LiFeP04 Batteries for Solar & BMS

[Living Large]

I'm just trying to figure out alternatives to a $60-120k utility connection fee.

You and me both. I am right in the same ballpark at $60K and $133K, depending on which route is approved by my HOA.

It does not seem out of the realm of good engineering to be able to repurpose battery packs assuming safety is taken into account. But if this is not kosher let me know, I actually would rather discuss panels sizing/wattage/ground mount suggestions.

Question: How do you recycle 200k LI battery packs? How is society going to recycle all those battery packs? What an interesting thought. I mean we are quickly getting to the point where 50k a year will be coming out of service (say in 2020?).

You could start a thread on recycling L-I batteries, if that is an interest - where it would be more "kosher". As far as repurposing EV batteries in solar applications, my read is that discussion has already taken place here, assuming it isn't deleted by attempting to continue.

[SunEagle]

I know nothing about the 123 issues but I guess folks were hawking rejects from that process. I suspect that LG, NEC, and Tesla/Panasonic will all be hawking battery packs. The Tesla packs are interesting right now and like all Musk things...well he is going to sell. I've got no crystal ball but having met Musk I can assure everyone that he will sell. I also don't understand some of the comments about making a buck off of Musk. The only person that is going to make a buck off of Musk will be SolarCity and Tesla shareholders. Having seen some pictures of the "home made projects" some of these projects seem too "hacked" to be safe. Some seem to be very well engineered compared to professional jobs, to compare I guess I need to tour some off grid homes. Is there such a tour in the mid-atlantic? I guess I'd need an engineer to tour with.

Are some folks here saying that the Tesla power packs are not safe? If so why? Has any commercial EV ever caught fire sitting in a garage? By commercial I mean Tesla, Leaf, Volt too I guess.

I didn't mean to contribute to a hornets nest either. It just seems like a logical fate for 200k (and growing) EV battery packs. I don't see them getting destroyed anymore than a used anything with value getting destroyed and if bouncing around in a hot vehicle did not cause the battery packs to destroy themselves than I don't see how sitting still in a controlled space will make them more dangerous. I'm just trying to figure out alternatives to a $60-120k utility connection fee. I'm a year away from building in any case so I suspect I will see lots of news on the PowerPacks etc in the meantime. It does not seem out of the realm of good engineering to be able to repurpose battery packs assuming safety is taken into account. But if this is not kosher let me know, I actually would rather discuss panels sizing/wattage/ground mount suggestions.

Question: How do you recycle 200k LI battery packs? FAL is messy but understood now (caused a lot of issues figuring it out though). How is society going to recycle all those battery packs? What an interesting thought. I mean we are quickly getting to the point where 50k a year will be coming out of service (say in 2020?).

My mistake was in trusting that the EV sellers (like Nissan and Tesla) to have a plan in place to properly dispose or retire used battery banks because as you noted there are going to be a lot of them in a few years. If they have not done their due diligence of creating a disposal plan then they have contributed to a very big issue by adding to our toxic waste problems.

I am not complaining about batteries used in commercially built EV's. They continue to get safer and better and I will probably purchase one in the future.

I am concerned about the DIY're reusing EV Lithium battery packs for home energy storage systems. While some of the home built systems look "engineered" they are not. Add the complexity of a volatile battery chemistry with a very unique charging system and cooling requirements just increases the chance of someone making a mistake and causing a fire. Even the experts make mistakes.

I just want to caution others who think they can save money reusing old batteries that sometimes saving a few bucks results in pain and sorrow if safety isn't kept at the top of the list.

[Sunking]

Question: How do you recycle 200k LI battery packs? FAL is messy but understood now (caused a lot of issues figuring it out though). How is society going to recycle all those battery packs?

It is easy to recycle lithium batteries. Issue is there is no money or demand for lithium recycling. The cost of obtaining lithium from recycling batteries is 5 times higher than buying it from a refined source from South America. No company would chose to use recycled lithium.

Don't think just because lithium is not recycled there are tons of batteries just lying around because that is not the case. Recycle operators run them through the hammer mills to recover Cobalt, Nickel, Copper, Aluminum, and Manganese. The lithium recovered, what little there is, (3% by battery weight) is thrown in the trash pile because there is no market for it.

[nativewolf]

It is easy to recycle lithium batteries. Issue is there is no money or demand for lithium recycling. The cost of obtaining lithium from recycling batteries is 5 times higher than buying it from a refined source from South America. No company would chose to use recycled lithium.

Don't think just because lithium is not recycled there are tons of batteries just lying around because that is not the case. Recycle operators run them through the hammer mills to recover Cobalt, Nickel, Copper, Aluminum, and Manganese. The lithium recovered, what little there is, (3% by battery weight) is thrown in the trash pile because there is no market for it.

Interesting. So, the heavy metals are worth recovering. Well, at least the stream is getting processed.

[Sunking]

Interesting. So, the heavy metals are worth recovering. Well, at least the stream is getting processed.

My comment is in respect to the after market of used or salvaged EV batteries.

There is a market for salvaged batteries. In fact a huge demand and every Auto Salvage Yard operation knows it. They have waiting list and prices are fixed high for what you get which equates to a huge gamble. When you look at the end result, the economics are not there even if the gamble pays off unless it is a niche application like a Go-Kart, Golf Cart, E-Bike, Electric Buggie etc. gain a considerable loss of weight and higher energy density boost. In a solar application role there is little to no benefit lithium energy density brings with it unless it might be a boat or RV where space and weight come at a premium. But it would be insane to install salvaged batteries into an RV, Boat, or a home taking the chance to burn it down. No professional would even dare suggest or recommend such a thing.

As for Nissan, Tesla, Toyota, Chevy or whatever manufacture you want to name reclaiming used batteries and reselling them is complete nonsense for the same reason no professional would do that. Liability risk is huge. The batteries are worth more sold as SCRAP to a recycling center. Only time a manufacture is going to take possession of a used battery is a Warranty Claim replacement or Maintenance replacement. Otherwise all others go to Salvage dealers who sale it as Junk.

Salvage Yards are the only ones who can get away with selling wrecked or used batteries. The fact that you are buying them knowing they are salvaged and no warranty or liability is assumed by the seller. You bought junk knowingly.

Putting salvaged batteries in something like a Go Kart or Golf Cart is one thing where there are no codes or ethics. Putting them in a home, RV, or Boat is just plain dangerous and careless. It does not conform to any known or defensible codes or practices. Something a Hack or DIY does either out of ignorance or stupidity if they know better.

Manufactures do not sell used underwear.

[PNjunction]

Thank you Sunking for bringing us back to reality.

It's enough to make one want to crumple their tinfoil conspiracy-hat in disgust. I know I did, and am still fine tuning the new one.

The litmus-test for me always has been availability to the common man, under NORMAL means of business without having to hack anything. There are hacking forums for the hacking crowd. Not all of them are safety-unaware, but because kids don't see lifepo4 at their local auto store, they may assume that getting damaged goods is how it is done.

Ok, my tinfoil hat is adjusted and properly blocking the gamma rays now. Time for me to cool off I guess.

[Sunking]

The litmus-test for me always has been availability to the common man, under NORMAL means of business without having to hack anything. There are hacking forums for the hacking crowd. Not all of them are safety-unaware, but because kids don't see lifepo4 at their local auto store, they may assume that getting damaged goods is how it is done.

PN supply is the driving factor. Stop and think about it for a second PN. You already know one thing, may net be aware of it, but you and I cannot buy EV quality lithium batteries. Not th eones Ev manufactures use. Hell 8 years ago not even Tesla could access the batteries they needed. They gambled on LiCo laptop 18650 cells about the size of a AA battery made by Panasonic.

A123 came out with the Holly Grail th eLFP battery and it flopped. It lacked density and price point. That left the Chi-Coms LFP to the public domain. The scary part is LiCo, LiPo, LFP, and th elist goes on is just alphabet soup to the public. All they know is a Lithium Battery. We know the public cannot buy quality Lithium batteries at competitive prices. Tool. gadget, and auto makes have all the good ones tied up in production.

[PNjunction]

PN supply is the driving factor. Stop and think about it for a second PN. You already know one thing, may net be aware of it, but you and I cannot buy EV quality lithium batteries. Not th eones Ev manufactures use. Hell 8 years ago not even Tesla could access the batteries they needed. They gambled on LiCo laptop 18650 cells about the size of a AA battery made by Panasonic.

In another life-form, I love my recent Panasonic-built 18650 LiNMc's, but that is a totally different application.

Ah but the point here is that we don't *need* that kind of quality and capability for a solar bank sized appropriately for autonomy! The large prismatics from the established majors (GBS, CALB, Winston) are already quite a bit beyond our relatively low current needs. Unless one is charging with a genny, they are merely tickling the capabilities of these things. From a financial standpoint, the costlier small cylindricals are even worse since one will never use their 10C or more capability.

There is always the manufacturing quality issue - but if we take it to say the Pb realm, does everyone really need a Rolls or Trojan for their application? (retorical, other threads cover this!

The scary part is LiCo, LiPo, LFP, and th elist goes on is just alphabet soup to the public. All they know is a Lithium Battery. We know the public cannot buy quality Lithium batteries at competitive prices. Tool. gadget, and auto makes have all the good ones tied up in production.

I would say that the large prismatics available today *for our solar purposes* are good enough. Maybe not like Rolls or Trojan Pb builds for sure. Guys don't need to install an Enersys power-vault of high end agm's for every purpose either. Stopping here so I don't go off on pb issues..

While considering the needs of the general public is admirable, not knowing about lithium is not surprising considering that most don't know the difference in Pb batteries either - and that is 100 year old tech basically. So we aren't really in a manufacturer-mindset, but educators for those that WANT to know and come for guidance. Guidance, not salesmanship.

I'm just sort of dismayed that all roads (here and elsewhere) quickly lead back to Tesla, Fiskar, Boeing, E-bikes, EV, hacks, corporate politics, CFO's and other motive-power needs, when just the basics of lifepo4 for the guy interested to doing it with solar ends up buried in the noise. For many, finding the details you need to get started even just for personal experimentation becomes a non-starter.

Guess what - I needed a new backup system. Lifepo4 (or any other lithium) wasn't part of that plan. See ya in another thread about that!

[Sunking]

PN I know I am not telling you anything you already do not know. The demand from auto, laptop, power tool, and gizmo's manufactures consumes all the battery manufactures production. At least the better ones like Panasonic, EnerDel, and LG Chem. For Pete's sake that is what has opened up the door for Tesla to build Panasonic cells in the USA when they complete phase one and two of the so called Gigafactory. Even Tesla has problems with dried up supplies. Even A123 Systems, what is left of it, production is is consumed by GM, Daimler and a handful of other EV manufactures.

At the consumer level and DIY all there really is to chose from is Chi-Com LFP cells. You know the history there too, all from failed Thundersky comes CALB, GBS, Sinopoly, etc. All are on 3rd generation revisions in 8 short years because the first two are flops. Non could meet the claims, and time will tell if gen 3 can live up to the claims today which does not look good. Now there are some commercial offerings, some are not real like Powerwall, and others that you can buy in foreign markets. But the price of using high quality cells in a manufactured solution still cannot compete with PB technologies, and life cycle question cannot be answered for another 10 years.

I understand people want to eat the forbidden fruit of real EV batteries. But unless you are willing to pay huge money for the high quality lithium batteries. that cannot compete with long term cost of Pb, we are still a long ways off from lithium as power storage. It will come to the commercial market long before it arrives at the consume level. I do not see that happening anytime soon as production cannot even handle EV production today. Long way off from meeting the demand of EV, utility scale energy storage and consumer. Not even Tesla factory will change that.

For now cheap Chi_Com knock-offs is all we got. I was really disappointed Lithium Titanate clss realy never caught on for Energy storage. Those have the best chance of 5000 to 10,000 cycles. But Specific Energy Density is not much better than Pb, and right now it is EV's driving the technology and low Energy Density is not going to make it in any market. All but home solar demands high energy density, and there is no real market for a battery manufacture to make lithium cells for home energy. The money is in EV's, power tools, and gizmos.

[PNjunction]

At the consumer level and DIY all there really is to chose from is Chi-Com LFP cells. You know the history there too, all from failed Thundersky comes CALB, GBS, Sinopoly, etc. All are on 3rd generation revisions in 8 short years because the first two are flops. Non could meet the claims, and time will tell if gen 3 can live up to the claims today which does not look good. Now there are some commercial offerings, some are not real like Powerwall, and others that you can buy in foreign markets. But the price of using high quality cells in a manufactured solution still cannot compete with PB technologies, and life cycle question cannot be answered for another 10 years.

I can dig that, but for the reader, "failed" or bankrupt in the business world does not mean out for the count. Restructure, reorganize, IMPROVE the product. Don't forget that many of these early failures from the pioneers in lifepo4 prismatic EV were from total abuse, homebrew vampire balancers, - crappy wiring infrastructure, the whole plethora of badness from an amateur construction standpoint. They don't have the knowledge we do now.

I watched the same details more or less when every EV'er was lugging around Enersys (Genesis) agm's, Optima, Hawker, later Odysseys and their failures from many of the same issues! But back then, we didn't have the 'net in the state it is in now. I wonder if ANY high-end agm manufacturer could survive if the only reports we get from the field are from the guys who blew the tops off their systems with hydrogen explosions and everyone jumping on board to claim that agm's tech is bad, when it was the homebrew balancing boards (yes, they had them then too!) that threw the systems totally out of whack. That pesky mist!

For now cheap Chi_Com knock-offs is all we got.

Thank goodness for that! Every advancement since just plain old flooded seems destined for a total proprietary lock-in or patent-war fodder where the benefits to mankind are locked away or delayed forever. (Nimh patent encumbrance forcing us to a 10ah cell limitation, and so forth as just one old example). At least the common-man can get hold of the prismatics relatively easily, whose sizes allow us to abide by the KISS principle when doing something larger than just gadgetry.

You can bet that some looked at this for a historical template to restrict us all, manufacturers alike, to the small-cylindrical format, adding complexity, limiting choices, and basically a lock-down. I guess that STILL bugs me to this day:

https://en.wikipedia.org/wiki/Patent_encumbrance_of_large_automotive_NiMH_batteries

Ok, enough of my own weird tangent I suppose.

[Sunking]

You can bet that some looked at this for a historical template to restrict us all, manufacturers alike, to the small-cylindrical format, adding complexity, limiting choices, and basically a lock-down. I guess that STILL bugs me to this day:

https://en.wikipedia.org/wiki/Patent_encumbrance_of_large_automotive_NiMH_batteries

Ok, enough of my own weird tangent I suppose.

Yeah I followed that too but never bought into the Conspiracy thing. If you look back it just does not add up. What I see is sour grapes being eaten by Dr O****ani. He sold his patent and surrendered his rights. Kind of like Nickoli Tesla selling all his patents to Westinghouse and JP Morgan. Brilliant Scientist, lousy businessman. You cannot blame GM, Chevron, and Texaco for wanting a lock on NiMh batteries anymore than you can blame Gates for a lock on PC's. It is just biz. At the time GM thought EV's would be powered by NiMh and they wanted a piece of the action. They lost the bet and their investment. Chit happens. What killed the EV was the market and lacking technology, not GM. Same thing today.

[Living Large]

Manufactures do not sell used underwear.

I'd like to comment on this, but I won't. It would be off-topic...

[Jerry Liebler]

Why I prefer top banancing!

With either top balancing or bottom balancing, the weakest cell goes through EXACTLY the same cycle! The ONLY advantage of bottom balancing is that the better cells are not charged as fully and therefore have a longer life (but pack life is determined by that weakest cell). The real advantage of top balancing, as typically implemented, by using voltage controlled shunts, is that it is "refreshed" with every charge cycle and thus eliminates any drift which would go unmitigated with a bottom balanced pack. With either method a per cell monitoring is vital to discharge termination. With bottom balancing per cell monitoring MUST (at least once) be used for charge termination while with top balance and "voltage controlled shunts" pack voltage can safely be used for charge termination.

[Sunking]

The ONLY advantage of bottom balancing is that the better cells are not charged as fully and therefore have a longer life (but pack life is determined by that weakest cell).

Incorrect statement. Capacity is determined by the weakest cell, not cycle life as you hav e indicated is completely false.

The real advantage of top balancing, as typically implemented, by using voltage controlled shunts, is that it is "refreshed" with every charge cycle and thus eliminates any drift which would go unmitigated with a bottom balanced pack.

Another incorrect assumption. Cells do not drift unless you use cell monitor and other parasitic loads. When in series and BB, all cells have the eexact same capacity at any SOC level.

With either method a per cell monitoring is vital to discharge termination. With bottom balancing per cell monitoring MUST (at least once) be used for charge termination while with top balance and "voltage controlled shunts" pack voltage can safely be used for charge termination.

BB balance requires absolutely NO Cell Level Monitoring at discharge. All the cells reach 2.5 volts at the same time. Actually they all reach 3 volts at the exact same time, but 2.5 volts is what you want to say at or above. On a 4S or 12 volt pack, you set your Inverter at 12 volt Low Voltage Disconnect or 3 vpc a full 2 volt above 10 volt do not go below. You can drive a truck through a 2 volt window blindfolded. Once your cells reach 2,5 vpc, no adjacent cell can possibly discharge through another 2.5 vpc. There is no energy left, only voltage. That makes it impossible to over discharge a BB pack. One can very easily over discharge a TB pack.

[Jerry Liebler]

Incorrect statement. Capacity is determined by the weakest cell, not cycle life as you hav e indicated is completely false.

Cell life is a function of depth of the cycles and the number of cycles. The cell being cycled over more of it's capacity WILL have a shorter life span. I'll accept your apology!

Another incorrect assumption. Cells do not drift unless you use cell monitor and other parasitic loads. When in series and BB, all cells have the eexact same capacity at any SOC level.

ONLY if they are at the same temperature and have identical parasitic leakage.
I'll agree cell drift is a minor concern but it is measurable and real.

BB balance requires absolutely NO Cell Level Monitoring at discharge. All the cells reach 2.5 volts at the same time. Actually they all reach 3 volts at the exact same time, but 2.5 volts is what you want to say at or above. On a 4S or 12 volt pack, you set your Inverter at 12 volt Low Voltage Disconnect or 3 vpc a full 2 volt above 10 volt do not go below. You can drive a truck through a 2 volt window blindfolded. Once your cells reach 2,5 vpc, no adjacent cell can possibly discharge through another 2.5 vpc. There is no energy left, only voltage. That makes it impossible to over discharge a BB pack. One can very easily over discharge a TB pack.

You can make the argument that pack voltage is sufficient at the "balanced" end, if they are still balanced, but must admit that per cell measurement is required at the other end, at least once!
Depending on pack voltage at BOTH extremes invites disaster no matter how the cells were balanced.

IF as you seem to believe LIFEPO4 cells never change, the only benefit of ANY attempt at balancing is increased capacity and operation between 2 pack voltage limits, once characterized by per cell measurements, will work forever.

Like it or not even these cells suffer many forms of degradation and change many characteristics. The whole idea of battery management is reducing the risks that operation will be outside the "safe area of operation".

Many so called BMS are actually battery murdering systems because of the parasitic load they place on the cells. These loads often vary wildly from cell to cell making the situation worse. Well designed BMS hardware is very cost effective assurance of good cell life and almost all such hardware uses top balancing with shunts and per cell low voltage limits.