to door. and freight on  about 15Kilos was $350 AUD.  The 8 of 50Ah cells I got as samples for $200 AUD approx
_____
Depending on the use case and your care protocols for checking / monitoring, there are many choices how to implement "BMS" functionality.

Sure LVC / HVC and temp failsafes can be critical, adjustability is key,

but thousands of banks built from new quality cells don't need any re-balancing at all cared for properly, zero capacity loss over thousands of daily cycles, some hitting a decade now. This seems to be a bit of a gross generalisation and unsubstantiated. Do you have any specific references to cells geting to a decade old? .

My experience so far can only point to about 4 years of untroubled use with a BMS as used on boats but I look for some long lived examples if you have them?  I feel anyone who uses these cells without a BMS is a fool. All cells differ and suffer manufacturing abnormalities in the cells production . The aim is to keep them consistent but manufacturing conditions can and do vary from day to day. Mixes of lithium and iron powders vary too. The copper and aluminium binder plates have impurities , the plastic separator has more or less electrolyte impregnated in it. Inside the plates are bolted together and corrosion can interfere ,etc  . Unless its price exhorbitant why would you not use a BMS ?

[john61ct]

BMS does not "automate maintenance", but yes good ones are relatively expensive for a small pack (under 200Ah @48V nominal or say 10kWh).

That size would be under $900 for deep cycle Pb, EPM/Deka FLA delivered. And no need for new charging gear, protective hardware etc.

Compare to LFP.

These are the only packaged systems I'd consider: OPE-Li3 (Lithionics/Ocean Planet), Victron, MasterVolt

For bare cells: ​Winston/Thundersky/Voltronix, CALB, GBS, Sinopoly and A123 (now Lithium Werks / Valence / Super B)

Delivered cost in the US, with ability to warranty return domestically, is very very high compared to lead. Much higher price ratio than elsewhere, and people there often would go with inferior AGM as well, and often of meh quality as well.

So as with most things "it depends".

PS any links to decent BMS lines, e.g. that allow user adjustability of setpoints and are considered reliable would be appreciated.

[Psi]

Anyone got recommendations for storing 8kWh over a 1 hour period?

I want to dump 35A at mains voltage (220V) into a battery for 8kWh of storage and only have 1 hour to do it.

You see, I get 1 hour of free power every day from my power company 

[john61ct]

Great that Australia, the Lucky Country, doesn't require Hazmat, also much closer to and tighter economic integration with China.

The US does require Hazmat, with very high fines for trying to cheat. Much higher shipping, and big tariffs coming RSN I'd bet.

And self-importing makes effective warranty moot, roll of the dice, with thousands at stake I'd want a trusted domestic seller myself. US distribution channels for quality cells are **very** under-developed.

Tort law liability risks along with the much cheaper availability of quality deep cycling lead are the two biggest factors IMO.

And yes quality matched cells in many use cases do not need "a BMS" as such, as long as all the required functionality is there.

Crappy BMSs have killed many banks, can give the owner a false sense of security.

To stand a chance of getting a decade or more you need to start with top notch quality and also know what you're doing.

And if you don't think they'll last that long why go that way?

Quality FLA routinely goes much longer, cheaper up front - at least in NA - and lots less stress.

Does Rolls / Surrette sell down under?

[john61ct]

Anyone got recommendations for storing 8kWh over a 1 hour period?

I want to dump 35A at mains voltage (220V) into a battery for 8kWh of storage and only have 1 hour to do it.

You see, I get 1 hour of free power every day from my power company 

Get a very big bank.

Going over 0.3C will reduce longevity. Over 1C even more so.

High charge/discharge rates are why life cycles are quoted so low, EV and other propulsion use cases being the norm more than low-rate House bank usage.

[tytower]

User adjustability on BMS is not something I have come across. Generally what I have seen is the use of a chosen values chip.
There is no reason you could not engineer a suitable chip onto a board or even search and obtain a pre-made board that has your chip on it.

I'll post a chip datasheet when I find it to demonstrate that.(Might take a while,not on my desktop)

The problem area though is amps through it and I have not seen many cheap ones that go above 60 amps continuous. They can be paralleled but it gets messy then doesn't it. Mine run at 24 volts Nom so 60 Amps at say 27 Volts is 1620 watts with peaks of about 3000 watts for short bursts.

I don't pull but about 5 amps continuous right now through a 1000 watt inverter so I don't know if those tops stack up.
Probably the best device I have added is the active balancer to "automate" my pack. It is keeping each cell within 30 mv very effectively atm and I have had problems with cells going really badly out of balance.

On a much larger capacity system those variations would not be as noticeable but on a 50 Ah bank they sure are a problem . I've been watching it for a fortnight or so now and have had the best looking Cellog8 balance readings I have ever had. If I had a bad cell then the loss of voltage from that cell would be fed from higher cells maintaining overall stability and the loss of pack capacity barely affects me as solar pulls them all up next day.

[tytower]

Oh I see now . Silly me  You are still flogging Lead acid . Its a dead horse mate .

[john61ct]

I'm not flogging anything.

Just saying there is no "one correct choice" across the board. Fanboyism is counter-productive.

The scales outside the NA market favor LFP in a higher % of use cases.

[electrodacus]

Anyone got recommendations for storing 8kWh over a 1 hour period?

I want to dump 35A at mains voltage (220V) into a battery for 8kWh of storage and only have 1 hour to do it.

You see, I get 1 hour of free power every day from my power company 

How much is the cost of energy outside of that 1h when is "free" if it is less than 25 to 30 cent/kWh then it will not be economical to add a battery to store that "free" energy.
Even so you will need 15 to 20 years of free energy storage to break even and is unlikely this 1h of free energy will last that long.
There is no place in my opinion for grid connected storage at this time if you care about economics.

[tytower]

Going over 0.3C will reduce longevity. Over 1C even more so. High charge/discharge rates are why life cycles are quoted so low, EV and other propulsion use cases being the norm more than low-rate House bank usage.

This thinking pervades present day use of batteries and seems to be a hangover of lead acid which is made for auto use of a quick discharge  to starter with an immediate recharge to 100 % SOC . Use in Solar systems try not to discharge below 50% and you find the guys claiming more than 3 years life simply are not using them.

Contrast that with what is said and what I'm finding with LFP is that discharge even down to 20% SOC is uneventful. They come back up and hold capacity normally despite repeated incursions into this territory.

Most manufacturers suggest 1C discharge rates and I have seen some at 5C.(The problem here being lithium metal plating of the electrode)  I'll stick to 1C and see .I expect to get 8000 cycles at least at that rate  should last 22 years if discharged daily and still be at 80% capacity even then . Time will tell.(You can buy bags of Lithium Iron mix online if you want to play)

Boating users that I am familiar with can only claim 4 or 5 years that I have seen so its early days but believe me USE your LFP pack to get full advantage of its capabilities. That's why the cost comparisons with lead acid just leave those in the dust.

If you get half your present L/A capacity in LFP you will still have twice the available useable power so factor that in along with their lifespan and it should be obvious where the future is going with LFP.

There are big things coming with LFP too getting up to 3 times more from much the same chemical composition and cheaper cost.
For just a general example of charge and discharge rates that are generally acceptable see here but there are many examples out there.




For a comparison of price with L/A see here

 

[Psi]

How much is the cost of energy outside of that 1h when is "free" if it is less than 25 to 30 cent/kWh then it will not be economical to add a battery to store that "free" energy.

Yep, that's the main reason i've not build it yet.
But if i ever run into a huge box of free 2nd hand 18650 cells i'll consider giving it a try.
The main issue is i would need a massive number of cells to be able to store 8kW that quickly. Probably like 20-30kW of capacity.

Setting up your electric car to only charge within that hour each day might be a good use of the hour. Get a 30A 230V fast charger installed in ya garage.

[tytower]

Make sure everything that runs gets switched on at that time.

[john61ct]

Going over 0.3C will reduce longevity. Over 1C even more so. High charge/discharge rates are why life cycles are quoted so low, EV and other propulsion use cases being the norm more than low-rate House bank usage.

Most manufacturers suggest 1C discharge rates and I have seen some at 5C.

Yes, following the vendor specs is not optimal for longevity.

They are absolute maximum "stress ratings", the limits to which the devices can be stressed without causing immediate damage. These limits are not recommended for normal operating.

Operating frequently at those limits will produce reduced reliability/lifetime.

Of course the owner may truly **need** to fast charge, and if 8000 cycles is expected otherwise, not be interested in trying for more.

Same sort of curve between average DoD% and total lifecycles with LFP as with lead, BTW.

Your rig your choice, just know what the trade-offs are.